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Commit | Line | Data |
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1da177e4 | 1 | /* |
1da177e4 LT |
2 | * Copyright (C) 1991, 1992 Linus Torvalds |
3 | * Copyright (C) 1994, Karl Keyte: Added support for disk statistics | |
4 | * Elevator latency, (C) 2000 Andrea Arcangeli <andrea@suse.de> SuSE | |
5 | * Queue request tables / lock, selectable elevator, Jens Axboe <axboe@suse.de> | |
6 | * kernel-doc documentation started by NeilBrown <neilb@cse.unsw.edu.au> - July2000 | |
7 | * bio rewrite, highmem i/o, etc, Jens Axboe <axboe@suse.de> - may 2001 | |
8 | */ | |
9 | ||
10 | /* | |
11 | * This handles all read/write requests to block devices | |
12 | */ | |
1da177e4 LT |
13 | #include <linux/kernel.h> |
14 | #include <linux/module.h> | |
15 | #include <linux/backing-dev.h> | |
16 | #include <linux/bio.h> | |
17 | #include <linux/blkdev.h> | |
18 | #include <linux/highmem.h> | |
19 | #include <linux/mm.h> | |
20 | #include <linux/kernel_stat.h> | |
21 | #include <linux/string.h> | |
22 | #include <linux/init.h> | |
23 | #include <linux/bootmem.h> /* for max_pfn/max_low_pfn */ | |
24 | #include <linux/completion.h> | |
25 | #include <linux/slab.h> | |
26 | #include <linux/swap.h> | |
27 | #include <linux/writeback.h> | |
faccbd4b | 28 | #include <linux/task_io_accounting_ops.h> |
ff856bad JA |
29 | #include <linux/interrupt.h> |
30 | #include <linux/cpu.h> | |
2056a782 | 31 | #include <linux/blktrace_api.h> |
c17bb495 | 32 | #include <linux/fault-inject.h> |
1da177e4 LT |
33 | |
34 | /* | |
35 | * for max sense size | |
36 | */ | |
37 | #include <scsi/scsi_cmnd.h> | |
38 | ||
65f27f38 | 39 | static void blk_unplug_work(struct work_struct *work); |
1da177e4 | 40 | static void blk_unplug_timeout(unsigned long data); |
93d17d3d | 41 | static void drive_stat_acct(struct request *rq, int nr_sectors, int new_io); |
52d9e675 | 42 | static void init_request_from_bio(struct request *req, struct bio *bio); |
165125e1 | 43 | static int __make_request(struct request_queue *q, struct bio *bio); |
b5deef90 | 44 | static struct io_context *current_io_context(gfp_t gfp_flags, int node); |
9dfa5283 | 45 | static void blk_recalc_rq_segments(struct request *rq); |
66846572 N |
46 | static void blk_rq_bio_prep(struct request_queue *q, struct request *rq, |
47 | struct bio *bio); | |
1da177e4 LT |
48 | |
49 | /* | |
50 | * For the allocated request tables | |
51 | */ | |
e18b890b | 52 | static struct kmem_cache *request_cachep; |
1da177e4 LT |
53 | |
54 | /* | |
55 | * For queue allocation | |
56 | */ | |
e18b890b | 57 | static struct kmem_cache *requestq_cachep; |
1da177e4 LT |
58 | |
59 | /* | |
60 | * For io context allocations | |
61 | */ | |
e18b890b | 62 | static struct kmem_cache *iocontext_cachep; |
1da177e4 | 63 | |
1da177e4 LT |
64 | /* |
65 | * Controlling structure to kblockd | |
66 | */ | |
ff856bad | 67 | static struct workqueue_struct *kblockd_workqueue; |
1da177e4 LT |
68 | |
69 | unsigned long blk_max_low_pfn, blk_max_pfn; | |
70 | ||
71 | EXPORT_SYMBOL(blk_max_low_pfn); | |
72 | EXPORT_SYMBOL(blk_max_pfn); | |
73 | ||
ff856bad JA |
74 | static DEFINE_PER_CPU(struct list_head, blk_cpu_done); |
75 | ||
1da177e4 LT |
76 | /* Amount of time in which a process may batch requests */ |
77 | #define BLK_BATCH_TIME (HZ/50UL) | |
78 | ||
79 | /* Number of requests a "batching" process may submit */ | |
80 | #define BLK_BATCH_REQ 32 | |
81 | ||
82 | /* | |
83 | * Return the threshold (number of used requests) at which the queue is | |
84 | * considered to be congested. It include a little hysteresis to keep the | |
85 | * context switch rate down. | |
86 | */ | |
87 | static inline int queue_congestion_on_threshold(struct request_queue *q) | |
88 | { | |
89 | return q->nr_congestion_on; | |
90 | } | |
91 | ||
92 | /* | |
93 | * The threshold at which a queue is considered to be uncongested | |
94 | */ | |
95 | static inline int queue_congestion_off_threshold(struct request_queue *q) | |
96 | { | |
97 | return q->nr_congestion_off; | |
98 | } | |
99 | ||
100 | static void blk_queue_congestion_threshold(struct request_queue *q) | |
101 | { | |
102 | int nr; | |
103 | ||
104 | nr = q->nr_requests - (q->nr_requests / 8) + 1; | |
105 | if (nr > q->nr_requests) | |
106 | nr = q->nr_requests; | |
107 | q->nr_congestion_on = nr; | |
108 | ||
109 | nr = q->nr_requests - (q->nr_requests / 8) - (q->nr_requests / 16) - 1; | |
110 | if (nr < 1) | |
111 | nr = 1; | |
112 | q->nr_congestion_off = nr; | |
113 | } | |
114 | ||
1da177e4 LT |
115 | /** |
116 | * blk_get_backing_dev_info - get the address of a queue's backing_dev_info | |
117 | * @bdev: device | |
118 | * | |
119 | * Locates the passed device's request queue and returns the address of its | |
120 | * backing_dev_info | |
121 | * | |
122 | * Will return NULL if the request queue cannot be located. | |
123 | */ | |
124 | struct backing_dev_info *blk_get_backing_dev_info(struct block_device *bdev) | |
125 | { | |
126 | struct backing_dev_info *ret = NULL; | |
165125e1 | 127 | struct request_queue *q = bdev_get_queue(bdev); |
1da177e4 LT |
128 | |
129 | if (q) | |
130 | ret = &q->backing_dev_info; | |
131 | return ret; | |
132 | } | |
1da177e4 LT |
133 | EXPORT_SYMBOL(blk_get_backing_dev_info); |
134 | ||
1da177e4 LT |
135 | /** |
136 | * blk_queue_prep_rq - set a prepare_request function for queue | |
137 | * @q: queue | |
138 | * @pfn: prepare_request function | |
139 | * | |
140 | * It's possible for a queue to register a prepare_request callback which | |
141 | * is invoked before the request is handed to the request_fn. The goal of | |
142 | * the function is to prepare a request for I/O, it can be used to build a | |
143 | * cdb from the request data for instance. | |
144 | * | |
145 | */ | |
165125e1 | 146 | void blk_queue_prep_rq(struct request_queue *q, prep_rq_fn *pfn) |
1da177e4 LT |
147 | { |
148 | q->prep_rq_fn = pfn; | |
149 | } | |
150 | ||
151 | EXPORT_SYMBOL(blk_queue_prep_rq); | |
152 | ||
153 | /** | |
154 | * blk_queue_merge_bvec - set a merge_bvec function for queue | |
155 | * @q: queue | |
156 | * @mbfn: merge_bvec_fn | |
157 | * | |
158 | * Usually queues have static limitations on the max sectors or segments that | |
159 | * we can put in a request. Stacking drivers may have some settings that | |
160 | * are dynamic, and thus we have to query the queue whether it is ok to | |
161 | * add a new bio_vec to a bio at a given offset or not. If the block device | |
162 | * has such limitations, it needs to register a merge_bvec_fn to control | |
163 | * the size of bio's sent to it. Note that a block device *must* allow a | |
164 | * single page to be added to an empty bio. The block device driver may want | |
165 | * to use the bio_split() function to deal with these bio's. By default | |
166 | * no merge_bvec_fn is defined for a queue, and only the fixed limits are | |
167 | * honored. | |
168 | */ | |
165125e1 | 169 | void blk_queue_merge_bvec(struct request_queue *q, merge_bvec_fn *mbfn) |
1da177e4 LT |
170 | { |
171 | q->merge_bvec_fn = mbfn; | |
172 | } | |
173 | ||
174 | EXPORT_SYMBOL(blk_queue_merge_bvec); | |
175 | ||
165125e1 | 176 | void blk_queue_softirq_done(struct request_queue *q, softirq_done_fn *fn) |
ff856bad JA |
177 | { |
178 | q->softirq_done_fn = fn; | |
179 | } | |
180 | ||
181 | EXPORT_SYMBOL(blk_queue_softirq_done); | |
182 | ||
1da177e4 LT |
183 | /** |
184 | * blk_queue_make_request - define an alternate make_request function for a device | |
185 | * @q: the request queue for the device to be affected | |
186 | * @mfn: the alternate make_request function | |
187 | * | |
188 | * Description: | |
189 | * The normal way for &struct bios to be passed to a device | |
190 | * driver is for them to be collected into requests on a request | |
191 | * queue, and then to allow the device driver to select requests | |
192 | * off that queue when it is ready. This works well for many block | |
193 | * devices. However some block devices (typically virtual devices | |
194 | * such as md or lvm) do not benefit from the processing on the | |
195 | * request queue, and are served best by having the requests passed | |
196 | * directly to them. This can be achieved by providing a function | |
197 | * to blk_queue_make_request(). | |
198 | * | |
199 | * Caveat: | |
200 | * The driver that does this *must* be able to deal appropriately | |
201 | * with buffers in "highmemory". This can be accomplished by either calling | |
202 | * __bio_kmap_atomic() to get a temporary kernel mapping, or by calling | |
203 | * blk_queue_bounce() to create a buffer in normal memory. | |
204 | **/ | |
165125e1 | 205 | void blk_queue_make_request(struct request_queue * q, make_request_fn * mfn) |
1da177e4 LT |
206 | { |
207 | /* | |
208 | * set defaults | |
209 | */ | |
210 | q->nr_requests = BLKDEV_MAX_RQ; | |
309c0a1d SM |
211 | blk_queue_max_phys_segments(q, MAX_PHYS_SEGMENTS); |
212 | blk_queue_max_hw_segments(q, MAX_HW_SEGMENTS); | |
1da177e4 LT |
213 | q->make_request_fn = mfn; |
214 | q->backing_dev_info.ra_pages = (VM_MAX_READAHEAD * 1024) / PAGE_CACHE_SIZE; | |
215 | q->backing_dev_info.state = 0; | |
216 | q->backing_dev_info.capabilities = BDI_CAP_MAP_COPY; | |
defd94b7 | 217 | blk_queue_max_sectors(q, SAFE_MAX_SECTORS); |
1da177e4 LT |
218 | blk_queue_hardsect_size(q, 512); |
219 | blk_queue_dma_alignment(q, 511); | |
220 | blk_queue_congestion_threshold(q); | |
221 | q->nr_batching = BLK_BATCH_REQ; | |
222 | ||
223 | q->unplug_thresh = 4; /* hmm */ | |
224 | q->unplug_delay = (3 * HZ) / 1000; /* 3 milliseconds */ | |
225 | if (q->unplug_delay == 0) | |
226 | q->unplug_delay = 1; | |
227 | ||
65f27f38 | 228 | INIT_WORK(&q->unplug_work, blk_unplug_work); |
1da177e4 LT |
229 | |
230 | q->unplug_timer.function = blk_unplug_timeout; | |
231 | q->unplug_timer.data = (unsigned long)q; | |
232 | ||
233 | /* | |
234 | * by default assume old behaviour and bounce for any highmem page | |
235 | */ | |
236 | blk_queue_bounce_limit(q, BLK_BOUNCE_HIGH); | |
1da177e4 LT |
237 | } |
238 | ||
239 | EXPORT_SYMBOL(blk_queue_make_request); | |
240 | ||
165125e1 | 241 | static void rq_init(struct request_queue *q, struct request *rq) |
1da177e4 LT |
242 | { |
243 | INIT_LIST_HEAD(&rq->queuelist); | |
ff856bad | 244 | INIT_LIST_HEAD(&rq->donelist); |
1da177e4 LT |
245 | |
246 | rq->errors = 0; | |
1da177e4 | 247 | rq->bio = rq->biotail = NULL; |
2e662b65 JA |
248 | INIT_HLIST_NODE(&rq->hash); |
249 | RB_CLEAR_NODE(&rq->rb_node); | |
22e2c507 | 250 | rq->ioprio = 0; |
1da177e4 LT |
251 | rq->buffer = NULL; |
252 | rq->ref_count = 1; | |
253 | rq->q = q; | |
1da177e4 LT |
254 | rq->special = NULL; |
255 | rq->data_len = 0; | |
256 | rq->data = NULL; | |
df46b9a4 | 257 | rq->nr_phys_segments = 0; |
1da177e4 LT |
258 | rq->sense = NULL; |
259 | rq->end_io = NULL; | |
260 | rq->end_io_data = NULL; | |
ff856bad | 261 | rq->completion_data = NULL; |
abae1fde | 262 | rq->next_rq = NULL; |
1da177e4 LT |
263 | } |
264 | ||
265 | /** | |
266 | * blk_queue_ordered - does this queue support ordered writes | |
797e7dbb TH |
267 | * @q: the request queue |
268 | * @ordered: one of QUEUE_ORDERED_* | |
fddfdeaf | 269 | * @prepare_flush_fn: rq setup helper for cache flush ordered writes |
1da177e4 LT |
270 | * |
271 | * Description: | |
272 | * For journalled file systems, doing ordered writes on a commit | |
273 | * block instead of explicitly doing wait_on_buffer (which is bad | |
274 | * for performance) can be a big win. Block drivers supporting this | |
275 | * feature should call this function and indicate so. | |
276 | * | |
277 | **/ | |
165125e1 | 278 | int blk_queue_ordered(struct request_queue *q, unsigned ordered, |
797e7dbb TH |
279 | prepare_flush_fn *prepare_flush_fn) |
280 | { | |
281 | if (ordered & (QUEUE_ORDERED_PREFLUSH | QUEUE_ORDERED_POSTFLUSH) && | |
282 | prepare_flush_fn == NULL) { | |
283 | printk(KERN_ERR "blk_queue_ordered: prepare_flush_fn required\n"); | |
284 | return -EINVAL; | |
285 | } | |
286 | ||
287 | if (ordered != QUEUE_ORDERED_NONE && | |
288 | ordered != QUEUE_ORDERED_DRAIN && | |
289 | ordered != QUEUE_ORDERED_DRAIN_FLUSH && | |
290 | ordered != QUEUE_ORDERED_DRAIN_FUA && | |
291 | ordered != QUEUE_ORDERED_TAG && | |
292 | ordered != QUEUE_ORDERED_TAG_FLUSH && | |
293 | ordered != QUEUE_ORDERED_TAG_FUA) { | |
294 | printk(KERN_ERR "blk_queue_ordered: bad value %d\n", ordered); | |
295 | return -EINVAL; | |
1da177e4 | 296 | } |
797e7dbb | 297 | |
60481b12 | 298 | q->ordered = ordered; |
797e7dbb TH |
299 | q->next_ordered = ordered; |
300 | q->prepare_flush_fn = prepare_flush_fn; | |
301 | ||
302 | return 0; | |
1da177e4 LT |
303 | } |
304 | ||
305 | EXPORT_SYMBOL(blk_queue_ordered); | |
306 | ||
1da177e4 LT |
307 | /* |
308 | * Cache flushing for ordered writes handling | |
309 | */ | |
165125e1 | 310 | inline unsigned blk_ordered_cur_seq(struct request_queue *q) |
1da177e4 | 311 | { |
797e7dbb TH |
312 | if (!q->ordseq) |
313 | return 0; | |
314 | return 1 << ffz(q->ordseq); | |
1da177e4 LT |
315 | } |
316 | ||
797e7dbb | 317 | unsigned blk_ordered_req_seq(struct request *rq) |
1da177e4 | 318 | { |
165125e1 | 319 | struct request_queue *q = rq->q; |
1da177e4 | 320 | |
797e7dbb | 321 | BUG_ON(q->ordseq == 0); |
8922e16c | 322 | |
797e7dbb TH |
323 | if (rq == &q->pre_flush_rq) |
324 | return QUEUE_ORDSEQ_PREFLUSH; | |
325 | if (rq == &q->bar_rq) | |
326 | return QUEUE_ORDSEQ_BAR; | |
327 | if (rq == &q->post_flush_rq) | |
328 | return QUEUE_ORDSEQ_POSTFLUSH; | |
1da177e4 | 329 | |
bc90ba09 TH |
330 | /* |
331 | * !fs requests don't need to follow barrier ordering. Always | |
332 | * put them at the front. This fixes the following deadlock. | |
333 | * | |
334 | * http://thread.gmane.org/gmane.linux.kernel/537473 | |
335 | */ | |
336 | if (!blk_fs_request(rq)) | |
337 | return QUEUE_ORDSEQ_DRAIN; | |
338 | ||
4aff5e23 JA |
339 | if ((rq->cmd_flags & REQ_ORDERED_COLOR) == |
340 | (q->orig_bar_rq->cmd_flags & REQ_ORDERED_COLOR)) | |
797e7dbb TH |
341 | return QUEUE_ORDSEQ_DRAIN; |
342 | else | |
343 | return QUEUE_ORDSEQ_DONE; | |
1da177e4 LT |
344 | } |
345 | ||
165125e1 | 346 | void blk_ordered_complete_seq(struct request_queue *q, unsigned seq, int error) |
1da177e4 | 347 | { |
797e7dbb TH |
348 | struct request *rq; |
349 | int uptodate; | |
1da177e4 | 350 | |
797e7dbb TH |
351 | if (error && !q->orderr) |
352 | q->orderr = error; | |
1da177e4 | 353 | |
797e7dbb TH |
354 | BUG_ON(q->ordseq & seq); |
355 | q->ordseq |= seq; | |
1da177e4 | 356 | |
797e7dbb TH |
357 | if (blk_ordered_cur_seq(q) != QUEUE_ORDSEQ_DONE) |
358 | return; | |
1da177e4 LT |
359 | |
360 | /* | |
797e7dbb | 361 | * Okay, sequence complete. |
1da177e4 | 362 | */ |
4fa253f3 JA |
363 | uptodate = 1; |
364 | if (q->orderr) | |
365 | uptodate = q->orderr; | |
1da177e4 | 366 | |
797e7dbb | 367 | q->ordseq = 0; |
4fa253f3 | 368 | rq = q->orig_bar_rq; |
1da177e4 | 369 | |
797e7dbb TH |
370 | end_that_request_first(rq, uptodate, rq->hard_nr_sectors); |
371 | end_that_request_last(rq, uptodate); | |
1da177e4 LT |
372 | } |
373 | ||
797e7dbb | 374 | static void pre_flush_end_io(struct request *rq, int error) |
1da177e4 | 375 | { |
797e7dbb TH |
376 | elv_completed_request(rq->q, rq); |
377 | blk_ordered_complete_seq(rq->q, QUEUE_ORDSEQ_PREFLUSH, error); | |
378 | } | |
1da177e4 | 379 | |
797e7dbb TH |
380 | static void bar_end_io(struct request *rq, int error) |
381 | { | |
382 | elv_completed_request(rq->q, rq); | |
383 | blk_ordered_complete_seq(rq->q, QUEUE_ORDSEQ_BAR, error); | |
384 | } | |
1da177e4 | 385 | |
797e7dbb TH |
386 | static void post_flush_end_io(struct request *rq, int error) |
387 | { | |
388 | elv_completed_request(rq->q, rq); | |
389 | blk_ordered_complete_seq(rq->q, QUEUE_ORDSEQ_POSTFLUSH, error); | |
390 | } | |
1da177e4 | 391 | |
165125e1 | 392 | static void queue_flush(struct request_queue *q, unsigned which) |
797e7dbb TH |
393 | { |
394 | struct request *rq; | |
395 | rq_end_io_fn *end_io; | |
1da177e4 | 396 | |
797e7dbb TH |
397 | if (which == QUEUE_ORDERED_PREFLUSH) { |
398 | rq = &q->pre_flush_rq; | |
399 | end_io = pre_flush_end_io; | |
400 | } else { | |
401 | rq = &q->post_flush_rq; | |
402 | end_io = post_flush_end_io; | |
1da177e4 | 403 | } |
797e7dbb | 404 | |
4aff5e23 | 405 | rq->cmd_flags = REQ_HARDBARRIER; |
797e7dbb | 406 | rq_init(q, rq); |
797e7dbb | 407 | rq->elevator_private = NULL; |
c00895ab | 408 | rq->elevator_private2 = NULL; |
797e7dbb | 409 | rq->rq_disk = q->bar_rq.rq_disk; |
797e7dbb TH |
410 | rq->end_io = end_io; |
411 | q->prepare_flush_fn(q, rq); | |
412 | ||
30e9656c | 413 | elv_insert(q, rq, ELEVATOR_INSERT_FRONT); |
1da177e4 LT |
414 | } |
415 | ||
165125e1 | 416 | static inline struct request *start_ordered(struct request_queue *q, |
797e7dbb | 417 | struct request *rq) |
1da177e4 | 418 | { |
797e7dbb TH |
419 | q->orderr = 0; |
420 | q->ordered = q->next_ordered; | |
421 | q->ordseq |= QUEUE_ORDSEQ_STARTED; | |
422 | ||
423 | /* | |
424 | * Prep proxy barrier request. | |
425 | */ | |
426 | blkdev_dequeue_request(rq); | |
427 | q->orig_bar_rq = rq; | |
428 | rq = &q->bar_rq; | |
4aff5e23 | 429 | rq->cmd_flags = 0; |
797e7dbb | 430 | rq_init(q, rq); |
4aff5e23 JA |
431 | if (bio_data_dir(q->orig_bar_rq->bio) == WRITE) |
432 | rq->cmd_flags |= REQ_RW; | |
4fa253f3 JA |
433 | if (q->ordered & QUEUE_ORDERED_FUA) |
434 | rq->cmd_flags |= REQ_FUA; | |
797e7dbb | 435 | rq->elevator_private = NULL; |
c00895ab | 436 | rq->elevator_private2 = NULL; |
797e7dbb TH |
437 | init_request_from_bio(rq, q->orig_bar_rq->bio); |
438 | rq->end_io = bar_end_io; | |
439 | ||
440 | /* | |
441 | * Queue ordered sequence. As we stack them at the head, we | |
442 | * need to queue in reverse order. Note that we rely on that | |
443 | * no fs request uses ELEVATOR_INSERT_FRONT and thus no fs | |
bf2de6f5 JA |
444 | * request gets inbetween ordered sequence. If this request is |
445 | * an empty barrier, we don't need to do a postflush ever since | |
446 | * there will be no data written between the pre and post flush. | |
447 | * Hence a single flush will suffice. | |
797e7dbb | 448 | */ |
bf2de6f5 | 449 | if ((q->ordered & QUEUE_ORDERED_POSTFLUSH) && !blk_empty_barrier(rq)) |
797e7dbb TH |
450 | queue_flush(q, QUEUE_ORDERED_POSTFLUSH); |
451 | else | |
452 | q->ordseq |= QUEUE_ORDSEQ_POSTFLUSH; | |
453 | ||
30e9656c | 454 | elv_insert(q, rq, ELEVATOR_INSERT_FRONT); |
797e7dbb TH |
455 | |
456 | if (q->ordered & QUEUE_ORDERED_PREFLUSH) { | |
457 | queue_flush(q, QUEUE_ORDERED_PREFLUSH); | |
458 | rq = &q->pre_flush_rq; | |
459 | } else | |
460 | q->ordseq |= QUEUE_ORDSEQ_PREFLUSH; | |
1da177e4 | 461 | |
797e7dbb TH |
462 | if ((q->ordered & QUEUE_ORDERED_TAG) || q->in_flight == 0) |
463 | q->ordseq |= QUEUE_ORDSEQ_DRAIN; | |
464 | else | |
465 | rq = NULL; | |
466 | ||
467 | return rq; | |
1da177e4 LT |
468 | } |
469 | ||
165125e1 | 470 | int blk_do_ordered(struct request_queue *q, struct request **rqp) |
1da177e4 | 471 | { |
9a7a67af | 472 | struct request *rq = *rqp; |
bf2de6f5 | 473 | const int is_barrier = blk_fs_request(rq) && blk_barrier_rq(rq); |
1da177e4 | 474 | |
797e7dbb TH |
475 | if (!q->ordseq) { |
476 | if (!is_barrier) | |
477 | return 1; | |
1da177e4 | 478 | |
797e7dbb TH |
479 | if (q->next_ordered != QUEUE_ORDERED_NONE) { |
480 | *rqp = start_ordered(q, rq); | |
481 | return 1; | |
482 | } else { | |
483 | /* | |
484 | * This can happen when the queue switches to | |
485 | * ORDERED_NONE while this request is on it. | |
486 | */ | |
487 | blkdev_dequeue_request(rq); | |
488 | end_that_request_first(rq, -EOPNOTSUPP, | |
489 | rq->hard_nr_sectors); | |
490 | end_that_request_last(rq, -EOPNOTSUPP); | |
491 | *rqp = NULL; | |
492 | return 0; | |
493 | } | |
494 | } | |
1da177e4 | 495 | |
9a7a67af JA |
496 | /* |
497 | * Ordered sequence in progress | |
498 | */ | |
499 | ||
500 | /* Special requests are not subject to ordering rules. */ | |
501 | if (!blk_fs_request(rq) && | |
502 | rq != &q->pre_flush_rq && rq != &q->post_flush_rq) | |
503 | return 1; | |
504 | ||
797e7dbb | 505 | if (q->ordered & QUEUE_ORDERED_TAG) { |
9a7a67af | 506 | /* Ordered by tag. Blocking the next barrier is enough. */ |
797e7dbb TH |
507 | if (is_barrier && rq != &q->bar_rq) |
508 | *rqp = NULL; | |
9a7a67af JA |
509 | } else { |
510 | /* Ordered by draining. Wait for turn. */ | |
511 | WARN_ON(blk_ordered_req_seq(rq) < blk_ordered_cur_seq(q)); | |
512 | if (blk_ordered_req_seq(rq) > blk_ordered_cur_seq(q)) | |
513 | *rqp = NULL; | |
1da177e4 LT |
514 | } |
515 | ||
516 | return 1; | |
517 | } | |
518 | ||
5bb23a68 N |
519 | static void req_bio_endio(struct request *rq, struct bio *bio, |
520 | unsigned int nbytes, int error) | |
1da177e4 | 521 | { |
165125e1 | 522 | struct request_queue *q = rq->q; |
797e7dbb | 523 | |
5bb23a68 N |
524 | if (&q->bar_rq != rq) { |
525 | if (error) | |
526 | clear_bit(BIO_UPTODATE, &bio->bi_flags); | |
527 | else if (!test_bit(BIO_UPTODATE, &bio->bi_flags)) | |
528 | error = -EIO; | |
797e7dbb | 529 | |
5bb23a68 N |
530 | if (unlikely(nbytes > bio->bi_size)) { |
531 | printk("%s: want %u bytes done, only %u left\n", | |
532 | __FUNCTION__, nbytes, bio->bi_size); | |
533 | nbytes = bio->bi_size; | |
534 | } | |
797e7dbb | 535 | |
5bb23a68 N |
536 | bio->bi_size -= nbytes; |
537 | bio->bi_sector += (nbytes >> 9); | |
538 | if (bio->bi_size == 0) | |
6712ecf8 | 539 | bio_endio(bio, error); |
5bb23a68 N |
540 | } else { |
541 | ||
542 | /* | |
543 | * Okay, this is the barrier request in progress, just | |
544 | * record the error; | |
545 | */ | |
546 | if (error && !q->orderr) | |
547 | q->orderr = error; | |
548 | } | |
1da177e4 | 549 | } |
1da177e4 LT |
550 | |
551 | /** | |
552 | * blk_queue_bounce_limit - set bounce buffer limit for queue | |
553 | * @q: the request queue for the device | |
554 | * @dma_addr: bus address limit | |
555 | * | |
556 | * Description: | |
557 | * Different hardware can have different requirements as to what pages | |
558 | * it can do I/O directly to. A low level driver can call | |
559 | * blk_queue_bounce_limit to have lower memory pages allocated as bounce | |
5ee1af9f | 560 | * buffers for doing I/O to pages residing above @page. |
1da177e4 | 561 | **/ |
165125e1 | 562 | void blk_queue_bounce_limit(struct request_queue *q, u64 dma_addr) |
1da177e4 LT |
563 | { |
564 | unsigned long bounce_pfn = dma_addr >> PAGE_SHIFT; | |
5ee1af9f AK |
565 | int dma = 0; |
566 | ||
567 | q->bounce_gfp = GFP_NOIO; | |
568 | #if BITS_PER_LONG == 64 | |
569 | /* Assume anything <= 4GB can be handled by IOMMU. | |
570 | Actually some IOMMUs can handle everything, but I don't | |
571 | know of a way to test this here. */ | |
8269730b | 572 | if (bounce_pfn < (min_t(u64,0xffffffff,BLK_BOUNCE_HIGH) >> PAGE_SHIFT)) |
5ee1af9f AK |
573 | dma = 1; |
574 | q->bounce_pfn = max_low_pfn; | |
575 | #else | |
576 | if (bounce_pfn < blk_max_low_pfn) | |
577 | dma = 1; | |
578 | q->bounce_pfn = bounce_pfn; | |
579 | #endif | |
580 | if (dma) { | |
1da177e4 LT |
581 | init_emergency_isa_pool(); |
582 | q->bounce_gfp = GFP_NOIO | GFP_DMA; | |
5ee1af9f AK |
583 | q->bounce_pfn = bounce_pfn; |
584 | } | |
1da177e4 LT |
585 | } |
586 | ||
587 | EXPORT_SYMBOL(blk_queue_bounce_limit); | |
588 | ||
589 | /** | |
590 | * blk_queue_max_sectors - set max sectors for a request for this queue | |
591 | * @q: the request queue for the device | |
592 | * @max_sectors: max sectors in the usual 512b unit | |
593 | * | |
594 | * Description: | |
595 | * Enables a low level driver to set an upper limit on the size of | |
596 | * received requests. | |
597 | **/ | |
165125e1 | 598 | void blk_queue_max_sectors(struct request_queue *q, unsigned int max_sectors) |
1da177e4 LT |
599 | { |
600 | if ((max_sectors << 9) < PAGE_CACHE_SIZE) { | |
601 | max_sectors = 1 << (PAGE_CACHE_SHIFT - 9); | |
602 | printk("%s: set to minimum %d\n", __FUNCTION__, max_sectors); | |
603 | } | |
604 | ||
defd94b7 MC |
605 | if (BLK_DEF_MAX_SECTORS > max_sectors) |
606 | q->max_hw_sectors = q->max_sectors = max_sectors; | |
607 | else { | |
608 | q->max_sectors = BLK_DEF_MAX_SECTORS; | |
609 | q->max_hw_sectors = max_sectors; | |
610 | } | |
1da177e4 LT |
611 | } |
612 | ||
613 | EXPORT_SYMBOL(blk_queue_max_sectors); | |
614 | ||
615 | /** | |
616 | * blk_queue_max_phys_segments - set max phys segments for a request for this queue | |
617 | * @q: the request queue for the device | |
618 | * @max_segments: max number of segments | |
619 | * | |
620 | * Description: | |
621 | * Enables a low level driver to set an upper limit on the number of | |
622 | * physical data segments in a request. This would be the largest sized | |
623 | * scatter list the driver could handle. | |
624 | **/ | |
165125e1 JA |
625 | void blk_queue_max_phys_segments(struct request_queue *q, |
626 | unsigned short max_segments) | |
1da177e4 LT |
627 | { |
628 | if (!max_segments) { | |
629 | max_segments = 1; | |
630 | printk("%s: set to minimum %d\n", __FUNCTION__, max_segments); | |
631 | } | |
632 | ||
633 | q->max_phys_segments = max_segments; | |
634 | } | |
635 | ||
636 | EXPORT_SYMBOL(blk_queue_max_phys_segments); | |
637 | ||
638 | /** | |
639 | * blk_queue_max_hw_segments - set max hw segments for a request for this queue | |
640 | * @q: the request queue for the device | |
641 | * @max_segments: max number of segments | |
642 | * | |
643 | * Description: | |
644 | * Enables a low level driver to set an upper limit on the number of | |
645 | * hw data segments in a request. This would be the largest number of | |
646 | * address/length pairs the host adapter can actually give as once | |
647 | * to the device. | |
648 | **/ | |
165125e1 JA |
649 | void blk_queue_max_hw_segments(struct request_queue *q, |
650 | unsigned short max_segments) | |
1da177e4 LT |
651 | { |
652 | if (!max_segments) { | |
653 | max_segments = 1; | |
654 | printk("%s: set to minimum %d\n", __FUNCTION__, max_segments); | |
655 | } | |
656 | ||
657 | q->max_hw_segments = max_segments; | |
658 | } | |
659 | ||
660 | EXPORT_SYMBOL(blk_queue_max_hw_segments); | |
661 | ||
662 | /** | |
663 | * blk_queue_max_segment_size - set max segment size for blk_rq_map_sg | |
664 | * @q: the request queue for the device | |
665 | * @max_size: max size of segment in bytes | |
666 | * | |
667 | * Description: | |
668 | * Enables a low level driver to set an upper limit on the size of a | |
669 | * coalesced segment | |
670 | **/ | |
165125e1 | 671 | void blk_queue_max_segment_size(struct request_queue *q, unsigned int max_size) |
1da177e4 LT |
672 | { |
673 | if (max_size < PAGE_CACHE_SIZE) { | |
674 | max_size = PAGE_CACHE_SIZE; | |
675 | printk("%s: set to minimum %d\n", __FUNCTION__, max_size); | |
676 | } | |
677 | ||
678 | q->max_segment_size = max_size; | |
679 | } | |
680 | ||
681 | EXPORT_SYMBOL(blk_queue_max_segment_size); | |
682 | ||
683 | /** | |
684 | * blk_queue_hardsect_size - set hardware sector size for the queue | |
685 | * @q: the request queue for the device | |
686 | * @size: the hardware sector size, in bytes | |
687 | * | |
688 | * Description: | |
689 | * This should typically be set to the lowest possible sector size | |
690 | * that the hardware can operate on (possible without reverting to | |
691 | * even internal read-modify-write operations). Usually the default | |
692 | * of 512 covers most hardware. | |
693 | **/ | |
165125e1 | 694 | void blk_queue_hardsect_size(struct request_queue *q, unsigned short size) |
1da177e4 LT |
695 | { |
696 | q->hardsect_size = size; | |
697 | } | |
698 | ||
699 | EXPORT_SYMBOL(blk_queue_hardsect_size); | |
700 | ||
701 | /* | |
702 | * Returns the minimum that is _not_ zero, unless both are zero. | |
703 | */ | |
704 | #define min_not_zero(l, r) (l == 0) ? r : ((r == 0) ? l : min(l, r)) | |
705 | ||
706 | /** | |
707 | * blk_queue_stack_limits - inherit underlying queue limits for stacked drivers | |
708 | * @t: the stacking driver (top) | |
709 | * @b: the underlying device (bottom) | |
710 | **/ | |
165125e1 | 711 | void blk_queue_stack_limits(struct request_queue *t, struct request_queue *b) |
1da177e4 LT |
712 | { |
713 | /* zero is "infinity" */ | |
defd94b7 MC |
714 | t->max_sectors = min_not_zero(t->max_sectors,b->max_sectors); |
715 | t->max_hw_sectors = min_not_zero(t->max_hw_sectors,b->max_hw_sectors); | |
1da177e4 LT |
716 | |
717 | t->max_phys_segments = min(t->max_phys_segments,b->max_phys_segments); | |
718 | t->max_hw_segments = min(t->max_hw_segments,b->max_hw_segments); | |
719 | t->max_segment_size = min(t->max_segment_size,b->max_segment_size); | |
720 | t->hardsect_size = max(t->hardsect_size,b->hardsect_size); | |
89e5c8b5 N |
721 | if (!test_bit(QUEUE_FLAG_CLUSTER, &b->queue_flags)) |
722 | clear_bit(QUEUE_FLAG_CLUSTER, &t->queue_flags); | |
1da177e4 LT |
723 | } |
724 | ||
725 | EXPORT_SYMBOL(blk_queue_stack_limits); | |
726 | ||
727 | /** | |
728 | * blk_queue_segment_boundary - set boundary rules for segment merging | |
729 | * @q: the request queue for the device | |
730 | * @mask: the memory boundary mask | |
731 | **/ | |
165125e1 | 732 | void blk_queue_segment_boundary(struct request_queue *q, unsigned long mask) |
1da177e4 LT |
733 | { |
734 | if (mask < PAGE_CACHE_SIZE - 1) { | |
735 | mask = PAGE_CACHE_SIZE - 1; | |
736 | printk("%s: set to minimum %lx\n", __FUNCTION__, mask); | |
737 | } | |
738 | ||
739 | q->seg_boundary_mask = mask; | |
740 | } | |
741 | ||
742 | EXPORT_SYMBOL(blk_queue_segment_boundary); | |
743 | ||
744 | /** | |
745 | * blk_queue_dma_alignment - set dma length and memory alignment | |
746 | * @q: the request queue for the device | |
747 | * @mask: alignment mask | |
748 | * | |
749 | * description: | |
750 | * set required memory and length aligment for direct dma transactions. | |
751 | * this is used when buiding direct io requests for the queue. | |
752 | * | |
753 | **/ | |
165125e1 | 754 | void blk_queue_dma_alignment(struct request_queue *q, int mask) |
1da177e4 LT |
755 | { |
756 | q->dma_alignment = mask; | |
757 | } | |
758 | ||
759 | EXPORT_SYMBOL(blk_queue_dma_alignment); | |
760 | ||
761 | /** | |
762 | * blk_queue_find_tag - find a request by its tag and queue | |
1da177e4 LT |
763 | * @q: The request queue for the device |
764 | * @tag: The tag of the request | |
765 | * | |
766 | * Notes: | |
767 | * Should be used when a device returns a tag and you want to match | |
768 | * it with a request. | |
769 | * | |
770 | * no locks need be held. | |
771 | **/ | |
165125e1 | 772 | struct request *blk_queue_find_tag(struct request_queue *q, int tag) |
1da177e4 | 773 | { |
f583f492 | 774 | return blk_map_queue_find_tag(q->queue_tags, tag); |
1da177e4 LT |
775 | } |
776 | ||
777 | EXPORT_SYMBOL(blk_queue_find_tag); | |
778 | ||
779 | /** | |
492dfb48 JB |
780 | * __blk_free_tags - release a given set of tag maintenance info |
781 | * @bqt: the tag map to free | |
1da177e4 | 782 | * |
492dfb48 JB |
783 | * Tries to free the specified @bqt@. Returns true if it was |
784 | * actually freed and false if there are still references using it | |
785 | */ | |
786 | static int __blk_free_tags(struct blk_queue_tag *bqt) | |
1da177e4 | 787 | { |
492dfb48 | 788 | int retval; |
1da177e4 | 789 | |
492dfb48 JB |
790 | retval = atomic_dec_and_test(&bqt->refcnt); |
791 | if (retval) { | |
1da177e4 LT |
792 | BUG_ON(bqt->busy); |
793 | BUG_ON(!list_empty(&bqt->busy_list)); | |
794 | ||
795 | kfree(bqt->tag_index); | |
796 | bqt->tag_index = NULL; | |
797 | ||
798 | kfree(bqt->tag_map); | |
799 | bqt->tag_map = NULL; | |
800 | ||
801 | kfree(bqt); | |
492dfb48 | 802 | |
1da177e4 LT |
803 | } |
804 | ||
492dfb48 JB |
805 | return retval; |
806 | } | |
807 | ||
808 | /** | |
809 | * __blk_queue_free_tags - release tag maintenance info | |
810 | * @q: the request queue for the device | |
811 | * | |
812 | * Notes: | |
813 | * blk_cleanup_queue() will take care of calling this function, if tagging | |
814 | * has been used. So there's no need to call this directly. | |
815 | **/ | |
165125e1 | 816 | static void __blk_queue_free_tags(struct request_queue *q) |
492dfb48 JB |
817 | { |
818 | struct blk_queue_tag *bqt = q->queue_tags; | |
819 | ||
820 | if (!bqt) | |
821 | return; | |
822 | ||
823 | __blk_free_tags(bqt); | |
824 | ||
1da177e4 LT |
825 | q->queue_tags = NULL; |
826 | q->queue_flags &= ~(1 << QUEUE_FLAG_QUEUED); | |
827 | } | |
828 | ||
492dfb48 JB |
829 | |
830 | /** | |
831 | * blk_free_tags - release a given set of tag maintenance info | |
832 | * @bqt: the tag map to free | |
833 | * | |
834 | * For externally managed @bqt@ frees the map. Callers of this | |
835 | * function must guarantee to have released all the queues that | |
836 | * might have been using this tag map. | |
837 | */ | |
838 | void blk_free_tags(struct blk_queue_tag *bqt) | |
839 | { | |
840 | if (unlikely(!__blk_free_tags(bqt))) | |
841 | BUG(); | |
842 | } | |
843 | EXPORT_SYMBOL(blk_free_tags); | |
844 | ||
1da177e4 LT |
845 | /** |
846 | * blk_queue_free_tags - release tag maintenance info | |
847 | * @q: the request queue for the device | |
848 | * | |
849 | * Notes: | |
850 | * This is used to disabled tagged queuing to a device, yet leave | |
851 | * queue in function. | |
852 | **/ | |
165125e1 | 853 | void blk_queue_free_tags(struct request_queue *q) |
1da177e4 LT |
854 | { |
855 | clear_bit(QUEUE_FLAG_QUEUED, &q->queue_flags); | |
856 | } | |
857 | ||
858 | EXPORT_SYMBOL(blk_queue_free_tags); | |
859 | ||
860 | static int | |
165125e1 | 861 | init_tag_map(struct request_queue *q, struct blk_queue_tag *tags, int depth) |
1da177e4 | 862 | { |
1da177e4 LT |
863 | struct request **tag_index; |
864 | unsigned long *tag_map; | |
fa72b903 | 865 | int nr_ulongs; |
1da177e4 | 866 | |
492dfb48 | 867 | if (q && depth > q->nr_requests * 2) { |
1da177e4 LT |
868 | depth = q->nr_requests * 2; |
869 | printk(KERN_ERR "%s: adjusted depth to %d\n", | |
870 | __FUNCTION__, depth); | |
871 | } | |
872 | ||
f68110fc | 873 | tag_index = kzalloc(depth * sizeof(struct request *), GFP_ATOMIC); |
1da177e4 LT |
874 | if (!tag_index) |
875 | goto fail; | |
876 | ||
f7d37d02 | 877 | nr_ulongs = ALIGN(depth, BITS_PER_LONG) / BITS_PER_LONG; |
f68110fc | 878 | tag_map = kzalloc(nr_ulongs * sizeof(unsigned long), GFP_ATOMIC); |
1da177e4 LT |
879 | if (!tag_map) |
880 | goto fail; | |
881 | ||
ba025082 | 882 | tags->real_max_depth = depth; |
1da177e4 | 883 | tags->max_depth = depth; |
1da177e4 LT |
884 | tags->tag_index = tag_index; |
885 | tags->tag_map = tag_map; | |
886 | ||
1da177e4 LT |
887 | return 0; |
888 | fail: | |
889 | kfree(tag_index); | |
890 | return -ENOMEM; | |
891 | } | |
892 | ||
492dfb48 JB |
893 | static struct blk_queue_tag *__blk_queue_init_tags(struct request_queue *q, |
894 | int depth) | |
895 | { | |
896 | struct blk_queue_tag *tags; | |
897 | ||
898 | tags = kmalloc(sizeof(struct blk_queue_tag), GFP_ATOMIC); | |
899 | if (!tags) | |
900 | goto fail; | |
901 | ||
902 | if (init_tag_map(q, tags, depth)) | |
903 | goto fail; | |
904 | ||
905 | INIT_LIST_HEAD(&tags->busy_list); | |
906 | tags->busy = 0; | |
907 | atomic_set(&tags->refcnt, 1); | |
908 | return tags; | |
909 | fail: | |
910 | kfree(tags); | |
911 | return NULL; | |
912 | } | |
913 | ||
914 | /** | |
915 | * blk_init_tags - initialize the tag info for an external tag map | |
916 | * @depth: the maximum queue depth supported | |
917 | * @tags: the tag to use | |
918 | **/ | |
919 | struct blk_queue_tag *blk_init_tags(int depth) | |
920 | { | |
921 | return __blk_queue_init_tags(NULL, depth); | |
922 | } | |
923 | EXPORT_SYMBOL(blk_init_tags); | |
924 | ||
1da177e4 LT |
925 | /** |
926 | * blk_queue_init_tags - initialize the queue tag info | |
927 | * @q: the request queue for the device | |
928 | * @depth: the maximum queue depth supported | |
929 | * @tags: the tag to use | |
930 | **/ | |
165125e1 | 931 | int blk_queue_init_tags(struct request_queue *q, int depth, |
1da177e4 LT |
932 | struct blk_queue_tag *tags) |
933 | { | |
934 | int rc; | |
935 | ||
936 | BUG_ON(tags && q->queue_tags && tags != q->queue_tags); | |
937 | ||
938 | if (!tags && !q->queue_tags) { | |
492dfb48 | 939 | tags = __blk_queue_init_tags(q, depth); |
1da177e4 | 940 | |
492dfb48 | 941 | if (!tags) |
1da177e4 | 942 | goto fail; |
1da177e4 LT |
943 | } else if (q->queue_tags) { |
944 | if ((rc = blk_queue_resize_tags(q, depth))) | |
945 | return rc; | |
946 | set_bit(QUEUE_FLAG_QUEUED, &q->queue_flags); | |
947 | return 0; | |
948 | } else | |
949 | atomic_inc(&tags->refcnt); | |
950 | ||
951 | /* | |
952 | * assign it, all done | |
953 | */ | |
954 | q->queue_tags = tags; | |
955 | q->queue_flags |= (1 << QUEUE_FLAG_QUEUED); | |
956 | return 0; | |
957 | fail: | |
958 | kfree(tags); | |
959 | return -ENOMEM; | |
960 | } | |
961 | ||
962 | EXPORT_SYMBOL(blk_queue_init_tags); | |
963 | ||
964 | /** | |
965 | * blk_queue_resize_tags - change the queueing depth | |
966 | * @q: the request queue for the device | |
967 | * @new_depth: the new max command queueing depth | |
968 | * | |
969 | * Notes: | |
970 | * Must be called with the queue lock held. | |
971 | **/ | |
165125e1 | 972 | int blk_queue_resize_tags(struct request_queue *q, int new_depth) |
1da177e4 LT |
973 | { |
974 | struct blk_queue_tag *bqt = q->queue_tags; | |
975 | struct request **tag_index; | |
976 | unsigned long *tag_map; | |
fa72b903 | 977 | int max_depth, nr_ulongs; |
1da177e4 LT |
978 | |
979 | if (!bqt) | |
980 | return -ENXIO; | |
981 | ||
ba025082 TH |
982 | /* |
983 | * if we already have large enough real_max_depth. just | |
984 | * adjust max_depth. *NOTE* as requests with tag value | |
985 | * between new_depth and real_max_depth can be in-flight, tag | |
986 | * map can not be shrunk blindly here. | |
987 | */ | |
988 | if (new_depth <= bqt->real_max_depth) { | |
989 | bqt->max_depth = new_depth; | |
990 | return 0; | |
991 | } | |
992 | ||
492dfb48 JB |
993 | /* |
994 | * Currently cannot replace a shared tag map with a new | |
995 | * one, so error out if this is the case | |
996 | */ | |
997 | if (atomic_read(&bqt->refcnt) != 1) | |
998 | return -EBUSY; | |
999 | ||
1da177e4 LT |
1000 | /* |
1001 | * save the old state info, so we can copy it back | |
1002 | */ | |
1003 | tag_index = bqt->tag_index; | |
1004 | tag_map = bqt->tag_map; | |
ba025082 | 1005 | max_depth = bqt->real_max_depth; |
1da177e4 LT |
1006 | |
1007 | if (init_tag_map(q, bqt, new_depth)) | |
1008 | return -ENOMEM; | |
1009 | ||
1010 | memcpy(bqt->tag_index, tag_index, max_depth * sizeof(struct request *)); | |
f7d37d02 | 1011 | nr_ulongs = ALIGN(max_depth, BITS_PER_LONG) / BITS_PER_LONG; |
fa72b903 | 1012 | memcpy(bqt->tag_map, tag_map, nr_ulongs * sizeof(unsigned long)); |
1da177e4 LT |
1013 | |
1014 | kfree(tag_index); | |
1015 | kfree(tag_map); | |
1016 | return 0; | |
1017 | } | |
1018 | ||
1019 | EXPORT_SYMBOL(blk_queue_resize_tags); | |
1020 | ||
1021 | /** | |
1022 | * blk_queue_end_tag - end tag operations for a request | |
1023 | * @q: the request queue for the device | |
1024 | * @rq: the request that has completed | |
1025 | * | |
1026 | * Description: | |
1027 | * Typically called when end_that_request_first() returns 0, meaning | |
1028 | * all transfers have been done for a request. It's important to call | |
1029 | * this function before end_that_request_last(), as that will put the | |
1030 | * request back on the free list thus corrupting the internal tag list. | |
1031 | * | |
1032 | * Notes: | |
1033 | * queue lock must be held. | |
1034 | **/ | |
165125e1 | 1035 | void blk_queue_end_tag(struct request_queue *q, struct request *rq) |
1da177e4 LT |
1036 | { |
1037 | struct blk_queue_tag *bqt = q->queue_tags; | |
1038 | int tag = rq->tag; | |
1039 | ||
1040 | BUG_ON(tag == -1); | |
1041 | ||
ba025082 | 1042 | if (unlikely(tag >= bqt->real_max_depth)) |
040c928c TH |
1043 | /* |
1044 | * This can happen after tag depth has been reduced. | |
1045 | * FIXME: how about a warning or info message here? | |
1046 | */ | |
1da177e4 LT |
1047 | return; |
1048 | ||
1da177e4 | 1049 | list_del_init(&rq->queuelist); |
4aff5e23 | 1050 | rq->cmd_flags &= ~REQ_QUEUED; |
1da177e4 LT |
1051 | rq->tag = -1; |
1052 | ||
1053 | if (unlikely(bqt->tag_index[tag] == NULL)) | |
040c928c TH |
1054 | printk(KERN_ERR "%s: tag %d is missing\n", |
1055 | __FUNCTION__, tag); | |
1da177e4 LT |
1056 | |
1057 | bqt->tag_index[tag] = NULL; | |
f3da54ba | 1058 | |
dd941252 NP |
1059 | /* |
1060 | * We use test_and_clear_bit's memory ordering properties here. | |
1061 | * The tag_map bit acts as a lock for tag_index[bit], so we need | |
1062 | * a barrer before clearing the bit (precisely: release semantics). | |
1063 | * Could use clear_bit_unlock when it is merged. | |
1064 | */ | |
f3da54ba JA |
1065 | if (unlikely(!test_and_clear_bit(tag, bqt->tag_map))) { |
1066 | printk(KERN_ERR "%s: attempt to clear non-busy tag (%d)\n", | |
1067 | __FUNCTION__, tag); | |
1068 | return; | |
1069 | } | |
1070 | ||
1da177e4 LT |
1071 | bqt->busy--; |
1072 | } | |
1073 | ||
1074 | EXPORT_SYMBOL(blk_queue_end_tag); | |
1075 | ||
1076 | /** | |
1077 | * blk_queue_start_tag - find a free tag and assign it | |
1078 | * @q: the request queue for the device | |
1079 | * @rq: the block request that needs tagging | |
1080 | * | |
1081 | * Description: | |
1082 | * This can either be used as a stand-alone helper, or possibly be | |
1083 | * assigned as the queue &prep_rq_fn (in which case &struct request | |
1084 | * automagically gets a tag assigned). Note that this function | |
1085 | * assumes that any type of request can be queued! if this is not | |
1086 | * true for your device, you must check the request type before | |
1087 | * calling this function. The request will also be removed from | |
1088 | * the request queue, so it's the drivers responsibility to readd | |
1089 | * it if it should need to be restarted for some reason. | |
1090 | * | |
1091 | * Notes: | |
1092 | * queue lock must be held. | |
1093 | **/ | |
165125e1 | 1094 | int blk_queue_start_tag(struct request_queue *q, struct request *rq) |
1da177e4 LT |
1095 | { |
1096 | struct blk_queue_tag *bqt = q->queue_tags; | |
2bf0fdad | 1097 | int tag; |
1da177e4 | 1098 | |
4aff5e23 | 1099 | if (unlikely((rq->cmd_flags & REQ_QUEUED))) { |
1da177e4 | 1100 | printk(KERN_ERR |
040c928c TH |
1101 | "%s: request %p for device [%s] already tagged %d", |
1102 | __FUNCTION__, rq, | |
1103 | rq->rq_disk ? rq->rq_disk->disk_name : "?", rq->tag); | |
1da177e4 LT |
1104 | BUG(); |
1105 | } | |
1106 | ||
059af497 JA |
1107 | /* |
1108 | * Protect against shared tag maps, as we may not have exclusive | |
1109 | * access to the tag map. | |
1110 | */ | |
1111 | do { | |
1112 | tag = find_first_zero_bit(bqt->tag_map, bqt->max_depth); | |
1113 | if (tag >= bqt->max_depth) | |
1114 | return 1; | |
1da177e4 | 1115 | |
059af497 | 1116 | } while (test_and_set_bit(tag, bqt->tag_map)); |
dd941252 NP |
1117 | /* |
1118 | * We rely on test_and_set_bit providing lock memory ordering semantics | |
1119 | * (could use test_and_set_bit_lock when it is merged). | |
1120 | */ | |
1da177e4 | 1121 | |
4aff5e23 | 1122 | rq->cmd_flags |= REQ_QUEUED; |
1da177e4 LT |
1123 | rq->tag = tag; |
1124 | bqt->tag_index[tag] = rq; | |
1125 | blkdev_dequeue_request(rq); | |
1126 | list_add(&rq->queuelist, &bqt->busy_list); | |
1127 | bqt->busy++; | |
1128 | return 0; | |
1129 | } | |
1130 | ||
1131 | EXPORT_SYMBOL(blk_queue_start_tag); | |
1132 | ||
1133 | /** | |
1134 | * blk_queue_invalidate_tags - invalidate all pending tags | |
1135 | * @q: the request queue for the device | |
1136 | * | |
1137 | * Description: | |
1138 | * Hardware conditions may dictate a need to stop all pending requests. | |
1139 | * In this case, we will safely clear the block side of the tag queue and | |
1140 | * readd all requests to the request queue in the right order. | |
1141 | * | |
1142 | * Notes: | |
1143 | * queue lock must be held. | |
1144 | **/ | |
165125e1 | 1145 | void blk_queue_invalidate_tags(struct request_queue *q) |
1da177e4 LT |
1146 | { |
1147 | struct blk_queue_tag *bqt = q->queue_tags; | |
1148 | struct list_head *tmp, *n; | |
1149 | struct request *rq; | |
1150 | ||
1151 | list_for_each_safe(tmp, n, &bqt->busy_list) { | |
1152 | rq = list_entry_rq(tmp); | |
1153 | ||
1154 | if (rq->tag == -1) { | |
040c928c TH |
1155 | printk(KERN_ERR |
1156 | "%s: bad tag found on list\n", __FUNCTION__); | |
1da177e4 | 1157 | list_del_init(&rq->queuelist); |
4aff5e23 | 1158 | rq->cmd_flags &= ~REQ_QUEUED; |
1da177e4 LT |
1159 | } else |
1160 | blk_queue_end_tag(q, rq); | |
1161 | ||
4aff5e23 | 1162 | rq->cmd_flags &= ~REQ_STARTED; |
1da177e4 LT |
1163 | __elv_add_request(q, rq, ELEVATOR_INSERT_BACK, 0); |
1164 | } | |
1165 | } | |
1166 | ||
1167 | EXPORT_SYMBOL(blk_queue_invalidate_tags); | |
1168 | ||
1da177e4 LT |
1169 | void blk_dump_rq_flags(struct request *rq, char *msg) |
1170 | { | |
1171 | int bit; | |
1172 | ||
4aff5e23 JA |
1173 | printk("%s: dev %s: type=%x, flags=%x\n", msg, |
1174 | rq->rq_disk ? rq->rq_disk->disk_name : "?", rq->cmd_type, | |
1175 | rq->cmd_flags); | |
1da177e4 LT |
1176 | |
1177 | printk("\nsector %llu, nr/cnr %lu/%u\n", (unsigned long long)rq->sector, | |
1178 | rq->nr_sectors, | |
1179 | rq->current_nr_sectors); | |
1180 | printk("bio %p, biotail %p, buffer %p, data %p, len %u\n", rq->bio, rq->biotail, rq->buffer, rq->data, rq->data_len); | |
1181 | ||
4aff5e23 | 1182 | if (blk_pc_request(rq)) { |
1da177e4 LT |
1183 | printk("cdb: "); |
1184 | for (bit = 0; bit < sizeof(rq->cmd); bit++) | |
1185 | printk("%02x ", rq->cmd[bit]); | |
1186 | printk("\n"); | |
1187 | } | |
1188 | } | |
1189 | ||
1190 | EXPORT_SYMBOL(blk_dump_rq_flags); | |
1191 | ||
165125e1 | 1192 | void blk_recount_segments(struct request_queue *q, struct bio *bio) |
1da177e4 | 1193 | { |
9dfa5283 N |
1194 | struct request rq; |
1195 | struct bio *nxt = bio->bi_next; | |
1196 | rq.q = q; | |
1197 | rq.bio = rq.biotail = bio; | |
1198 | bio->bi_next = NULL; | |
1199 | blk_recalc_rq_segments(&rq); | |
1200 | bio->bi_next = nxt; | |
1201 | bio->bi_phys_segments = rq.nr_phys_segments; | |
1202 | bio->bi_hw_segments = rq.nr_hw_segments; | |
1203 | bio->bi_flags |= (1 << BIO_SEG_VALID); | |
1204 | } | |
1205 | EXPORT_SYMBOL(blk_recount_segments); | |
1206 | ||
1207 | static void blk_recalc_rq_segments(struct request *rq) | |
1208 | { | |
1209 | int nr_phys_segs; | |
1210 | int nr_hw_segs; | |
1211 | unsigned int phys_size; | |
1212 | unsigned int hw_size; | |
1da177e4 | 1213 | struct bio_vec *bv, *bvprv = NULL; |
9dfa5283 N |
1214 | int seg_size; |
1215 | int hw_seg_size; | |
1216 | int cluster; | |
5705f702 | 1217 | struct req_iterator iter; |
1da177e4 | 1218 | int high, highprv = 1; |
9dfa5283 | 1219 | struct request_queue *q = rq->q; |
1da177e4 | 1220 | |
9dfa5283 | 1221 | if (!rq->bio) |
1da177e4 LT |
1222 | return; |
1223 | ||
1224 | cluster = q->queue_flags & (1 << QUEUE_FLAG_CLUSTER); | |
9dfa5283 N |
1225 | hw_seg_size = seg_size = 0; |
1226 | phys_size = hw_size = nr_phys_segs = nr_hw_segs = 0; | |
5705f702 | 1227 | rq_for_each_segment(bv, rq, iter) { |
1da177e4 LT |
1228 | /* |
1229 | * the trick here is making sure that a high page is never | |
1230 | * considered part of another segment, since that might | |
1231 | * change with the bounce page. | |
1232 | */ | |
f772b3d9 | 1233 | high = page_to_pfn(bv->bv_page) > q->bounce_pfn; |
1da177e4 LT |
1234 | if (high || highprv) |
1235 | goto new_hw_segment; | |
1236 | if (cluster) { | |
1237 | if (seg_size + bv->bv_len > q->max_segment_size) | |
1238 | goto new_segment; | |
1239 | if (!BIOVEC_PHYS_MERGEABLE(bvprv, bv)) | |
1240 | goto new_segment; | |
1241 | if (!BIOVEC_SEG_BOUNDARY(q, bvprv, bv)) | |
1242 | goto new_segment; | |
1243 | if (BIOVEC_VIRT_OVERSIZE(hw_seg_size + bv->bv_len)) | |
1244 | goto new_hw_segment; | |
1245 | ||
1246 | seg_size += bv->bv_len; | |
1247 | hw_seg_size += bv->bv_len; | |
1248 | bvprv = bv; | |
1249 | continue; | |
1250 | } | |
1251 | new_segment: | |
1252 | if (BIOVEC_VIRT_MERGEABLE(bvprv, bv) && | |
9dfa5283 | 1253 | !BIOVEC_VIRT_OVERSIZE(hw_seg_size + bv->bv_len)) |
1da177e4 | 1254 | hw_seg_size += bv->bv_len; |
9dfa5283 | 1255 | else { |
1da177e4 | 1256 | new_hw_segment: |
9dfa5283 N |
1257 | if (nr_hw_segs == 1 && |
1258 | hw_seg_size > rq->bio->bi_hw_front_size) | |
1259 | rq->bio->bi_hw_front_size = hw_seg_size; | |
1da177e4 LT |
1260 | hw_seg_size = BIOVEC_VIRT_START_SIZE(bv) + bv->bv_len; |
1261 | nr_hw_segs++; | |
1262 | } | |
1263 | ||
1264 | nr_phys_segs++; | |
1265 | bvprv = bv; | |
1266 | seg_size = bv->bv_len; | |
1267 | highprv = high; | |
1268 | } | |
9dfa5283 N |
1269 | |
1270 | if (nr_hw_segs == 1 && | |
1271 | hw_seg_size > rq->bio->bi_hw_front_size) | |
1272 | rq->bio->bi_hw_front_size = hw_seg_size; | |
1273 | if (hw_seg_size > rq->biotail->bi_hw_back_size) | |
1274 | rq->biotail->bi_hw_back_size = hw_seg_size; | |
1275 | rq->nr_phys_segments = nr_phys_segs; | |
1276 | rq->nr_hw_segments = nr_hw_segs; | |
1da177e4 | 1277 | } |
1da177e4 | 1278 | |
165125e1 | 1279 | static int blk_phys_contig_segment(struct request_queue *q, struct bio *bio, |
1da177e4 LT |
1280 | struct bio *nxt) |
1281 | { | |
1282 | if (!(q->queue_flags & (1 << QUEUE_FLAG_CLUSTER))) | |
1283 | return 0; | |
1284 | ||
1285 | if (!BIOVEC_PHYS_MERGEABLE(__BVEC_END(bio), __BVEC_START(nxt))) | |
1286 | return 0; | |
1287 | if (bio->bi_size + nxt->bi_size > q->max_segment_size) | |
1288 | return 0; | |
1289 | ||
1290 | /* | |
1291 | * bio and nxt are contigous in memory, check if the queue allows | |
1292 | * these two to be merged into one | |
1293 | */ | |
1294 | if (BIO_SEG_BOUNDARY(q, bio, nxt)) | |
1295 | return 1; | |
1296 | ||
1297 | return 0; | |
1298 | } | |
1299 | ||
165125e1 | 1300 | static int blk_hw_contig_segment(struct request_queue *q, struct bio *bio, |
1da177e4 LT |
1301 | struct bio *nxt) |
1302 | { | |
1303 | if (unlikely(!bio_flagged(bio, BIO_SEG_VALID))) | |
1304 | blk_recount_segments(q, bio); | |
1305 | if (unlikely(!bio_flagged(nxt, BIO_SEG_VALID))) | |
1306 | blk_recount_segments(q, nxt); | |
1307 | if (!BIOVEC_VIRT_MERGEABLE(__BVEC_END(bio), __BVEC_START(nxt)) || | |
32eef964 | 1308 | BIOVEC_VIRT_OVERSIZE(bio->bi_hw_back_size + nxt->bi_hw_front_size)) |
1da177e4 | 1309 | return 0; |
32eef964 | 1310 | if (bio->bi_hw_back_size + nxt->bi_hw_front_size > q->max_segment_size) |
1da177e4 LT |
1311 | return 0; |
1312 | ||
1313 | return 1; | |
1314 | } | |
1315 | ||
1da177e4 LT |
1316 | /* |
1317 | * map a request to scatterlist, return number of sg entries setup. Caller | |
1318 | * must make sure sg can hold rq->nr_phys_segments entries | |
1319 | */ | |
165125e1 JA |
1320 | int blk_rq_map_sg(struct request_queue *q, struct request *rq, |
1321 | struct scatterlist *sg) | |
1da177e4 LT |
1322 | { |
1323 | struct bio_vec *bvec, *bvprv; | |
5705f702 N |
1324 | struct req_iterator iter; |
1325 | int nsegs, cluster; | |
1da177e4 LT |
1326 | |
1327 | nsegs = 0; | |
1328 | cluster = q->queue_flags & (1 << QUEUE_FLAG_CLUSTER); | |
1329 | ||
1330 | /* | |
1331 | * for each bio in rq | |
1332 | */ | |
1333 | bvprv = NULL; | |
5705f702 | 1334 | rq_for_each_segment(bvec, rq, iter) { |
6c92e699 | 1335 | int nbytes = bvec->bv_len; |
1da177e4 | 1336 | |
6c92e699 JA |
1337 | if (bvprv && cluster) { |
1338 | if (sg[nsegs - 1].length + nbytes > q->max_segment_size) | |
1339 | goto new_segment; | |
1da177e4 | 1340 | |
6c92e699 JA |
1341 | if (!BIOVEC_PHYS_MERGEABLE(bvprv, bvec)) |
1342 | goto new_segment; | |
1343 | if (!BIOVEC_SEG_BOUNDARY(q, bvprv, bvec)) | |
1344 | goto new_segment; | |
1da177e4 | 1345 | |
6c92e699 JA |
1346 | sg[nsegs - 1].length += nbytes; |
1347 | } else { | |
1da177e4 | 1348 | new_segment: |
6c92e699 JA |
1349 | memset(&sg[nsegs],0,sizeof(struct scatterlist)); |
1350 | sg[nsegs].page = bvec->bv_page; | |
1351 | sg[nsegs].length = nbytes; | |
1352 | sg[nsegs].offset = bvec->bv_offset; | |
1353 | ||
1354 | nsegs++; | |
1355 | } | |
1356 | bvprv = bvec; | |
5705f702 | 1357 | } /* segments in rq */ |
1da177e4 LT |
1358 | |
1359 | return nsegs; | |
1360 | } | |
1361 | ||
1362 | EXPORT_SYMBOL(blk_rq_map_sg); | |
1363 | ||
1364 | /* | |
1365 | * the standard queue merge functions, can be overridden with device | |
1366 | * specific ones if so desired | |
1367 | */ | |
1368 | ||
165125e1 | 1369 | static inline int ll_new_mergeable(struct request_queue *q, |
1da177e4 LT |
1370 | struct request *req, |
1371 | struct bio *bio) | |
1372 | { | |
1373 | int nr_phys_segs = bio_phys_segments(q, bio); | |
1374 | ||
1375 | if (req->nr_phys_segments + nr_phys_segs > q->max_phys_segments) { | |
4aff5e23 | 1376 | req->cmd_flags |= REQ_NOMERGE; |
1da177e4 LT |
1377 | if (req == q->last_merge) |
1378 | q->last_merge = NULL; | |
1379 | return 0; | |
1380 | } | |
1381 | ||
1382 | /* | |
1383 | * A hw segment is just getting larger, bump just the phys | |
1384 | * counter. | |
1385 | */ | |
1386 | req->nr_phys_segments += nr_phys_segs; | |
1387 | return 1; | |
1388 | } | |
1389 | ||
165125e1 | 1390 | static inline int ll_new_hw_segment(struct request_queue *q, |
1da177e4 LT |
1391 | struct request *req, |
1392 | struct bio *bio) | |
1393 | { | |
1394 | int nr_hw_segs = bio_hw_segments(q, bio); | |
1395 | int nr_phys_segs = bio_phys_segments(q, bio); | |
1396 | ||
1397 | if (req->nr_hw_segments + nr_hw_segs > q->max_hw_segments | |
1398 | || req->nr_phys_segments + nr_phys_segs > q->max_phys_segments) { | |
4aff5e23 | 1399 | req->cmd_flags |= REQ_NOMERGE; |
1da177e4 LT |
1400 | if (req == q->last_merge) |
1401 | q->last_merge = NULL; | |
1402 | return 0; | |
1403 | } | |
1404 | ||
1405 | /* | |
1406 | * This will form the start of a new hw segment. Bump both | |
1407 | * counters. | |
1408 | */ | |
1409 | req->nr_hw_segments += nr_hw_segs; | |
1410 | req->nr_phys_segments += nr_phys_segs; | |
1411 | return 1; | |
1412 | } | |
1413 | ||
3001ca77 N |
1414 | static int ll_back_merge_fn(struct request_queue *q, struct request *req, |
1415 | struct bio *bio) | |
1da177e4 | 1416 | { |
defd94b7 | 1417 | unsigned short max_sectors; |
1da177e4 LT |
1418 | int len; |
1419 | ||
defd94b7 MC |
1420 | if (unlikely(blk_pc_request(req))) |
1421 | max_sectors = q->max_hw_sectors; | |
1422 | else | |
1423 | max_sectors = q->max_sectors; | |
1424 | ||
1425 | if (req->nr_sectors + bio_sectors(bio) > max_sectors) { | |
4aff5e23 | 1426 | req->cmd_flags |= REQ_NOMERGE; |
1da177e4 LT |
1427 | if (req == q->last_merge) |
1428 | q->last_merge = NULL; | |
1429 | return 0; | |
1430 | } | |
1431 | if (unlikely(!bio_flagged(req->biotail, BIO_SEG_VALID))) | |
1432 | blk_recount_segments(q, req->biotail); | |
1433 | if (unlikely(!bio_flagged(bio, BIO_SEG_VALID))) | |
1434 | blk_recount_segments(q, bio); | |
1435 | len = req->biotail->bi_hw_back_size + bio->bi_hw_front_size; | |
1436 | if (BIOVEC_VIRT_MERGEABLE(__BVEC_END(req->biotail), __BVEC_START(bio)) && | |
1437 | !BIOVEC_VIRT_OVERSIZE(len)) { | |
1438 | int mergeable = ll_new_mergeable(q, req, bio); | |
1439 | ||
1440 | if (mergeable) { | |
1441 | if (req->nr_hw_segments == 1) | |
1442 | req->bio->bi_hw_front_size = len; | |
1443 | if (bio->bi_hw_segments == 1) | |
1444 | bio->bi_hw_back_size = len; | |
1445 | } | |
1446 | return mergeable; | |
1447 | } | |
1448 | ||
1449 | return ll_new_hw_segment(q, req, bio); | |
1450 | } | |
1451 | ||
165125e1 | 1452 | static int ll_front_merge_fn(struct request_queue *q, struct request *req, |
1da177e4 LT |
1453 | struct bio *bio) |
1454 | { | |
defd94b7 | 1455 | unsigned short max_sectors; |
1da177e4 LT |
1456 | int len; |
1457 | ||
defd94b7 MC |
1458 | if (unlikely(blk_pc_request(req))) |
1459 | max_sectors = q->max_hw_sectors; | |
1460 | else | |
1461 | max_sectors = q->max_sectors; | |
1462 | ||
1463 | ||
1464 | if (req->nr_sectors + bio_sectors(bio) > max_sectors) { | |
4aff5e23 | 1465 | req->cmd_flags |= REQ_NOMERGE; |
1da177e4 LT |
1466 | if (req == q->last_merge) |
1467 | q->last_merge = NULL; | |
1468 | return 0; | |
1469 | } | |
1470 | len = bio->bi_hw_back_size + req->bio->bi_hw_front_size; | |
1471 | if (unlikely(!bio_flagged(bio, BIO_SEG_VALID))) | |
1472 | blk_recount_segments(q, bio); | |
1473 | if (unlikely(!bio_flagged(req->bio, BIO_SEG_VALID))) | |
1474 | blk_recount_segments(q, req->bio); | |
1475 | if (BIOVEC_VIRT_MERGEABLE(__BVEC_END(bio), __BVEC_START(req->bio)) && | |
1476 | !BIOVEC_VIRT_OVERSIZE(len)) { | |
1477 | int mergeable = ll_new_mergeable(q, req, bio); | |
1478 | ||
1479 | if (mergeable) { | |
1480 | if (bio->bi_hw_segments == 1) | |
1481 | bio->bi_hw_front_size = len; | |
1482 | if (req->nr_hw_segments == 1) | |
1483 | req->biotail->bi_hw_back_size = len; | |
1484 | } | |
1485 | return mergeable; | |
1486 | } | |
1487 | ||
1488 | return ll_new_hw_segment(q, req, bio); | |
1489 | } | |
1490 | ||
165125e1 | 1491 | static int ll_merge_requests_fn(struct request_queue *q, struct request *req, |
1da177e4 LT |
1492 | struct request *next) |
1493 | { | |
dfa1a553 ND |
1494 | int total_phys_segments; |
1495 | int total_hw_segments; | |
1da177e4 LT |
1496 | |
1497 | /* | |
1498 | * First check if the either of the requests are re-queued | |
1499 | * requests. Can't merge them if they are. | |
1500 | */ | |
1501 | if (req->special || next->special) | |
1502 | return 0; | |
1503 | ||
1504 | /* | |
dfa1a553 | 1505 | * Will it become too large? |
1da177e4 LT |
1506 | */ |
1507 | if ((req->nr_sectors + next->nr_sectors) > q->max_sectors) | |
1508 | return 0; | |
1509 | ||
1510 | total_phys_segments = req->nr_phys_segments + next->nr_phys_segments; | |
1511 | if (blk_phys_contig_segment(q, req->biotail, next->bio)) | |
1512 | total_phys_segments--; | |
1513 | ||
1514 | if (total_phys_segments > q->max_phys_segments) | |
1515 | return 0; | |
1516 | ||
1517 | total_hw_segments = req->nr_hw_segments + next->nr_hw_segments; | |
1518 | if (blk_hw_contig_segment(q, req->biotail, next->bio)) { | |
1519 | int len = req->biotail->bi_hw_back_size + next->bio->bi_hw_front_size; | |
1520 | /* | |
1521 | * propagate the combined length to the end of the requests | |
1522 | */ | |
1523 | if (req->nr_hw_segments == 1) | |
1524 | req->bio->bi_hw_front_size = len; | |
1525 | if (next->nr_hw_segments == 1) | |
1526 | next->biotail->bi_hw_back_size = len; | |
1527 | total_hw_segments--; | |
1528 | } | |
1529 | ||
1530 | if (total_hw_segments > q->max_hw_segments) | |
1531 | return 0; | |
1532 | ||
1533 | /* Merge is OK... */ | |
1534 | req->nr_phys_segments = total_phys_segments; | |
1535 | req->nr_hw_segments = total_hw_segments; | |
1536 | return 1; | |
1537 | } | |
1538 | ||
1539 | /* | |
1540 | * "plug" the device if there are no outstanding requests: this will | |
1541 | * force the transfer to start only after we have put all the requests | |
1542 | * on the list. | |
1543 | * | |
1544 | * This is called with interrupts off and no requests on the queue and | |
1545 | * with the queue lock held. | |
1546 | */ | |
165125e1 | 1547 | void blk_plug_device(struct request_queue *q) |
1da177e4 LT |
1548 | { |
1549 | WARN_ON(!irqs_disabled()); | |
1550 | ||
1551 | /* | |
1552 | * don't plug a stopped queue, it must be paired with blk_start_queue() | |
1553 | * which will restart the queueing | |
1554 | */ | |
7daac490 | 1555 | if (blk_queue_stopped(q)) |
1da177e4 LT |
1556 | return; |
1557 | ||
2056a782 | 1558 | if (!test_and_set_bit(QUEUE_FLAG_PLUGGED, &q->queue_flags)) { |
1da177e4 | 1559 | mod_timer(&q->unplug_timer, jiffies + q->unplug_delay); |
2056a782 JA |
1560 | blk_add_trace_generic(q, NULL, 0, BLK_TA_PLUG); |
1561 | } | |
1da177e4 LT |
1562 | } |
1563 | ||
1564 | EXPORT_SYMBOL(blk_plug_device); | |
1565 | ||
1566 | /* | |
1567 | * remove the queue from the plugged list, if present. called with | |
1568 | * queue lock held and interrupts disabled. | |
1569 | */ | |
165125e1 | 1570 | int blk_remove_plug(struct request_queue *q) |
1da177e4 LT |
1571 | { |
1572 | WARN_ON(!irqs_disabled()); | |
1573 | ||
1574 | if (!test_and_clear_bit(QUEUE_FLAG_PLUGGED, &q->queue_flags)) | |
1575 | return 0; | |
1576 | ||
1577 | del_timer(&q->unplug_timer); | |
1578 | return 1; | |
1579 | } | |
1580 | ||
1581 | EXPORT_SYMBOL(blk_remove_plug); | |
1582 | ||
1583 | /* | |
1584 | * remove the plug and let it rip.. | |
1585 | */ | |
165125e1 | 1586 | void __generic_unplug_device(struct request_queue *q) |
1da177e4 | 1587 | { |
7daac490 | 1588 | if (unlikely(blk_queue_stopped(q))) |
1da177e4 LT |
1589 | return; |
1590 | ||
1591 | if (!blk_remove_plug(q)) | |
1592 | return; | |
1593 | ||
22e2c507 | 1594 | q->request_fn(q); |
1da177e4 LT |
1595 | } |
1596 | EXPORT_SYMBOL(__generic_unplug_device); | |
1597 | ||
1598 | /** | |
1599 | * generic_unplug_device - fire a request queue | |
165125e1 | 1600 | * @q: The &struct request_queue in question |
1da177e4 LT |
1601 | * |
1602 | * Description: | |
1603 | * Linux uses plugging to build bigger requests queues before letting | |
1604 | * the device have at them. If a queue is plugged, the I/O scheduler | |
1605 | * is still adding and merging requests on the queue. Once the queue | |
1606 | * gets unplugged, the request_fn defined for the queue is invoked and | |
1607 | * transfers started. | |
1608 | **/ | |
165125e1 | 1609 | void generic_unplug_device(struct request_queue *q) |
1da177e4 LT |
1610 | { |
1611 | spin_lock_irq(q->queue_lock); | |
1612 | __generic_unplug_device(q); | |
1613 | spin_unlock_irq(q->queue_lock); | |
1614 | } | |
1615 | EXPORT_SYMBOL(generic_unplug_device); | |
1616 | ||
1617 | static void blk_backing_dev_unplug(struct backing_dev_info *bdi, | |
1618 | struct page *page) | |
1619 | { | |
165125e1 | 1620 | struct request_queue *q = bdi->unplug_io_data; |
1da177e4 LT |
1621 | |
1622 | /* | |
1623 | * devices don't necessarily have an ->unplug_fn defined | |
1624 | */ | |
2056a782 JA |
1625 | if (q->unplug_fn) { |
1626 | blk_add_trace_pdu_int(q, BLK_TA_UNPLUG_IO, NULL, | |
1627 | q->rq.count[READ] + q->rq.count[WRITE]); | |
1628 | ||
1da177e4 | 1629 | q->unplug_fn(q); |
2056a782 | 1630 | } |
1da177e4 LT |
1631 | } |
1632 | ||
65f27f38 | 1633 | static void blk_unplug_work(struct work_struct *work) |
1da177e4 | 1634 | { |
165125e1 JA |
1635 | struct request_queue *q = |
1636 | container_of(work, struct request_queue, unplug_work); | |
1da177e4 | 1637 | |
2056a782 JA |
1638 | blk_add_trace_pdu_int(q, BLK_TA_UNPLUG_IO, NULL, |
1639 | q->rq.count[READ] + q->rq.count[WRITE]); | |
1640 | ||
1da177e4 LT |
1641 | q->unplug_fn(q); |
1642 | } | |
1643 | ||
1644 | static void blk_unplug_timeout(unsigned long data) | |
1645 | { | |
165125e1 | 1646 | struct request_queue *q = (struct request_queue *)data; |
1da177e4 | 1647 | |
2056a782 JA |
1648 | blk_add_trace_pdu_int(q, BLK_TA_UNPLUG_TIMER, NULL, |
1649 | q->rq.count[READ] + q->rq.count[WRITE]); | |
1650 | ||
1da177e4 LT |
1651 | kblockd_schedule_work(&q->unplug_work); |
1652 | } | |
1653 | ||
1654 | /** | |
1655 | * blk_start_queue - restart a previously stopped queue | |
165125e1 | 1656 | * @q: The &struct request_queue in question |
1da177e4 LT |
1657 | * |
1658 | * Description: | |
1659 | * blk_start_queue() will clear the stop flag on the queue, and call | |
1660 | * the request_fn for the queue if it was in a stopped state when | |
1661 | * entered. Also see blk_stop_queue(). Queue lock must be held. | |
1662 | **/ | |
165125e1 | 1663 | void blk_start_queue(struct request_queue *q) |
1da177e4 | 1664 | { |
a038e253 PBG |
1665 | WARN_ON(!irqs_disabled()); |
1666 | ||
1da177e4 LT |
1667 | clear_bit(QUEUE_FLAG_STOPPED, &q->queue_flags); |
1668 | ||
1669 | /* | |
1670 | * one level of recursion is ok and is much faster than kicking | |
1671 | * the unplug handling | |
1672 | */ | |
1673 | if (!test_and_set_bit(QUEUE_FLAG_REENTER, &q->queue_flags)) { | |
1674 | q->request_fn(q); | |
1675 | clear_bit(QUEUE_FLAG_REENTER, &q->queue_flags); | |
1676 | } else { | |
1677 | blk_plug_device(q); | |
1678 | kblockd_schedule_work(&q->unplug_work); | |
1679 | } | |
1680 | } | |
1681 | ||
1682 | EXPORT_SYMBOL(blk_start_queue); | |
1683 | ||
1684 | /** | |
1685 | * blk_stop_queue - stop a queue | |
165125e1 | 1686 | * @q: The &struct request_queue in question |
1da177e4 LT |
1687 | * |
1688 | * Description: | |
1689 | * The Linux block layer assumes that a block driver will consume all | |
1690 | * entries on the request queue when the request_fn strategy is called. | |
1691 | * Often this will not happen, because of hardware limitations (queue | |
1692 | * depth settings). If a device driver gets a 'queue full' response, | |
1693 | * or if it simply chooses not to queue more I/O at one point, it can | |
1694 | * call this function to prevent the request_fn from being called until | |
1695 | * the driver has signalled it's ready to go again. This happens by calling | |
1696 | * blk_start_queue() to restart queue operations. Queue lock must be held. | |
1697 | **/ | |
165125e1 | 1698 | void blk_stop_queue(struct request_queue *q) |
1da177e4 LT |
1699 | { |
1700 | blk_remove_plug(q); | |
1701 | set_bit(QUEUE_FLAG_STOPPED, &q->queue_flags); | |
1702 | } | |
1703 | EXPORT_SYMBOL(blk_stop_queue); | |
1704 | ||
1705 | /** | |
1706 | * blk_sync_queue - cancel any pending callbacks on a queue | |
1707 | * @q: the queue | |
1708 | * | |
1709 | * Description: | |
1710 | * The block layer may perform asynchronous callback activity | |
1711 | * on a queue, such as calling the unplug function after a timeout. | |
1712 | * A block device may call blk_sync_queue to ensure that any | |
1713 | * such activity is cancelled, thus allowing it to release resources | |
59c51591 | 1714 | * that the callbacks might use. The caller must already have made sure |
1da177e4 LT |
1715 | * that its ->make_request_fn will not re-add plugging prior to calling |
1716 | * this function. | |
1717 | * | |
1718 | */ | |
1719 | void blk_sync_queue(struct request_queue *q) | |
1720 | { | |
1721 | del_timer_sync(&q->unplug_timer); | |
1da177e4 LT |
1722 | } |
1723 | EXPORT_SYMBOL(blk_sync_queue); | |
1724 | ||
1725 | /** | |
1726 | * blk_run_queue - run a single device queue | |
1727 | * @q: The queue to run | |
1728 | */ | |
1729 | void blk_run_queue(struct request_queue *q) | |
1730 | { | |
1731 | unsigned long flags; | |
1732 | ||
1733 | spin_lock_irqsave(q->queue_lock, flags); | |
1734 | blk_remove_plug(q); | |
dac07ec1 JA |
1735 | |
1736 | /* | |
1737 | * Only recurse once to avoid overrunning the stack, let the unplug | |
1738 | * handling reinvoke the handler shortly if we already got there. | |
1739 | */ | |
1740 | if (!elv_queue_empty(q)) { | |
1741 | if (!test_and_set_bit(QUEUE_FLAG_REENTER, &q->queue_flags)) { | |
1742 | q->request_fn(q); | |
1743 | clear_bit(QUEUE_FLAG_REENTER, &q->queue_flags); | |
1744 | } else { | |
1745 | blk_plug_device(q); | |
1746 | kblockd_schedule_work(&q->unplug_work); | |
1747 | } | |
1748 | } | |
1749 | ||
1da177e4 LT |
1750 | spin_unlock_irqrestore(q->queue_lock, flags); |
1751 | } | |
1752 | EXPORT_SYMBOL(blk_run_queue); | |
1753 | ||
1754 | /** | |
165125e1 | 1755 | * blk_cleanup_queue: - release a &struct request_queue when it is no longer needed |
a580290c | 1756 | * @kobj: the kobj belonging of the request queue to be released |
1da177e4 LT |
1757 | * |
1758 | * Description: | |
1759 | * blk_cleanup_queue is the pair to blk_init_queue() or | |
1760 | * blk_queue_make_request(). It should be called when a request queue is | |
1761 | * being released; typically when a block device is being de-registered. | |
1762 | * Currently, its primary task it to free all the &struct request | |
1763 | * structures that were allocated to the queue and the queue itself. | |
1764 | * | |
1765 | * Caveat: | |
1766 | * Hopefully the low level driver will have finished any | |
1767 | * outstanding requests first... | |
1768 | **/ | |
483f4afc | 1769 | static void blk_release_queue(struct kobject *kobj) |
1da177e4 | 1770 | { |
165125e1 JA |
1771 | struct request_queue *q = |
1772 | container_of(kobj, struct request_queue, kobj); | |
1da177e4 LT |
1773 | struct request_list *rl = &q->rq; |
1774 | ||
1da177e4 LT |
1775 | blk_sync_queue(q); |
1776 | ||
1777 | if (rl->rq_pool) | |
1778 | mempool_destroy(rl->rq_pool); | |
1779 | ||
1780 | if (q->queue_tags) | |
1781 | __blk_queue_free_tags(q); | |
1782 | ||
6c5c9341 | 1783 | blk_trace_shutdown(q); |
2056a782 | 1784 | |
1da177e4 LT |
1785 | kmem_cache_free(requestq_cachep, q); |
1786 | } | |
1787 | ||
165125e1 | 1788 | void blk_put_queue(struct request_queue *q) |
483f4afc AV |
1789 | { |
1790 | kobject_put(&q->kobj); | |
1791 | } | |
1792 | EXPORT_SYMBOL(blk_put_queue); | |
1793 | ||
165125e1 | 1794 | void blk_cleanup_queue(struct request_queue * q) |
483f4afc AV |
1795 | { |
1796 | mutex_lock(&q->sysfs_lock); | |
1797 | set_bit(QUEUE_FLAG_DEAD, &q->queue_flags); | |
1798 | mutex_unlock(&q->sysfs_lock); | |
1799 | ||
1800 | if (q->elevator) | |
1801 | elevator_exit(q->elevator); | |
1802 | ||
1803 | blk_put_queue(q); | |
1804 | } | |
1805 | ||
1da177e4 LT |
1806 | EXPORT_SYMBOL(blk_cleanup_queue); |
1807 | ||
165125e1 | 1808 | static int blk_init_free_list(struct request_queue *q) |
1da177e4 LT |
1809 | { |
1810 | struct request_list *rl = &q->rq; | |
1811 | ||
1812 | rl->count[READ] = rl->count[WRITE] = 0; | |
1813 | rl->starved[READ] = rl->starved[WRITE] = 0; | |
cb98fc8b | 1814 | rl->elvpriv = 0; |
1da177e4 LT |
1815 | init_waitqueue_head(&rl->wait[READ]); |
1816 | init_waitqueue_head(&rl->wait[WRITE]); | |
1da177e4 | 1817 | |
1946089a CL |
1818 | rl->rq_pool = mempool_create_node(BLKDEV_MIN_RQ, mempool_alloc_slab, |
1819 | mempool_free_slab, request_cachep, q->node); | |
1da177e4 LT |
1820 | |
1821 | if (!rl->rq_pool) | |
1822 | return -ENOMEM; | |
1823 | ||
1824 | return 0; | |
1825 | } | |
1826 | ||
165125e1 | 1827 | struct request_queue *blk_alloc_queue(gfp_t gfp_mask) |
1da177e4 | 1828 | { |
1946089a CL |
1829 | return blk_alloc_queue_node(gfp_mask, -1); |
1830 | } | |
1831 | EXPORT_SYMBOL(blk_alloc_queue); | |
1da177e4 | 1832 | |
483f4afc AV |
1833 | static struct kobj_type queue_ktype; |
1834 | ||
165125e1 | 1835 | struct request_queue *blk_alloc_queue_node(gfp_t gfp_mask, int node_id) |
1946089a | 1836 | { |
165125e1 | 1837 | struct request_queue *q; |
1946089a | 1838 | |
94f6030c CL |
1839 | q = kmem_cache_alloc_node(requestq_cachep, |
1840 | gfp_mask | __GFP_ZERO, node_id); | |
1da177e4 LT |
1841 | if (!q) |
1842 | return NULL; | |
1843 | ||
1da177e4 | 1844 | init_timer(&q->unplug_timer); |
483f4afc | 1845 | |
19c38de8 | 1846 | kobject_set_name(&q->kobj, "%s", "queue"); |
483f4afc AV |
1847 | q->kobj.ktype = &queue_ktype; |
1848 | kobject_init(&q->kobj); | |
1da177e4 LT |
1849 | |
1850 | q->backing_dev_info.unplug_io_fn = blk_backing_dev_unplug; | |
1851 | q->backing_dev_info.unplug_io_data = q; | |
1852 | ||
483f4afc AV |
1853 | mutex_init(&q->sysfs_lock); |
1854 | ||
1da177e4 LT |
1855 | return q; |
1856 | } | |
1946089a | 1857 | EXPORT_SYMBOL(blk_alloc_queue_node); |
1da177e4 LT |
1858 | |
1859 | /** | |
1860 | * blk_init_queue - prepare a request queue for use with a block device | |
1861 | * @rfn: The function to be called to process requests that have been | |
1862 | * placed on the queue. | |
1863 | * @lock: Request queue spin lock | |
1864 | * | |
1865 | * Description: | |
1866 | * If a block device wishes to use the standard request handling procedures, | |
1867 | * which sorts requests and coalesces adjacent requests, then it must | |
1868 | * call blk_init_queue(). The function @rfn will be called when there | |
1869 | * are requests on the queue that need to be processed. If the device | |
1870 | * supports plugging, then @rfn may not be called immediately when requests | |
1871 | * are available on the queue, but may be called at some time later instead. | |
1872 | * Plugged queues are generally unplugged when a buffer belonging to one | |
1873 | * of the requests on the queue is needed, or due to memory pressure. | |
1874 | * | |
1875 | * @rfn is not required, or even expected, to remove all requests off the | |
1876 | * queue, but only as many as it can handle at a time. If it does leave | |
1877 | * requests on the queue, it is responsible for arranging that the requests | |
1878 | * get dealt with eventually. | |
1879 | * | |
1880 | * The queue spin lock must be held while manipulating the requests on the | |
a038e253 PBG |
1881 | * request queue; this lock will be taken also from interrupt context, so irq |
1882 | * disabling is needed for it. | |
1da177e4 LT |
1883 | * |
1884 | * Function returns a pointer to the initialized request queue, or NULL if | |
1885 | * it didn't succeed. | |
1886 | * | |
1887 | * Note: | |
1888 | * blk_init_queue() must be paired with a blk_cleanup_queue() call | |
1889 | * when the block device is deactivated (such as at module unload). | |
1890 | **/ | |
1946089a | 1891 | |
165125e1 | 1892 | struct request_queue *blk_init_queue(request_fn_proc *rfn, spinlock_t *lock) |
1da177e4 | 1893 | { |
1946089a CL |
1894 | return blk_init_queue_node(rfn, lock, -1); |
1895 | } | |
1896 | EXPORT_SYMBOL(blk_init_queue); | |
1897 | ||
165125e1 | 1898 | struct request_queue * |
1946089a CL |
1899 | blk_init_queue_node(request_fn_proc *rfn, spinlock_t *lock, int node_id) |
1900 | { | |
165125e1 | 1901 | struct request_queue *q = blk_alloc_queue_node(GFP_KERNEL, node_id); |
1da177e4 LT |
1902 | |
1903 | if (!q) | |
1904 | return NULL; | |
1905 | ||
1946089a | 1906 | q->node = node_id; |
8669aafd AV |
1907 | if (blk_init_free_list(q)) { |
1908 | kmem_cache_free(requestq_cachep, q); | |
1909 | return NULL; | |
1910 | } | |
1da177e4 | 1911 | |
152587de JA |
1912 | /* |
1913 | * if caller didn't supply a lock, they get per-queue locking with | |
1914 | * our embedded lock | |
1915 | */ | |
1916 | if (!lock) { | |
1917 | spin_lock_init(&q->__queue_lock); | |
1918 | lock = &q->__queue_lock; | |
1919 | } | |
1920 | ||
1da177e4 | 1921 | q->request_fn = rfn; |
1da177e4 LT |
1922 | q->prep_rq_fn = NULL; |
1923 | q->unplug_fn = generic_unplug_device; | |
1924 | q->queue_flags = (1 << QUEUE_FLAG_CLUSTER); | |
1925 | q->queue_lock = lock; | |
1926 | ||
1927 | blk_queue_segment_boundary(q, 0xffffffff); | |
1928 | ||
1929 | blk_queue_make_request(q, __make_request); | |
1930 | blk_queue_max_segment_size(q, MAX_SEGMENT_SIZE); | |
1931 | ||
1932 | blk_queue_max_hw_segments(q, MAX_HW_SEGMENTS); | |
1933 | blk_queue_max_phys_segments(q, MAX_PHYS_SEGMENTS); | |
1934 | ||
44ec9542 AS |
1935 | q->sg_reserved_size = INT_MAX; |
1936 | ||
1da177e4 LT |
1937 | /* |
1938 | * all done | |
1939 | */ | |
1940 | if (!elevator_init(q, NULL)) { | |
1941 | blk_queue_congestion_threshold(q); | |
1942 | return q; | |
1943 | } | |
1944 | ||
8669aafd | 1945 | blk_put_queue(q); |
1da177e4 LT |
1946 | return NULL; |
1947 | } | |
1946089a | 1948 | EXPORT_SYMBOL(blk_init_queue_node); |
1da177e4 | 1949 | |
165125e1 | 1950 | int blk_get_queue(struct request_queue *q) |
1da177e4 | 1951 | { |
fde6ad22 | 1952 | if (likely(!test_bit(QUEUE_FLAG_DEAD, &q->queue_flags))) { |
483f4afc | 1953 | kobject_get(&q->kobj); |
1da177e4 LT |
1954 | return 0; |
1955 | } | |
1956 | ||
1957 | return 1; | |
1958 | } | |
1959 | ||
1960 | EXPORT_SYMBOL(blk_get_queue); | |
1961 | ||
165125e1 | 1962 | static inline void blk_free_request(struct request_queue *q, struct request *rq) |
1da177e4 | 1963 | { |
4aff5e23 | 1964 | if (rq->cmd_flags & REQ_ELVPRIV) |
cb98fc8b | 1965 | elv_put_request(q, rq); |
1da177e4 LT |
1966 | mempool_free(rq, q->rq.rq_pool); |
1967 | } | |
1968 | ||
1ea25ecb | 1969 | static struct request * |
165125e1 | 1970 | blk_alloc_request(struct request_queue *q, int rw, int priv, gfp_t gfp_mask) |
1da177e4 LT |
1971 | { |
1972 | struct request *rq = mempool_alloc(q->rq.rq_pool, gfp_mask); | |
1973 | ||
1974 | if (!rq) | |
1975 | return NULL; | |
1976 | ||
1977 | /* | |
4aff5e23 | 1978 | * first three bits are identical in rq->cmd_flags and bio->bi_rw, |
1da177e4 LT |
1979 | * see bio.h and blkdev.h |
1980 | */ | |
49171e5c | 1981 | rq->cmd_flags = rw | REQ_ALLOCED; |
1da177e4 | 1982 | |
cb98fc8b | 1983 | if (priv) { |
cb78b285 | 1984 | if (unlikely(elv_set_request(q, rq, gfp_mask))) { |
cb98fc8b TH |
1985 | mempool_free(rq, q->rq.rq_pool); |
1986 | return NULL; | |
1987 | } | |
4aff5e23 | 1988 | rq->cmd_flags |= REQ_ELVPRIV; |
cb98fc8b | 1989 | } |
1da177e4 | 1990 | |
cb98fc8b | 1991 | return rq; |
1da177e4 LT |
1992 | } |
1993 | ||
1994 | /* | |
1995 | * ioc_batching returns true if the ioc is a valid batching request and | |
1996 | * should be given priority access to a request. | |
1997 | */ | |
165125e1 | 1998 | static inline int ioc_batching(struct request_queue *q, struct io_context *ioc) |
1da177e4 LT |
1999 | { |
2000 | if (!ioc) | |
2001 | return 0; | |
2002 | ||
2003 | /* | |
2004 | * Make sure the process is able to allocate at least 1 request | |
2005 | * even if the batch times out, otherwise we could theoretically | |
2006 | * lose wakeups. | |
2007 | */ | |
2008 | return ioc->nr_batch_requests == q->nr_batching || | |
2009 | (ioc->nr_batch_requests > 0 | |
2010 | && time_before(jiffies, ioc->last_waited + BLK_BATCH_TIME)); | |
2011 | } | |
2012 | ||
2013 | /* | |
2014 | * ioc_set_batching sets ioc to be a new "batcher" if it is not one. This | |
2015 | * will cause the process to be a "batcher" on all queues in the system. This | |
2016 | * is the behaviour we want though - once it gets a wakeup it should be given | |
2017 | * a nice run. | |
2018 | */ | |
165125e1 | 2019 | static void ioc_set_batching(struct request_queue *q, struct io_context *ioc) |
1da177e4 LT |
2020 | { |
2021 | if (!ioc || ioc_batching(q, ioc)) | |
2022 | return; | |
2023 | ||
2024 | ioc->nr_batch_requests = q->nr_batching; | |
2025 | ioc->last_waited = jiffies; | |
2026 | } | |
2027 | ||
165125e1 | 2028 | static void __freed_request(struct request_queue *q, int rw) |
1da177e4 LT |
2029 | { |
2030 | struct request_list *rl = &q->rq; | |
2031 | ||
2032 | if (rl->count[rw] < queue_congestion_off_threshold(q)) | |
79e2de4b | 2033 | blk_clear_queue_congested(q, rw); |
1da177e4 LT |
2034 | |
2035 | if (rl->count[rw] + 1 <= q->nr_requests) { | |
1da177e4 LT |
2036 | if (waitqueue_active(&rl->wait[rw])) |
2037 | wake_up(&rl->wait[rw]); | |
2038 | ||
2039 | blk_clear_queue_full(q, rw); | |
2040 | } | |
2041 | } | |
2042 | ||
2043 | /* | |
2044 | * A request has just been released. Account for it, update the full and | |
2045 | * congestion status, wake up any waiters. Called under q->queue_lock. | |
2046 | */ | |
165125e1 | 2047 | static void freed_request(struct request_queue *q, int rw, int priv) |
1da177e4 LT |
2048 | { |
2049 | struct request_list *rl = &q->rq; | |
2050 | ||
2051 | rl->count[rw]--; | |
cb98fc8b TH |
2052 | if (priv) |
2053 | rl->elvpriv--; | |
1da177e4 LT |
2054 | |
2055 | __freed_request(q, rw); | |
2056 | ||
2057 | if (unlikely(rl->starved[rw ^ 1])) | |
2058 | __freed_request(q, rw ^ 1); | |
1da177e4 LT |
2059 | } |
2060 | ||
2061 | #define blkdev_free_rq(list) list_entry((list)->next, struct request, queuelist) | |
2062 | /* | |
d6344532 NP |
2063 | * Get a free request, queue_lock must be held. |
2064 | * Returns NULL on failure, with queue_lock held. | |
2065 | * Returns !NULL on success, with queue_lock *not held*. | |
1da177e4 | 2066 | */ |
165125e1 | 2067 | static struct request *get_request(struct request_queue *q, int rw_flags, |
7749a8d4 | 2068 | struct bio *bio, gfp_t gfp_mask) |
1da177e4 LT |
2069 | { |
2070 | struct request *rq = NULL; | |
2071 | struct request_list *rl = &q->rq; | |
88ee5ef1 | 2072 | struct io_context *ioc = NULL; |
7749a8d4 | 2073 | const int rw = rw_flags & 0x01; |
88ee5ef1 JA |
2074 | int may_queue, priv; |
2075 | ||
7749a8d4 | 2076 | may_queue = elv_may_queue(q, rw_flags); |
88ee5ef1 JA |
2077 | if (may_queue == ELV_MQUEUE_NO) |
2078 | goto rq_starved; | |
2079 | ||
2080 | if (rl->count[rw]+1 >= queue_congestion_on_threshold(q)) { | |
2081 | if (rl->count[rw]+1 >= q->nr_requests) { | |
b5deef90 | 2082 | ioc = current_io_context(GFP_ATOMIC, q->node); |
88ee5ef1 JA |
2083 | /* |
2084 | * The queue will fill after this allocation, so set | |
2085 | * it as full, and mark this process as "batching". | |
2086 | * This process will be allowed to complete a batch of | |
2087 | * requests, others will be blocked. | |
2088 | */ | |
2089 | if (!blk_queue_full(q, rw)) { | |
2090 | ioc_set_batching(q, ioc); | |
2091 | blk_set_queue_full(q, rw); | |
2092 | } else { | |
2093 | if (may_queue != ELV_MQUEUE_MUST | |
2094 | && !ioc_batching(q, ioc)) { | |
2095 | /* | |
2096 | * The queue is full and the allocating | |
2097 | * process is not a "batcher", and not | |
2098 | * exempted by the IO scheduler | |
2099 | */ | |
2100 | goto out; | |
2101 | } | |
2102 | } | |
1da177e4 | 2103 | } |
79e2de4b | 2104 | blk_set_queue_congested(q, rw); |
1da177e4 LT |
2105 | } |
2106 | ||
082cf69e JA |
2107 | /* |
2108 | * Only allow batching queuers to allocate up to 50% over the defined | |
2109 | * limit of requests, otherwise we could have thousands of requests | |
2110 | * allocated with any setting of ->nr_requests | |
2111 | */ | |
fd782a4a | 2112 | if (rl->count[rw] >= (3 * q->nr_requests / 2)) |
082cf69e | 2113 | goto out; |
fd782a4a | 2114 | |
1da177e4 LT |
2115 | rl->count[rw]++; |
2116 | rl->starved[rw] = 0; | |
cb98fc8b | 2117 | |
64521d1a | 2118 | priv = !test_bit(QUEUE_FLAG_ELVSWITCH, &q->queue_flags); |
cb98fc8b TH |
2119 | if (priv) |
2120 | rl->elvpriv++; | |
2121 | ||
1da177e4 LT |
2122 | spin_unlock_irq(q->queue_lock); |
2123 | ||
7749a8d4 | 2124 | rq = blk_alloc_request(q, rw_flags, priv, gfp_mask); |
88ee5ef1 | 2125 | if (unlikely(!rq)) { |
1da177e4 LT |
2126 | /* |
2127 | * Allocation failed presumably due to memory. Undo anything | |
2128 | * we might have messed up. | |
2129 | * | |
2130 | * Allocating task should really be put onto the front of the | |
2131 | * wait queue, but this is pretty rare. | |
2132 | */ | |
2133 | spin_lock_irq(q->queue_lock); | |
cb98fc8b | 2134 | freed_request(q, rw, priv); |
1da177e4 LT |
2135 | |
2136 | /* | |
2137 | * in the very unlikely event that allocation failed and no | |
2138 | * requests for this direction was pending, mark us starved | |
2139 | * so that freeing of a request in the other direction will | |
2140 | * notice us. another possible fix would be to split the | |
2141 | * rq mempool into READ and WRITE | |
2142 | */ | |
2143 | rq_starved: | |
2144 | if (unlikely(rl->count[rw] == 0)) | |
2145 | rl->starved[rw] = 1; | |
2146 | ||
1da177e4 LT |
2147 | goto out; |
2148 | } | |
2149 | ||
88ee5ef1 JA |
2150 | /* |
2151 | * ioc may be NULL here, and ioc_batching will be false. That's | |
2152 | * OK, if the queue is under the request limit then requests need | |
2153 | * not count toward the nr_batch_requests limit. There will always | |
2154 | * be some limit enforced by BLK_BATCH_TIME. | |
2155 | */ | |
1da177e4 LT |
2156 | if (ioc_batching(q, ioc)) |
2157 | ioc->nr_batch_requests--; | |
2158 | ||
2159 | rq_init(q, rq); | |
2056a782 JA |
2160 | |
2161 | blk_add_trace_generic(q, bio, rw, BLK_TA_GETRQ); | |
1da177e4 | 2162 | out: |
1da177e4 LT |
2163 | return rq; |
2164 | } | |
2165 | ||
2166 | /* | |
2167 | * No available requests for this queue, unplug the device and wait for some | |
2168 | * requests to become available. | |
d6344532 NP |
2169 | * |
2170 | * Called with q->queue_lock held, and returns with it unlocked. | |
1da177e4 | 2171 | */ |
165125e1 | 2172 | static struct request *get_request_wait(struct request_queue *q, int rw_flags, |
22e2c507 | 2173 | struct bio *bio) |
1da177e4 | 2174 | { |
7749a8d4 | 2175 | const int rw = rw_flags & 0x01; |
1da177e4 LT |
2176 | struct request *rq; |
2177 | ||
7749a8d4 | 2178 | rq = get_request(q, rw_flags, bio, GFP_NOIO); |
450991bc NP |
2179 | while (!rq) { |
2180 | DEFINE_WAIT(wait); | |
1da177e4 LT |
2181 | struct request_list *rl = &q->rq; |
2182 | ||
2183 | prepare_to_wait_exclusive(&rl->wait[rw], &wait, | |
2184 | TASK_UNINTERRUPTIBLE); | |
2185 | ||
7749a8d4 | 2186 | rq = get_request(q, rw_flags, bio, GFP_NOIO); |
1da177e4 LT |
2187 | |
2188 | if (!rq) { | |
2189 | struct io_context *ioc; | |
2190 | ||
2056a782 JA |
2191 | blk_add_trace_generic(q, bio, rw, BLK_TA_SLEEPRQ); |
2192 | ||
d6344532 NP |
2193 | __generic_unplug_device(q); |
2194 | spin_unlock_irq(q->queue_lock); | |
1da177e4 LT |
2195 | io_schedule(); |
2196 | ||
2197 | /* | |
2198 | * After sleeping, we become a "batching" process and | |
2199 | * will be able to allocate at least one request, and | |
2200 | * up to a big batch of them for a small period time. | |
2201 | * See ioc_batching, ioc_set_batching | |
2202 | */ | |
b5deef90 | 2203 | ioc = current_io_context(GFP_NOIO, q->node); |
1da177e4 | 2204 | ioc_set_batching(q, ioc); |
d6344532 NP |
2205 | |
2206 | spin_lock_irq(q->queue_lock); | |
1da177e4 LT |
2207 | } |
2208 | finish_wait(&rl->wait[rw], &wait); | |
450991bc | 2209 | } |
1da177e4 LT |
2210 | |
2211 | return rq; | |
2212 | } | |
2213 | ||
165125e1 | 2214 | struct request *blk_get_request(struct request_queue *q, int rw, gfp_t gfp_mask) |
1da177e4 LT |
2215 | { |
2216 | struct request *rq; | |
2217 | ||
2218 | BUG_ON(rw != READ && rw != WRITE); | |
2219 | ||
d6344532 NP |
2220 | spin_lock_irq(q->queue_lock); |
2221 | if (gfp_mask & __GFP_WAIT) { | |
22e2c507 | 2222 | rq = get_request_wait(q, rw, NULL); |
d6344532 | 2223 | } else { |
22e2c507 | 2224 | rq = get_request(q, rw, NULL, gfp_mask); |
d6344532 NP |
2225 | if (!rq) |
2226 | spin_unlock_irq(q->queue_lock); | |
2227 | } | |
2228 | /* q->queue_lock is unlocked at this point */ | |
1da177e4 LT |
2229 | |
2230 | return rq; | |
2231 | } | |
1da177e4 LT |
2232 | EXPORT_SYMBOL(blk_get_request); |
2233 | ||
dc72ef4a JA |
2234 | /** |
2235 | * blk_start_queueing - initiate dispatch of requests to device | |
2236 | * @q: request queue to kick into gear | |
2237 | * | |
2238 | * This is basically a helper to remove the need to know whether a queue | |
2239 | * is plugged or not if someone just wants to initiate dispatch of requests | |
2240 | * for this queue. | |
2241 | * | |
2242 | * The queue lock must be held with interrupts disabled. | |
2243 | */ | |
165125e1 | 2244 | void blk_start_queueing(struct request_queue *q) |
dc72ef4a JA |
2245 | { |
2246 | if (!blk_queue_plugged(q)) | |
2247 | q->request_fn(q); | |
2248 | else | |
2249 | __generic_unplug_device(q); | |
2250 | } | |
2251 | EXPORT_SYMBOL(blk_start_queueing); | |
2252 | ||
1da177e4 LT |
2253 | /** |
2254 | * blk_requeue_request - put a request back on queue | |
2255 | * @q: request queue where request should be inserted | |
2256 | * @rq: request to be inserted | |
2257 | * | |
2258 | * Description: | |
2259 | * Drivers often keep queueing requests until the hardware cannot accept | |
2260 | * more, when that condition happens we need to put the request back | |
2261 | * on the queue. Must be called with queue lock held. | |
2262 | */ | |
165125e1 | 2263 | void blk_requeue_request(struct request_queue *q, struct request *rq) |
1da177e4 | 2264 | { |
2056a782 JA |
2265 | blk_add_trace_rq(q, rq, BLK_TA_REQUEUE); |
2266 | ||
1da177e4 LT |
2267 | if (blk_rq_tagged(rq)) |
2268 | blk_queue_end_tag(q, rq); | |
2269 | ||
2270 | elv_requeue_request(q, rq); | |
2271 | } | |
2272 | ||
2273 | EXPORT_SYMBOL(blk_requeue_request); | |
2274 | ||
2275 | /** | |
2276 | * blk_insert_request - insert a special request in to a request queue | |
2277 | * @q: request queue where request should be inserted | |
2278 | * @rq: request to be inserted | |
2279 | * @at_head: insert request at head or tail of queue | |
2280 | * @data: private data | |
1da177e4 LT |
2281 | * |
2282 | * Description: | |
2283 | * Many block devices need to execute commands asynchronously, so they don't | |
2284 | * block the whole kernel from preemption during request execution. This is | |
2285 | * accomplished normally by inserting aritficial requests tagged as | |
2286 | * REQ_SPECIAL in to the corresponding request queue, and letting them be | |
2287 | * scheduled for actual execution by the request queue. | |
2288 | * | |
2289 | * We have the option of inserting the head or the tail of the queue. | |
2290 | * Typically we use the tail for new ioctls and so forth. We use the head | |
2291 | * of the queue for things like a QUEUE_FULL message from a device, or a | |
2292 | * host that is unable to accept a particular command. | |
2293 | */ | |
165125e1 | 2294 | void blk_insert_request(struct request_queue *q, struct request *rq, |
867d1191 | 2295 | int at_head, void *data) |
1da177e4 | 2296 | { |
867d1191 | 2297 | int where = at_head ? ELEVATOR_INSERT_FRONT : ELEVATOR_INSERT_BACK; |
1da177e4 LT |
2298 | unsigned long flags; |
2299 | ||
2300 | /* | |
2301 | * tell I/O scheduler that this isn't a regular read/write (ie it | |
2302 | * must not attempt merges on this) and that it acts as a soft | |
2303 | * barrier | |
2304 | */ | |
4aff5e23 JA |
2305 | rq->cmd_type = REQ_TYPE_SPECIAL; |
2306 | rq->cmd_flags |= REQ_SOFTBARRIER; | |
1da177e4 LT |
2307 | |
2308 | rq->special = data; | |
2309 | ||
2310 | spin_lock_irqsave(q->queue_lock, flags); | |
2311 | ||
2312 | /* | |
2313 | * If command is tagged, release the tag | |
2314 | */ | |
867d1191 TH |
2315 | if (blk_rq_tagged(rq)) |
2316 | blk_queue_end_tag(q, rq); | |
1da177e4 | 2317 | |
867d1191 TH |
2318 | drive_stat_acct(rq, rq->nr_sectors, 1); |
2319 | __elv_add_request(q, rq, where, 0); | |
dc72ef4a | 2320 | blk_start_queueing(q); |
1da177e4 LT |
2321 | spin_unlock_irqrestore(q->queue_lock, flags); |
2322 | } | |
2323 | ||
2324 | EXPORT_SYMBOL(blk_insert_request); | |
2325 | ||
0e75f906 MC |
2326 | static int __blk_rq_unmap_user(struct bio *bio) |
2327 | { | |
2328 | int ret = 0; | |
2329 | ||
2330 | if (bio) { | |
2331 | if (bio_flagged(bio, BIO_USER_MAPPED)) | |
2332 | bio_unmap_user(bio); | |
2333 | else | |
2334 | ret = bio_uncopy_user(bio); | |
2335 | } | |
2336 | ||
2337 | return ret; | |
2338 | } | |
2339 | ||
3001ca77 N |
2340 | int blk_rq_append_bio(struct request_queue *q, struct request *rq, |
2341 | struct bio *bio) | |
2342 | { | |
2343 | if (!rq->bio) | |
2344 | blk_rq_bio_prep(q, rq, bio); | |
2345 | else if (!ll_back_merge_fn(q, rq, bio)) | |
2346 | return -EINVAL; | |
2347 | else { | |
2348 | rq->biotail->bi_next = bio; | |
2349 | rq->biotail = bio; | |
2350 | ||
2351 | rq->data_len += bio->bi_size; | |
2352 | } | |
2353 | return 0; | |
2354 | } | |
2355 | EXPORT_SYMBOL(blk_rq_append_bio); | |
2356 | ||
165125e1 | 2357 | static int __blk_rq_map_user(struct request_queue *q, struct request *rq, |
0e75f906 MC |
2358 | void __user *ubuf, unsigned int len) |
2359 | { | |
2360 | unsigned long uaddr; | |
2361 | struct bio *bio, *orig_bio; | |
2362 | int reading, ret; | |
2363 | ||
2364 | reading = rq_data_dir(rq) == READ; | |
2365 | ||
2366 | /* | |
2367 | * if alignment requirement is satisfied, map in user pages for | |
2368 | * direct dma. else, set up kernel bounce buffers | |
2369 | */ | |
2370 | uaddr = (unsigned long) ubuf; | |
2371 | if (!(uaddr & queue_dma_alignment(q)) && !(len & queue_dma_alignment(q))) | |
2372 | bio = bio_map_user(q, NULL, uaddr, len, reading); | |
2373 | else | |
2374 | bio = bio_copy_user(q, uaddr, len, reading); | |
2375 | ||
2985259b | 2376 | if (IS_ERR(bio)) |
0e75f906 | 2377 | return PTR_ERR(bio); |
0e75f906 MC |
2378 | |
2379 | orig_bio = bio; | |
2380 | blk_queue_bounce(q, &bio); | |
2985259b | 2381 | |
0e75f906 MC |
2382 | /* |
2383 | * We link the bounce buffer in and could have to traverse it | |
2384 | * later so we have to get a ref to prevent it from being freed | |
2385 | */ | |
2386 | bio_get(bio); | |
2387 | ||
3001ca77 N |
2388 | ret = blk_rq_append_bio(q, rq, bio); |
2389 | if (!ret) | |
2390 | return bio->bi_size; | |
0e75f906 | 2391 | |
0e75f906 | 2392 | /* if it was boucned we must call the end io function */ |
6712ecf8 | 2393 | bio_endio(bio, 0); |
0e75f906 MC |
2394 | __blk_rq_unmap_user(orig_bio); |
2395 | bio_put(bio); | |
2396 | return ret; | |
2397 | } | |
2398 | ||
1da177e4 LT |
2399 | /** |
2400 | * blk_rq_map_user - map user data to a request, for REQ_BLOCK_PC usage | |
2401 | * @q: request queue where request should be inserted | |
73747aed | 2402 | * @rq: request structure to fill |
1da177e4 LT |
2403 | * @ubuf: the user buffer |
2404 | * @len: length of user data | |
2405 | * | |
2406 | * Description: | |
2407 | * Data will be mapped directly for zero copy io, if possible. Otherwise | |
2408 | * a kernel bounce buffer is used. | |
2409 | * | |
2410 | * A matching blk_rq_unmap_user() must be issued at the end of io, while | |
2411 | * still in process context. | |
2412 | * | |
2413 | * Note: The mapped bio may need to be bounced through blk_queue_bounce() | |
2414 | * before being submitted to the device, as pages mapped may be out of | |
2415 | * reach. It's the callers responsibility to make sure this happens. The | |
2416 | * original bio must be passed back in to blk_rq_unmap_user() for proper | |
2417 | * unmapping. | |
2418 | */ | |
165125e1 JA |
2419 | int blk_rq_map_user(struct request_queue *q, struct request *rq, |
2420 | void __user *ubuf, unsigned long len) | |
1da177e4 | 2421 | { |
0e75f906 | 2422 | unsigned long bytes_read = 0; |
8e5cfc45 | 2423 | struct bio *bio = NULL; |
0e75f906 | 2424 | int ret; |
1da177e4 | 2425 | |
defd94b7 | 2426 | if (len > (q->max_hw_sectors << 9)) |
dd1cab95 JA |
2427 | return -EINVAL; |
2428 | if (!len || !ubuf) | |
2429 | return -EINVAL; | |
1da177e4 | 2430 | |
0e75f906 MC |
2431 | while (bytes_read != len) { |
2432 | unsigned long map_len, end, start; | |
1da177e4 | 2433 | |
0e75f906 MC |
2434 | map_len = min_t(unsigned long, len - bytes_read, BIO_MAX_SIZE); |
2435 | end = ((unsigned long)ubuf + map_len + PAGE_SIZE - 1) | |
2436 | >> PAGE_SHIFT; | |
2437 | start = (unsigned long)ubuf >> PAGE_SHIFT; | |
1da177e4 | 2438 | |
0e75f906 MC |
2439 | /* |
2440 | * A bad offset could cause us to require BIO_MAX_PAGES + 1 | |
2441 | * pages. If this happens we just lower the requested | |
2442 | * mapping len by a page so that we can fit | |
2443 | */ | |
2444 | if (end - start > BIO_MAX_PAGES) | |
2445 | map_len -= PAGE_SIZE; | |
1da177e4 | 2446 | |
0e75f906 MC |
2447 | ret = __blk_rq_map_user(q, rq, ubuf, map_len); |
2448 | if (ret < 0) | |
2449 | goto unmap_rq; | |
8e5cfc45 JA |
2450 | if (!bio) |
2451 | bio = rq->bio; | |
0e75f906 MC |
2452 | bytes_read += ret; |
2453 | ubuf += ret; | |
1da177e4 LT |
2454 | } |
2455 | ||
0e75f906 MC |
2456 | rq->buffer = rq->data = NULL; |
2457 | return 0; | |
2458 | unmap_rq: | |
8e5cfc45 | 2459 | blk_rq_unmap_user(bio); |
0e75f906 | 2460 | return ret; |
1da177e4 LT |
2461 | } |
2462 | ||
2463 | EXPORT_SYMBOL(blk_rq_map_user); | |
2464 | ||
f1970baf JB |
2465 | /** |
2466 | * blk_rq_map_user_iov - map user data to a request, for REQ_BLOCK_PC usage | |
2467 | * @q: request queue where request should be inserted | |
2468 | * @rq: request to map data to | |
2469 | * @iov: pointer to the iovec | |
2470 | * @iov_count: number of elements in the iovec | |
af9997e4 | 2471 | * @len: I/O byte count |
f1970baf JB |
2472 | * |
2473 | * Description: | |
2474 | * Data will be mapped directly for zero copy io, if possible. Otherwise | |
2475 | * a kernel bounce buffer is used. | |
2476 | * | |
2477 | * A matching blk_rq_unmap_user() must be issued at the end of io, while | |
2478 | * still in process context. | |
2479 | * | |
2480 | * Note: The mapped bio may need to be bounced through blk_queue_bounce() | |
2481 | * before being submitted to the device, as pages mapped may be out of | |
2482 | * reach. It's the callers responsibility to make sure this happens. The | |
2483 | * original bio must be passed back in to blk_rq_unmap_user() for proper | |
2484 | * unmapping. | |
2485 | */ | |
165125e1 | 2486 | int blk_rq_map_user_iov(struct request_queue *q, struct request *rq, |
0e75f906 | 2487 | struct sg_iovec *iov, int iov_count, unsigned int len) |
f1970baf JB |
2488 | { |
2489 | struct bio *bio; | |
2490 | ||
2491 | if (!iov || iov_count <= 0) | |
2492 | return -EINVAL; | |
2493 | ||
2494 | /* we don't allow misaligned data like bio_map_user() does. If the | |
2495 | * user is using sg, they're expected to know the alignment constraints | |
2496 | * and respect them accordingly */ | |
2497 | bio = bio_map_user_iov(q, NULL, iov, iov_count, rq_data_dir(rq)== READ); | |
2498 | if (IS_ERR(bio)) | |
2499 | return PTR_ERR(bio); | |
2500 | ||
0e75f906 | 2501 | if (bio->bi_size != len) { |
6712ecf8 | 2502 | bio_endio(bio, 0); |
0e75f906 MC |
2503 | bio_unmap_user(bio); |
2504 | return -EINVAL; | |
2505 | } | |
2506 | ||
2507 | bio_get(bio); | |
f1970baf JB |
2508 | blk_rq_bio_prep(q, rq, bio); |
2509 | rq->buffer = rq->data = NULL; | |
f1970baf JB |
2510 | return 0; |
2511 | } | |
2512 | ||
2513 | EXPORT_SYMBOL(blk_rq_map_user_iov); | |
2514 | ||
1da177e4 LT |
2515 | /** |
2516 | * blk_rq_unmap_user - unmap a request with user data | |
8e5cfc45 | 2517 | * @bio: start of bio list |
1da177e4 LT |
2518 | * |
2519 | * Description: | |
8e5cfc45 JA |
2520 | * Unmap a rq previously mapped by blk_rq_map_user(). The caller must |
2521 | * supply the original rq->bio from the blk_rq_map_user() return, since | |
2522 | * the io completion may have changed rq->bio. | |
1da177e4 | 2523 | */ |
8e5cfc45 | 2524 | int blk_rq_unmap_user(struct bio *bio) |
1da177e4 | 2525 | { |
8e5cfc45 | 2526 | struct bio *mapped_bio; |
48785bb9 | 2527 | int ret = 0, ret2; |
1da177e4 | 2528 | |
8e5cfc45 JA |
2529 | while (bio) { |
2530 | mapped_bio = bio; | |
2531 | if (unlikely(bio_flagged(bio, BIO_BOUNCED))) | |
0e75f906 | 2532 | mapped_bio = bio->bi_private; |
1da177e4 | 2533 | |
48785bb9 JA |
2534 | ret2 = __blk_rq_unmap_user(mapped_bio); |
2535 | if (ret2 && !ret) | |
2536 | ret = ret2; | |
2537 | ||
8e5cfc45 JA |
2538 | mapped_bio = bio; |
2539 | bio = bio->bi_next; | |
2540 | bio_put(mapped_bio); | |
0e75f906 | 2541 | } |
48785bb9 JA |
2542 | |
2543 | return ret; | |
1da177e4 LT |
2544 | } |
2545 | ||
2546 | EXPORT_SYMBOL(blk_rq_unmap_user); | |
2547 | ||
df46b9a4 MC |
2548 | /** |
2549 | * blk_rq_map_kern - map kernel data to a request, for REQ_BLOCK_PC usage | |
2550 | * @q: request queue where request should be inserted | |
73747aed | 2551 | * @rq: request to fill |
df46b9a4 MC |
2552 | * @kbuf: the kernel buffer |
2553 | * @len: length of user data | |
73747aed | 2554 | * @gfp_mask: memory allocation flags |
df46b9a4 | 2555 | */ |
165125e1 | 2556 | int blk_rq_map_kern(struct request_queue *q, struct request *rq, void *kbuf, |
8267e268 | 2557 | unsigned int len, gfp_t gfp_mask) |
df46b9a4 | 2558 | { |
df46b9a4 MC |
2559 | struct bio *bio; |
2560 | ||
defd94b7 | 2561 | if (len > (q->max_hw_sectors << 9)) |
dd1cab95 JA |
2562 | return -EINVAL; |
2563 | if (!len || !kbuf) | |
2564 | return -EINVAL; | |
df46b9a4 MC |
2565 | |
2566 | bio = bio_map_kern(q, kbuf, len, gfp_mask); | |
dd1cab95 JA |
2567 | if (IS_ERR(bio)) |
2568 | return PTR_ERR(bio); | |
df46b9a4 | 2569 | |
dd1cab95 JA |
2570 | if (rq_data_dir(rq) == WRITE) |
2571 | bio->bi_rw |= (1 << BIO_RW); | |
df46b9a4 | 2572 | |
dd1cab95 | 2573 | blk_rq_bio_prep(q, rq, bio); |
821de3a2 | 2574 | blk_queue_bounce(q, &rq->bio); |
dd1cab95 | 2575 | rq->buffer = rq->data = NULL; |
dd1cab95 | 2576 | return 0; |
df46b9a4 MC |
2577 | } |
2578 | ||
2579 | EXPORT_SYMBOL(blk_rq_map_kern); | |
2580 | ||
73747aed CH |
2581 | /** |
2582 | * blk_execute_rq_nowait - insert a request into queue for execution | |
2583 | * @q: queue to insert the request in | |
2584 | * @bd_disk: matching gendisk | |
2585 | * @rq: request to insert | |
2586 | * @at_head: insert request at head or tail of queue | |
2587 | * @done: I/O completion handler | |
2588 | * | |
2589 | * Description: | |
2590 | * Insert a fully prepared request at the back of the io scheduler queue | |
2591 | * for execution. Don't wait for completion. | |
2592 | */ | |
165125e1 | 2593 | void blk_execute_rq_nowait(struct request_queue *q, struct gendisk *bd_disk, |
f1970baf | 2594 | struct request *rq, int at_head, |
8ffdc655 | 2595 | rq_end_io_fn *done) |
f1970baf JB |
2596 | { |
2597 | int where = at_head ? ELEVATOR_INSERT_FRONT : ELEVATOR_INSERT_BACK; | |
2598 | ||
2599 | rq->rq_disk = bd_disk; | |
4aff5e23 | 2600 | rq->cmd_flags |= REQ_NOMERGE; |
f1970baf | 2601 | rq->end_io = done; |
4c5d0bbd AM |
2602 | WARN_ON(irqs_disabled()); |
2603 | spin_lock_irq(q->queue_lock); | |
2604 | __elv_add_request(q, rq, where, 1); | |
2605 | __generic_unplug_device(q); | |
2606 | spin_unlock_irq(q->queue_lock); | |
f1970baf | 2607 | } |
6e39b69e MC |
2608 | EXPORT_SYMBOL_GPL(blk_execute_rq_nowait); |
2609 | ||
1da177e4 LT |
2610 | /** |
2611 | * blk_execute_rq - insert a request into queue for execution | |
2612 | * @q: queue to insert the request in | |
2613 | * @bd_disk: matching gendisk | |
2614 | * @rq: request to insert | |
994ca9a1 | 2615 | * @at_head: insert request at head or tail of queue |
1da177e4 LT |
2616 | * |
2617 | * Description: | |
2618 | * Insert a fully prepared request at the back of the io scheduler queue | |
73747aed | 2619 | * for execution and wait for completion. |
1da177e4 | 2620 | */ |
165125e1 | 2621 | int blk_execute_rq(struct request_queue *q, struct gendisk *bd_disk, |
994ca9a1 | 2622 | struct request *rq, int at_head) |
1da177e4 | 2623 | { |
60be6b9a | 2624 | DECLARE_COMPLETION_ONSTACK(wait); |
1da177e4 LT |
2625 | char sense[SCSI_SENSE_BUFFERSIZE]; |
2626 | int err = 0; | |
2627 | ||
1da177e4 LT |
2628 | /* |
2629 | * we need an extra reference to the request, so we can look at | |
2630 | * it after io completion | |
2631 | */ | |
2632 | rq->ref_count++; | |
2633 | ||
2634 | if (!rq->sense) { | |
2635 | memset(sense, 0, sizeof(sense)); | |
2636 | rq->sense = sense; | |
2637 | rq->sense_len = 0; | |
2638 | } | |
2639 | ||
c00895ab | 2640 | rq->end_io_data = &wait; |
994ca9a1 | 2641 | blk_execute_rq_nowait(q, bd_disk, rq, at_head, blk_end_sync_rq); |
1da177e4 | 2642 | wait_for_completion(&wait); |
1da177e4 LT |
2643 | |
2644 | if (rq->errors) | |
2645 | err = -EIO; | |
2646 | ||
2647 | return err; | |
2648 | } | |
2649 | ||
2650 | EXPORT_SYMBOL(blk_execute_rq); | |
2651 | ||
fd5d8062 JA |
2652 | static void bio_end_empty_barrier(struct bio *bio, int err) |
2653 | { | |
2654 | if (err) | |
2655 | clear_bit(BIO_UPTODATE, &bio->bi_flags); | |
2656 | ||
2657 | complete(bio->bi_private); | |
2658 | } | |
2659 | ||
1da177e4 LT |
2660 | /** |
2661 | * blkdev_issue_flush - queue a flush | |
2662 | * @bdev: blockdev to issue flush for | |
2663 | * @error_sector: error sector | |
2664 | * | |
2665 | * Description: | |
2666 | * Issue a flush for the block device in question. Caller can supply | |
2667 | * room for storing the error offset in case of a flush error, if they | |
2668 | * wish to. Caller must run wait_for_completion() on its own. | |
2669 | */ | |
2670 | int blkdev_issue_flush(struct block_device *bdev, sector_t *error_sector) | |
2671 | { | |
fd5d8062 | 2672 | DECLARE_COMPLETION_ONSTACK(wait); |
165125e1 | 2673 | struct request_queue *q; |
fd5d8062 JA |
2674 | struct bio *bio; |
2675 | int ret; | |
1da177e4 LT |
2676 | |
2677 | if (bdev->bd_disk == NULL) | |
2678 | return -ENXIO; | |
2679 | ||
2680 | q = bdev_get_queue(bdev); | |
2681 | if (!q) | |
2682 | return -ENXIO; | |
1da177e4 | 2683 | |
fd5d8062 JA |
2684 | bio = bio_alloc(GFP_KERNEL, 0); |
2685 | if (!bio) | |
2686 | return -ENOMEM; | |
2687 | ||
2688 | bio->bi_end_io = bio_end_empty_barrier; | |
2689 | bio->bi_private = &wait; | |
2690 | bio->bi_bdev = bdev; | |
2691 | submit_bio(1 << BIO_RW_BARRIER, bio); | |
2692 | ||
2693 | wait_for_completion(&wait); | |
2694 | ||
2695 | /* | |
2696 | * The driver must store the error location in ->bi_sector, if | |
2697 | * it supports it. For non-stacked drivers, this should be copied | |
2698 | * from rq->sector. | |
2699 | */ | |
2700 | if (error_sector) | |
2701 | *error_sector = bio->bi_sector; | |
2702 | ||
2703 | ret = 0; | |
2704 | if (!bio_flagged(bio, BIO_UPTODATE)) | |
2705 | ret = -EIO; | |
2706 | ||
2707 | bio_put(bio); | |
2708 | return ret; | |
1da177e4 LT |
2709 | } |
2710 | ||
2711 | EXPORT_SYMBOL(blkdev_issue_flush); | |
2712 | ||
93d17d3d | 2713 | static void drive_stat_acct(struct request *rq, int nr_sectors, int new_io) |
1da177e4 LT |
2714 | { |
2715 | int rw = rq_data_dir(rq); | |
2716 | ||
2717 | if (!blk_fs_request(rq) || !rq->rq_disk) | |
2718 | return; | |
2719 | ||
d72d904a | 2720 | if (!new_io) { |
a362357b | 2721 | __disk_stat_inc(rq->rq_disk, merges[rw]); |
d72d904a | 2722 | } else { |
1da177e4 LT |
2723 | disk_round_stats(rq->rq_disk); |
2724 | rq->rq_disk->in_flight++; | |
2725 | } | |
2726 | } | |
2727 | ||
2728 | /* | |
2729 | * add-request adds a request to the linked list. | |
2730 | * queue lock is held and interrupts disabled, as we muck with the | |
2731 | * request queue list. | |
2732 | */ | |
165125e1 | 2733 | static inline void add_request(struct request_queue * q, struct request * req) |
1da177e4 LT |
2734 | { |
2735 | drive_stat_acct(req, req->nr_sectors, 1); | |
2736 | ||
1da177e4 LT |
2737 | /* |
2738 | * elevator indicated where it wants this request to be | |
2739 | * inserted at elevator_merge time | |
2740 | */ | |
2741 | __elv_add_request(q, req, ELEVATOR_INSERT_SORT, 0); | |
2742 | } | |
2743 | ||
2744 | /* | |
2745 | * disk_round_stats() - Round off the performance stats on a struct | |
2746 | * disk_stats. | |
2747 | * | |
2748 | * The average IO queue length and utilisation statistics are maintained | |
2749 | * by observing the current state of the queue length and the amount of | |
2750 | * time it has been in this state for. | |
2751 | * | |
2752 | * Normally, that accounting is done on IO completion, but that can result | |
2753 | * in more than a second's worth of IO being accounted for within any one | |
2754 | * second, leading to >100% utilisation. To deal with that, we call this | |
2755 | * function to do a round-off before returning the results when reading | |
2756 | * /proc/diskstats. This accounts immediately for all queue usage up to | |
2757 | * the current jiffies and restarts the counters again. | |
2758 | */ | |
2759 | void disk_round_stats(struct gendisk *disk) | |
2760 | { | |
2761 | unsigned long now = jiffies; | |
2762 | ||
b2982649 KC |
2763 | if (now == disk->stamp) |
2764 | return; | |
1da177e4 | 2765 | |
20e5c81f KC |
2766 | if (disk->in_flight) { |
2767 | __disk_stat_add(disk, time_in_queue, | |
2768 | disk->in_flight * (now - disk->stamp)); | |
2769 | __disk_stat_add(disk, io_ticks, (now - disk->stamp)); | |
2770 | } | |
1da177e4 | 2771 | disk->stamp = now; |
1da177e4 LT |
2772 | } |
2773 | ||
3eaf840e JNN |
2774 | EXPORT_SYMBOL_GPL(disk_round_stats); |
2775 | ||
1da177e4 LT |
2776 | /* |
2777 | * queue lock must be held | |
2778 | */ | |
165125e1 | 2779 | void __blk_put_request(struct request_queue *q, struct request *req) |
1da177e4 | 2780 | { |
1da177e4 LT |
2781 | if (unlikely(!q)) |
2782 | return; | |
2783 | if (unlikely(--req->ref_count)) | |
2784 | return; | |
2785 | ||
8922e16c TH |
2786 | elv_completed_request(q, req); |
2787 | ||
1da177e4 LT |
2788 | /* |
2789 | * Request may not have originated from ll_rw_blk. if not, | |
2790 | * it didn't come out of our reserved rq pools | |
2791 | */ | |
49171e5c | 2792 | if (req->cmd_flags & REQ_ALLOCED) { |
1da177e4 | 2793 | int rw = rq_data_dir(req); |
4aff5e23 | 2794 | int priv = req->cmd_flags & REQ_ELVPRIV; |
1da177e4 | 2795 | |
1da177e4 | 2796 | BUG_ON(!list_empty(&req->queuelist)); |
9817064b | 2797 | BUG_ON(!hlist_unhashed(&req->hash)); |
1da177e4 LT |
2798 | |
2799 | blk_free_request(q, req); | |
cb98fc8b | 2800 | freed_request(q, rw, priv); |
1da177e4 LT |
2801 | } |
2802 | } | |
2803 | ||
6e39b69e MC |
2804 | EXPORT_SYMBOL_GPL(__blk_put_request); |
2805 | ||
1da177e4 LT |
2806 | void blk_put_request(struct request *req) |
2807 | { | |
8922e16c | 2808 | unsigned long flags; |
165125e1 | 2809 | struct request_queue *q = req->q; |
8922e16c | 2810 | |
1da177e4 | 2811 | /* |
8922e16c TH |
2812 | * Gee, IDE calls in w/ NULL q. Fix IDE and remove the |
2813 | * following if (q) test. | |
1da177e4 | 2814 | */ |
8922e16c | 2815 | if (q) { |
1da177e4 LT |
2816 | spin_lock_irqsave(q->queue_lock, flags); |
2817 | __blk_put_request(q, req); | |
2818 | spin_unlock_irqrestore(q->queue_lock, flags); | |
2819 | } | |
2820 | } | |
2821 | ||
2822 | EXPORT_SYMBOL(blk_put_request); | |
2823 | ||
2824 | /** | |
2825 | * blk_end_sync_rq - executes a completion event on a request | |
2826 | * @rq: request to complete | |
fddfdeaf | 2827 | * @error: end io status of the request |
1da177e4 | 2828 | */ |
8ffdc655 | 2829 | void blk_end_sync_rq(struct request *rq, int error) |
1da177e4 | 2830 | { |
c00895ab | 2831 | struct completion *waiting = rq->end_io_data; |
1da177e4 | 2832 | |
c00895ab | 2833 | rq->end_io_data = NULL; |
1da177e4 LT |
2834 | __blk_put_request(rq->q, rq); |
2835 | ||
2836 | /* | |
2837 | * complete last, if this is a stack request the process (and thus | |
2838 | * the rq pointer) could be invalid right after this complete() | |
2839 | */ | |
2840 | complete(waiting); | |
2841 | } | |
2842 | EXPORT_SYMBOL(blk_end_sync_rq); | |
2843 | ||
1da177e4 LT |
2844 | /* |
2845 | * Has to be called with the request spinlock acquired | |
2846 | */ | |
165125e1 | 2847 | static int attempt_merge(struct request_queue *q, struct request *req, |
1da177e4 LT |
2848 | struct request *next) |
2849 | { | |
2850 | if (!rq_mergeable(req) || !rq_mergeable(next)) | |
2851 | return 0; | |
2852 | ||
2853 | /* | |
d6e05edc | 2854 | * not contiguous |
1da177e4 LT |
2855 | */ |
2856 | if (req->sector + req->nr_sectors != next->sector) | |
2857 | return 0; | |
2858 | ||
2859 | if (rq_data_dir(req) != rq_data_dir(next) | |
2860 | || req->rq_disk != next->rq_disk | |
c00895ab | 2861 | || next->special) |
1da177e4 LT |
2862 | return 0; |
2863 | ||
2864 | /* | |
2865 | * If we are allowed to merge, then append bio list | |
2866 | * from next to rq and release next. merge_requests_fn | |
2867 | * will have updated segment counts, update sector | |
2868 | * counts here. | |
2869 | */ | |
1aa4f24f | 2870 | if (!ll_merge_requests_fn(q, req, next)) |
1da177e4 LT |
2871 | return 0; |
2872 | ||
2873 | /* | |
2874 | * At this point we have either done a back merge | |
2875 | * or front merge. We need the smaller start_time of | |
2876 | * the merged requests to be the current request | |
2877 | * for accounting purposes. | |
2878 | */ | |
2879 | if (time_after(req->start_time, next->start_time)) | |
2880 | req->start_time = next->start_time; | |
2881 | ||
2882 | req->biotail->bi_next = next->bio; | |
2883 | req->biotail = next->biotail; | |
2884 | ||
2885 | req->nr_sectors = req->hard_nr_sectors += next->hard_nr_sectors; | |
2886 | ||
2887 | elv_merge_requests(q, req, next); | |
2888 | ||
2889 | if (req->rq_disk) { | |
2890 | disk_round_stats(req->rq_disk); | |
2891 | req->rq_disk->in_flight--; | |
2892 | } | |
2893 | ||
22e2c507 JA |
2894 | req->ioprio = ioprio_best(req->ioprio, next->ioprio); |
2895 | ||
1da177e4 LT |
2896 | __blk_put_request(q, next); |
2897 | return 1; | |
2898 | } | |
2899 | ||
165125e1 JA |
2900 | static inline int attempt_back_merge(struct request_queue *q, |
2901 | struct request *rq) | |
1da177e4 LT |
2902 | { |
2903 | struct request *next = elv_latter_request(q, rq); | |
2904 | ||
2905 | if (next) | |
2906 | return attempt_merge(q, rq, next); | |
2907 | ||
2908 | return 0; | |
2909 | } | |
2910 | ||
165125e1 JA |
2911 | static inline int attempt_front_merge(struct request_queue *q, |
2912 | struct request *rq) | |
1da177e4 LT |
2913 | { |
2914 | struct request *prev = elv_former_request(q, rq); | |
2915 | ||
2916 | if (prev) | |
2917 | return attempt_merge(q, prev, rq); | |
2918 | ||
2919 | return 0; | |
2920 | } | |
2921 | ||
52d9e675 TH |
2922 | static void init_request_from_bio(struct request *req, struct bio *bio) |
2923 | { | |
4aff5e23 | 2924 | req->cmd_type = REQ_TYPE_FS; |
52d9e675 TH |
2925 | |
2926 | /* | |
2927 | * inherit FAILFAST from bio (for read-ahead, and explicit FAILFAST) | |
2928 | */ | |
2929 | if (bio_rw_ahead(bio) || bio_failfast(bio)) | |
4aff5e23 | 2930 | req->cmd_flags |= REQ_FAILFAST; |
52d9e675 TH |
2931 | |
2932 | /* | |
2933 | * REQ_BARRIER implies no merging, but lets make it explicit | |
2934 | */ | |
2935 | if (unlikely(bio_barrier(bio))) | |
4aff5e23 | 2936 | req->cmd_flags |= (REQ_HARDBARRIER | REQ_NOMERGE); |
52d9e675 | 2937 | |
b31dc66a | 2938 | if (bio_sync(bio)) |
4aff5e23 | 2939 | req->cmd_flags |= REQ_RW_SYNC; |
5404bc7a JA |
2940 | if (bio_rw_meta(bio)) |
2941 | req->cmd_flags |= REQ_RW_META; | |
b31dc66a | 2942 | |
52d9e675 TH |
2943 | req->errors = 0; |
2944 | req->hard_sector = req->sector = bio->bi_sector; | |
52d9e675 | 2945 | req->ioprio = bio_prio(bio); |
52d9e675 | 2946 | req->start_time = jiffies; |
bc1c56fd | 2947 | blk_rq_bio_prep(req->q, req, bio); |
52d9e675 TH |
2948 | } |
2949 | ||
165125e1 | 2950 | static int __make_request(struct request_queue *q, struct bio *bio) |
1da177e4 | 2951 | { |
450991bc | 2952 | struct request *req; |
51da90fc JA |
2953 | int el_ret, nr_sectors, barrier, err; |
2954 | const unsigned short prio = bio_prio(bio); | |
2955 | const int sync = bio_sync(bio); | |
7749a8d4 | 2956 | int rw_flags; |
1da177e4 | 2957 | |
1da177e4 | 2958 | nr_sectors = bio_sectors(bio); |
1da177e4 LT |
2959 | |
2960 | /* | |
2961 | * low level driver can indicate that it wants pages above a | |
2962 | * certain limit bounced to low memory (ie for highmem, or even | |
2963 | * ISA dma in theory) | |
2964 | */ | |
2965 | blk_queue_bounce(q, &bio); | |
2966 | ||
1da177e4 | 2967 | barrier = bio_barrier(bio); |
797e7dbb | 2968 | if (unlikely(barrier) && (q->next_ordered == QUEUE_ORDERED_NONE)) { |
1da177e4 LT |
2969 | err = -EOPNOTSUPP; |
2970 | goto end_io; | |
2971 | } | |
2972 | ||
1da177e4 LT |
2973 | spin_lock_irq(q->queue_lock); |
2974 | ||
450991bc | 2975 | if (unlikely(barrier) || elv_queue_empty(q)) |
1da177e4 LT |
2976 | goto get_rq; |
2977 | ||
2978 | el_ret = elv_merge(q, &req, bio); | |
2979 | switch (el_ret) { | |
2980 | case ELEVATOR_BACK_MERGE: | |
2981 | BUG_ON(!rq_mergeable(req)); | |
2982 | ||
1aa4f24f | 2983 | if (!ll_back_merge_fn(q, req, bio)) |
1da177e4 LT |
2984 | break; |
2985 | ||
2056a782 JA |
2986 | blk_add_trace_bio(q, bio, BLK_TA_BACKMERGE); |
2987 | ||
1da177e4 LT |
2988 | req->biotail->bi_next = bio; |
2989 | req->biotail = bio; | |
2990 | req->nr_sectors = req->hard_nr_sectors += nr_sectors; | |
22e2c507 | 2991 | req->ioprio = ioprio_best(req->ioprio, prio); |
1da177e4 LT |
2992 | drive_stat_acct(req, nr_sectors, 0); |
2993 | if (!attempt_back_merge(q, req)) | |
2e662b65 | 2994 | elv_merged_request(q, req, el_ret); |
1da177e4 LT |
2995 | goto out; |
2996 | ||
2997 | case ELEVATOR_FRONT_MERGE: | |
2998 | BUG_ON(!rq_mergeable(req)); | |
2999 | ||
1aa4f24f | 3000 | if (!ll_front_merge_fn(q, req, bio)) |
1da177e4 LT |
3001 | break; |
3002 | ||
2056a782 JA |
3003 | blk_add_trace_bio(q, bio, BLK_TA_FRONTMERGE); |
3004 | ||
1da177e4 LT |
3005 | bio->bi_next = req->bio; |
3006 | req->bio = bio; | |
3007 | ||
3008 | /* | |
3009 | * may not be valid. if the low level driver said | |
3010 | * it didn't need a bounce buffer then it better | |
3011 | * not touch req->buffer either... | |
3012 | */ | |
3013 | req->buffer = bio_data(bio); | |
51da90fc JA |
3014 | req->current_nr_sectors = bio_cur_sectors(bio); |
3015 | req->hard_cur_sectors = req->current_nr_sectors; | |
3016 | req->sector = req->hard_sector = bio->bi_sector; | |
1da177e4 | 3017 | req->nr_sectors = req->hard_nr_sectors += nr_sectors; |
22e2c507 | 3018 | req->ioprio = ioprio_best(req->ioprio, prio); |
1da177e4 LT |
3019 | drive_stat_acct(req, nr_sectors, 0); |
3020 | if (!attempt_front_merge(q, req)) | |
2e662b65 | 3021 | elv_merged_request(q, req, el_ret); |
1da177e4 LT |
3022 | goto out; |
3023 | ||
450991bc | 3024 | /* ELV_NO_MERGE: elevator says don't/can't merge. */ |
1da177e4 | 3025 | default: |
450991bc | 3026 | ; |
1da177e4 LT |
3027 | } |
3028 | ||
450991bc | 3029 | get_rq: |
7749a8d4 JA |
3030 | /* |
3031 | * This sync check and mask will be re-done in init_request_from_bio(), | |
3032 | * but we need to set it earlier to expose the sync flag to the | |
3033 | * rq allocator and io schedulers. | |
3034 | */ | |
3035 | rw_flags = bio_data_dir(bio); | |
3036 | if (sync) | |
3037 | rw_flags |= REQ_RW_SYNC; | |
3038 | ||
1da177e4 | 3039 | /* |
450991bc | 3040 | * Grab a free request. This is might sleep but can not fail. |
d6344532 | 3041 | * Returns with the queue unlocked. |
450991bc | 3042 | */ |
7749a8d4 | 3043 | req = get_request_wait(q, rw_flags, bio); |
d6344532 | 3044 | |
450991bc NP |
3045 | /* |
3046 | * After dropping the lock and possibly sleeping here, our request | |
3047 | * may now be mergeable after it had proven unmergeable (above). | |
3048 | * We don't worry about that case for efficiency. It won't happen | |
3049 | * often, and the elevators are able to handle it. | |
1da177e4 | 3050 | */ |
52d9e675 | 3051 | init_request_from_bio(req, bio); |
1da177e4 | 3052 | |
450991bc NP |
3053 | spin_lock_irq(q->queue_lock); |
3054 | if (elv_queue_empty(q)) | |
3055 | blk_plug_device(q); | |
1da177e4 LT |
3056 | add_request(q, req); |
3057 | out: | |
4a534f93 | 3058 | if (sync) |
1da177e4 LT |
3059 | __generic_unplug_device(q); |
3060 | ||
3061 | spin_unlock_irq(q->queue_lock); | |
3062 | return 0; | |
3063 | ||
3064 | end_io: | |
6712ecf8 | 3065 | bio_endio(bio, err); |
1da177e4 LT |
3066 | return 0; |
3067 | } | |
3068 | ||
3069 | /* | |
3070 | * If bio->bi_dev is a partition, remap the location | |
3071 | */ | |
3072 | static inline void blk_partition_remap(struct bio *bio) | |
3073 | { | |
3074 | struct block_device *bdev = bio->bi_bdev; | |
3075 | ||
bf2de6f5 | 3076 | if (bio_sectors(bio) && bdev != bdev->bd_contains) { |
1da177e4 | 3077 | struct hd_struct *p = bdev->bd_part; |
a362357b JA |
3078 | const int rw = bio_data_dir(bio); |
3079 | ||
3080 | p->sectors[rw] += bio_sectors(bio); | |
3081 | p->ios[rw]++; | |
1da177e4 | 3082 | |
1da177e4 LT |
3083 | bio->bi_sector += p->start_sect; |
3084 | bio->bi_bdev = bdev->bd_contains; | |
c7149d6b AB |
3085 | |
3086 | blk_add_trace_remap(bdev_get_queue(bio->bi_bdev), bio, | |
3087 | bdev->bd_dev, bio->bi_sector, | |
3088 | bio->bi_sector - p->start_sect); | |
1da177e4 LT |
3089 | } |
3090 | } | |
3091 | ||
1da177e4 LT |
3092 | static void handle_bad_sector(struct bio *bio) |
3093 | { | |
3094 | char b[BDEVNAME_SIZE]; | |
3095 | ||
3096 | printk(KERN_INFO "attempt to access beyond end of device\n"); | |
3097 | printk(KERN_INFO "%s: rw=%ld, want=%Lu, limit=%Lu\n", | |
3098 | bdevname(bio->bi_bdev, b), | |
3099 | bio->bi_rw, | |
3100 | (unsigned long long)bio->bi_sector + bio_sectors(bio), | |
3101 | (long long)(bio->bi_bdev->bd_inode->i_size >> 9)); | |
3102 | ||
3103 | set_bit(BIO_EOF, &bio->bi_flags); | |
3104 | } | |
3105 | ||
c17bb495 AM |
3106 | #ifdef CONFIG_FAIL_MAKE_REQUEST |
3107 | ||
3108 | static DECLARE_FAULT_ATTR(fail_make_request); | |
3109 | ||
3110 | static int __init setup_fail_make_request(char *str) | |
3111 | { | |
3112 | return setup_fault_attr(&fail_make_request, str); | |
3113 | } | |
3114 | __setup("fail_make_request=", setup_fail_make_request); | |
3115 | ||
3116 | static int should_fail_request(struct bio *bio) | |
3117 | { | |
3118 | if ((bio->bi_bdev->bd_disk->flags & GENHD_FL_FAIL) || | |
3119 | (bio->bi_bdev->bd_part && bio->bi_bdev->bd_part->make_it_fail)) | |
3120 | return should_fail(&fail_make_request, bio->bi_size); | |
3121 | ||
3122 | return 0; | |
3123 | } | |
3124 | ||
3125 | static int __init fail_make_request_debugfs(void) | |
3126 | { | |
3127 | return init_fault_attr_dentries(&fail_make_request, | |
3128 | "fail_make_request"); | |
3129 | } | |
3130 | ||
3131 | late_initcall(fail_make_request_debugfs); | |
3132 | ||
3133 | #else /* CONFIG_FAIL_MAKE_REQUEST */ | |
3134 | ||
3135 | static inline int should_fail_request(struct bio *bio) | |
3136 | { | |
3137 | return 0; | |
3138 | } | |
3139 | ||
3140 | #endif /* CONFIG_FAIL_MAKE_REQUEST */ | |
3141 | ||
c07e2b41 JA |
3142 | /* |
3143 | * Check whether this bio extends beyond the end of the device. | |
3144 | */ | |
3145 | static inline int bio_check_eod(struct bio *bio, unsigned int nr_sectors) | |
3146 | { | |
3147 | sector_t maxsector; | |
3148 | ||
3149 | if (!nr_sectors) | |
3150 | return 0; | |
3151 | ||
3152 | /* Test device or partition size, when known. */ | |
3153 | maxsector = bio->bi_bdev->bd_inode->i_size >> 9; | |
3154 | if (maxsector) { | |
3155 | sector_t sector = bio->bi_sector; | |
3156 | ||
3157 | if (maxsector < nr_sectors || maxsector - nr_sectors < sector) { | |
3158 | /* | |
3159 | * This may well happen - the kernel calls bread() | |
3160 | * without checking the size of the device, e.g., when | |
3161 | * mounting a device. | |
3162 | */ | |
3163 | handle_bad_sector(bio); | |
3164 | return 1; | |
3165 | } | |
3166 | } | |
3167 | ||
3168 | return 0; | |
3169 | } | |
3170 | ||
1da177e4 LT |
3171 | /** |
3172 | * generic_make_request: hand a buffer to its device driver for I/O | |
3173 | * @bio: The bio describing the location in memory and on the device. | |
3174 | * | |
3175 | * generic_make_request() is used to make I/O requests of block | |
3176 | * devices. It is passed a &struct bio, which describes the I/O that needs | |
3177 | * to be done. | |
3178 | * | |
3179 | * generic_make_request() does not return any status. The | |
3180 | * success/failure status of the request, along with notification of | |
3181 | * completion, is delivered asynchronously through the bio->bi_end_io | |
3182 | * function described (one day) else where. | |
3183 | * | |
3184 | * The caller of generic_make_request must make sure that bi_io_vec | |
3185 | * are set to describe the memory buffer, and that bi_dev and bi_sector are | |
3186 | * set to describe the device address, and the | |
3187 | * bi_end_io and optionally bi_private are set to describe how | |
3188 | * completion notification should be signaled. | |
3189 | * | |
3190 | * generic_make_request and the drivers it calls may use bi_next if this | |
3191 | * bio happens to be merged with someone else, and may change bi_dev and | |
3192 | * bi_sector for remaps as it sees fit. So the values of these fields | |
3193 | * should NOT be depended on after the call to generic_make_request. | |
3194 | */ | |
d89d8796 | 3195 | static inline void __generic_make_request(struct bio *bio) |
1da177e4 | 3196 | { |
165125e1 | 3197 | struct request_queue *q; |
5ddfe969 | 3198 | sector_t old_sector; |
1da177e4 | 3199 | int ret, nr_sectors = bio_sectors(bio); |
2056a782 | 3200 | dev_t old_dev; |
1da177e4 LT |
3201 | |
3202 | might_sleep(); | |
1da177e4 | 3203 | |
c07e2b41 JA |
3204 | if (bio_check_eod(bio, nr_sectors)) |
3205 | goto end_io; | |
1da177e4 LT |
3206 | |
3207 | /* | |
3208 | * Resolve the mapping until finished. (drivers are | |
3209 | * still free to implement/resolve their own stacking | |
3210 | * by explicitly returning 0) | |
3211 | * | |
3212 | * NOTE: we don't repeat the blk_size check for each new device. | |
3213 | * Stacking drivers are expected to know what they are doing. | |
3214 | */ | |
5ddfe969 | 3215 | old_sector = -1; |
2056a782 | 3216 | old_dev = 0; |
1da177e4 LT |
3217 | do { |
3218 | char b[BDEVNAME_SIZE]; | |
3219 | ||
3220 | q = bdev_get_queue(bio->bi_bdev); | |
3221 | if (!q) { | |
3222 | printk(KERN_ERR | |
3223 | "generic_make_request: Trying to access " | |
3224 | "nonexistent block-device %s (%Lu)\n", | |
3225 | bdevname(bio->bi_bdev, b), | |
3226 | (long long) bio->bi_sector); | |
3227 | end_io: | |
6712ecf8 | 3228 | bio_endio(bio, -EIO); |
1da177e4 LT |
3229 | break; |
3230 | } | |
3231 | ||
4fa253f3 | 3232 | if (unlikely(nr_sectors > q->max_hw_sectors)) { |
1da177e4 LT |
3233 | printk("bio too big device %s (%u > %u)\n", |
3234 | bdevname(bio->bi_bdev, b), | |
3235 | bio_sectors(bio), | |
3236 | q->max_hw_sectors); | |
3237 | goto end_io; | |
3238 | } | |
3239 | ||
fde6ad22 | 3240 | if (unlikely(test_bit(QUEUE_FLAG_DEAD, &q->queue_flags))) |
1da177e4 LT |
3241 | goto end_io; |
3242 | ||
c17bb495 AM |
3243 | if (should_fail_request(bio)) |
3244 | goto end_io; | |
3245 | ||
1da177e4 LT |
3246 | /* |
3247 | * If this device has partitions, remap block n | |
3248 | * of partition p to block n+start(p) of the disk. | |
3249 | */ | |
3250 | blk_partition_remap(bio); | |
3251 | ||
5ddfe969 | 3252 | if (old_sector != -1) |
4fa253f3 | 3253 | blk_add_trace_remap(q, bio, old_dev, bio->bi_sector, |
5ddfe969 | 3254 | old_sector); |
2056a782 JA |
3255 | |
3256 | blk_add_trace_bio(q, bio, BLK_TA_QUEUE); | |
3257 | ||
5ddfe969 | 3258 | old_sector = bio->bi_sector; |
2056a782 JA |
3259 | old_dev = bio->bi_bdev->bd_dev; |
3260 | ||
c07e2b41 JA |
3261 | if (bio_check_eod(bio, nr_sectors)) |
3262 | goto end_io; | |
5ddfe969 | 3263 | |
1da177e4 LT |
3264 | ret = q->make_request_fn(q, bio); |
3265 | } while (ret); | |
3266 | } | |
3267 | ||
d89d8796 NB |
3268 | /* |
3269 | * We only want one ->make_request_fn to be active at a time, | |
3270 | * else stack usage with stacked devices could be a problem. | |
3271 | * So use current->bio_{list,tail} to keep a list of requests | |
3272 | * submited by a make_request_fn function. | |
3273 | * current->bio_tail is also used as a flag to say if | |
3274 | * generic_make_request is currently active in this task or not. | |
3275 | * If it is NULL, then no make_request is active. If it is non-NULL, | |
3276 | * then a make_request is active, and new requests should be added | |
3277 | * at the tail | |
3278 | */ | |
3279 | void generic_make_request(struct bio *bio) | |
3280 | { | |
3281 | if (current->bio_tail) { | |
3282 | /* make_request is active */ | |
3283 | *(current->bio_tail) = bio; | |
3284 | bio->bi_next = NULL; | |
3285 | current->bio_tail = &bio->bi_next; | |
3286 | return; | |
3287 | } | |
3288 | /* following loop may be a bit non-obvious, and so deserves some | |
3289 | * explanation. | |
3290 | * Before entering the loop, bio->bi_next is NULL (as all callers | |
3291 | * ensure that) so we have a list with a single bio. | |
3292 | * We pretend that we have just taken it off a longer list, so | |
3293 | * we assign bio_list to the next (which is NULL) and bio_tail | |
3294 | * to &bio_list, thus initialising the bio_list of new bios to be | |
3295 | * added. __generic_make_request may indeed add some more bios | |
3296 | * through a recursive call to generic_make_request. If it | |
3297 | * did, we find a non-NULL value in bio_list and re-enter the loop | |
3298 | * from the top. In this case we really did just take the bio | |
3299 | * of the top of the list (no pretending) and so fixup bio_list and | |
3300 | * bio_tail or bi_next, and call into __generic_make_request again. | |
3301 | * | |
3302 | * The loop was structured like this to make only one call to | |
3303 | * __generic_make_request (which is important as it is large and | |
3304 | * inlined) and to keep the structure simple. | |
3305 | */ | |
3306 | BUG_ON(bio->bi_next); | |
3307 | do { | |
3308 | current->bio_list = bio->bi_next; | |
3309 | if (bio->bi_next == NULL) | |
3310 | current->bio_tail = ¤t->bio_list; | |
3311 | else | |
3312 | bio->bi_next = NULL; | |
3313 | __generic_make_request(bio); | |
3314 | bio = current->bio_list; | |
3315 | } while (bio); | |
3316 | current->bio_tail = NULL; /* deactivate */ | |
3317 | } | |
3318 | ||
1da177e4 LT |
3319 | EXPORT_SYMBOL(generic_make_request); |
3320 | ||
3321 | /** | |
3322 | * submit_bio: submit a bio to the block device layer for I/O | |
3323 | * @rw: whether to %READ or %WRITE, or maybe to %READA (read ahead) | |
3324 | * @bio: The &struct bio which describes the I/O | |
3325 | * | |
3326 | * submit_bio() is very similar in purpose to generic_make_request(), and | |
3327 | * uses that function to do most of the work. Both are fairly rough | |
3328 | * interfaces, @bio must be presetup and ready for I/O. | |
3329 | * | |
3330 | */ | |
3331 | void submit_bio(int rw, struct bio *bio) | |
3332 | { | |
3333 | int count = bio_sectors(bio); | |
3334 | ||
22e2c507 | 3335 | bio->bi_rw |= rw; |
1da177e4 | 3336 | |
bf2de6f5 JA |
3337 | /* |
3338 | * If it's a regular read/write or a barrier with data attached, | |
3339 | * go through the normal accounting stuff before submission. | |
3340 | */ | |
3341 | if (!bio_empty_barrier(bio)) { | |
3342 | ||
3343 | BIO_BUG_ON(!bio->bi_size); | |
3344 | BIO_BUG_ON(!bio->bi_io_vec); | |
3345 | ||
3346 | if (rw & WRITE) { | |
3347 | count_vm_events(PGPGOUT, count); | |
3348 | } else { | |
3349 | task_io_account_read(bio->bi_size); | |
3350 | count_vm_events(PGPGIN, count); | |
3351 | } | |
3352 | ||
3353 | if (unlikely(block_dump)) { | |
3354 | char b[BDEVNAME_SIZE]; | |
3355 | printk(KERN_DEBUG "%s(%d): %s block %Lu on %s\n", | |
3356 | current->comm, current->pid, | |
3357 | (rw & WRITE) ? "WRITE" : "READ", | |
3358 | (unsigned long long)bio->bi_sector, | |
3359 | bdevname(bio->bi_bdev,b)); | |
3360 | } | |
1da177e4 LT |
3361 | } |
3362 | ||
3363 | generic_make_request(bio); | |
3364 | } | |
3365 | ||
3366 | EXPORT_SYMBOL(submit_bio); | |
3367 | ||
93d17d3d | 3368 | static void blk_recalc_rq_sectors(struct request *rq, int nsect) |
1da177e4 LT |
3369 | { |
3370 | if (blk_fs_request(rq)) { | |
3371 | rq->hard_sector += nsect; | |
3372 | rq->hard_nr_sectors -= nsect; | |
3373 | ||
3374 | /* | |
3375 | * Move the I/O submission pointers ahead if required. | |
3376 | */ | |
3377 | if ((rq->nr_sectors >= rq->hard_nr_sectors) && | |
3378 | (rq->sector <= rq->hard_sector)) { | |
3379 | rq->sector = rq->hard_sector; | |
3380 | rq->nr_sectors = rq->hard_nr_sectors; | |
3381 | rq->hard_cur_sectors = bio_cur_sectors(rq->bio); | |
3382 | rq->current_nr_sectors = rq->hard_cur_sectors; | |
3383 | rq->buffer = bio_data(rq->bio); | |
3384 | } | |
3385 | ||
3386 | /* | |
3387 | * if total number of sectors is less than the first segment | |
3388 | * size, something has gone terribly wrong | |
3389 | */ | |
3390 | if (rq->nr_sectors < rq->current_nr_sectors) { | |
3391 | printk("blk: request botched\n"); | |
3392 | rq->nr_sectors = rq->current_nr_sectors; | |
3393 | } | |
3394 | } | |
3395 | } | |
3396 | ||
3397 | static int __end_that_request_first(struct request *req, int uptodate, | |
3398 | int nr_bytes) | |
3399 | { | |
3400 | int total_bytes, bio_nbytes, error, next_idx = 0; | |
3401 | struct bio *bio; | |
3402 | ||
2056a782 JA |
3403 | blk_add_trace_rq(req->q, req, BLK_TA_COMPLETE); |
3404 | ||
1da177e4 LT |
3405 | /* |
3406 | * extend uptodate bool to allow < 0 value to be direct io error | |
3407 | */ | |
3408 | error = 0; | |
3409 | if (end_io_error(uptodate)) | |
3410 | error = !uptodate ? -EIO : uptodate; | |
3411 | ||
3412 | /* | |
3413 | * for a REQ_BLOCK_PC request, we want to carry any eventual | |
3414 | * sense key with us all the way through | |
3415 | */ | |
3416 | if (!blk_pc_request(req)) | |
3417 | req->errors = 0; | |
3418 | ||
3419 | if (!uptodate) { | |
4aff5e23 | 3420 | if (blk_fs_request(req) && !(req->cmd_flags & REQ_QUIET)) |
1da177e4 LT |
3421 | printk("end_request: I/O error, dev %s, sector %llu\n", |
3422 | req->rq_disk ? req->rq_disk->disk_name : "?", | |
3423 | (unsigned long long)req->sector); | |
3424 | } | |
3425 | ||
d72d904a | 3426 | if (blk_fs_request(req) && req->rq_disk) { |
a362357b JA |
3427 | const int rw = rq_data_dir(req); |
3428 | ||
53e86061 | 3429 | disk_stat_add(req->rq_disk, sectors[rw], nr_bytes >> 9); |
d72d904a JA |
3430 | } |
3431 | ||
1da177e4 LT |
3432 | total_bytes = bio_nbytes = 0; |
3433 | while ((bio = req->bio) != NULL) { | |
3434 | int nbytes; | |
3435 | ||
bf2de6f5 JA |
3436 | /* |
3437 | * For an empty barrier request, the low level driver must | |
3438 | * store a potential error location in ->sector. We pass | |
3439 | * that back up in ->bi_sector. | |
3440 | */ | |
3441 | if (blk_empty_barrier(req)) | |
3442 | bio->bi_sector = req->sector; | |
3443 | ||
1da177e4 LT |
3444 | if (nr_bytes >= bio->bi_size) { |
3445 | req->bio = bio->bi_next; | |
3446 | nbytes = bio->bi_size; | |
5bb23a68 | 3447 | req_bio_endio(req, bio, nbytes, error); |
1da177e4 LT |
3448 | next_idx = 0; |
3449 | bio_nbytes = 0; | |
3450 | } else { | |
3451 | int idx = bio->bi_idx + next_idx; | |
3452 | ||
3453 | if (unlikely(bio->bi_idx >= bio->bi_vcnt)) { | |
3454 | blk_dump_rq_flags(req, "__end_that"); | |
3455 | printk("%s: bio idx %d >= vcnt %d\n", | |
3456 | __FUNCTION__, | |
3457 | bio->bi_idx, bio->bi_vcnt); | |
3458 | break; | |
3459 | } | |
3460 | ||
3461 | nbytes = bio_iovec_idx(bio, idx)->bv_len; | |
3462 | BIO_BUG_ON(nbytes > bio->bi_size); | |
3463 | ||
3464 | /* | |
3465 | * not a complete bvec done | |
3466 | */ | |
3467 | if (unlikely(nbytes > nr_bytes)) { | |
3468 | bio_nbytes += nr_bytes; | |
3469 | total_bytes += nr_bytes; | |
3470 | break; | |
3471 | } | |
3472 | ||
3473 | /* | |
3474 | * advance to the next vector | |
3475 | */ | |
3476 | next_idx++; | |
3477 | bio_nbytes += nbytes; | |
3478 | } | |
3479 | ||
3480 | total_bytes += nbytes; | |
3481 | nr_bytes -= nbytes; | |
3482 | ||
3483 | if ((bio = req->bio)) { | |
3484 | /* | |
3485 | * end more in this run, or just return 'not-done' | |
3486 | */ | |
3487 | if (unlikely(nr_bytes <= 0)) | |
3488 | break; | |
3489 | } | |
3490 | } | |
3491 | ||
3492 | /* | |
3493 | * completely done | |
3494 | */ | |
3495 | if (!req->bio) | |
3496 | return 0; | |
3497 | ||
3498 | /* | |
3499 | * if the request wasn't completed, update state | |
3500 | */ | |
3501 | if (bio_nbytes) { | |
5bb23a68 | 3502 | req_bio_endio(req, bio, bio_nbytes, error); |
1da177e4 LT |
3503 | bio->bi_idx += next_idx; |
3504 | bio_iovec(bio)->bv_offset += nr_bytes; | |
3505 | bio_iovec(bio)->bv_len -= nr_bytes; | |
3506 | } | |
3507 | ||
3508 | blk_recalc_rq_sectors(req, total_bytes >> 9); | |
3509 | blk_recalc_rq_segments(req); | |
3510 | return 1; | |
3511 | } | |
3512 | ||
3513 | /** | |
3514 | * end_that_request_first - end I/O on a request | |
3515 | * @req: the request being processed | |
3516 | * @uptodate: 1 for success, 0 for I/O error, < 0 for specific error | |
3517 | * @nr_sectors: number of sectors to end I/O on | |
3518 | * | |
3519 | * Description: | |
3520 | * Ends I/O on a number of sectors attached to @req, and sets it up | |
3521 | * for the next range of segments (if any) in the cluster. | |
3522 | * | |
3523 | * Return: | |
3524 | * 0 - we are done with this request, call end_that_request_last() | |
3525 | * 1 - still buffers pending for this request | |
3526 | **/ | |
3527 | int end_that_request_first(struct request *req, int uptodate, int nr_sectors) | |
3528 | { | |
3529 | return __end_that_request_first(req, uptodate, nr_sectors << 9); | |
3530 | } | |
3531 | ||
3532 | EXPORT_SYMBOL(end_that_request_first); | |
3533 | ||
3534 | /** | |
3535 | * end_that_request_chunk - end I/O on a request | |
3536 | * @req: the request being processed | |
3537 | * @uptodate: 1 for success, 0 for I/O error, < 0 for specific error | |
3538 | * @nr_bytes: number of bytes to complete | |
3539 | * | |
3540 | * Description: | |
3541 | * Ends I/O on a number of bytes attached to @req, and sets it up | |
3542 | * for the next range of segments (if any). Like end_that_request_first(), | |
3543 | * but deals with bytes instead of sectors. | |
3544 | * | |
3545 | * Return: | |
3546 | * 0 - we are done with this request, call end_that_request_last() | |
3547 | * 1 - still buffers pending for this request | |
3548 | **/ | |
3549 | int end_that_request_chunk(struct request *req, int uptodate, int nr_bytes) | |
3550 | { | |
3551 | return __end_that_request_first(req, uptodate, nr_bytes); | |
3552 | } | |
3553 | ||
3554 | EXPORT_SYMBOL(end_that_request_chunk); | |
3555 | ||
ff856bad JA |
3556 | /* |
3557 | * splice the completion data to a local structure and hand off to | |
3558 | * process_completion_queue() to complete the requests | |
3559 | */ | |
3560 | static void blk_done_softirq(struct softirq_action *h) | |
3561 | { | |
626ab0e6 | 3562 | struct list_head *cpu_list, local_list; |
ff856bad JA |
3563 | |
3564 | local_irq_disable(); | |
3565 | cpu_list = &__get_cpu_var(blk_cpu_done); | |
626ab0e6 | 3566 | list_replace_init(cpu_list, &local_list); |
ff856bad JA |
3567 | local_irq_enable(); |
3568 | ||
3569 | while (!list_empty(&local_list)) { | |
3570 | struct request *rq = list_entry(local_list.next, struct request, donelist); | |
3571 | ||
3572 | list_del_init(&rq->donelist); | |
3573 | rq->q->softirq_done_fn(rq); | |
3574 | } | |
3575 | } | |
3576 | ||
db47d475 | 3577 | static int __cpuinit blk_cpu_notify(struct notifier_block *self, unsigned long action, |
ff856bad JA |
3578 | void *hcpu) |
3579 | { | |
3580 | /* | |
3581 | * If a CPU goes away, splice its entries to the current CPU | |
3582 | * and trigger a run of the softirq | |
3583 | */ | |
8bb78442 | 3584 | if (action == CPU_DEAD || action == CPU_DEAD_FROZEN) { |
ff856bad JA |
3585 | int cpu = (unsigned long) hcpu; |
3586 | ||
3587 | local_irq_disable(); | |
3588 | list_splice_init(&per_cpu(blk_cpu_done, cpu), | |
3589 | &__get_cpu_var(blk_cpu_done)); | |
3590 | raise_softirq_irqoff(BLOCK_SOFTIRQ); | |
3591 | local_irq_enable(); | |
3592 | } | |
3593 | ||
3594 | return NOTIFY_OK; | |
3595 | } | |
3596 | ||
3597 | ||
db47d475 | 3598 | static struct notifier_block blk_cpu_notifier __cpuinitdata = { |
ff856bad JA |
3599 | .notifier_call = blk_cpu_notify, |
3600 | }; | |
3601 | ||
ff856bad JA |
3602 | /** |
3603 | * blk_complete_request - end I/O on a request | |
3604 | * @req: the request being processed | |
3605 | * | |
3606 | * Description: | |
3607 | * Ends all I/O on a request. It does not handle partial completions, | |
d6e05edc | 3608 | * unless the driver actually implements this in its completion callback |
4fa253f3 | 3609 | * through requeueing. The actual completion happens out-of-order, |
ff856bad JA |
3610 | * through a softirq handler. The user must have registered a completion |
3611 | * callback through blk_queue_softirq_done(). | |
3612 | **/ | |
3613 | ||
3614 | void blk_complete_request(struct request *req) | |
3615 | { | |
3616 | struct list_head *cpu_list; | |
3617 | unsigned long flags; | |
3618 | ||
3619 | BUG_ON(!req->q->softirq_done_fn); | |
3620 | ||
3621 | local_irq_save(flags); | |
3622 | ||
3623 | cpu_list = &__get_cpu_var(blk_cpu_done); | |
3624 | list_add_tail(&req->donelist, cpu_list); | |
3625 | raise_softirq_irqoff(BLOCK_SOFTIRQ); | |
3626 | ||
3627 | local_irq_restore(flags); | |
3628 | } | |
3629 | ||
3630 | EXPORT_SYMBOL(blk_complete_request); | |
3631 | ||
1da177e4 LT |
3632 | /* |
3633 | * queue lock must be held | |
3634 | */ | |
8ffdc655 | 3635 | void end_that_request_last(struct request *req, int uptodate) |
1da177e4 LT |
3636 | { |
3637 | struct gendisk *disk = req->rq_disk; | |
8ffdc655 TH |
3638 | int error; |
3639 | ||
3640 | /* | |
3641 | * extend uptodate bool to allow < 0 value to be direct io error | |
3642 | */ | |
3643 | error = 0; | |
3644 | if (end_io_error(uptodate)) | |
3645 | error = !uptodate ? -EIO : uptodate; | |
1da177e4 LT |
3646 | |
3647 | if (unlikely(laptop_mode) && blk_fs_request(req)) | |
3648 | laptop_io_completion(); | |
3649 | ||
fd0ff8aa JA |
3650 | /* |
3651 | * Account IO completion. bar_rq isn't accounted as a normal | |
3652 | * IO on queueing nor completion. Accounting the containing | |
3653 | * request is enough. | |
3654 | */ | |
3655 | if (disk && blk_fs_request(req) && req != &req->q->bar_rq) { | |
1da177e4 | 3656 | unsigned long duration = jiffies - req->start_time; |
a362357b JA |
3657 | const int rw = rq_data_dir(req); |
3658 | ||
3659 | __disk_stat_inc(disk, ios[rw]); | |
3660 | __disk_stat_add(disk, ticks[rw], duration); | |
1da177e4 LT |
3661 | disk_round_stats(disk); |
3662 | disk->in_flight--; | |
3663 | } | |
3664 | if (req->end_io) | |
8ffdc655 | 3665 | req->end_io(req, error); |
1da177e4 LT |
3666 | else |
3667 | __blk_put_request(req->q, req); | |
3668 | } | |
3669 | ||
3670 | EXPORT_SYMBOL(end_that_request_last); | |
3671 | ||
a0cd1285 JA |
3672 | static inline void __end_request(struct request *rq, int uptodate, |
3673 | unsigned int nr_bytes, int dequeue) | |
1da177e4 | 3674 | { |
a0cd1285 JA |
3675 | if (!end_that_request_chunk(rq, uptodate, nr_bytes)) { |
3676 | if (dequeue) | |
3677 | blkdev_dequeue_request(rq); | |
3678 | add_disk_randomness(rq->rq_disk); | |
3679 | end_that_request_last(rq, uptodate); | |
1da177e4 LT |
3680 | } |
3681 | } | |
3682 | ||
a0cd1285 JA |
3683 | static unsigned int rq_byte_size(struct request *rq) |
3684 | { | |
3685 | if (blk_fs_request(rq)) | |
3686 | return rq->hard_nr_sectors << 9; | |
3687 | ||
3688 | return rq->data_len; | |
3689 | } | |
3690 | ||
3691 | /** | |
3692 | * end_queued_request - end all I/O on a queued request | |
3693 | * @rq: the request being processed | |
3694 | * @uptodate: error value or 0/1 uptodate flag | |
3695 | * | |
3696 | * Description: | |
3697 | * Ends all I/O on a request, and removes it from the block layer queues. | |
3698 | * Not suitable for normal IO completion, unless the driver still has | |
3699 | * the request attached to the block layer. | |
3700 | * | |
3701 | **/ | |
3702 | void end_queued_request(struct request *rq, int uptodate) | |
3703 | { | |
3704 | __end_request(rq, uptodate, rq_byte_size(rq), 1); | |
3705 | } | |
3706 | EXPORT_SYMBOL(end_queued_request); | |
3707 | ||
3708 | /** | |
3709 | * end_dequeued_request - end all I/O on a dequeued request | |
3710 | * @rq: the request being processed | |
3711 | * @uptodate: error value or 0/1 uptodate flag | |
3712 | * | |
3713 | * Description: | |
3714 | * Ends all I/O on a request. The request must already have been | |
3715 | * dequeued using blkdev_dequeue_request(), as is normally the case | |
3716 | * for most drivers. | |
3717 | * | |
3718 | **/ | |
3719 | void end_dequeued_request(struct request *rq, int uptodate) | |
3720 | { | |
3721 | __end_request(rq, uptodate, rq_byte_size(rq), 0); | |
3722 | } | |
3723 | EXPORT_SYMBOL(end_dequeued_request); | |
3724 | ||
3725 | ||
3726 | /** | |
3727 | * end_request - end I/O on the current segment of the request | |
3728 | * @rq: the request being processed | |
3729 | * @uptodate: error value or 0/1 uptodate flag | |
3730 | * | |
3731 | * Description: | |
3732 | * Ends I/O on the current segment of a request. If that is the only | |
3733 | * remaining segment, the request is also completed and freed. | |
3734 | * | |
3735 | * This is a remnant of how older block drivers handled IO completions. | |
3736 | * Modern drivers typically end IO on the full request in one go, unless | |
3737 | * they have a residual value to account for. For that case this function | |
3738 | * isn't really useful, unless the residual just happens to be the | |
3739 | * full current segment. In other words, don't use this function in new | |
3740 | * code. Either use end_request_completely(), or the | |
3741 | * end_that_request_chunk() (along with end_that_request_last()) for | |
3742 | * partial completions. | |
3743 | * | |
3744 | **/ | |
3745 | void end_request(struct request *req, int uptodate) | |
3746 | { | |
3747 | __end_request(req, uptodate, req->hard_cur_sectors << 9, 1); | |
3748 | } | |
1da177e4 LT |
3749 | EXPORT_SYMBOL(end_request); |
3750 | ||
66846572 N |
3751 | static void blk_rq_bio_prep(struct request_queue *q, struct request *rq, |
3752 | struct bio *bio) | |
1da177e4 | 3753 | { |
4aff5e23 JA |
3754 | /* first two bits are identical in rq->cmd_flags and bio->bi_rw */ |
3755 | rq->cmd_flags |= (bio->bi_rw & 3); | |
1da177e4 LT |
3756 | |
3757 | rq->nr_phys_segments = bio_phys_segments(q, bio); | |
3758 | rq->nr_hw_segments = bio_hw_segments(q, bio); | |
3759 | rq->current_nr_sectors = bio_cur_sectors(bio); | |
3760 | rq->hard_cur_sectors = rq->current_nr_sectors; | |
3761 | rq->hard_nr_sectors = rq->nr_sectors = bio_sectors(bio); | |
3762 | rq->buffer = bio_data(bio); | |
0e75f906 | 3763 | rq->data_len = bio->bi_size; |
1da177e4 LT |
3764 | |
3765 | rq->bio = rq->biotail = bio; | |
1da177e4 | 3766 | |
66846572 N |
3767 | if (bio->bi_bdev) |
3768 | rq->rq_disk = bio->bi_bdev->bd_disk; | |
3769 | } | |
1da177e4 LT |
3770 | |
3771 | int kblockd_schedule_work(struct work_struct *work) | |
3772 | { | |
3773 | return queue_work(kblockd_workqueue, work); | |
3774 | } | |
3775 | ||
3776 | EXPORT_SYMBOL(kblockd_schedule_work); | |
3777 | ||
19a75d83 | 3778 | void kblockd_flush_work(struct work_struct *work) |
1da177e4 | 3779 | { |
28e53bdd | 3780 | cancel_work_sync(work); |
1da177e4 | 3781 | } |
19a75d83 | 3782 | EXPORT_SYMBOL(kblockd_flush_work); |
1da177e4 LT |
3783 | |
3784 | int __init blk_dev_init(void) | |
3785 | { | |
ff856bad JA |
3786 | int i; |
3787 | ||
1da177e4 LT |
3788 | kblockd_workqueue = create_workqueue("kblockd"); |
3789 | if (!kblockd_workqueue) | |
3790 | panic("Failed to create kblockd\n"); | |
3791 | ||
3792 | request_cachep = kmem_cache_create("blkdev_requests", | |
20c2df83 | 3793 | sizeof(struct request), 0, SLAB_PANIC, NULL); |
1da177e4 LT |
3794 | |
3795 | requestq_cachep = kmem_cache_create("blkdev_queue", | |
165125e1 | 3796 | sizeof(struct request_queue), 0, SLAB_PANIC, NULL); |
1da177e4 LT |
3797 | |
3798 | iocontext_cachep = kmem_cache_create("blkdev_ioc", | |
20c2df83 | 3799 | sizeof(struct io_context), 0, SLAB_PANIC, NULL); |
1da177e4 | 3800 | |
0a945022 | 3801 | for_each_possible_cpu(i) |
ff856bad JA |
3802 | INIT_LIST_HEAD(&per_cpu(blk_cpu_done, i)); |
3803 | ||
3804 | open_softirq(BLOCK_SOFTIRQ, blk_done_softirq, NULL); | |
5a67e4c5 | 3805 | register_hotcpu_notifier(&blk_cpu_notifier); |
ff856bad | 3806 | |
f772b3d9 VT |
3807 | blk_max_low_pfn = max_low_pfn - 1; |
3808 | blk_max_pfn = max_pfn - 1; | |
1da177e4 LT |
3809 | |
3810 | return 0; | |
3811 | } | |
3812 | ||
3813 | /* | |
3814 | * IO Context helper functions | |
3815 | */ | |
3816 | void put_io_context(struct io_context *ioc) | |
3817 | { | |
3818 | if (ioc == NULL) | |
3819 | return; | |
3820 | ||
3821 | BUG_ON(atomic_read(&ioc->refcount) == 0); | |
3822 | ||
3823 | if (atomic_dec_and_test(&ioc->refcount)) { | |
e2d74ac0 JA |
3824 | struct cfq_io_context *cic; |
3825 | ||
334e94de | 3826 | rcu_read_lock(); |
1da177e4 LT |
3827 | if (ioc->aic && ioc->aic->dtor) |
3828 | ioc->aic->dtor(ioc->aic); | |
e2d74ac0 | 3829 | if (ioc->cic_root.rb_node != NULL) { |
7143dd4b JA |
3830 | struct rb_node *n = rb_first(&ioc->cic_root); |
3831 | ||
3832 | cic = rb_entry(n, struct cfq_io_context, rb_node); | |
e2d74ac0 JA |
3833 | cic->dtor(ioc); |
3834 | } | |
334e94de | 3835 | rcu_read_unlock(); |
1da177e4 LT |
3836 | |
3837 | kmem_cache_free(iocontext_cachep, ioc); | |
3838 | } | |
3839 | } | |
3840 | EXPORT_SYMBOL(put_io_context); | |
3841 | ||
3842 | /* Called by the exitting task */ | |
3843 | void exit_io_context(void) | |
3844 | { | |
1da177e4 | 3845 | struct io_context *ioc; |
e2d74ac0 | 3846 | struct cfq_io_context *cic; |
1da177e4 | 3847 | |
22e2c507 | 3848 | task_lock(current); |
1da177e4 LT |
3849 | ioc = current->io_context; |
3850 | current->io_context = NULL; | |
22e2c507 | 3851 | task_unlock(current); |
1da177e4 | 3852 | |
25034d7a | 3853 | ioc->task = NULL; |
1da177e4 LT |
3854 | if (ioc->aic && ioc->aic->exit) |
3855 | ioc->aic->exit(ioc->aic); | |
e2d74ac0 JA |
3856 | if (ioc->cic_root.rb_node != NULL) { |
3857 | cic = rb_entry(rb_first(&ioc->cic_root), struct cfq_io_context, rb_node); | |
3858 | cic->exit(ioc); | |
3859 | } | |
25034d7a | 3860 | |
1da177e4 LT |
3861 | put_io_context(ioc); |
3862 | } | |
3863 | ||
3864 | /* | |
3865 | * If the current task has no IO context then create one and initialise it. | |
fb3cc432 | 3866 | * Otherwise, return its existing IO context. |
1da177e4 | 3867 | * |
fb3cc432 NP |
3868 | * This returned IO context doesn't have a specifically elevated refcount, |
3869 | * but since the current task itself holds a reference, the context can be | |
3870 | * used in general code, so long as it stays within `current` context. | |
1da177e4 | 3871 | */ |
b5deef90 | 3872 | static struct io_context *current_io_context(gfp_t gfp_flags, int node) |
1da177e4 LT |
3873 | { |
3874 | struct task_struct *tsk = current; | |
1da177e4 LT |
3875 | struct io_context *ret; |
3876 | ||
1da177e4 | 3877 | ret = tsk->io_context; |
fb3cc432 NP |
3878 | if (likely(ret)) |
3879 | return ret; | |
1da177e4 | 3880 | |
b5deef90 | 3881 | ret = kmem_cache_alloc_node(iocontext_cachep, gfp_flags, node); |
1da177e4 LT |
3882 | if (ret) { |
3883 | atomic_set(&ret->refcount, 1); | |
22e2c507 | 3884 | ret->task = current; |
fc46379d | 3885 | ret->ioprio_changed = 0; |
1da177e4 LT |
3886 | ret->last_waited = jiffies; /* doesn't matter... */ |
3887 | ret->nr_batch_requests = 0; /* because this is 0 */ | |
3888 | ret->aic = NULL; | |
e2d74ac0 | 3889 | ret->cic_root.rb_node = NULL; |
4e521c27 | 3890 | ret->ioc_data = NULL; |
9f83e45e ON |
3891 | /* make sure set_task_ioprio() sees the settings above */ |
3892 | smp_wmb(); | |
fb3cc432 NP |
3893 | tsk->io_context = ret; |
3894 | } | |
1da177e4 | 3895 | |
fb3cc432 NP |
3896 | return ret; |
3897 | } | |
1da177e4 | 3898 | |
fb3cc432 NP |
3899 | /* |
3900 | * If the current task has no IO context then create one and initialise it. | |
3901 | * If it does have a context, take a ref on it. | |
3902 | * | |
3903 | * This is always called in the context of the task which submitted the I/O. | |
3904 | */ | |
b5deef90 | 3905 | struct io_context *get_io_context(gfp_t gfp_flags, int node) |
fb3cc432 NP |
3906 | { |
3907 | struct io_context *ret; | |
b5deef90 | 3908 | ret = current_io_context(gfp_flags, node); |
fb3cc432 | 3909 | if (likely(ret)) |
1da177e4 | 3910 | atomic_inc(&ret->refcount); |
1da177e4 LT |
3911 | return ret; |
3912 | } | |
3913 | EXPORT_SYMBOL(get_io_context); | |
3914 | ||
3915 | void copy_io_context(struct io_context **pdst, struct io_context **psrc) | |
3916 | { | |
3917 | struct io_context *src = *psrc; | |
3918 | struct io_context *dst = *pdst; | |
3919 | ||
3920 | if (src) { | |
3921 | BUG_ON(atomic_read(&src->refcount) == 0); | |
3922 | atomic_inc(&src->refcount); | |
3923 | put_io_context(dst); | |
3924 | *pdst = src; | |
3925 | } | |
3926 | } | |
3927 | EXPORT_SYMBOL(copy_io_context); | |
3928 | ||
3929 | void swap_io_context(struct io_context **ioc1, struct io_context **ioc2) | |
3930 | { | |
3931 | struct io_context *temp; | |
3932 | temp = *ioc1; | |
3933 | *ioc1 = *ioc2; | |
3934 | *ioc2 = temp; | |
3935 | } | |
3936 | EXPORT_SYMBOL(swap_io_context); | |
3937 | ||
3938 | /* | |
3939 | * sysfs parts below | |
3940 | */ | |
3941 | struct queue_sysfs_entry { | |
3942 | struct attribute attr; | |
3943 | ssize_t (*show)(struct request_queue *, char *); | |
3944 | ssize_t (*store)(struct request_queue *, const char *, size_t); | |
3945 | }; | |
3946 | ||
3947 | static ssize_t | |
3948 | queue_var_show(unsigned int var, char *page) | |
3949 | { | |
3950 | return sprintf(page, "%d\n", var); | |
3951 | } | |
3952 | ||
3953 | static ssize_t | |
3954 | queue_var_store(unsigned long *var, const char *page, size_t count) | |
3955 | { | |
3956 | char *p = (char *) page; | |
3957 | ||
3958 | *var = simple_strtoul(p, &p, 10); | |
3959 | return count; | |
3960 | } | |
3961 | ||
3962 | static ssize_t queue_requests_show(struct request_queue *q, char *page) | |
3963 | { | |
3964 | return queue_var_show(q->nr_requests, (page)); | |
3965 | } | |
3966 | ||
3967 | static ssize_t | |
3968 | queue_requests_store(struct request_queue *q, const char *page, size_t count) | |
3969 | { | |
3970 | struct request_list *rl = &q->rq; | |
c981ff9f AV |
3971 | unsigned long nr; |
3972 | int ret = queue_var_store(&nr, page, count); | |
3973 | if (nr < BLKDEV_MIN_RQ) | |
3974 | nr = BLKDEV_MIN_RQ; | |
1da177e4 | 3975 | |
c981ff9f AV |
3976 | spin_lock_irq(q->queue_lock); |
3977 | q->nr_requests = nr; | |
1da177e4 LT |
3978 | blk_queue_congestion_threshold(q); |
3979 | ||
3980 | if (rl->count[READ] >= queue_congestion_on_threshold(q)) | |
79e2de4b | 3981 | blk_set_queue_congested(q, READ); |
1da177e4 | 3982 | else if (rl->count[READ] < queue_congestion_off_threshold(q)) |
79e2de4b | 3983 | blk_clear_queue_congested(q, READ); |
1da177e4 LT |
3984 | |
3985 | if (rl->count[WRITE] >= queue_congestion_on_threshold(q)) | |
79e2de4b | 3986 | blk_set_queue_congested(q, WRITE); |
1da177e4 | 3987 | else if (rl->count[WRITE] < queue_congestion_off_threshold(q)) |
79e2de4b | 3988 | blk_clear_queue_congested(q, WRITE); |
1da177e4 LT |
3989 | |
3990 | if (rl->count[READ] >= q->nr_requests) { | |
3991 | blk_set_queue_full(q, READ); | |
3992 | } else if (rl->count[READ]+1 <= q->nr_requests) { | |
3993 | blk_clear_queue_full(q, READ); | |
3994 | wake_up(&rl->wait[READ]); | |
3995 | } | |
3996 | ||
3997 | if (rl->count[WRITE] >= q->nr_requests) { | |
3998 | blk_set_queue_full(q, WRITE); | |
3999 | } else if (rl->count[WRITE]+1 <= q->nr_requests) { | |
4000 | blk_clear_queue_full(q, WRITE); | |
4001 | wake_up(&rl->wait[WRITE]); | |
4002 | } | |
c981ff9f | 4003 | spin_unlock_irq(q->queue_lock); |
1da177e4 LT |
4004 | return ret; |
4005 | } | |
4006 | ||
4007 | static ssize_t queue_ra_show(struct request_queue *q, char *page) | |
4008 | { | |
4009 | int ra_kb = q->backing_dev_info.ra_pages << (PAGE_CACHE_SHIFT - 10); | |
4010 | ||
4011 | return queue_var_show(ra_kb, (page)); | |
4012 | } | |
4013 | ||
4014 | static ssize_t | |
4015 | queue_ra_store(struct request_queue *q, const char *page, size_t count) | |
4016 | { | |
4017 | unsigned long ra_kb; | |
4018 | ssize_t ret = queue_var_store(&ra_kb, page, count); | |
4019 | ||
4020 | spin_lock_irq(q->queue_lock); | |
1da177e4 LT |
4021 | q->backing_dev_info.ra_pages = ra_kb >> (PAGE_CACHE_SHIFT - 10); |
4022 | spin_unlock_irq(q->queue_lock); | |
4023 | ||
4024 | return ret; | |
4025 | } | |
4026 | ||
4027 | static ssize_t queue_max_sectors_show(struct request_queue *q, char *page) | |
4028 | { | |
4029 | int max_sectors_kb = q->max_sectors >> 1; | |
4030 | ||
4031 | return queue_var_show(max_sectors_kb, (page)); | |
4032 | } | |
4033 | ||
4034 | static ssize_t | |
4035 | queue_max_sectors_store(struct request_queue *q, const char *page, size_t count) | |
4036 | { | |
4037 | unsigned long max_sectors_kb, | |
4038 | max_hw_sectors_kb = q->max_hw_sectors >> 1, | |
4039 | page_kb = 1 << (PAGE_CACHE_SHIFT - 10); | |
4040 | ssize_t ret = queue_var_store(&max_sectors_kb, page, count); | |
4041 | int ra_kb; | |
4042 | ||
4043 | if (max_sectors_kb > max_hw_sectors_kb || max_sectors_kb < page_kb) | |
4044 | return -EINVAL; | |
4045 | /* | |
4046 | * Take the queue lock to update the readahead and max_sectors | |
4047 | * values synchronously: | |
4048 | */ | |
4049 | spin_lock_irq(q->queue_lock); | |
4050 | /* | |
4051 | * Trim readahead window as well, if necessary: | |
4052 | */ | |
4053 | ra_kb = q->backing_dev_info.ra_pages << (PAGE_CACHE_SHIFT - 10); | |
4054 | if (ra_kb > max_sectors_kb) | |
4055 | q->backing_dev_info.ra_pages = | |
4056 | max_sectors_kb >> (PAGE_CACHE_SHIFT - 10); | |
4057 | ||
4058 | q->max_sectors = max_sectors_kb << 1; | |
4059 | spin_unlock_irq(q->queue_lock); | |
4060 | ||
4061 | return ret; | |
4062 | } | |
4063 | ||
4064 | static ssize_t queue_max_hw_sectors_show(struct request_queue *q, char *page) | |
4065 | { | |
4066 | int max_hw_sectors_kb = q->max_hw_sectors >> 1; | |
4067 | ||
4068 | return queue_var_show(max_hw_sectors_kb, (page)); | |
4069 | } | |
4070 | ||
4071 | ||
4072 | static struct queue_sysfs_entry queue_requests_entry = { | |
4073 | .attr = {.name = "nr_requests", .mode = S_IRUGO | S_IWUSR }, | |
4074 | .show = queue_requests_show, | |
4075 | .store = queue_requests_store, | |
4076 | }; | |
4077 | ||
4078 | static struct queue_sysfs_entry queue_ra_entry = { | |
4079 | .attr = {.name = "read_ahead_kb", .mode = S_IRUGO | S_IWUSR }, | |
4080 | .show = queue_ra_show, | |
4081 | .store = queue_ra_store, | |
4082 | }; | |
4083 | ||
4084 | static struct queue_sysfs_entry queue_max_sectors_entry = { | |
4085 | .attr = {.name = "max_sectors_kb", .mode = S_IRUGO | S_IWUSR }, | |
4086 | .show = queue_max_sectors_show, | |
4087 | .store = queue_max_sectors_store, | |
4088 | }; | |
4089 | ||
4090 | static struct queue_sysfs_entry queue_max_hw_sectors_entry = { | |
4091 | .attr = {.name = "max_hw_sectors_kb", .mode = S_IRUGO }, | |
4092 | .show = queue_max_hw_sectors_show, | |
4093 | }; | |
4094 | ||
4095 | static struct queue_sysfs_entry queue_iosched_entry = { | |
4096 | .attr = {.name = "scheduler", .mode = S_IRUGO | S_IWUSR }, | |
4097 | .show = elv_iosched_show, | |
4098 | .store = elv_iosched_store, | |
4099 | }; | |
4100 | ||
4101 | static struct attribute *default_attrs[] = { | |
4102 | &queue_requests_entry.attr, | |
4103 | &queue_ra_entry.attr, | |
4104 | &queue_max_hw_sectors_entry.attr, | |
4105 | &queue_max_sectors_entry.attr, | |
4106 | &queue_iosched_entry.attr, | |
4107 | NULL, | |
4108 | }; | |
4109 | ||
4110 | #define to_queue(atr) container_of((atr), struct queue_sysfs_entry, attr) | |
4111 | ||
4112 | static ssize_t | |
4113 | queue_attr_show(struct kobject *kobj, struct attribute *attr, char *page) | |
4114 | { | |
4115 | struct queue_sysfs_entry *entry = to_queue(attr); | |
165125e1 JA |
4116 | struct request_queue *q = |
4117 | container_of(kobj, struct request_queue, kobj); | |
483f4afc | 4118 | ssize_t res; |
1da177e4 | 4119 | |
1da177e4 | 4120 | if (!entry->show) |
6c1852a0 | 4121 | return -EIO; |
483f4afc AV |
4122 | mutex_lock(&q->sysfs_lock); |
4123 | if (test_bit(QUEUE_FLAG_DEAD, &q->queue_flags)) { | |
4124 | mutex_unlock(&q->sysfs_lock); | |
4125 | return -ENOENT; | |
4126 | } | |
4127 | res = entry->show(q, page); | |
4128 | mutex_unlock(&q->sysfs_lock); | |
4129 | return res; | |
1da177e4 LT |
4130 | } |
4131 | ||
4132 | static ssize_t | |
4133 | queue_attr_store(struct kobject *kobj, struct attribute *attr, | |
4134 | const char *page, size_t length) | |
4135 | { | |
4136 | struct queue_sysfs_entry *entry = to_queue(attr); | |
165125e1 | 4137 | struct request_queue *q = container_of(kobj, struct request_queue, kobj); |
483f4afc AV |
4138 | |
4139 | ssize_t res; | |
1da177e4 | 4140 | |
1da177e4 | 4141 | if (!entry->store) |
6c1852a0 | 4142 | return -EIO; |
483f4afc AV |
4143 | mutex_lock(&q->sysfs_lock); |
4144 | if (test_bit(QUEUE_FLAG_DEAD, &q->queue_flags)) { | |
4145 | mutex_unlock(&q->sysfs_lock); | |
4146 | return -ENOENT; | |
4147 | } | |
4148 | res = entry->store(q, page, length); | |
4149 | mutex_unlock(&q->sysfs_lock); | |
4150 | return res; | |
1da177e4 LT |
4151 | } |
4152 | ||
4153 | static struct sysfs_ops queue_sysfs_ops = { | |
4154 | .show = queue_attr_show, | |
4155 | .store = queue_attr_store, | |
4156 | }; | |
4157 | ||
93d17d3d | 4158 | static struct kobj_type queue_ktype = { |
1da177e4 LT |
4159 | .sysfs_ops = &queue_sysfs_ops, |
4160 | .default_attrs = default_attrs, | |
483f4afc | 4161 | .release = blk_release_queue, |
1da177e4 LT |
4162 | }; |
4163 | ||
4164 | int blk_register_queue(struct gendisk *disk) | |
4165 | { | |
4166 | int ret; | |
4167 | ||
165125e1 | 4168 | struct request_queue *q = disk->queue; |
1da177e4 LT |
4169 | |
4170 | if (!q || !q->request_fn) | |
4171 | return -ENXIO; | |
4172 | ||
4173 | q->kobj.parent = kobject_get(&disk->kobj); | |
1da177e4 | 4174 | |
483f4afc | 4175 | ret = kobject_add(&q->kobj); |
1da177e4 LT |
4176 | if (ret < 0) |
4177 | return ret; | |
4178 | ||
483f4afc AV |
4179 | kobject_uevent(&q->kobj, KOBJ_ADD); |
4180 | ||
1da177e4 LT |
4181 | ret = elv_register_queue(q); |
4182 | if (ret) { | |
483f4afc AV |
4183 | kobject_uevent(&q->kobj, KOBJ_REMOVE); |
4184 | kobject_del(&q->kobj); | |
1da177e4 LT |
4185 | return ret; |
4186 | } | |
4187 | ||
4188 | return 0; | |
4189 | } | |
4190 | ||
4191 | void blk_unregister_queue(struct gendisk *disk) | |
4192 | { | |
165125e1 | 4193 | struct request_queue *q = disk->queue; |
1da177e4 LT |
4194 | |
4195 | if (q && q->request_fn) { | |
4196 | elv_unregister_queue(q); | |
4197 | ||
483f4afc AV |
4198 | kobject_uevent(&q->kobj, KOBJ_REMOVE); |
4199 | kobject_del(&q->kobj); | |
1da177e4 LT |
4200 | kobject_put(&disk->kobj); |
4201 | } | |
4202 | } |