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