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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> | |
6728cb0e JA |
6 | * kernel-doc documentation started by NeilBrown <neilb@cse.unsw.edu.au> |
7 | * - July2000 | |
1da177e4 LT |
8 | * bio rewrite, highmem i/o, etc, Jens Axboe <axboe@suse.de> - may 2001 |
9 | */ | |
10 | ||
11 | /* | |
12 | * This handles all read/write requests to block devices | |
13 | */ | |
1da177e4 LT |
14 | #include <linux/kernel.h> |
15 | #include <linux/module.h> | |
16 | #include <linux/backing-dev.h> | |
17 | #include <linux/bio.h> | |
18 | #include <linux/blkdev.h> | |
320ae51f | 19 | #include <linux/blk-mq.h> |
1da177e4 LT |
20 | #include <linux/highmem.h> |
21 | #include <linux/mm.h> | |
22 | #include <linux/kernel_stat.h> | |
23 | #include <linux/string.h> | |
24 | #include <linux/init.h> | |
1da177e4 LT |
25 | #include <linux/completion.h> |
26 | #include <linux/slab.h> | |
27 | #include <linux/swap.h> | |
28 | #include <linux/writeback.h> | |
faccbd4b | 29 | #include <linux/task_io_accounting_ops.h> |
c17bb495 | 30 | #include <linux/fault-inject.h> |
73c10101 | 31 | #include <linux/list_sort.h> |
e3c78ca5 | 32 | #include <linux/delay.h> |
aaf7c680 | 33 | #include <linux/ratelimit.h> |
6c954667 | 34 | #include <linux/pm_runtime.h> |
eea8f41c | 35 | #include <linux/blk-cgroup.h> |
18fbda91 | 36 | #include <linux/debugfs.h> |
30abb3a6 | 37 | #include <linux/bpf.h> |
55782138 LZ |
38 | |
39 | #define CREATE_TRACE_POINTS | |
40 | #include <trace/events/block.h> | |
1da177e4 | 41 | |
8324aa91 | 42 | #include "blk.h" |
43a5e4e2 | 43 | #include "blk-mq.h" |
bd166ef1 | 44 | #include "blk-mq-sched.h" |
bca6b067 | 45 | #include "blk-pm.h" |
c1c80384 | 46 | #include "blk-rq-qos.h" |
8324aa91 | 47 | |
18fbda91 OS |
48 | #ifdef CONFIG_DEBUG_FS |
49 | struct dentry *blk_debugfs_root; | |
50 | #endif | |
51 | ||
d07335e5 | 52 | EXPORT_TRACEPOINT_SYMBOL_GPL(block_bio_remap); |
b0da3f0d | 53 | EXPORT_TRACEPOINT_SYMBOL_GPL(block_rq_remap); |
0a82a8d1 | 54 | EXPORT_TRACEPOINT_SYMBOL_GPL(block_bio_complete); |
3291fa57 | 55 | EXPORT_TRACEPOINT_SYMBOL_GPL(block_split); |
cbae8d45 | 56 | EXPORT_TRACEPOINT_SYMBOL_GPL(block_unplug); |
0bfc2455 | 57 | |
a73f730d TH |
58 | DEFINE_IDA(blk_queue_ida); |
59 | ||
1da177e4 LT |
60 | /* |
61 | * For the allocated request tables | |
62 | */ | |
d674d414 | 63 | struct kmem_cache *request_cachep; |
1da177e4 LT |
64 | |
65 | /* | |
66 | * For queue allocation | |
67 | */ | |
6728cb0e | 68 | struct kmem_cache *blk_requestq_cachep; |
1da177e4 | 69 | |
1da177e4 LT |
70 | /* |
71 | * Controlling structure to kblockd | |
72 | */ | |
ff856bad | 73 | static struct workqueue_struct *kblockd_workqueue; |
1da177e4 | 74 | |
8814ce8a BVA |
75 | /** |
76 | * blk_queue_flag_set - atomically set a queue flag | |
77 | * @flag: flag to be set | |
78 | * @q: request queue | |
79 | */ | |
80 | void blk_queue_flag_set(unsigned int flag, struct request_queue *q) | |
81 | { | |
82 | unsigned long flags; | |
83 | ||
84 | spin_lock_irqsave(q->queue_lock, flags); | |
85 | queue_flag_set(flag, q); | |
86 | spin_unlock_irqrestore(q->queue_lock, flags); | |
87 | } | |
88 | EXPORT_SYMBOL(blk_queue_flag_set); | |
89 | ||
90 | /** | |
91 | * blk_queue_flag_clear - atomically clear a queue flag | |
92 | * @flag: flag to be cleared | |
93 | * @q: request queue | |
94 | */ | |
95 | void blk_queue_flag_clear(unsigned int flag, struct request_queue *q) | |
96 | { | |
97 | unsigned long flags; | |
98 | ||
99 | spin_lock_irqsave(q->queue_lock, flags); | |
100 | queue_flag_clear(flag, q); | |
101 | spin_unlock_irqrestore(q->queue_lock, flags); | |
102 | } | |
103 | EXPORT_SYMBOL(blk_queue_flag_clear); | |
104 | ||
105 | /** | |
106 | * blk_queue_flag_test_and_set - atomically test and set a queue flag | |
107 | * @flag: flag to be set | |
108 | * @q: request queue | |
109 | * | |
110 | * Returns the previous value of @flag - 0 if the flag was not set and 1 if | |
111 | * the flag was already set. | |
112 | */ | |
113 | bool blk_queue_flag_test_and_set(unsigned int flag, struct request_queue *q) | |
114 | { | |
115 | unsigned long flags; | |
116 | bool res; | |
117 | ||
118 | spin_lock_irqsave(q->queue_lock, flags); | |
119 | res = queue_flag_test_and_set(flag, q); | |
120 | spin_unlock_irqrestore(q->queue_lock, flags); | |
121 | ||
122 | return res; | |
123 | } | |
124 | EXPORT_SYMBOL_GPL(blk_queue_flag_test_and_set); | |
125 | ||
126 | /** | |
127 | * blk_queue_flag_test_and_clear - atomically test and clear a queue flag | |
128 | * @flag: flag to be cleared | |
129 | * @q: request queue | |
130 | * | |
131 | * Returns the previous value of @flag - 0 if the flag was not set and 1 if | |
132 | * the flag was set. | |
133 | */ | |
134 | bool blk_queue_flag_test_and_clear(unsigned int flag, struct request_queue *q) | |
135 | { | |
136 | unsigned long flags; | |
137 | bool res; | |
138 | ||
139 | spin_lock_irqsave(q->queue_lock, flags); | |
140 | res = queue_flag_test_and_clear(flag, q); | |
141 | spin_unlock_irqrestore(q->queue_lock, flags); | |
142 | ||
143 | return res; | |
144 | } | |
145 | EXPORT_SYMBOL_GPL(blk_queue_flag_test_and_clear); | |
146 | ||
d40f75a0 TH |
147 | static void blk_clear_congested(struct request_list *rl, int sync) |
148 | { | |
d40f75a0 TH |
149 | #ifdef CONFIG_CGROUP_WRITEBACK |
150 | clear_wb_congested(rl->blkg->wb_congested, sync); | |
151 | #else | |
482cf79c TH |
152 | /* |
153 | * If !CGROUP_WRITEBACK, all blkg's map to bdi->wb and we shouldn't | |
154 | * flip its congestion state for events on other blkcgs. | |
155 | */ | |
156 | if (rl == &rl->q->root_rl) | |
dc3b17cc | 157 | clear_wb_congested(rl->q->backing_dev_info->wb.congested, sync); |
d40f75a0 TH |
158 | #endif |
159 | } | |
160 | ||
161 | static void blk_set_congested(struct request_list *rl, int sync) | |
162 | { | |
d40f75a0 TH |
163 | #ifdef CONFIG_CGROUP_WRITEBACK |
164 | set_wb_congested(rl->blkg->wb_congested, sync); | |
165 | #else | |
482cf79c TH |
166 | /* see blk_clear_congested() */ |
167 | if (rl == &rl->q->root_rl) | |
dc3b17cc | 168 | set_wb_congested(rl->q->backing_dev_info->wb.congested, sync); |
d40f75a0 TH |
169 | #endif |
170 | } | |
171 | ||
8324aa91 | 172 | void blk_queue_congestion_threshold(struct request_queue *q) |
1da177e4 LT |
173 | { |
174 | int nr; | |
175 | ||
176 | nr = q->nr_requests - (q->nr_requests / 8) + 1; | |
177 | if (nr > q->nr_requests) | |
178 | nr = q->nr_requests; | |
179 | q->nr_congestion_on = nr; | |
180 | ||
181 | nr = q->nr_requests - (q->nr_requests / 8) - (q->nr_requests / 16) - 1; | |
182 | if (nr < 1) | |
183 | nr = 1; | |
184 | q->nr_congestion_off = nr; | |
185 | } | |
186 | ||
2a4aa30c | 187 | void blk_rq_init(struct request_queue *q, struct request *rq) |
1da177e4 | 188 | { |
1afb20f3 FT |
189 | memset(rq, 0, sizeof(*rq)); |
190 | ||
1da177e4 | 191 | INIT_LIST_HEAD(&rq->queuelist); |
242f9dcb | 192 | INIT_LIST_HEAD(&rq->timeout_list); |
c7c22e4d | 193 | rq->cpu = -1; |
63a71386 | 194 | rq->q = q; |
a2dec7b3 | 195 | rq->__sector = (sector_t) -1; |
2e662b65 JA |
196 | INIT_HLIST_NODE(&rq->hash); |
197 | RB_CLEAR_NODE(&rq->rb_node); | |
63a71386 | 198 | rq->tag = -1; |
bd166ef1 | 199 | rq->internal_tag = -1; |
522a7775 | 200 | rq->start_time_ns = ktime_get_ns(); |
09e099d4 | 201 | rq->part = NULL; |
1da177e4 | 202 | } |
2a4aa30c | 203 | EXPORT_SYMBOL(blk_rq_init); |
1da177e4 | 204 | |
2a842aca CH |
205 | static const struct { |
206 | int errno; | |
207 | const char *name; | |
208 | } blk_errors[] = { | |
209 | [BLK_STS_OK] = { 0, "" }, | |
210 | [BLK_STS_NOTSUPP] = { -EOPNOTSUPP, "operation not supported" }, | |
211 | [BLK_STS_TIMEOUT] = { -ETIMEDOUT, "timeout" }, | |
212 | [BLK_STS_NOSPC] = { -ENOSPC, "critical space allocation" }, | |
213 | [BLK_STS_TRANSPORT] = { -ENOLINK, "recoverable transport" }, | |
214 | [BLK_STS_TARGET] = { -EREMOTEIO, "critical target" }, | |
215 | [BLK_STS_NEXUS] = { -EBADE, "critical nexus" }, | |
216 | [BLK_STS_MEDIUM] = { -ENODATA, "critical medium" }, | |
217 | [BLK_STS_PROTECTION] = { -EILSEQ, "protection" }, | |
218 | [BLK_STS_RESOURCE] = { -ENOMEM, "kernel resource" }, | |
86ff7c2a | 219 | [BLK_STS_DEV_RESOURCE] = { -EBUSY, "device resource" }, |
03a07c92 | 220 | [BLK_STS_AGAIN] = { -EAGAIN, "nonblocking retry" }, |
2a842aca | 221 | |
4e4cbee9 CH |
222 | /* device mapper special case, should not leak out: */ |
223 | [BLK_STS_DM_REQUEUE] = { -EREMCHG, "dm internal retry" }, | |
224 | ||
2a842aca CH |
225 | /* everything else not covered above: */ |
226 | [BLK_STS_IOERR] = { -EIO, "I/O" }, | |
227 | }; | |
228 | ||
229 | blk_status_t errno_to_blk_status(int errno) | |
230 | { | |
231 | int i; | |
232 | ||
233 | for (i = 0; i < ARRAY_SIZE(blk_errors); i++) { | |
234 | if (blk_errors[i].errno == errno) | |
235 | return (__force blk_status_t)i; | |
236 | } | |
237 | ||
238 | return BLK_STS_IOERR; | |
239 | } | |
240 | EXPORT_SYMBOL_GPL(errno_to_blk_status); | |
241 | ||
242 | int blk_status_to_errno(blk_status_t status) | |
243 | { | |
244 | int idx = (__force int)status; | |
245 | ||
34bd9c1c | 246 | if (WARN_ON_ONCE(idx >= ARRAY_SIZE(blk_errors))) |
2a842aca CH |
247 | return -EIO; |
248 | return blk_errors[idx].errno; | |
249 | } | |
250 | EXPORT_SYMBOL_GPL(blk_status_to_errno); | |
251 | ||
252 | static void print_req_error(struct request *req, blk_status_t status) | |
253 | { | |
254 | int idx = (__force int)status; | |
255 | ||
34bd9c1c | 256 | if (WARN_ON_ONCE(idx >= ARRAY_SIZE(blk_errors))) |
2a842aca CH |
257 | return; |
258 | ||
259 | printk_ratelimited(KERN_ERR "%s: %s error, dev %s, sector %llu\n", | |
260 | __func__, blk_errors[idx].name, req->rq_disk ? | |
261 | req->rq_disk->disk_name : "?", | |
262 | (unsigned long long)blk_rq_pos(req)); | |
263 | } | |
264 | ||
5bb23a68 | 265 | static void req_bio_endio(struct request *rq, struct bio *bio, |
2a842aca | 266 | unsigned int nbytes, blk_status_t error) |
1da177e4 | 267 | { |
78d8e58a | 268 | if (error) |
4e4cbee9 | 269 | bio->bi_status = error; |
797e7dbb | 270 | |
e8064021 | 271 | if (unlikely(rq->rq_flags & RQF_QUIET)) |
b7c44ed9 | 272 | bio_set_flag(bio, BIO_QUIET); |
08bafc03 | 273 | |
f79ea416 | 274 | bio_advance(bio, nbytes); |
7ba1ba12 | 275 | |
143a87f4 | 276 | /* don't actually finish bio if it's part of flush sequence */ |
e8064021 | 277 | if (bio->bi_iter.bi_size == 0 && !(rq->rq_flags & RQF_FLUSH_SEQ)) |
4246a0b6 | 278 | bio_endio(bio); |
1da177e4 | 279 | } |
1da177e4 | 280 | |
1da177e4 LT |
281 | void blk_dump_rq_flags(struct request *rq, char *msg) |
282 | { | |
aebf526b CH |
283 | printk(KERN_INFO "%s: dev %s: flags=%llx\n", msg, |
284 | rq->rq_disk ? rq->rq_disk->disk_name : "?", | |
5953316d | 285 | (unsigned long long) rq->cmd_flags); |
1da177e4 | 286 | |
83096ebf TH |
287 | printk(KERN_INFO " sector %llu, nr/cnr %u/%u\n", |
288 | (unsigned long long)blk_rq_pos(rq), | |
289 | blk_rq_sectors(rq), blk_rq_cur_sectors(rq)); | |
b4f42e28 JA |
290 | printk(KERN_INFO " bio %p, biotail %p, len %u\n", |
291 | rq->bio, rq->biotail, blk_rq_bytes(rq)); | |
1da177e4 | 292 | } |
1da177e4 LT |
293 | EXPORT_SYMBOL(blk_dump_rq_flags); |
294 | ||
3cca6dc1 | 295 | static void blk_delay_work(struct work_struct *work) |
1da177e4 | 296 | { |
3cca6dc1 | 297 | struct request_queue *q; |
1da177e4 | 298 | |
3cca6dc1 JA |
299 | q = container_of(work, struct request_queue, delay_work.work); |
300 | spin_lock_irq(q->queue_lock); | |
24ecfbe2 | 301 | __blk_run_queue(q); |
3cca6dc1 | 302 | spin_unlock_irq(q->queue_lock); |
1da177e4 | 303 | } |
1da177e4 LT |
304 | |
305 | /** | |
3cca6dc1 JA |
306 | * blk_delay_queue - restart queueing after defined interval |
307 | * @q: The &struct request_queue in question | |
308 | * @msecs: Delay in msecs | |
1da177e4 LT |
309 | * |
310 | * Description: | |
3cca6dc1 JA |
311 | * Sometimes queueing needs to be postponed for a little while, to allow |
312 | * resources to come back. This function will make sure that queueing is | |
2fff8a92 | 313 | * restarted around the specified time. |
3cca6dc1 JA |
314 | */ |
315 | void blk_delay_queue(struct request_queue *q, unsigned long msecs) | |
2ad8b1ef | 316 | { |
2fff8a92 | 317 | lockdep_assert_held(q->queue_lock); |
332ebbf7 | 318 | WARN_ON_ONCE(q->mq_ops); |
2fff8a92 | 319 | |
70460571 BVA |
320 | if (likely(!blk_queue_dead(q))) |
321 | queue_delayed_work(kblockd_workqueue, &q->delay_work, | |
322 | msecs_to_jiffies(msecs)); | |
2ad8b1ef | 323 | } |
3cca6dc1 | 324 | EXPORT_SYMBOL(blk_delay_queue); |
2ad8b1ef | 325 | |
21491412 JA |
326 | /** |
327 | * blk_start_queue_async - asynchronously restart a previously stopped queue | |
328 | * @q: The &struct request_queue in question | |
329 | * | |
330 | * Description: | |
331 | * blk_start_queue_async() will clear the stop flag on the queue, and | |
332 | * ensure that the request_fn for the queue is run from an async | |
333 | * context. | |
334 | **/ | |
335 | void blk_start_queue_async(struct request_queue *q) | |
336 | { | |
2fff8a92 | 337 | lockdep_assert_held(q->queue_lock); |
332ebbf7 | 338 | WARN_ON_ONCE(q->mq_ops); |
2fff8a92 | 339 | |
21491412 JA |
340 | queue_flag_clear(QUEUE_FLAG_STOPPED, q); |
341 | blk_run_queue_async(q); | |
342 | } | |
343 | EXPORT_SYMBOL(blk_start_queue_async); | |
344 | ||
1da177e4 LT |
345 | /** |
346 | * blk_start_queue - restart a previously stopped queue | |
165125e1 | 347 | * @q: The &struct request_queue in question |
1da177e4 LT |
348 | * |
349 | * Description: | |
350 | * blk_start_queue() will clear the stop flag on the queue, and call | |
351 | * the request_fn for the queue if it was in a stopped state when | |
2fff8a92 | 352 | * entered. Also see blk_stop_queue(). |
1da177e4 | 353 | **/ |
165125e1 | 354 | void blk_start_queue(struct request_queue *q) |
1da177e4 | 355 | { |
2fff8a92 | 356 | lockdep_assert_held(q->queue_lock); |
332ebbf7 | 357 | WARN_ON_ONCE(q->mq_ops); |
a038e253 | 358 | |
75ad23bc | 359 | queue_flag_clear(QUEUE_FLAG_STOPPED, q); |
24ecfbe2 | 360 | __blk_run_queue(q); |
1da177e4 | 361 | } |
1da177e4 LT |
362 | EXPORT_SYMBOL(blk_start_queue); |
363 | ||
364 | /** | |
365 | * blk_stop_queue - stop a queue | |
165125e1 | 366 | * @q: The &struct request_queue in question |
1da177e4 LT |
367 | * |
368 | * Description: | |
369 | * The Linux block layer assumes that a block driver will consume all | |
370 | * entries on the request queue when the request_fn strategy is called. | |
371 | * Often this will not happen, because of hardware limitations (queue | |
372 | * depth settings). If a device driver gets a 'queue full' response, | |
373 | * or if it simply chooses not to queue more I/O at one point, it can | |
374 | * call this function to prevent the request_fn from being called until | |
375 | * the driver has signalled it's ready to go again. This happens by calling | |
2fff8a92 | 376 | * blk_start_queue() to restart queue operations. |
1da177e4 | 377 | **/ |
165125e1 | 378 | void blk_stop_queue(struct request_queue *q) |
1da177e4 | 379 | { |
2fff8a92 | 380 | lockdep_assert_held(q->queue_lock); |
332ebbf7 | 381 | WARN_ON_ONCE(q->mq_ops); |
2fff8a92 | 382 | |
136b5721 | 383 | cancel_delayed_work(&q->delay_work); |
75ad23bc | 384 | queue_flag_set(QUEUE_FLAG_STOPPED, q); |
1da177e4 LT |
385 | } |
386 | EXPORT_SYMBOL(blk_stop_queue); | |
387 | ||
388 | /** | |
389 | * blk_sync_queue - cancel any pending callbacks on a queue | |
390 | * @q: the queue | |
391 | * | |
392 | * Description: | |
393 | * The block layer may perform asynchronous callback activity | |
394 | * on a queue, such as calling the unplug function after a timeout. | |
395 | * A block device may call blk_sync_queue to ensure that any | |
396 | * such activity is cancelled, thus allowing it to release resources | |
59c51591 | 397 | * that the callbacks might use. The caller must already have made sure |
1da177e4 LT |
398 | * that its ->make_request_fn will not re-add plugging prior to calling |
399 | * this function. | |
400 | * | |
da527770 | 401 | * This function does not cancel any asynchronous activity arising |
da3dae54 | 402 | * out of elevator or throttling code. That would require elevator_exit() |
5efd6113 | 403 | * and blkcg_exit_queue() to be called with queue lock initialized. |
da527770 | 404 | * |
1da177e4 LT |
405 | */ |
406 | void blk_sync_queue(struct request_queue *q) | |
407 | { | |
70ed28b9 | 408 | del_timer_sync(&q->timeout); |
4e9b6f20 | 409 | cancel_work_sync(&q->timeout_work); |
f04c1fe7 ML |
410 | |
411 | if (q->mq_ops) { | |
412 | struct blk_mq_hw_ctx *hctx; | |
413 | int i; | |
414 | ||
aba7afc5 | 415 | cancel_delayed_work_sync(&q->requeue_work); |
21c6e939 | 416 | queue_for_each_hw_ctx(q, hctx, i) |
9f993737 | 417 | cancel_delayed_work_sync(&hctx->run_work); |
f04c1fe7 ML |
418 | } else { |
419 | cancel_delayed_work_sync(&q->delay_work); | |
420 | } | |
1da177e4 LT |
421 | } |
422 | EXPORT_SYMBOL(blk_sync_queue); | |
423 | ||
c9254f2d | 424 | /** |
cd84a62e | 425 | * blk_set_pm_only - increment pm_only counter |
c9254f2d | 426 | * @q: request queue pointer |
c9254f2d | 427 | */ |
cd84a62e | 428 | void blk_set_pm_only(struct request_queue *q) |
c9254f2d | 429 | { |
cd84a62e | 430 | atomic_inc(&q->pm_only); |
c9254f2d | 431 | } |
cd84a62e | 432 | EXPORT_SYMBOL_GPL(blk_set_pm_only); |
c9254f2d | 433 | |
cd84a62e | 434 | void blk_clear_pm_only(struct request_queue *q) |
c9254f2d | 435 | { |
cd84a62e BVA |
436 | int pm_only; |
437 | ||
438 | pm_only = atomic_dec_return(&q->pm_only); | |
439 | WARN_ON_ONCE(pm_only < 0); | |
440 | if (pm_only == 0) | |
441 | wake_up_all(&q->mq_freeze_wq); | |
c9254f2d | 442 | } |
cd84a62e | 443 | EXPORT_SYMBOL_GPL(blk_clear_pm_only); |
c9254f2d | 444 | |
c246e80d BVA |
445 | /** |
446 | * __blk_run_queue_uncond - run a queue whether or not it has been stopped | |
447 | * @q: The queue to run | |
448 | * | |
449 | * Description: | |
450 | * Invoke request handling on a queue if there are any pending requests. | |
451 | * May be used to restart request handling after a request has completed. | |
452 | * This variant runs the queue whether or not the queue has been | |
453 | * stopped. Must be called with the queue lock held and interrupts | |
454 | * disabled. See also @blk_run_queue. | |
455 | */ | |
456 | inline void __blk_run_queue_uncond(struct request_queue *q) | |
457 | { | |
2fff8a92 | 458 | lockdep_assert_held(q->queue_lock); |
332ebbf7 | 459 | WARN_ON_ONCE(q->mq_ops); |
2fff8a92 | 460 | |
c246e80d BVA |
461 | if (unlikely(blk_queue_dead(q))) |
462 | return; | |
463 | ||
24faf6f6 BVA |
464 | /* |
465 | * Some request_fn implementations, e.g. scsi_request_fn(), unlock | |
466 | * the queue lock internally. As a result multiple threads may be | |
467 | * running such a request function concurrently. Keep track of the | |
468 | * number of active request_fn invocations such that blk_drain_queue() | |
469 | * can wait until all these request_fn calls have finished. | |
470 | */ | |
471 | q->request_fn_active++; | |
c246e80d | 472 | q->request_fn(q); |
24faf6f6 | 473 | q->request_fn_active--; |
c246e80d | 474 | } |
a7928c15 | 475 | EXPORT_SYMBOL_GPL(__blk_run_queue_uncond); |
c246e80d | 476 | |
1da177e4 | 477 | /** |
80a4b58e | 478 | * __blk_run_queue - run a single device queue |
1da177e4 | 479 | * @q: The queue to run |
80a4b58e JA |
480 | * |
481 | * Description: | |
2fff8a92 | 482 | * See @blk_run_queue. |
1da177e4 | 483 | */ |
24ecfbe2 | 484 | void __blk_run_queue(struct request_queue *q) |
1da177e4 | 485 | { |
2fff8a92 | 486 | lockdep_assert_held(q->queue_lock); |
332ebbf7 | 487 | WARN_ON_ONCE(q->mq_ops); |
2fff8a92 | 488 | |
a538cd03 TH |
489 | if (unlikely(blk_queue_stopped(q))) |
490 | return; | |
491 | ||
c246e80d | 492 | __blk_run_queue_uncond(q); |
75ad23bc NP |
493 | } |
494 | EXPORT_SYMBOL(__blk_run_queue); | |
dac07ec1 | 495 | |
24ecfbe2 CH |
496 | /** |
497 | * blk_run_queue_async - run a single device queue in workqueue context | |
498 | * @q: The queue to run | |
499 | * | |
500 | * Description: | |
501 | * Tells kblockd to perform the equivalent of @blk_run_queue on behalf | |
2fff8a92 BVA |
502 | * of us. |
503 | * | |
504 | * Note: | |
505 | * Since it is not allowed to run q->delay_work after blk_cleanup_queue() | |
506 | * has canceled q->delay_work, callers must hold the queue lock to avoid | |
507 | * race conditions between blk_cleanup_queue() and blk_run_queue_async(). | |
24ecfbe2 CH |
508 | */ |
509 | void blk_run_queue_async(struct request_queue *q) | |
510 | { | |
2fff8a92 | 511 | lockdep_assert_held(q->queue_lock); |
332ebbf7 | 512 | WARN_ON_ONCE(q->mq_ops); |
2fff8a92 | 513 | |
70460571 | 514 | if (likely(!blk_queue_stopped(q) && !blk_queue_dead(q))) |
e7c2f967 | 515 | mod_delayed_work(kblockd_workqueue, &q->delay_work, 0); |
24ecfbe2 | 516 | } |
c21e6beb | 517 | EXPORT_SYMBOL(blk_run_queue_async); |
24ecfbe2 | 518 | |
75ad23bc NP |
519 | /** |
520 | * blk_run_queue - run a single device queue | |
521 | * @q: The queue to run | |
80a4b58e JA |
522 | * |
523 | * Description: | |
524 | * Invoke request handling on this queue, if it has pending work to do. | |
a7f55792 | 525 | * May be used to restart queueing when a request has completed. |
75ad23bc NP |
526 | */ |
527 | void blk_run_queue(struct request_queue *q) | |
528 | { | |
529 | unsigned long flags; | |
530 | ||
332ebbf7 BVA |
531 | WARN_ON_ONCE(q->mq_ops); |
532 | ||
75ad23bc | 533 | spin_lock_irqsave(q->queue_lock, flags); |
24ecfbe2 | 534 | __blk_run_queue(q); |
1da177e4 LT |
535 | spin_unlock_irqrestore(q->queue_lock, flags); |
536 | } | |
537 | EXPORT_SYMBOL(blk_run_queue); | |
538 | ||
165125e1 | 539 | void blk_put_queue(struct request_queue *q) |
483f4afc AV |
540 | { |
541 | kobject_put(&q->kobj); | |
542 | } | |
d86e0e83 | 543 | EXPORT_SYMBOL(blk_put_queue); |
483f4afc | 544 | |
e3c78ca5 | 545 | /** |
807592a4 | 546 | * __blk_drain_queue - drain requests from request_queue |
e3c78ca5 | 547 | * @q: queue to drain |
c9a929dd | 548 | * @drain_all: whether to drain all requests or only the ones w/ ELVPRIV |
e3c78ca5 | 549 | * |
c9a929dd TH |
550 | * Drain requests from @q. If @drain_all is set, all requests are drained. |
551 | * If not, only ELVPRIV requests are drained. The caller is responsible | |
552 | * for ensuring that no new requests which need to be drained are queued. | |
e3c78ca5 | 553 | */ |
807592a4 BVA |
554 | static void __blk_drain_queue(struct request_queue *q, bool drain_all) |
555 | __releases(q->queue_lock) | |
556 | __acquires(q->queue_lock) | |
e3c78ca5 | 557 | { |
458f27a9 AH |
558 | int i; |
559 | ||
807592a4 | 560 | lockdep_assert_held(q->queue_lock); |
332ebbf7 | 561 | WARN_ON_ONCE(q->mq_ops); |
807592a4 | 562 | |
e3c78ca5 | 563 | while (true) { |
481a7d64 | 564 | bool drain = false; |
e3c78ca5 | 565 | |
b855b04a TH |
566 | /* |
567 | * The caller might be trying to drain @q before its | |
568 | * elevator is initialized. | |
569 | */ | |
570 | if (q->elevator) | |
571 | elv_drain_elevator(q); | |
572 | ||
5efd6113 | 573 | blkcg_drain_queue(q); |
e3c78ca5 | 574 | |
4eabc941 TH |
575 | /* |
576 | * This function might be called on a queue which failed | |
b855b04a TH |
577 | * driver init after queue creation or is not yet fully |
578 | * active yet. Some drivers (e.g. fd and loop) get unhappy | |
579 | * in such cases. Kick queue iff dispatch queue has | |
580 | * something on it and @q has request_fn set. | |
4eabc941 | 581 | */ |
b855b04a | 582 | if (!list_empty(&q->queue_head) && q->request_fn) |
4eabc941 | 583 | __blk_run_queue(q); |
c9a929dd | 584 | |
8a5ecdd4 | 585 | drain |= q->nr_rqs_elvpriv; |
24faf6f6 | 586 | drain |= q->request_fn_active; |
481a7d64 TH |
587 | |
588 | /* | |
589 | * Unfortunately, requests are queued at and tracked from | |
590 | * multiple places and there's no single counter which can | |
591 | * be drained. Check all the queues and counters. | |
592 | */ | |
593 | if (drain_all) { | |
e97c293c | 594 | struct blk_flush_queue *fq = blk_get_flush_queue(q, NULL); |
481a7d64 TH |
595 | drain |= !list_empty(&q->queue_head); |
596 | for (i = 0; i < 2; i++) { | |
8a5ecdd4 | 597 | drain |= q->nr_rqs[i]; |
481a7d64 | 598 | drain |= q->in_flight[i]; |
7c94e1c1 ML |
599 | if (fq) |
600 | drain |= !list_empty(&fq->flush_queue[i]); | |
481a7d64 TH |
601 | } |
602 | } | |
e3c78ca5 | 603 | |
481a7d64 | 604 | if (!drain) |
e3c78ca5 | 605 | break; |
807592a4 BVA |
606 | |
607 | spin_unlock_irq(q->queue_lock); | |
608 | ||
e3c78ca5 | 609 | msleep(10); |
807592a4 BVA |
610 | |
611 | spin_lock_irq(q->queue_lock); | |
e3c78ca5 | 612 | } |
458f27a9 AH |
613 | |
614 | /* | |
615 | * With queue marked dead, any woken up waiter will fail the | |
616 | * allocation path, so the wakeup chaining is lost and we're | |
617 | * left with hung waiters. We need to wake up those waiters. | |
618 | */ | |
619 | if (q->request_fn) { | |
a051661c TH |
620 | struct request_list *rl; |
621 | ||
a051661c TH |
622 | blk_queue_for_each_rl(rl, q) |
623 | for (i = 0; i < ARRAY_SIZE(rl->wait); i++) | |
624 | wake_up_all(&rl->wait[i]); | |
458f27a9 | 625 | } |
e3c78ca5 TH |
626 | } |
627 | ||
454be724 ML |
628 | void blk_drain_queue(struct request_queue *q) |
629 | { | |
630 | spin_lock_irq(q->queue_lock); | |
631 | __blk_drain_queue(q, true); | |
632 | spin_unlock_irq(q->queue_lock); | |
633 | } | |
634 | ||
d732580b TH |
635 | /** |
636 | * blk_queue_bypass_start - enter queue bypass mode | |
637 | * @q: queue of interest | |
638 | * | |
639 | * In bypass mode, only the dispatch FIFO queue of @q is used. This | |
640 | * function makes @q enter bypass mode and drains all requests which were | |
6ecf23af | 641 | * throttled or issued before. On return, it's guaranteed that no request |
80fd9979 TH |
642 | * is being throttled or has ELVPRIV set and blk_queue_bypass() %true |
643 | * inside queue or RCU read lock. | |
d732580b TH |
644 | */ |
645 | void blk_queue_bypass_start(struct request_queue *q) | |
646 | { | |
332ebbf7 BVA |
647 | WARN_ON_ONCE(q->mq_ops); |
648 | ||
d732580b | 649 | spin_lock_irq(q->queue_lock); |
776687bc | 650 | q->bypass_depth++; |
d732580b TH |
651 | queue_flag_set(QUEUE_FLAG_BYPASS, q); |
652 | spin_unlock_irq(q->queue_lock); | |
653 | ||
776687bc TH |
654 | /* |
655 | * Queues start drained. Skip actual draining till init is | |
656 | * complete. This avoids lenghty delays during queue init which | |
657 | * can happen many times during boot. | |
658 | */ | |
659 | if (blk_queue_init_done(q)) { | |
807592a4 BVA |
660 | spin_lock_irq(q->queue_lock); |
661 | __blk_drain_queue(q, false); | |
662 | spin_unlock_irq(q->queue_lock); | |
663 | ||
b82d4b19 TH |
664 | /* ensure blk_queue_bypass() is %true inside RCU read lock */ |
665 | synchronize_rcu(); | |
666 | } | |
d732580b TH |
667 | } |
668 | EXPORT_SYMBOL_GPL(blk_queue_bypass_start); | |
669 | ||
670 | /** | |
671 | * blk_queue_bypass_end - leave queue bypass mode | |
672 | * @q: queue of interest | |
673 | * | |
674 | * Leave bypass mode and restore the normal queueing behavior. | |
332ebbf7 BVA |
675 | * |
676 | * Note: although blk_queue_bypass_start() is only called for blk-sq queues, | |
677 | * this function is called for both blk-sq and blk-mq queues. | |
d732580b TH |
678 | */ |
679 | void blk_queue_bypass_end(struct request_queue *q) | |
680 | { | |
681 | spin_lock_irq(q->queue_lock); | |
682 | if (!--q->bypass_depth) | |
683 | queue_flag_clear(QUEUE_FLAG_BYPASS, q); | |
684 | WARN_ON_ONCE(q->bypass_depth < 0); | |
685 | spin_unlock_irq(q->queue_lock); | |
686 | } | |
687 | EXPORT_SYMBOL_GPL(blk_queue_bypass_end); | |
688 | ||
aed3ea94 JA |
689 | void blk_set_queue_dying(struct request_queue *q) |
690 | { | |
8814ce8a | 691 | blk_queue_flag_set(QUEUE_FLAG_DYING, q); |
aed3ea94 | 692 | |
d3cfb2a0 ML |
693 | /* |
694 | * When queue DYING flag is set, we need to block new req | |
695 | * entering queue, so we call blk_freeze_queue_start() to | |
696 | * prevent I/O from crossing blk_queue_enter(). | |
697 | */ | |
698 | blk_freeze_queue_start(q); | |
699 | ||
aed3ea94 JA |
700 | if (q->mq_ops) |
701 | blk_mq_wake_waiters(q); | |
702 | else { | |
703 | struct request_list *rl; | |
704 | ||
bbfc3c5d | 705 | spin_lock_irq(q->queue_lock); |
aed3ea94 JA |
706 | blk_queue_for_each_rl(rl, q) { |
707 | if (rl->rq_pool) { | |
34d9715a ML |
708 | wake_up_all(&rl->wait[BLK_RW_SYNC]); |
709 | wake_up_all(&rl->wait[BLK_RW_ASYNC]); | |
aed3ea94 JA |
710 | } |
711 | } | |
bbfc3c5d | 712 | spin_unlock_irq(q->queue_lock); |
aed3ea94 | 713 | } |
055f6e18 ML |
714 | |
715 | /* Make blk_queue_enter() reexamine the DYING flag. */ | |
716 | wake_up_all(&q->mq_freeze_wq); | |
aed3ea94 JA |
717 | } |
718 | EXPORT_SYMBOL_GPL(blk_set_queue_dying); | |
719 | ||
4cf6324b BVA |
720 | /* Unconfigure the I/O scheduler and dissociate from the cgroup controller. */ |
721 | void blk_exit_queue(struct request_queue *q) | |
722 | { | |
723 | /* | |
724 | * Since the I/O scheduler exit code may access cgroup information, | |
725 | * perform I/O scheduler exit before disassociating from the block | |
726 | * cgroup controller. | |
727 | */ | |
728 | if (q->elevator) { | |
729 | ioc_clear_queue(q); | |
730 | elevator_exit(q, q->elevator); | |
731 | q->elevator = NULL; | |
732 | } | |
733 | ||
734 | /* | |
735 | * Remove all references to @q from the block cgroup controller before | |
736 | * restoring @q->queue_lock to avoid that restoring this pointer causes | |
737 | * e.g. blkcg_print_blkgs() to crash. | |
738 | */ | |
739 | blkcg_exit_queue(q); | |
740 | ||
741 | /* | |
742 | * Since the cgroup code may dereference the @q->backing_dev_info | |
743 | * pointer, only decrease its reference count after having removed the | |
744 | * association with the block cgroup controller. | |
745 | */ | |
746 | bdi_put(q->backing_dev_info); | |
747 | } | |
748 | ||
c9a929dd TH |
749 | /** |
750 | * blk_cleanup_queue - shutdown a request queue | |
751 | * @q: request queue to shutdown | |
752 | * | |
c246e80d BVA |
753 | * Mark @q DYING, drain all pending requests, mark @q DEAD, destroy and |
754 | * put it. All future requests will be failed immediately with -ENODEV. | |
c94a96ac | 755 | */ |
6728cb0e | 756 | void blk_cleanup_queue(struct request_queue *q) |
483f4afc | 757 | { |
c9a929dd | 758 | spinlock_t *lock = q->queue_lock; |
e3335de9 | 759 | |
3f3299d5 | 760 | /* mark @q DYING, no new request or merges will be allowed afterwards */ |
483f4afc | 761 | mutex_lock(&q->sysfs_lock); |
aed3ea94 | 762 | blk_set_queue_dying(q); |
c9a929dd | 763 | spin_lock_irq(lock); |
6ecf23af | 764 | |
80fd9979 | 765 | /* |
3f3299d5 | 766 | * A dying queue is permanently in bypass mode till released. Note |
80fd9979 TH |
767 | * that, unlike blk_queue_bypass_start(), we aren't performing |
768 | * synchronize_rcu() after entering bypass mode to avoid the delay | |
769 | * as some drivers create and destroy a lot of queues while | |
770 | * probing. This is still safe because blk_release_queue() will be | |
771 | * called only after the queue refcnt drops to zero and nothing, | |
772 | * RCU or not, would be traversing the queue by then. | |
773 | */ | |
6ecf23af TH |
774 | q->bypass_depth++; |
775 | queue_flag_set(QUEUE_FLAG_BYPASS, q); | |
776 | ||
c9a929dd TH |
777 | queue_flag_set(QUEUE_FLAG_NOMERGES, q); |
778 | queue_flag_set(QUEUE_FLAG_NOXMERGES, q); | |
3f3299d5 | 779 | queue_flag_set(QUEUE_FLAG_DYING, q); |
c9a929dd TH |
780 | spin_unlock_irq(lock); |
781 | mutex_unlock(&q->sysfs_lock); | |
782 | ||
c246e80d BVA |
783 | /* |
784 | * Drain all requests queued before DYING marking. Set DEAD flag to | |
785 | * prevent that q->request_fn() gets invoked after draining finished. | |
786 | */ | |
3ef28e83 | 787 | blk_freeze_queue(q); |
c57cdf7a ML |
788 | |
789 | rq_qos_exit(q); | |
790 | ||
9c1051aa | 791 | spin_lock_irq(lock); |
c246e80d | 792 | queue_flag_set(QUEUE_FLAG_DEAD, q); |
807592a4 | 793 | spin_unlock_irq(lock); |
c9a929dd | 794 | |
c2856ae2 ML |
795 | /* |
796 | * make sure all in-progress dispatch are completed because | |
797 | * blk_freeze_queue() can only complete all requests, and | |
798 | * dispatch may still be in-progress since we dispatch requests | |
1311326c ML |
799 | * from more than one contexts. |
800 | * | |
8dc765d4 ML |
801 | * We rely on driver to deal with the race in case that queue |
802 | * initialization isn't done. | |
c2856ae2 | 803 | */ |
1311326c | 804 | if (q->mq_ops && blk_queue_init_done(q)) |
c2856ae2 ML |
805 | blk_mq_quiesce_queue(q); |
806 | ||
5a48fc14 DW |
807 | /* for synchronous bio-based driver finish in-flight integrity i/o */ |
808 | blk_flush_integrity(); | |
809 | ||
c9a929dd | 810 | /* @q won't process any more request, flush async actions */ |
dc3b17cc | 811 | del_timer_sync(&q->backing_dev_info->laptop_mode_wb_timer); |
c9a929dd TH |
812 | blk_sync_queue(q); |
813 | ||
a063057d BVA |
814 | /* |
815 | * I/O scheduler exit is only safe after the sysfs scheduler attribute | |
816 | * has been removed. | |
817 | */ | |
818 | WARN_ON_ONCE(q->kobj.state_in_sysfs); | |
819 | ||
4cf6324b | 820 | blk_exit_queue(q); |
a063057d | 821 | |
45a9c9d9 BVA |
822 | if (q->mq_ops) |
823 | blk_mq_free_queue(q); | |
3ef28e83 | 824 | percpu_ref_exit(&q->q_usage_counter); |
45a9c9d9 | 825 | |
5e5cfac0 AH |
826 | spin_lock_irq(lock); |
827 | if (q->queue_lock != &q->__queue_lock) | |
828 | q->queue_lock = &q->__queue_lock; | |
829 | spin_unlock_irq(lock); | |
830 | ||
c9a929dd | 831 | /* @q is and will stay empty, shutdown and put */ |
483f4afc AV |
832 | blk_put_queue(q); |
833 | } | |
1da177e4 LT |
834 | EXPORT_SYMBOL(blk_cleanup_queue); |
835 | ||
271508db | 836 | /* Allocate memory local to the request queue */ |
6d247d7f | 837 | static void *alloc_request_simple(gfp_t gfp_mask, void *data) |
271508db | 838 | { |
6d247d7f CH |
839 | struct request_queue *q = data; |
840 | ||
841 | return kmem_cache_alloc_node(request_cachep, gfp_mask, q->node); | |
271508db DR |
842 | } |
843 | ||
6d247d7f | 844 | static void free_request_simple(void *element, void *data) |
271508db DR |
845 | { |
846 | kmem_cache_free(request_cachep, element); | |
847 | } | |
848 | ||
6d247d7f CH |
849 | static void *alloc_request_size(gfp_t gfp_mask, void *data) |
850 | { | |
851 | struct request_queue *q = data; | |
852 | struct request *rq; | |
853 | ||
854 | rq = kmalloc_node(sizeof(struct request) + q->cmd_size, gfp_mask, | |
855 | q->node); | |
856 | if (rq && q->init_rq_fn && q->init_rq_fn(q, rq, gfp_mask) < 0) { | |
857 | kfree(rq); | |
858 | rq = NULL; | |
859 | } | |
860 | return rq; | |
861 | } | |
862 | ||
863 | static void free_request_size(void *element, void *data) | |
864 | { | |
865 | struct request_queue *q = data; | |
866 | ||
867 | if (q->exit_rq_fn) | |
868 | q->exit_rq_fn(q, element); | |
869 | kfree(element); | |
870 | } | |
871 | ||
5b788ce3 TH |
872 | int blk_init_rl(struct request_list *rl, struct request_queue *q, |
873 | gfp_t gfp_mask) | |
1da177e4 | 874 | { |
85acb3ba | 875 | if (unlikely(rl->rq_pool) || q->mq_ops) |
1abec4fd MS |
876 | return 0; |
877 | ||
5b788ce3 | 878 | rl->q = q; |
1faa16d2 JA |
879 | rl->count[BLK_RW_SYNC] = rl->count[BLK_RW_ASYNC] = 0; |
880 | rl->starved[BLK_RW_SYNC] = rl->starved[BLK_RW_ASYNC] = 0; | |
1faa16d2 JA |
881 | init_waitqueue_head(&rl->wait[BLK_RW_SYNC]); |
882 | init_waitqueue_head(&rl->wait[BLK_RW_ASYNC]); | |
1da177e4 | 883 | |
6d247d7f CH |
884 | if (q->cmd_size) { |
885 | rl->rq_pool = mempool_create_node(BLKDEV_MIN_RQ, | |
886 | alloc_request_size, free_request_size, | |
887 | q, gfp_mask, q->node); | |
888 | } else { | |
889 | rl->rq_pool = mempool_create_node(BLKDEV_MIN_RQ, | |
890 | alloc_request_simple, free_request_simple, | |
891 | q, gfp_mask, q->node); | |
892 | } | |
1da177e4 LT |
893 | if (!rl->rq_pool) |
894 | return -ENOMEM; | |
895 | ||
b425e504 BVA |
896 | if (rl != &q->root_rl) |
897 | WARN_ON_ONCE(!blk_get_queue(q)); | |
898 | ||
1da177e4 LT |
899 | return 0; |
900 | } | |
901 | ||
b425e504 | 902 | void blk_exit_rl(struct request_queue *q, struct request_list *rl) |
5b788ce3 | 903 | { |
b425e504 | 904 | if (rl->rq_pool) { |
5b788ce3 | 905 | mempool_destroy(rl->rq_pool); |
b425e504 BVA |
906 | if (rl != &q->root_rl) |
907 | blk_put_queue(q); | |
908 | } | |
5b788ce3 TH |
909 | } |
910 | ||
165125e1 | 911 | struct request_queue *blk_alloc_queue(gfp_t gfp_mask) |
1da177e4 | 912 | { |
5ee0524b | 913 | return blk_alloc_queue_node(gfp_mask, NUMA_NO_NODE, NULL); |
1946089a CL |
914 | } |
915 | EXPORT_SYMBOL(blk_alloc_queue); | |
1da177e4 | 916 | |
3a0a5299 BVA |
917 | /** |
918 | * blk_queue_enter() - try to increase q->q_usage_counter | |
919 | * @q: request queue pointer | |
920 | * @flags: BLK_MQ_REQ_NOWAIT and/or BLK_MQ_REQ_PREEMPT | |
921 | */ | |
9a95e4ef | 922 | int blk_queue_enter(struct request_queue *q, blk_mq_req_flags_t flags) |
3ef28e83 | 923 | { |
cd84a62e | 924 | const bool pm = flags & BLK_MQ_REQ_PREEMPT; |
3a0a5299 | 925 | |
3ef28e83 | 926 | while (true) { |
3a0a5299 | 927 | bool success = false; |
3ef28e83 | 928 | |
818e0fa2 | 929 | rcu_read_lock(); |
3a0a5299 BVA |
930 | if (percpu_ref_tryget_live(&q->q_usage_counter)) { |
931 | /* | |
cd84a62e BVA |
932 | * The code that increments the pm_only counter is |
933 | * responsible for ensuring that that counter is | |
934 | * globally visible before the queue is unfrozen. | |
3a0a5299 | 935 | */ |
cd84a62e | 936 | if (pm || !blk_queue_pm_only(q)) { |
3a0a5299 BVA |
937 | success = true; |
938 | } else { | |
939 | percpu_ref_put(&q->q_usage_counter); | |
940 | } | |
941 | } | |
818e0fa2 | 942 | rcu_read_unlock(); |
3a0a5299 BVA |
943 | |
944 | if (success) | |
3ef28e83 DW |
945 | return 0; |
946 | ||
3a0a5299 | 947 | if (flags & BLK_MQ_REQ_NOWAIT) |
3ef28e83 DW |
948 | return -EBUSY; |
949 | ||
5ed61d3f | 950 | /* |
1671d522 | 951 | * read pair of barrier in blk_freeze_queue_start(), |
5ed61d3f | 952 | * we need to order reading __PERCPU_REF_DEAD flag of |
d3cfb2a0 ML |
953 | * .q_usage_counter and reading .mq_freeze_depth or |
954 | * queue dying flag, otherwise the following wait may | |
955 | * never return if the two reads are reordered. | |
5ed61d3f ML |
956 | */ |
957 | smp_rmb(); | |
958 | ||
1dc3039b AJ |
959 | wait_event(q->mq_freeze_wq, |
960 | (atomic_read(&q->mq_freeze_depth) == 0 && | |
0d25bd07 BVA |
961 | (pm || (blk_pm_request_resume(q), |
962 | !blk_queue_pm_only(q)))) || | |
1dc3039b | 963 | blk_queue_dying(q)); |
3ef28e83 DW |
964 | if (blk_queue_dying(q)) |
965 | return -ENODEV; | |
3ef28e83 DW |
966 | } |
967 | } | |
968 | ||
969 | void blk_queue_exit(struct request_queue *q) | |
970 | { | |
971 | percpu_ref_put(&q->q_usage_counter); | |
972 | } | |
973 | ||
974 | static void blk_queue_usage_counter_release(struct percpu_ref *ref) | |
975 | { | |
976 | struct request_queue *q = | |
977 | container_of(ref, struct request_queue, q_usage_counter); | |
978 | ||
979 | wake_up_all(&q->mq_freeze_wq); | |
980 | } | |
981 | ||
bca237a5 | 982 | static void blk_rq_timed_out_timer(struct timer_list *t) |
287922eb | 983 | { |
bca237a5 | 984 | struct request_queue *q = from_timer(q, t, timeout); |
287922eb CH |
985 | |
986 | kblockd_schedule_work(&q->timeout_work); | |
987 | } | |
988 | ||
498f6650 BVA |
989 | /** |
990 | * blk_alloc_queue_node - allocate a request queue | |
991 | * @gfp_mask: memory allocation flags | |
992 | * @node_id: NUMA node to allocate memory from | |
993 | * @lock: For legacy queues, pointer to a spinlock that will be used to e.g. | |
994 | * serialize calls to the legacy .request_fn() callback. Ignored for | |
995 | * blk-mq request queues. | |
996 | * | |
997 | * Note: pass the queue lock as the third argument to this function instead of | |
998 | * setting the queue lock pointer explicitly to avoid triggering a sporadic | |
999 | * crash in the blkcg code. This function namely calls blkcg_init_queue() and | |
1000 | * the queue lock pointer must be set before blkcg_init_queue() is called. | |
1001 | */ | |
5ee0524b BVA |
1002 | struct request_queue *blk_alloc_queue_node(gfp_t gfp_mask, int node_id, |
1003 | spinlock_t *lock) | |
1946089a | 1004 | { |
165125e1 | 1005 | struct request_queue *q; |
338aa96d | 1006 | int ret; |
1946089a | 1007 | |
8324aa91 | 1008 | q = kmem_cache_alloc_node(blk_requestq_cachep, |
94f6030c | 1009 | gfp_mask | __GFP_ZERO, node_id); |
1da177e4 LT |
1010 | if (!q) |
1011 | return NULL; | |
1012 | ||
cbf62af3 CH |
1013 | INIT_LIST_HEAD(&q->queue_head); |
1014 | q->last_merge = NULL; | |
1015 | q->end_sector = 0; | |
1016 | q->boundary_rq = NULL; | |
1017 | ||
00380a40 | 1018 | q->id = ida_simple_get(&blk_queue_ida, 0, 0, gfp_mask); |
a73f730d | 1019 | if (q->id < 0) |
3d2936f4 | 1020 | goto fail_q; |
a73f730d | 1021 | |
338aa96d KO |
1022 | ret = bioset_init(&q->bio_split, BIO_POOL_SIZE, 0, BIOSET_NEED_BVECS); |
1023 | if (ret) | |
54efd50b KO |
1024 | goto fail_id; |
1025 | ||
d03f6cdc JK |
1026 | q->backing_dev_info = bdi_alloc_node(gfp_mask, node_id); |
1027 | if (!q->backing_dev_info) | |
1028 | goto fail_split; | |
1029 | ||
a83b576c JA |
1030 | q->stats = blk_alloc_queue_stats(); |
1031 | if (!q->stats) | |
1032 | goto fail_stats; | |
1033 | ||
dc3b17cc | 1034 | q->backing_dev_info->ra_pages = |
09cbfeaf | 1035 | (VM_MAX_READAHEAD * 1024) / PAGE_SIZE; |
dc3b17cc JK |
1036 | q->backing_dev_info->capabilities = BDI_CAP_CGROUP_WRITEBACK; |
1037 | q->backing_dev_info->name = "block"; | |
5151412d | 1038 | q->node = node_id; |
0989a025 | 1039 | |
bca237a5 KC |
1040 | timer_setup(&q->backing_dev_info->laptop_mode_wb_timer, |
1041 | laptop_mode_timer_fn, 0); | |
1042 | timer_setup(&q->timeout, blk_rq_timed_out_timer, 0); | |
4e9b6f20 | 1043 | INIT_WORK(&q->timeout_work, NULL); |
242f9dcb | 1044 | INIT_LIST_HEAD(&q->timeout_list); |
a612fddf | 1045 | INIT_LIST_HEAD(&q->icq_list); |
4eef3049 | 1046 | #ifdef CONFIG_BLK_CGROUP |
e8989fae | 1047 | INIT_LIST_HEAD(&q->blkg_list); |
4eef3049 | 1048 | #endif |
3cca6dc1 | 1049 | INIT_DELAYED_WORK(&q->delay_work, blk_delay_work); |
483f4afc | 1050 | |
8324aa91 | 1051 | kobject_init(&q->kobj, &blk_queue_ktype); |
1da177e4 | 1052 | |
5acb3cc2 WL |
1053 | #ifdef CONFIG_BLK_DEV_IO_TRACE |
1054 | mutex_init(&q->blk_trace_mutex); | |
1055 | #endif | |
483f4afc | 1056 | mutex_init(&q->sysfs_lock); |
e7e72bf6 | 1057 | spin_lock_init(&q->__queue_lock); |
483f4afc | 1058 | |
5e27891e | 1059 | q->queue_lock = lock ? : &q->__queue_lock; |
c94a96ac | 1060 | |
b82d4b19 TH |
1061 | /* |
1062 | * A queue starts its life with bypass turned on to avoid | |
1063 | * unnecessary bypass on/off overhead and nasty surprises during | |
749fefe6 TH |
1064 | * init. The initial bypass will be finished when the queue is |
1065 | * registered by blk_register_queue(). | |
b82d4b19 TH |
1066 | */ |
1067 | q->bypass_depth = 1; | |
f78bac2c | 1068 | queue_flag_set_unlocked(QUEUE_FLAG_BYPASS, q); |
b82d4b19 | 1069 | |
320ae51f JA |
1070 | init_waitqueue_head(&q->mq_freeze_wq); |
1071 | ||
3ef28e83 DW |
1072 | /* |
1073 | * Init percpu_ref in atomic mode so that it's faster to shutdown. | |
1074 | * See blk_register_queue() for details. | |
1075 | */ | |
1076 | if (percpu_ref_init(&q->q_usage_counter, | |
1077 | blk_queue_usage_counter_release, | |
1078 | PERCPU_REF_INIT_ATOMIC, GFP_KERNEL)) | |
fff4996b | 1079 | goto fail_bdi; |
f51b802c | 1080 | |
3ef28e83 DW |
1081 | if (blkcg_init_queue(q)) |
1082 | goto fail_ref; | |
1083 | ||
1da177e4 | 1084 | return q; |
a73f730d | 1085 | |
3ef28e83 DW |
1086 | fail_ref: |
1087 | percpu_ref_exit(&q->q_usage_counter); | |
fff4996b | 1088 | fail_bdi: |
a83b576c JA |
1089 | blk_free_queue_stats(q->stats); |
1090 | fail_stats: | |
d03f6cdc | 1091 | bdi_put(q->backing_dev_info); |
54efd50b | 1092 | fail_split: |
338aa96d | 1093 | bioset_exit(&q->bio_split); |
a73f730d TH |
1094 | fail_id: |
1095 | ida_simple_remove(&blk_queue_ida, q->id); | |
1096 | fail_q: | |
1097 | kmem_cache_free(blk_requestq_cachep, q); | |
1098 | return NULL; | |
1da177e4 | 1099 | } |
1946089a | 1100 | EXPORT_SYMBOL(blk_alloc_queue_node); |
1da177e4 LT |
1101 | |
1102 | /** | |
1103 | * blk_init_queue - prepare a request queue for use with a block device | |
1104 | * @rfn: The function to be called to process requests that have been | |
1105 | * placed on the queue. | |
1106 | * @lock: Request queue spin lock | |
1107 | * | |
1108 | * Description: | |
1109 | * If a block device wishes to use the standard request handling procedures, | |
1110 | * which sorts requests and coalesces adjacent requests, then it must | |
1111 | * call blk_init_queue(). The function @rfn will be called when there | |
1112 | * are requests on the queue that need to be processed. If the device | |
1113 | * supports plugging, then @rfn may not be called immediately when requests | |
1114 | * are available on the queue, but may be called at some time later instead. | |
1115 | * Plugged queues are generally unplugged when a buffer belonging to one | |
1116 | * of the requests on the queue is needed, or due to memory pressure. | |
1117 | * | |
1118 | * @rfn is not required, or even expected, to remove all requests off the | |
1119 | * queue, but only as many as it can handle at a time. If it does leave | |
1120 | * requests on the queue, it is responsible for arranging that the requests | |
1121 | * get dealt with eventually. | |
1122 | * | |
1123 | * The queue spin lock must be held while manipulating the requests on the | |
a038e253 PBG |
1124 | * request queue; this lock will be taken also from interrupt context, so irq |
1125 | * disabling is needed for it. | |
1da177e4 | 1126 | * |
710027a4 | 1127 | * Function returns a pointer to the initialized request queue, or %NULL if |
1da177e4 LT |
1128 | * it didn't succeed. |
1129 | * | |
1130 | * Note: | |
1131 | * blk_init_queue() must be paired with a blk_cleanup_queue() call | |
1132 | * when the block device is deactivated (such as at module unload). | |
1133 | **/ | |
1946089a | 1134 | |
165125e1 | 1135 | struct request_queue *blk_init_queue(request_fn_proc *rfn, spinlock_t *lock) |
1da177e4 | 1136 | { |
c304a51b | 1137 | return blk_init_queue_node(rfn, lock, NUMA_NO_NODE); |
1946089a CL |
1138 | } |
1139 | EXPORT_SYMBOL(blk_init_queue); | |
1140 | ||
165125e1 | 1141 | struct request_queue * |
1946089a CL |
1142 | blk_init_queue_node(request_fn_proc *rfn, spinlock_t *lock, int node_id) |
1143 | { | |
5ea708d1 | 1144 | struct request_queue *q; |
1da177e4 | 1145 | |
498f6650 | 1146 | q = blk_alloc_queue_node(GFP_KERNEL, node_id, lock); |
5ea708d1 | 1147 | if (!q) |
c86d1b8a MS |
1148 | return NULL; |
1149 | ||
5ea708d1 | 1150 | q->request_fn = rfn; |
5ea708d1 CH |
1151 | if (blk_init_allocated_queue(q) < 0) { |
1152 | blk_cleanup_queue(q); | |
1153 | return NULL; | |
1154 | } | |
18741986 | 1155 | |
7982e90c | 1156 | return q; |
01effb0d MS |
1157 | } |
1158 | EXPORT_SYMBOL(blk_init_queue_node); | |
1159 | ||
dece1635 | 1160 | static blk_qc_t blk_queue_bio(struct request_queue *q, struct bio *bio); |
336b7e1f | 1161 | |
1da177e4 | 1162 | |
5ea708d1 CH |
1163 | int blk_init_allocated_queue(struct request_queue *q) |
1164 | { | |
332ebbf7 BVA |
1165 | WARN_ON_ONCE(q->mq_ops); |
1166 | ||
5b202853 | 1167 | q->fq = blk_alloc_flush_queue(q, NUMA_NO_NODE, q->cmd_size, GFP_KERNEL); |
ba483388 | 1168 | if (!q->fq) |
5ea708d1 | 1169 | return -ENOMEM; |
7982e90c | 1170 | |
6d247d7f CH |
1171 | if (q->init_rq_fn && q->init_rq_fn(q, q->fq->flush_rq, GFP_KERNEL)) |
1172 | goto out_free_flush_queue; | |
7982e90c | 1173 | |
a051661c | 1174 | if (blk_init_rl(&q->root_rl, q, GFP_KERNEL)) |
6d247d7f | 1175 | goto out_exit_flush_rq; |
1da177e4 | 1176 | |
287922eb | 1177 | INIT_WORK(&q->timeout_work, blk_timeout_work); |
60ea8226 | 1178 | q->queue_flags |= QUEUE_FLAG_DEFAULT; |
c94a96ac | 1179 | |
f3b144aa JA |
1180 | /* |
1181 | * This also sets hw/phys segments, boundary and size | |
1182 | */ | |
c20e8de2 | 1183 | blk_queue_make_request(q, blk_queue_bio); |
1da177e4 | 1184 | |
44ec9542 AS |
1185 | q->sg_reserved_size = INT_MAX; |
1186 | ||
acddf3b3 | 1187 | if (elevator_init(q)) |
6d247d7f | 1188 | goto out_exit_flush_rq; |
5ea708d1 | 1189 | return 0; |
eb1c160b | 1190 | |
6d247d7f CH |
1191 | out_exit_flush_rq: |
1192 | if (q->exit_rq_fn) | |
1193 | q->exit_rq_fn(q, q->fq->flush_rq); | |
1194 | out_free_flush_queue: | |
ba483388 | 1195 | blk_free_flush_queue(q->fq); |
54648cf1 | 1196 | q->fq = NULL; |
5ea708d1 | 1197 | return -ENOMEM; |
1da177e4 | 1198 | } |
5151412d | 1199 | EXPORT_SYMBOL(blk_init_allocated_queue); |
1da177e4 | 1200 | |
09ac46c4 | 1201 | bool blk_get_queue(struct request_queue *q) |
1da177e4 | 1202 | { |
3f3299d5 | 1203 | if (likely(!blk_queue_dying(q))) { |
09ac46c4 TH |
1204 | __blk_get_queue(q); |
1205 | return true; | |
1da177e4 LT |
1206 | } |
1207 | ||
09ac46c4 | 1208 | return false; |
1da177e4 | 1209 | } |
d86e0e83 | 1210 | EXPORT_SYMBOL(blk_get_queue); |
1da177e4 | 1211 | |
5b788ce3 | 1212 | static inline void blk_free_request(struct request_list *rl, struct request *rq) |
1da177e4 | 1213 | { |
e8064021 | 1214 | if (rq->rq_flags & RQF_ELVPRIV) { |
5b788ce3 | 1215 | elv_put_request(rl->q, rq); |
f1f8cc94 | 1216 | if (rq->elv.icq) |
11a3122f | 1217 | put_io_context(rq->elv.icq->ioc); |
f1f8cc94 TH |
1218 | } |
1219 | ||
5b788ce3 | 1220 | mempool_free(rq, rl->rq_pool); |
1da177e4 LT |
1221 | } |
1222 | ||
1da177e4 LT |
1223 | /* |
1224 | * ioc_batching returns true if the ioc is a valid batching request and | |
1225 | * should be given priority access to a request. | |
1226 | */ | |
165125e1 | 1227 | static inline int ioc_batching(struct request_queue *q, struct io_context *ioc) |
1da177e4 LT |
1228 | { |
1229 | if (!ioc) | |
1230 | return 0; | |
1231 | ||
1232 | /* | |
1233 | * Make sure the process is able to allocate at least 1 request | |
1234 | * even if the batch times out, otherwise we could theoretically | |
1235 | * lose wakeups. | |
1236 | */ | |
1237 | return ioc->nr_batch_requests == q->nr_batching || | |
1238 | (ioc->nr_batch_requests > 0 | |
1239 | && time_before(jiffies, ioc->last_waited + BLK_BATCH_TIME)); | |
1240 | } | |
1241 | ||
1242 | /* | |
1243 | * ioc_set_batching sets ioc to be a new "batcher" if it is not one. This | |
1244 | * will cause the process to be a "batcher" on all queues in the system. This | |
1245 | * is the behaviour we want though - once it gets a wakeup it should be given | |
1246 | * a nice run. | |
1247 | */ | |
165125e1 | 1248 | static void ioc_set_batching(struct request_queue *q, struct io_context *ioc) |
1da177e4 LT |
1249 | { |
1250 | if (!ioc || ioc_batching(q, ioc)) | |
1251 | return; | |
1252 | ||
1253 | ioc->nr_batch_requests = q->nr_batching; | |
1254 | ioc->last_waited = jiffies; | |
1255 | } | |
1256 | ||
5b788ce3 | 1257 | static void __freed_request(struct request_list *rl, int sync) |
1da177e4 | 1258 | { |
5b788ce3 | 1259 | struct request_queue *q = rl->q; |
1da177e4 | 1260 | |
d40f75a0 TH |
1261 | if (rl->count[sync] < queue_congestion_off_threshold(q)) |
1262 | blk_clear_congested(rl, sync); | |
1da177e4 | 1263 | |
1faa16d2 JA |
1264 | if (rl->count[sync] + 1 <= q->nr_requests) { |
1265 | if (waitqueue_active(&rl->wait[sync])) | |
1266 | wake_up(&rl->wait[sync]); | |
1da177e4 | 1267 | |
5b788ce3 | 1268 | blk_clear_rl_full(rl, sync); |
1da177e4 LT |
1269 | } |
1270 | } | |
1271 | ||
1272 | /* | |
1273 | * A request has just been released. Account for it, update the full and | |
1274 | * congestion status, wake up any waiters. Called under q->queue_lock. | |
1275 | */ | |
e8064021 CH |
1276 | static void freed_request(struct request_list *rl, bool sync, |
1277 | req_flags_t rq_flags) | |
1da177e4 | 1278 | { |
5b788ce3 | 1279 | struct request_queue *q = rl->q; |
1da177e4 | 1280 | |
8a5ecdd4 | 1281 | q->nr_rqs[sync]--; |
1faa16d2 | 1282 | rl->count[sync]--; |
e8064021 | 1283 | if (rq_flags & RQF_ELVPRIV) |
8a5ecdd4 | 1284 | q->nr_rqs_elvpriv--; |
1da177e4 | 1285 | |
5b788ce3 | 1286 | __freed_request(rl, sync); |
1da177e4 | 1287 | |
1faa16d2 | 1288 | if (unlikely(rl->starved[sync ^ 1])) |
5b788ce3 | 1289 | __freed_request(rl, sync ^ 1); |
1da177e4 LT |
1290 | } |
1291 | ||
e3a2b3f9 JA |
1292 | int blk_update_nr_requests(struct request_queue *q, unsigned int nr) |
1293 | { | |
1294 | struct request_list *rl; | |
d40f75a0 | 1295 | int on_thresh, off_thresh; |
e3a2b3f9 | 1296 | |
332ebbf7 BVA |
1297 | WARN_ON_ONCE(q->mq_ops); |
1298 | ||
e3a2b3f9 JA |
1299 | spin_lock_irq(q->queue_lock); |
1300 | q->nr_requests = nr; | |
1301 | blk_queue_congestion_threshold(q); | |
d40f75a0 TH |
1302 | on_thresh = queue_congestion_on_threshold(q); |
1303 | off_thresh = queue_congestion_off_threshold(q); | |
e3a2b3f9 | 1304 | |
d40f75a0 TH |
1305 | blk_queue_for_each_rl(rl, q) { |
1306 | if (rl->count[BLK_RW_SYNC] >= on_thresh) | |
1307 | blk_set_congested(rl, BLK_RW_SYNC); | |
1308 | else if (rl->count[BLK_RW_SYNC] < off_thresh) | |
1309 | blk_clear_congested(rl, BLK_RW_SYNC); | |
e3a2b3f9 | 1310 | |
d40f75a0 TH |
1311 | if (rl->count[BLK_RW_ASYNC] >= on_thresh) |
1312 | blk_set_congested(rl, BLK_RW_ASYNC); | |
1313 | else if (rl->count[BLK_RW_ASYNC] < off_thresh) | |
1314 | blk_clear_congested(rl, BLK_RW_ASYNC); | |
e3a2b3f9 | 1315 | |
e3a2b3f9 JA |
1316 | if (rl->count[BLK_RW_SYNC] >= q->nr_requests) { |
1317 | blk_set_rl_full(rl, BLK_RW_SYNC); | |
1318 | } else { | |
1319 | blk_clear_rl_full(rl, BLK_RW_SYNC); | |
1320 | wake_up(&rl->wait[BLK_RW_SYNC]); | |
1321 | } | |
1322 | ||
1323 | if (rl->count[BLK_RW_ASYNC] >= q->nr_requests) { | |
1324 | blk_set_rl_full(rl, BLK_RW_ASYNC); | |
1325 | } else { | |
1326 | blk_clear_rl_full(rl, BLK_RW_ASYNC); | |
1327 | wake_up(&rl->wait[BLK_RW_ASYNC]); | |
1328 | } | |
1329 | } | |
1330 | ||
1331 | spin_unlock_irq(q->queue_lock); | |
1332 | return 0; | |
1333 | } | |
1334 | ||
da8303c6 | 1335 | /** |
a06e05e6 | 1336 | * __get_request - get a free request |
5b788ce3 | 1337 | * @rl: request list to allocate from |
ef295ecf | 1338 | * @op: operation and flags |
da8303c6 | 1339 | * @bio: bio to allocate request for (can be %NULL) |
6a15674d | 1340 | * @flags: BLQ_MQ_REQ_* flags |
4accf5fc | 1341 | * @gfp_mask: allocator flags |
da8303c6 TH |
1342 | * |
1343 | * Get a free request from @q. This function may fail under memory | |
1344 | * pressure or if @q is dead. | |
1345 | * | |
da3dae54 | 1346 | * Must be called with @q->queue_lock held and, |
a492f075 JL |
1347 | * Returns ERR_PTR on failure, with @q->queue_lock held. |
1348 | * Returns request pointer on success, with @q->queue_lock *not held*. | |
1da177e4 | 1349 | */ |
ef295ecf | 1350 | static struct request *__get_request(struct request_list *rl, unsigned int op, |
4accf5fc | 1351 | struct bio *bio, blk_mq_req_flags_t flags, gfp_t gfp_mask) |
1da177e4 | 1352 | { |
5b788ce3 | 1353 | struct request_queue *q = rl->q; |
b679281a | 1354 | struct request *rq; |
7f4b35d1 TH |
1355 | struct elevator_type *et = q->elevator->type; |
1356 | struct io_context *ioc = rq_ioc(bio); | |
f1f8cc94 | 1357 | struct io_cq *icq = NULL; |
ef295ecf | 1358 | const bool is_sync = op_is_sync(op); |
75eb6c37 | 1359 | int may_queue; |
e8064021 | 1360 | req_flags_t rq_flags = RQF_ALLOCED; |
88ee5ef1 | 1361 | |
2fff8a92 BVA |
1362 | lockdep_assert_held(q->queue_lock); |
1363 | ||
3f3299d5 | 1364 | if (unlikely(blk_queue_dying(q))) |
a492f075 | 1365 | return ERR_PTR(-ENODEV); |
da8303c6 | 1366 | |
ef295ecf | 1367 | may_queue = elv_may_queue(q, op); |
88ee5ef1 JA |
1368 | if (may_queue == ELV_MQUEUE_NO) |
1369 | goto rq_starved; | |
1370 | ||
1faa16d2 JA |
1371 | if (rl->count[is_sync]+1 >= queue_congestion_on_threshold(q)) { |
1372 | if (rl->count[is_sync]+1 >= q->nr_requests) { | |
88ee5ef1 JA |
1373 | /* |
1374 | * The queue will fill after this allocation, so set | |
1375 | * it as full, and mark this process as "batching". | |
1376 | * This process will be allowed to complete a batch of | |
1377 | * requests, others will be blocked. | |
1378 | */ | |
5b788ce3 | 1379 | if (!blk_rl_full(rl, is_sync)) { |
88ee5ef1 | 1380 | ioc_set_batching(q, ioc); |
5b788ce3 | 1381 | blk_set_rl_full(rl, is_sync); |
88ee5ef1 JA |
1382 | } else { |
1383 | if (may_queue != ELV_MQUEUE_MUST | |
1384 | && !ioc_batching(q, ioc)) { | |
1385 | /* | |
1386 | * The queue is full and the allocating | |
1387 | * process is not a "batcher", and not | |
1388 | * exempted by the IO scheduler | |
1389 | */ | |
a492f075 | 1390 | return ERR_PTR(-ENOMEM); |
88ee5ef1 JA |
1391 | } |
1392 | } | |
1da177e4 | 1393 | } |
d40f75a0 | 1394 | blk_set_congested(rl, is_sync); |
1da177e4 LT |
1395 | } |
1396 | ||
082cf69e JA |
1397 | /* |
1398 | * Only allow batching queuers to allocate up to 50% over the defined | |
1399 | * limit of requests, otherwise we could have thousands of requests | |
1400 | * allocated with any setting of ->nr_requests | |
1401 | */ | |
1faa16d2 | 1402 | if (rl->count[is_sync] >= (3 * q->nr_requests / 2)) |
a492f075 | 1403 | return ERR_PTR(-ENOMEM); |
fd782a4a | 1404 | |
8a5ecdd4 | 1405 | q->nr_rqs[is_sync]++; |
1faa16d2 JA |
1406 | rl->count[is_sync]++; |
1407 | rl->starved[is_sync] = 0; | |
cb98fc8b | 1408 | |
f1f8cc94 TH |
1409 | /* |
1410 | * Decide whether the new request will be managed by elevator. If | |
e8064021 | 1411 | * so, mark @rq_flags and increment elvpriv. Non-zero elvpriv will |
f1f8cc94 TH |
1412 | * prevent the current elevator from being destroyed until the new |
1413 | * request is freed. This guarantees icq's won't be destroyed and | |
1414 | * makes creating new ones safe. | |
1415 | * | |
e6f7f93d CH |
1416 | * Flush requests do not use the elevator so skip initialization. |
1417 | * This allows a request to share the flush and elevator data. | |
1418 | * | |
f1f8cc94 TH |
1419 | * Also, lookup icq while holding queue_lock. If it doesn't exist, |
1420 | * it will be created after releasing queue_lock. | |
1421 | */ | |
e6f7f93d | 1422 | if (!op_is_flush(op) && !blk_queue_bypass(q)) { |
e8064021 | 1423 | rq_flags |= RQF_ELVPRIV; |
8a5ecdd4 | 1424 | q->nr_rqs_elvpriv++; |
f1f8cc94 TH |
1425 | if (et->icq_cache && ioc) |
1426 | icq = ioc_lookup_icq(ioc, q); | |
9d5a4e94 | 1427 | } |
cb98fc8b | 1428 | |
f253b86b | 1429 | if (blk_queue_io_stat(q)) |
e8064021 | 1430 | rq_flags |= RQF_IO_STAT; |
1da177e4 LT |
1431 | spin_unlock_irq(q->queue_lock); |
1432 | ||
29e2b09a | 1433 | /* allocate and init request */ |
5b788ce3 | 1434 | rq = mempool_alloc(rl->rq_pool, gfp_mask); |
29e2b09a | 1435 | if (!rq) |
b679281a | 1436 | goto fail_alloc; |
1da177e4 | 1437 | |
29e2b09a | 1438 | blk_rq_init(q, rq); |
a051661c | 1439 | blk_rq_set_rl(rq, rl); |
ef295ecf | 1440 | rq->cmd_flags = op; |
e8064021 | 1441 | rq->rq_flags = rq_flags; |
1b6d65a0 BVA |
1442 | if (flags & BLK_MQ_REQ_PREEMPT) |
1443 | rq->rq_flags |= RQF_PREEMPT; | |
29e2b09a | 1444 | |
aaf7c680 | 1445 | /* init elvpriv */ |
e8064021 | 1446 | if (rq_flags & RQF_ELVPRIV) { |
aaf7c680 | 1447 | if (unlikely(et->icq_cache && !icq)) { |
7f4b35d1 TH |
1448 | if (ioc) |
1449 | icq = ioc_create_icq(ioc, q, gfp_mask); | |
aaf7c680 TH |
1450 | if (!icq) |
1451 | goto fail_elvpriv; | |
29e2b09a | 1452 | } |
aaf7c680 TH |
1453 | |
1454 | rq->elv.icq = icq; | |
1455 | if (unlikely(elv_set_request(q, rq, bio, gfp_mask))) | |
1456 | goto fail_elvpriv; | |
1457 | ||
1458 | /* @rq->elv.icq holds io_context until @rq is freed */ | |
29e2b09a TH |
1459 | if (icq) |
1460 | get_io_context(icq->ioc); | |
1461 | } | |
aaf7c680 | 1462 | out: |
88ee5ef1 JA |
1463 | /* |
1464 | * ioc may be NULL here, and ioc_batching will be false. That's | |
1465 | * OK, if the queue is under the request limit then requests need | |
1466 | * not count toward the nr_batch_requests limit. There will always | |
1467 | * be some limit enforced by BLK_BATCH_TIME. | |
1468 | */ | |
1da177e4 LT |
1469 | if (ioc_batching(q, ioc)) |
1470 | ioc->nr_batch_requests--; | |
6728cb0e | 1471 | |
e6a40b09 | 1472 | trace_block_getrq(q, bio, op); |
1da177e4 | 1473 | return rq; |
b679281a | 1474 | |
aaf7c680 TH |
1475 | fail_elvpriv: |
1476 | /* | |
1477 | * elvpriv init failed. ioc, icq and elvpriv aren't mempool backed | |
1478 | * and may fail indefinitely under memory pressure and thus | |
1479 | * shouldn't stall IO. Treat this request as !elvpriv. This will | |
1480 | * disturb iosched and blkcg but weird is bettern than dead. | |
1481 | */ | |
7b2b10e0 | 1482 | printk_ratelimited(KERN_WARNING "%s: dev %s: request aux data allocation failed, iosched may be disturbed\n", |
dc3b17cc | 1483 | __func__, dev_name(q->backing_dev_info->dev)); |
aaf7c680 | 1484 | |
e8064021 | 1485 | rq->rq_flags &= ~RQF_ELVPRIV; |
aaf7c680 TH |
1486 | rq->elv.icq = NULL; |
1487 | ||
1488 | spin_lock_irq(q->queue_lock); | |
8a5ecdd4 | 1489 | q->nr_rqs_elvpriv--; |
aaf7c680 TH |
1490 | spin_unlock_irq(q->queue_lock); |
1491 | goto out; | |
1492 | ||
b679281a TH |
1493 | fail_alloc: |
1494 | /* | |
1495 | * Allocation failed presumably due to memory. Undo anything we | |
1496 | * might have messed up. | |
1497 | * | |
1498 | * Allocating task should really be put onto the front of the wait | |
1499 | * queue, but this is pretty rare. | |
1500 | */ | |
1501 | spin_lock_irq(q->queue_lock); | |
e8064021 | 1502 | freed_request(rl, is_sync, rq_flags); |
b679281a TH |
1503 | |
1504 | /* | |
1505 | * in the very unlikely event that allocation failed and no | |
1506 | * requests for this direction was pending, mark us starved so that | |
1507 | * freeing of a request in the other direction will notice | |
1508 | * us. another possible fix would be to split the rq mempool into | |
1509 | * READ and WRITE | |
1510 | */ | |
1511 | rq_starved: | |
1512 | if (unlikely(rl->count[is_sync] == 0)) | |
1513 | rl->starved[is_sync] = 1; | |
a492f075 | 1514 | return ERR_PTR(-ENOMEM); |
1da177e4 LT |
1515 | } |
1516 | ||
da8303c6 | 1517 | /** |
a06e05e6 | 1518 | * get_request - get a free request |
da8303c6 | 1519 | * @q: request_queue to allocate request from |
ef295ecf | 1520 | * @op: operation and flags |
da8303c6 | 1521 | * @bio: bio to allocate request for (can be %NULL) |
6a15674d | 1522 | * @flags: BLK_MQ_REQ_* flags. |
4accf5fc | 1523 | * @gfp: allocator flags |
da8303c6 | 1524 | * |
a9a14d36 | 1525 | * Get a free request from @q. If %BLK_MQ_REQ_NOWAIT is set in @flags, |
d0164adc | 1526 | * this function keeps retrying under memory pressure and fails iff @q is dead. |
d6344532 | 1527 | * |
da3dae54 | 1528 | * Must be called with @q->queue_lock held and, |
a492f075 JL |
1529 | * Returns ERR_PTR on failure, with @q->queue_lock held. |
1530 | * Returns request pointer on success, with @q->queue_lock *not held*. | |
1da177e4 | 1531 | */ |
ef295ecf | 1532 | static struct request *get_request(struct request_queue *q, unsigned int op, |
4accf5fc | 1533 | struct bio *bio, blk_mq_req_flags_t flags, gfp_t gfp) |
1da177e4 | 1534 | { |
ef295ecf | 1535 | const bool is_sync = op_is_sync(op); |
a06e05e6 | 1536 | DEFINE_WAIT(wait); |
a051661c | 1537 | struct request_list *rl; |
1da177e4 | 1538 | struct request *rq; |
a051661c | 1539 | |
2fff8a92 | 1540 | lockdep_assert_held(q->queue_lock); |
332ebbf7 | 1541 | WARN_ON_ONCE(q->mq_ops); |
2fff8a92 | 1542 | |
a051661c | 1543 | rl = blk_get_rl(q, bio); /* transferred to @rq on success */ |
a06e05e6 | 1544 | retry: |
4accf5fc | 1545 | rq = __get_request(rl, op, bio, flags, gfp); |
a492f075 | 1546 | if (!IS_ERR(rq)) |
a06e05e6 | 1547 | return rq; |
1da177e4 | 1548 | |
03a07c92 GR |
1549 | if (op & REQ_NOWAIT) { |
1550 | blk_put_rl(rl); | |
1551 | return ERR_PTR(-EAGAIN); | |
1552 | } | |
1553 | ||
6a15674d | 1554 | if ((flags & BLK_MQ_REQ_NOWAIT) || unlikely(blk_queue_dying(q))) { |
a051661c | 1555 | blk_put_rl(rl); |
a492f075 | 1556 | return rq; |
a051661c | 1557 | } |
1da177e4 | 1558 | |
a06e05e6 TH |
1559 | /* wait on @rl and retry */ |
1560 | prepare_to_wait_exclusive(&rl->wait[is_sync], &wait, | |
1561 | TASK_UNINTERRUPTIBLE); | |
1da177e4 | 1562 | |
e6a40b09 | 1563 | trace_block_sleeprq(q, bio, op); |
1da177e4 | 1564 | |
a06e05e6 TH |
1565 | spin_unlock_irq(q->queue_lock); |
1566 | io_schedule(); | |
d6344532 | 1567 | |
a06e05e6 TH |
1568 | /* |
1569 | * After sleeping, we become a "batching" process and will be able | |
1570 | * to allocate at least one request, and up to a big batch of them | |
1571 | * for a small period time. See ioc_batching, ioc_set_batching | |
1572 | */ | |
a06e05e6 | 1573 | ioc_set_batching(q, current->io_context); |
05caf8db | 1574 | |
a06e05e6 TH |
1575 | spin_lock_irq(q->queue_lock); |
1576 | finish_wait(&rl->wait[is_sync], &wait); | |
1da177e4 | 1577 | |
a06e05e6 | 1578 | goto retry; |
1da177e4 LT |
1579 | } |
1580 | ||
6a15674d | 1581 | /* flags: BLK_MQ_REQ_PREEMPT and/or BLK_MQ_REQ_NOWAIT. */ |
cd6ce148 | 1582 | static struct request *blk_old_get_request(struct request_queue *q, |
9a95e4ef | 1583 | unsigned int op, blk_mq_req_flags_t flags) |
1da177e4 LT |
1584 | { |
1585 | struct request *rq; | |
c3036021 | 1586 | gfp_t gfp_mask = flags & BLK_MQ_REQ_NOWAIT ? GFP_ATOMIC : GFP_NOIO; |
055f6e18 | 1587 | int ret = 0; |
1da177e4 | 1588 | |
332ebbf7 BVA |
1589 | WARN_ON_ONCE(q->mq_ops); |
1590 | ||
7f4b35d1 TH |
1591 | /* create ioc upfront */ |
1592 | create_io_context(gfp_mask, q->node); | |
1593 | ||
3a0a5299 | 1594 | ret = blk_queue_enter(q, flags); |
055f6e18 ML |
1595 | if (ret) |
1596 | return ERR_PTR(ret); | |
d6344532 | 1597 | spin_lock_irq(q->queue_lock); |
4accf5fc | 1598 | rq = get_request(q, op, NULL, flags, gfp_mask); |
0c4de0f3 | 1599 | if (IS_ERR(rq)) { |
da8303c6 | 1600 | spin_unlock_irq(q->queue_lock); |
055f6e18 | 1601 | blk_queue_exit(q); |
0c4de0f3 CH |
1602 | return rq; |
1603 | } | |
1da177e4 | 1604 | |
0c4de0f3 CH |
1605 | /* q->queue_lock is unlocked at this point */ |
1606 | rq->__data_len = 0; | |
1607 | rq->__sector = (sector_t) -1; | |
1608 | rq->bio = rq->biotail = NULL; | |
1da177e4 LT |
1609 | return rq; |
1610 | } | |
320ae51f | 1611 | |
6a15674d | 1612 | /** |
ff005a06 | 1613 | * blk_get_request - allocate a request |
6a15674d BVA |
1614 | * @q: request queue to allocate a request for |
1615 | * @op: operation (REQ_OP_*) and REQ_* flags, e.g. REQ_SYNC. | |
1616 | * @flags: BLK_MQ_REQ_* flags, e.g. BLK_MQ_REQ_NOWAIT. | |
1617 | */ | |
ff005a06 CH |
1618 | struct request *blk_get_request(struct request_queue *q, unsigned int op, |
1619 | blk_mq_req_flags_t flags) | |
320ae51f | 1620 | { |
d280bab3 BVA |
1621 | struct request *req; |
1622 | ||
6a15674d | 1623 | WARN_ON_ONCE(op & REQ_NOWAIT); |
1b6d65a0 | 1624 | WARN_ON_ONCE(flags & ~(BLK_MQ_REQ_NOWAIT | BLK_MQ_REQ_PREEMPT)); |
6a15674d | 1625 | |
d280bab3 | 1626 | if (q->mq_ops) { |
6a15674d | 1627 | req = blk_mq_alloc_request(q, op, flags); |
d280bab3 BVA |
1628 | if (!IS_ERR(req) && q->mq_ops->initialize_rq_fn) |
1629 | q->mq_ops->initialize_rq_fn(req); | |
1630 | } else { | |
6a15674d | 1631 | req = blk_old_get_request(q, op, flags); |
d280bab3 BVA |
1632 | if (!IS_ERR(req) && q->initialize_rq_fn) |
1633 | q->initialize_rq_fn(req); | |
1634 | } | |
1635 | ||
1636 | return req; | |
320ae51f | 1637 | } |
1da177e4 LT |
1638 | EXPORT_SYMBOL(blk_get_request); |
1639 | ||
1640 | /** | |
1641 | * blk_requeue_request - put a request back on queue | |
1642 | * @q: request queue where request should be inserted | |
1643 | * @rq: request to be inserted | |
1644 | * | |
1645 | * Description: | |
1646 | * Drivers often keep queueing requests until the hardware cannot accept | |
1647 | * more, when that condition happens we need to put the request back | |
1648 | * on the queue. Must be called with queue lock held. | |
1649 | */ | |
165125e1 | 1650 | void blk_requeue_request(struct request_queue *q, struct request *rq) |
1da177e4 | 1651 | { |
2fff8a92 | 1652 | lockdep_assert_held(q->queue_lock); |
332ebbf7 | 1653 | WARN_ON_ONCE(q->mq_ops); |
2fff8a92 | 1654 | |
242f9dcb JA |
1655 | blk_delete_timer(rq); |
1656 | blk_clear_rq_complete(rq); | |
5f3ea37c | 1657 | trace_block_rq_requeue(q, rq); |
a7905043 | 1658 | rq_qos_requeue(q, rq); |
2056a782 | 1659 | |
e8064021 | 1660 | if (rq->rq_flags & RQF_QUEUED) |
1da177e4 LT |
1661 | blk_queue_end_tag(q, rq); |
1662 | ||
ba396a6c JB |
1663 | BUG_ON(blk_queued_rq(rq)); |
1664 | ||
1da177e4 LT |
1665 | elv_requeue_request(q, rq); |
1666 | } | |
1da177e4 LT |
1667 | EXPORT_SYMBOL(blk_requeue_request); |
1668 | ||
73c10101 JA |
1669 | static void add_acct_request(struct request_queue *q, struct request *rq, |
1670 | int where) | |
1671 | { | |
320ae51f | 1672 | blk_account_io_start(rq, true); |
7eaceacc | 1673 | __elv_add_request(q, rq, where); |
73c10101 JA |
1674 | } |
1675 | ||
d62e26b3 | 1676 | static void part_round_stats_single(struct request_queue *q, int cpu, |
b8d62b3a JA |
1677 | struct hd_struct *part, unsigned long now, |
1678 | unsigned int inflight) | |
074a7aca | 1679 | { |
b8d62b3a | 1680 | if (inflight) { |
074a7aca | 1681 | __part_stat_add(cpu, part, time_in_queue, |
b8d62b3a | 1682 | inflight * (now - part->stamp)); |
074a7aca TH |
1683 | __part_stat_add(cpu, part, io_ticks, (now - part->stamp)); |
1684 | } | |
1685 | part->stamp = now; | |
1686 | } | |
1687 | ||
1688 | /** | |
496aa8a9 | 1689 | * part_round_stats() - Round off the performance stats on a struct disk_stats. |
d62e26b3 | 1690 | * @q: target block queue |
496aa8a9 RD |
1691 | * @cpu: cpu number for stats access |
1692 | * @part: target partition | |
1da177e4 LT |
1693 | * |
1694 | * The average IO queue length and utilisation statistics are maintained | |
1695 | * by observing the current state of the queue length and the amount of | |
1696 | * time it has been in this state for. | |
1697 | * | |
1698 | * Normally, that accounting is done on IO completion, but that can result | |
1699 | * in more than a second's worth of IO being accounted for within any one | |
1700 | * second, leading to >100% utilisation. To deal with that, we call this | |
1701 | * function to do a round-off before returning the results when reading | |
1702 | * /proc/diskstats. This accounts immediately for all queue usage up to | |
1703 | * the current jiffies and restarts the counters again. | |
1704 | */ | |
d62e26b3 | 1705 | void part_round_stats(struct request_queue *q, int cpu, struct hd_struct *part) |
6f2576af | 1706 | { |
b8d62b3a | 1707 | struct hd_struct *part2 = NULL; |
6f2576af | 1708 | unsigned long now = jiffies; |
b8d62b3a JA |
1709 | unsigned int inflight[2]; |
1710 | int stats = 0; | |
1711 | ||
1712 | if (part->stamp != now) | |
1713 | stats |= 1; | |
1714 | ||
1715 | if (part->partno) { | |
1716 | part2 = &part_to_disk(part)->part0; | |
1717 | if (part2->stamp != now) | |
1718 | stats |= 2; | |
1719 | } | |
1720 | ||
1721 | if (!stats) | |
1722 | return; | |
1723 | ||
1724 | part_in_flight(q, part, inflight); | |
6f2576af | 1725 | |
b8d62b3a JA |
1726 | if (stats & 2) |
1727 | part_round_stats_single(q, cpu, part2, now, inflight[1]); | |
1728 | if (stats & 1) | |
1729 | part_round_stats_single(q, cpu, part, now, inflight[0]); | |
6f2576af | 1730 | } |
074a7aca | 1731 | EXPORT_SYMBOL_GPL(part_round_stats); |
6f2576af | 1732 | |
165125e1 | 1733 | void __blk_put_request(struct request_queue *q, struct request *req) |
1da177e4 | 1734 | { |
e8064021 CH |
1735 | req_flags_t rq_flags = req->rq_flags; |
1736 | ||
1da177e4 LT |
1737 | if (unlikely(!q)) |
1738 | return; | |
1da177e4 | 1739 | |
6f5ba581 CH |
1740 | if (q->mq_ops) { |
1741 | blk_mq_free_request(req); | |
1742 | return; | |
1743 | } | |
1744 | ||
2fff8a92 BVA |
1745 | lockdep_assert_held(q->queue_lock); |
1746 | ||
6cc77e9c | 1747 | blk_req_zone_write_unlock(req); |
c8158819 | 1748 | blk_pm_put_request(req); |
154b00d5 | 1749 | blk_pm_mark_last_busy(req); |
c8158819 | 1750 | |
8922e16c TH |
1751 | elv_completed_request(q, req); |
1752 | ||
1cd96c24 BH |
1753 | /* this is a bio leak */ |
1754 | WARN_ON(req->bio != NULL); | |
1755 | ||
a7905043 | 1756 | rq_qos_done(q, req); |
87760e5e | 1757 | |
1da177e4 LT |
1758 | /* |
1759 | * Request may not have originated from ll_rw_blk. if not, | |
1760 | * it didn't come out of our reserved rq pools | |
1761 | */ | |
e8064021 | 1762 | if (rq_flags & RQF_ALLOCED) { |
a051661c | 1763 | struct request_list *rl = blk_rq_rl(req); |
ef295ecf | 1764 | bool sync = op_is_sync(req->cmd_flags); |
1da177e4 | 1765 | |
1da177e4 | 1766 | BUG_ON(!list_empty(&req->queuelist)); |
360f92c2 | 1767 | BUG_ON(ELV_ON_HASH(req)); |
1da177e4 | 1768 | |
a051661c | 1769 | blk_free_request(rl, req); |
e8064021 | 1770 | freed_request(rl, sync, rq_flags); |
a051661c | 1771 | blk_put_rl(rl); |
055f6e18 | 1772 | blk_queue_exit(q); |
1da177e4 LT |
1773 | } |
1774 | } | |
6e39b69e MC |
1775 | EXPORT_SYMBOL_GPL(__blk_put_request); |
1776 | ||
1da177e4 LT |
1777 | void blk_put_request(struct request *req) |
1778 | { | |
165125e1 | 1779 | struct request_queue *q = req->q; |
8922e16c | 1780 | |
320ae51f JA |
1781 | if (q->mq_ops) |
1782 | blk_mq_free_request(req); | |
1783 | else { | |
1784 | unsigned long flags; | |
1785 | ||
1786 | spin_lock_irqsave(q->queue_lock, flags); | |
1787 | __blk_put_request(q, req); | |
1788 | spin_unlock_irqrestore(q->queue_lock, flags); | |
1789 | } | |
1da177e4 | 1790 | } |
1da177e4 LT |
1791 | EXPORT_SYMBOL(blk_put_request); |
1792 | ||
320ae51f JA |
1793 | bool bio_attempt_back_merge(struct request_queue *q, struct request *req, |
1794 | struct bio *bio) | |
73c10101 | 1795 | { |
1eff9d32 | 1796 | const int ff = bio->bi_opf & REQ_FAILFAST_MASK; |
73c10101 | 1797 | |
73c10101 JA |
1798 | if (!ll_back_merge_fn(q, req, bio)) |
1799 | return false; | |
1800 | ||
8c1cf6bb | 1801 | trace_block_bio_backmerge(q, req, bio); |
73c10101 JA |
1802 | |
1803 | if ((req->cmd_flags & REQ_FAILFAST_MASK) != ff) | |
1804 | blk_rq_set_mixed_merge(req); | |
1805 | ||
1806 | req->biotail->bi_next = bio; | |
1807 | req->biotail = bio; | |
4f024f37 | 1808 | req->__data_len += bio->bi_iter.bi_size; |
73c10101 JA |
1809 | req->ioprio = ioprio_best(req->ioprio, bio_prio(bio)); |
1810 | ||
320ae51f | 1811 | blk_account_io_start(req, false); |
73c10101 JA |
1812 | return true; |
1813 | } | |
1814 | ||
320ae51f JA |
1815 | bool bio_attempt_front_merge(struct request_queue *q, struct request *req, |
1816 | struct bio *bio) | |
73c10101 | 1817 | { |
1eff9d32 | 1818 | const int ff = bio->bi_opf & REQ_FAILFAST_MASK; |
73c10101 | 1819 | |
73c10101 JA |
1820 | if (!ll_front_merge_fn(q, req, bio)) |
1821 | return false; | |
1822 | ||
8c1cf6bb | 1823 | trace_block_bio_frontmerge(q, req, bio); |
73c10101 JA |
1824 | |
1825 | if ((req->cmd_flags & REQ_FAILFAST_MASK) != ff) | |
1826 | blk_rq_set_mixed_merge(req); | |
1827 | ||
73c10101 JA |
1828 | bio->bi_next = req->bio; |
1829 | req->bio = bio; | |
1830 | ||
4f024f37 KO |
1831 | req->__sector = bio->bi_iter.bi_sector; |
1832 | req->__data_len += bio->bi_iter.bi_size; | |
73c10101 JA |
1833 | req->ioprio = ioprio_best(req->ioprio, bio_prio(bio)); |
1834 | ||
320ae51f | 1835 | blk_account_io_start(req, false); |
73c10101 JA |
1836 | return true; |
1837 | } | |
1838 | ||
1e739730 CH |
1839 | bool bio_attempt_discard_merge(struct request_queue *q, struct request *req, |
1840 | struct bio *bio) | |
1841 | { | |
1842 | unsigned short segments = blk_rq_nr_discard_segments(req); | |
1843 | ||
1844 | if (segments >= queue_max_discard_segments(q)) | |
1845 | goto no_merge; | |
1846 | if (blk_rq_sectors(req) + bio_sectors(bio) > | |
1847 | blk_rq_get_max_sectors(req, blk_rq_pos(req))) | |
1848 | goto no_merge; | |
1849 | ||
1850 | req->biotail->bi_next = bio; | |
1851 | req->biotail = bio; | |
1852 | req->__data_len += bio->bi_iter.bi_size; | |
1853 | req->ioprio = ioprio_best(req->ioprio, bio_prio(bio)); | |
1854 | req->nr_phys_segments = segments + 1; | |
1855 | ||
1856 | blk_account_io_start(req, false); | |
1857 | return true; | |
1858 | no_merge: | |
1859 | req_set_nomerge(q, req); | |
1860 | return false; | |
1861 | } | |
1862 | ||
bd87b589 | 1863 | /** |
320ae51f | 1864 | * blk_attempt_plug_merge - try to merge with %current's plugged list |
bd87b589 TH |
1865 | * @q: request_queue new bio is being queued at |
1866 | * @bio: new bio being queued | |
1867 | * @request_count: out parameter for number of traversed plugged requests | |
ccc2600b RD |
1868 | * @same_queue_rq: pointer to &struct request that gets filled in when |
1869 | * another request associated with @q is found on the plug list | |
1870 | * (optional, may be %NULL) | |
bd87b589 TH |
1871 | * |
1872 | * Determine whether @bio being queued on @q can be merged with a request | |
1873 | * on %current's plugged list. Returns %true if merge was successful, | |
1874 | * otherwise %false. | |
1875 | * | |
07c2bd37 TH |
1876 | * Plugging coalesces IOs from the same issuer for the same purpose without |
1877 | * going through @q->queue_lock. As such it's more of an issuing mechanism | |
1878 | * than scheduling, and the request, while may have elvpriv data, is not | |
1879 | * added on the elevator at this point. In addition, we don't have | |
1880 | * reliable access to the elevator outside queue lock. Only check basic | |
1881 | * merging parameters without querying the elevator. | |
da41a589 RE |
1882 | * |
1883 | * Caller must ensure !blk_queue_nomerges(q) beforehand. | |
73c10101 | 1884 | */ |
320ae51f | 1885 | bool blk_attempt_plug_merge(struct request_queue *q, struct bio *bio, |
5b3f341f SL |
1886 | unsigned int *request_count, |
1887 | struct request **same_queue_rq) | |
73c10101 JA |
1888 | { |
1889 | struct blk_plug *plug; | |
1890 | struct request *rq; | |
92f399c7 | 1891 | struct list_head *plug_list; |
73c10101 | 1892 | |
bd87b589 | 1893 | plug = current->plug; |
73c10101 | 1894 | if (!plug) |
34fe7c05 | 1895 | return false; |
56ebdaf2 | 1896 | *request_count = 0; |
73c10101 | 1897 | |
92f399c7 SL |
1898 | if (q->mq_ops) |
1899 | plug_list = &plug->mq_list; | |
1900 | else | |
1901 | plug_list = &plug->list; | |
1902 | ||
1903 | list_for_each_entry_reverse(rq, plug_list, queuelist) { | |
34fe7c05 | 1904 | bool merged = false; |
73c10101 | 1905 | |
5b3f341f | 1906 | if (rq->q == q) { |
1b2e19f1 | 1907 | (*request_count)++; |
5b3f341f SL |
1908 | /* |
1909 | * Only blk-mq multiple hardware queues case checks the | |
1910 | * rq in the same queue, there should be only one such | |
1911 | * rq in a queue | |
1912 | **/ | |
1913 | if (same_queue_rq) | |
1914 | *same_queue_rq = rq; | |
1915 | } | |
56ebdaf2 | 1916 | |
07c2bd37 | 1917 | if (rq->q != q || !blk_rq_merge_ok(rq, bio)) |
73c10101 JA |
1918 | continue; |
1919 | ||
34fe7c05 CH |
1920 | switch (blk_try_merge(rq, bio)) { |
1921 | case ELEVATOR_BACK_MERGE: | |
1922 | merged = bio_attempt_back_merge(q, rq, bio); | |
1923 | break; | |
1924 | case ELEVATOR_FRONT_MERGE: | |
1925 | merged = bio_attempt_front_merge(q, rq, bio); | |
1926 | break; | |
1e739730 CH |
1927 | case ELEVATOR_DISCARD_MERGE: |
1928 | merged = bio_attempt_discard_merge(q, rq, bio); | |
1929 | break; | |
34fe7c05 CH |
1930 | default: |
1931 | break; | |
73c10101 | 1932 | } |
34fe7c05 CH |
1933 | |
1934 | if (merged) | |
1935 | return true; | |
73c10101 | 1936 | } |
34fe7c05 CH |
1937 | |
1938 | return false; | |
73c10101 JA |
1939 | } |
1940 | ||
0809e3ac JM |
1941 | unsigned int blk_plug_queued_count(struct request_queue *q) |
1942 | { | |
1943 | struct blk_plug *plug; | |
1944 | struct request *rq; | |
1945 | struct list_head *plug_list; | |
1946 | unsigned int ret = 0; | |
1947 | ||
1948 | plug = current->plug; | |
1949 | if (!plug) | |
1950 | goto out; | |
1951 | ||
1952 | if (q->mq_ops) | |
1953 | plug_list = &plug->mq_list; | |
1954 | else | |
1955 | plug_list = &plug->list; | |
1956 | ||
1957 | list_for_each_entry(rq, plug_list, queuelist) { | |
1958 | if (rq->q == q) | |
1959 | ret++; | |
1960 | } | |
1961 | out: | |
1962 | return ret; | |
1963 | } | |
1964 | ||
da8d7f07 | 1965 | void blk_init_request_from_bio(struct request *req, struct bio *bio) |
52d9e675 | 1966 | { |
0be0dee6 BVA |
1967 | struct io_context *ioc = rq_ioc(bio); |
1968 | ||
1eff9d32 | 1969 | if (bio->bi_opf & REQ_RAHEAD) |
a82afdfc | 1970 | req->cmd_flags |= REQ_FAILFAST_MASK; |
b31dc66a | 1971 | |
4f024f37 | 1972 | req->__sector = bio->bi_iter.bi_sector; |
5dc8b362 AM |
1973 | if (ioprio_valid(bio_prio(bio))) |
1974 | req->ioprio = bio_prio(bio); | |
0be0dee6 BVA |
1975 | else if (ioc) |
1976 | req->ioprio = ioc->ioprio; | |
1977 | else | |
1978 | req->ioprio = IOPRIO_PRIO_VALUE(IOPRIO_CLASS_NONE, 0); | |
cb6934f8 | 1979 | req->write_hint = bio->bi_write_hint; |
bc1c56fd | 1980 | blk_rq_bio_prep(req->q, req, bio); |
52d9e675 | 1981 | } |
da8d7f07 | 1982 | EXPORT_SYMBOL_GPL(blk_init_request_from_bio); |
52d9e675 | 1983 | |
dece1635 | 1984 | static blk_qc_t blk_queue_bio(struct request_queue *q, struct bio *bio) |
1da177e4 | 1985 | { |
73c10101 | 1986 | struct blk_plug *plug; |
34fe7c05 | 1987 | int where = ELEVATOR_INSERT_SORT; |
e4d750c9 | 1988 | struct request *req, *free; |
56ebdaf2 | 1989 | unsigned int request_count = 0; |
1da177e4 | 1990 | |
1da177e4 LT |
1991 | /* |
1992 | * low level driver can indicate that it wants pages above a | |
1993 | * certain limit bounced to low memory (ie for highmem, or even | |
1994 | * ISA dma in theory) | |
1995 | */ | |
1996 | blk_queue_bounce(q, &bio); | |
1997 | ||
af67c31f | 1998 | blk_queue_split(q, &bio); |
23688bf4 | 1999 | |
e23947bd | 2000 | if (!bio_integrity_prep(bio)) |
dece1635 | 2001 | return BLK_QC_T_NONE; |
ffecfd1a | 2002 | |
f73f44eb | 2003 | if (op_is_flush(bio->bi_opf)) { |
73c10101 | 2004 | spin_lock_irq(q->queue_lock); |
ae1b1539 | 2005 | where = ELEVATOR_INSERT_FLUSH; |
28e7d184 TH |
2006 | goto get_rq; |
2007 | } | |
2008 | ||
73c10101 JA |
2009 | /* |
2010 | * Check if we can merge with the plugged list before grabbing | |
2011 | * any locks. | |
2012 | */ | |
0809e3ac JM |
2013 | if (!blk_queue_nomerges(q)) { |
2014 | if (blk_attempt_plug_merge(q, bio, &request_count, NULL)) | |
dece1635 | 2015 | return BLK_QC_T_NONE; |
0809e3ac JM |
2016 | } else |
2017 | request_count = blk_plug_queued_count(q); | |
1da177e4 | 2018 | |
73c10101 | 2019 | spin_lock_irq(q->queue_lock); |
2056a782 | 2020 | |
34fe7c05 CH |
2021 | switch (elv_merge(q, &req, bio)) { |
2022 | case ELEVATOR_BACK_MERGE: | |
2023 | if (!bio_attempt_back_merge(q, req, bio)) | |
2024 | break; | |
2025 | elv_bio_merged(q, req, bio); | |
2026 | free = attempt_back_merge(q, req); | |
2027 | if (free) | |
2028 | __blk_put_request(q, free); | |
2029 | else | |
2030 | elv_merged_request(q, req, ELEVATOR_BACK_MERGE); | |
2031 | goto out_unlock; | |
2032 | case ELEVATOR_FRONT_MERGE: | |
2033 | if (!bio_attempt_front_merge(q, req, bio)) | |
2034 | break; | |
2035 | elv_bio_merged(q, req, bio); | |
2036 | free = attempt_front_merge(q, req); | |
2037 | if (free) | |
2038 | __blk_put_request(q, free); | |
2039 | else | |
2040 | elv_merged_request(q, req, ELEVATOR_FRONT_MERGE); | |
2041 | goto out_unlock; | |
2042 | default: | |
2043 | break; | |
1da177e4 LT |
2044 | } |
2045 | ||
450991bc | 2046 | get_rq: |
c1c80384 | 2047 | rq_qos_throttle(q, bio, q->queue_lock); |
87760e5e | 2048 | |
1da177e4 | 2049 | /* |
450991bc | 2050 | * Grab a free request. This is might sleep but can not fail. |
d6344532 | 2051 | * Returns with the queue unlocked. |
450991bc | 2052 | */ |
055f6e18 | 2053 | blk_queue_enter_live(q); |
c3036021 | 2054 | req = get_request(q, bio->bi_opf, bio, 0, GFP_NOIO); |
a492f075 | 2055 | if (IS_ERR(req)) { |
055f6e18 | 2056 | blk_queue_exit(q); |
c1c80384 | 2057 | rq_qos_cleanup(q, bio); |
4e4cbee9 CH |
2058 | if (PTR_ERR(req) == -ENOMEM) |
2059 | bio->bi_status = BLK_STS_RESOURCE; | |
2060 | else | |
2061 | bio->bi_status = BLK_STS_IOERR; | |
4246a0b6 | 2062 | bio_endio(bio); |
da8303c6 TH |
2063 | goto out_unlock; |
2064 | } | |
d6344532 | 2065 | |
c1c80384 | 2066 | rq_qos_track(q, req, bio); |
87760e5e | 2067 | |
450991bc NP |
2068 | /* |
2069 | * After dropping the lock and possibly sleeping here, our request | |
2070 | * may now be mergeable after it had proven unmergeable (above). | |
2071 | * We don't worry about that case for efficiency. It won't happen | |
2072 | * often, and the elevators are able to handle it. | |
1da177e4 | 2073 | */ |
da8d7f07 | 2074 | blk_init_request_from_bio(req, bio); |
1da177e4 | 2075 | |
9562ad9a | 2076 | if (test_bit(QUEUE_FLAG_SAME_COMP, &q->queue_flags)) |
11ccf116 | 2077 | req->cpu = raw_smp_processor_id(); |
73c10101 JA |
2078 | |
2079 | plug = current->plug; | |
721a9602 | 2080 | if (plug) { |
dc6d36c9 JA |
2081 | /* |
2082 | * If this is the first request added after a plug, fire | |
7aef2e78 | 2083 | * of a plug trace. |
0a6219a9 ML |
2084 | * |
2085 | * @request_count may become stale because of schedule | |
2086 | * out, so check plug list again. | |
dc6d36c9 | 2087 | */ |
0a6219a9 | 2088 | if (!request_count || list_empty(&plug->list)) |
dc6d36c9 | 2089 | trace_block_plug(q); |
3540d5e8 | 2090 | else { |
50d24c34 SL |
2091 | struct request *last = list_entry_rq(plug->list.prev); |
2092 | if (request_count >= BLK_MAX_REQUEST_COUNT || | |
2093 | blk_rq_bytes(last) >= BLK_PLUG_FLUSH_SIZE) { | |
3540d5e8 | 2094 | blk_flush_plug_list(plug, false); |
019ceb7d SL |
2095 | trace_block_plug(q); |
2096 | } | |
73c10101 | 2097 | } |
73c10101 | 2098 | list_add_tail(&req->queuelist, &plug->list); |
320ae51f | 2099 | blk_account_io_start(req, true); |
73c10101 JA |
2100 | } else { |
2101 | spin_lock_irq(q->queue_lock); | |
2102 | add_acct_request(q, req, where); | |
24ecfbe2 | 2103 | __blk_run_queue(q); |
73c10101 JA |
2104 | out_unlock: |
2105 | spin_unlock_irq(q->queue_lock); | |
2106 | } | |
dece1635 JA |
2107 | |
2108 | return BLK_QC_T_NONE; | |
1da177e4 LT |
2109 | } |
2110 | ||
52c5e62d | 2111 | static void handle_bad_sector(struct bio *bio, sector_t maxsector) |
1da177e4 LT |
2112 | { |
2113 | char b[BDEVNAME_SIZE]; | |
2114 | ||
2115 | printk(KERN_INFO "attempt to access beyond end of device\n"); | |
6296b960 | 2116 | printk(KERN_INFO "%s: rw=%d, want=%Lu, limit=%Lu\n", |
74d46992 | 2117 | bio_devname(bio, b), bio->bi_opf, |
f73a1c7d | 2118 | (unsigned long long)bio_end_sector(bio), |
52c5e62d | 2119 | (long long)maxsector); |
1da177e4 LT |
2120 | } |
2121 | ||
c17bb495 AM |
2122 | #ifdef CONFIG_FAIL_MAKE_REQUEST |
2123 | ||
2124 | static DECLARE_FAULT_ATTR(fail_make_request); | |
2125 | ||
2126 | static int __init setup_fail_make_request(char *str) | |
2127 | { | |
2128 | return setup_fault_attr(&fail_make_request, str); | |
2129 | } | |
2130 | __setup("fail_make_request=", setup_fail_make_request); | |
2131 | ||
b2c9cd37 | 2132 | static bool should_fail_request(struct hd_struct *part, unsigned int bytes) |
c17bb495 | 2133 | { |
b2c9cd37 | 2134 | return part->make_it_fail && should_fail(&fail_make_request, bytes); |
c17bb495 AM |
2135 | } |
2136 | ||
2137 | static int __init fail_make_request_debugfs(void) | |
2138 | { | |
dd48c085 AM |
2139 | struct dentry *dir = fault_create_debugfs_attr("fail_make_request", |
2140 | NULL, &fail_make_request); | |
2141 | ||
21f9fcd8 | 2142 | return PTR_ERR_OR_ZERO(dir); |
c17bb495 AM |
2143 | } |
2144 | ||
2145 | late_initcall(fail_make_request_debugfs); | |
2146 | ||
2147 | #else /* CONFIG_FAIL_MAKE_REQUEST */ | |
2148 | ||
b2c9cd37 AM |
2149 | static inline bool should_fail_request(struct hd_struct *part, |
2150 | unsigned int bytes) | |
c17bb495 | 2151 | { |
b2c9cd37 | 2152 | return false; |
c17bb495 AM |
2153 | } |
2154 | ||
2155 | #endif /* CONFIG_FAIL_MAKE_REQUEST */ | |
2156 | ||
721c7fc7 ID |
2157 | static inline bool bio_check_ro(struct bio *bio, struct hd_struct *part) |
2158 | { | |
b089cfd9 JA |
2159 | const int op = bio_op(bio); |
2160 | ||
8b2ded1c | 2161 | if (part->policy && op_is_write(op)) { |
721c7fc7 ID |
2162 | char b[BDEVNAME_SIZE]; |
2163 | ||
8b2ded1c MP |
2164 | if (op_is_flush(bio->bi_opf) && !bio_sectors(bio)) |
2165 | return false; | |
2166 | ||
a32e236e | 2167 | WARN_ONCE(1, |
721c7fc7 ID |
2168 | "generic_make_request: Trying to write " |
2169 | "to read-only block-device %s (partno %d)\n", | |
2170 | bio_devname(bio, b), part->partno); | |
a32e236e LT |
2171 | /* Older lvm-tools actually trigger this */ |
2172 | return false; | |
721c7fc7 ID |
2173 | } |
2174 | ||
2175 | return false; | |
2176 | } | |
2177 | ||
30abb3a6 HM |
2178 | static noinline int should_fail_bio(struct bio *bio) |
2179 | { | |
2180 | if (should_fail_request(&bio->bi_disk->part0, bio->bi_iter.bi_size)) | |
2181 | return -EIO; | |
2182 | return 0; | |
2183 | } | |
2184 | ALLOW_ERROR_INJECTION(should_fail_bio, ERRNO); | |
2185 | ||
52c5e62d CH |
2186 | /* |
2187 | * Check whether this bio extends beyond the end of the device or partition. | |
2188 | * This may well happen - the kernel calls bread() without checking the size of | |
2189 | * the device, e.g., when mounting a file system. | |
2190 | */ | |
2191 | static inline int bio_check_eod(struct bio *bio, sector_t maxsector) | |
2192 | { | |
2193 | unsigned int nr_sectors = bio_sectors(bio); | |
2194 | ||
2195 | if (nr_sectors && maxsector && | |
2196 | (nr_sectors > maxsector || | |
2197 | bio->bi_iter.bi_sector > maxsector - nr_sectors)) { | |
2198 | handle_bad_sector(bio, maxsector); | |
2199 | return -EIO; | |
2200 | } | |
2201 | return 0; | |
2202 | } | |
2203 | ||
74d46992 CH |
2204 | /* |
2205 | * Remap block n of partition p to block n+start(p) of the disk. | |
2206 | */ | |
2207 | static inline int blk_partition_remap(struct bio *bio) | |
2208 | { | |
2209 | struct hd_struct *p; | |
52c5e62d | 2210 | int ret = -EIO; |
74d46992 | 2211 | |
721c7fc7 ID |
2212 | rcu_read_lock(); |
2213 | p = __disk_get_part(bio->bi_disk, bio->bi_partno); | |
52c5e62d CH |
2214 | if (unlikely(!p)) |
2215 | goto out; | |
2216 | if (unlikely(should_fail_request(p, bio->bi_iter.bi_size))) | |
2217 | goto out; | |
2218 | if (unlikely(bio_check_ro(bio, p))) | |
721c7fc7 | 2219 | goto out; |
721c7fc7 | 2220 | |
74d46992 CH |
2221 | /* |
2222 | * Zone reset does not include bi_size so bio_sectors() is always 0. | |
2223 | * Include a test for the reset op code and perform the remap if needed. | |
2224 | */ | |
52c5e62d CH |
2225 | if (bio_sectors(bio) || bio_op(bio) == REQ_OP_ZONE_RESET) { |
2226 | if (bio_check_eod(bio, part_nr_sects_read(p))) | |
2227 | goto out; | |
2228 | bio->bi_iter.bi_sector += p->start_sect; | |
52c5e62d CH |
2229 | trace_block_bio_remap(bio->bi_disk->queue, bio, part_devt(p), |
2230 | bio->bi_iter.bi_sector - p->start_sect); | |
2231 | } | |
c04fa44b | 2232 | bio->bi_partno = 0; |
52c5e62d | 2233 | ret = 0; |
721c7fc7 ID |
2234 | out: |
2235 | rcu_read_unlock(); | |
74d46992 CH |
2236 | return ret; |
2237 | } | |
2238 | ||
27a84d54 CH |
2239 | static noinline_for_stack bool |
2240 | generic_make_request_checks(struct bio *bio) | |
1da177e4 | 2241 | { |
165125e1 | 2242 | struct request_queue *q; |
5a7bbad2 | 2243 | int nr_sectors = bio_sectors(bio); |
4e4cbee9 | 2244 | blk_status_t status = BLK_STS_IOERR; |
5a7bbad2 | 2245 | char b[BDEVNAME_SIZE]; |
1da177e4 LT |
2246 | |
2247 | might_sleep(); | |
1da177e4 | 2248 | |
74d46992 | 2249 | q = bio->bi_disk->queue; |
5a7bbad2 CH |
2250 | if (unlikely(!q)) { |
2251 | printk(KERN_ERR | |
2252 | "generic_make_request: Trying to access " | |
2253 | "nonexistent block-device %s (%Lu)\n", | |
74d46992 | 2254 | bio_devname(bio, b), (long long)bio->bi_iter.bi_sector); |
5a7bbad2 CH |
2255 | goto end_io; |
2256 | } | |
c17bb495 | 2257 | |
03a07c92 GR |
2258 | /* |
2259 | * For a REQ_NOWAIT based request, return -EOPNOTSUPP | |
2260 | * if queue is not a request based queue. | |
2261 | */ | |
03a07c92 GR |
2262 | if ((bio->bi_opf & REQ_NOWAIT) && !queue_is_rq_based(q)) |
2263 | goto not_supported; | |
2264 | ||
30abb3a6 | 2265 | if (should_fail_bio(bio)) |
5a7bbad2 | 2266 | goto end_io; |
2056a782 | 2267 | |
52c5e62d CH |
2268 | if (bio->bi_partno) { |
2269 | if (unlikely(blk_partition_remap(bio))) | |
721c7fc7 ID |
2270 | goto end_io; |
2271 | } else { | |
52c5e62d CH |
2272 | if (unlikely(bio_check_ro(bio, &bio->bi_disk->part0))) |
2273 | goto end_io; | |
2274 | if (unlikely(bio_check_eod(bio, get_capacity(bio->bi_disk)))) | |
721c7fc7 ID |
2275 | goto end_io; |
2276 | } | |
2056a782 | 2277 | |
5a7bbad2 CH |
2278 | /* |
2279 | * Filter flush bio's early so that make_request based | |
2280 | * drivers without flush support don't have to worry | |
2281 | * about them. | |
2282 | */ | |
f3a8ab7d | 2283 | if (op_is_flush(bio->bi_opf) && |
c888a8f9 | 2284 | !test_bit(QUEUE_FLAG_WC, &q->queue_flags)) { |
1eff9d32 | 2285 | bio->bi_opf &= ~(REQ_PREFLUSH | REQ_FUA); |
5a7bbad2 | 2286 | if (!nr_sectors) { |
4e4cbee9 | 2287 | status = BLK_STS_OK; |
51fd77bd JA |
2288 | goto end_io; |
2289 | } | |
5a7bbad2 | 2290 | } |
5ddfe969 | 2291 | |
288dab8a CH |
2292 | switch (bio_op(bio)) { |
2293 | case REQ_OP_DISCARD: | |
2294 | if (!blk_queue_discard(q)) | |
2295 | goto not_supported; | |
2296 | break; | |
2297 | case REQ_OP_SECURE_ERASE: | |
2298 | if (!blk_queue_secure_erase(q)) | |
2299 | goto not_supported; | |
2300 | break; | |
2301 | case REQ_OP_WRITE_SAME: | |
74d46992 | 2302 | if (!q->limits.max_write_same_sectors) |
288dab8a | 2303 | goto not_supported; |
58886785 | 2304 | break; |
2d253440 | 2305 | case REQ_OP_ZONE_RESET: |
74d46992 | 2306 | if (!blk_queue_is_zoned(q)) |
2d253440 | 2307 | goto not_supported; |
288dab8a | 2308 | break; |
a6f0788e | 2309 | case REQ_OP_WRITE_ZEROES: |
74d46992 | 2310 | if (!q->limits.max_write_zeroes_sectors) |
a6f0788e CK |
2311 | goto not_supported; |
2312 | break; | |
288dab8a CH |
2313 | default: |
2314 | break; | |
5a7bbad2 | 2315 | } |
01edede4 | 2316 | |
7f4b35d1 TH |
2317 | /* |
2318 | * Various block parts want %current->io_context and lazy ioc | |
2319 | * allocation ends up trading a lot of pain for a small amount of | |
2320 | * memory. Just allocate it upfront. This may fail and block | |
2321 | * layer knows how to live with it. | |
2322 | */ | |
2323 | create_io_context(GFP_ATOMIC, q->node); | |
2324 | ||
ae118896 TH |
2325 | if (!blkcg_bio_issue_check(q, bio)) |
2326 | return false; | |
27a84d54 | 2327 | |
fbbaf700 N |
2328 | if (!bio_flagged(bio, BIO_TRACE_COMPLETION)) { |
2329 | trace_block_bio_queue(q, bio); | |
2330 | /* Now that enqueuing has been traced, we need to trace | |
2331 | * completion as well. | |
2332 | */ | |
2333 | bio_set_flag(bio, BIO_TRACE_COMPLETION); | |
2334 | } | |
27a84d54 | 2335 | return true; |
a7384677 | 2336 | |
288dab8a | 2337 | not_supported: |
4e4cbee9 | 2338 | status = BLK_STS_NOTSUPP; |
a7384677 | 2339 | end_io: |
4e4cbee9 | 2340 | bio->bi_status = status; |
4246a0b6 | 2341 | bio_endio(bio); |
27a84d54 | 2342 | return false; |
1da177e4 LT |
2343 | } |
2344 | ||
27a84d54 CH |
2345 | /** |
2346 | * generic_make_request - hand a buffer to its device driver for I/O | |
2347 | * @bio: The bio describing the location in memory and on the device. | |
2348 | * | |
2349 | * generic_make_request() is used to make I/O requests of block | |
2350 | * devices. It is passed a &struct bio, which describes the I/O that needs | |
2351 | * to be done. | |
2352 | * | |
2353 | * generic_make_request() does not return any status. The | |
2354 | * success/failure status of the request, along with notification of | |
2355 | * completion, is delivered asynchronously through the bio->bi_end_io | |
2356 | * function described (one day) else where. | |
2357 | * | |
2358 | * The caller of generic_make_request must make sure that bi_io_vec | |
2359 | * are set to describe the memory buffer, and that bi_dev and bi_sector are | |
2360 | * set to describe the device address, and the | |
2361 | * bi_end_io and optionally bi_private are set to describe how | |
2362 | * completion notification should be signaled. | |
2363 | * | |
2364 | * generic_make_request and the drivers it calls may use bi_next if this | |
2365 | * bio happens to be merged with someone else, and may resubmit the bio to | |
2366 | * a lower device by calling into generic_make_request recursively, which | |
2367 | * means the bio should NOT be touched after the call to ->make_request_fn. | |
d89d8796 | 2368 | */ |
dece1635 | 2369 | blk_qc_t generic_make_request(struct bio *bio) |
d89d8796 | 2370 | { |
f5fe1b51 N |
2371 | /* |
2372 | * bio_list_on_stack[0] contains bios submitted by the current | |
2373 | * make_request_fn. | |
2374 | * bio_list_on_stack[1] contains bios that were submitted before | |
2375 | * the current make_request_fn, but that haven't been processed | |
2376 | * yet. | |
2377 | */ | |
2378 | struct bio_list bio_list_on_stack[2]; | |
37f9579f BVA |
2379 | blk_mq_req_flags_t flags = 0; |
2380 | struct request_queue *q = bio->bi_disk->queue; | |
dece1635 | 2381 | blk_qc_t ret = BLK_QC_T_NONE; |
bddd87c7 | 2382 | |
37f9579f BVA |
2383 | if (bio->bi_opf & REQ_NOWAIT) |
2384 | flags = BLK_MQ_REQ_NOWAIT; | |
cd4a4ae4 JA |
2385 | if (bio_flagged(bio, BIO_QUEUE_ENTERED)) |
2386 | blk_queue_enter_live(q); | |
2387 | else if (blk_queue_enter(q, flags) < 0) { | |
37f9579f BVA |
2388 | if (!blk_queue_dying(q) && (bio->bi_opf & REQ_NOWAIT)) |
2389 | bio_wouldblock_error(bio); | |
2390 | else | |
2391 | bio_io_error(bio); | |
2392 | return ret; | |
2393 | } | |
2394 | ||
27a84d54 | 2395 | if (!generic_make_request_checks(bio)) |
dece1635 | 2396 | goto out; |
27a84d54 CH |
2397 | |
2398 | /* | |
2399 | * We only want one ->make_request_fn to be active at a time, else | |
2400 | * stack usage with stacked devices could be a problem. So use | |
2401 | * current->bio_list to keep a list of requests submited by a | |
2402 | * make_request_fn function. current->bio_list is also used as a | |
2403 | * flag to say if generic_make_request is currently active in this | |
2404 | * task or not. If it is NULL, then no make_request is active. If | |
2405 | * it is non-NULL, then a make_request is active, and new requests | |
2406 | * should be added at the tail | |
2407 | */ | |
bddd87c7 | 2408 | if (current->bio_list) { |
f5fe1b51 | 2409 | bio_list_add(¤t->bio_list[0], bio); |
dece1635 | 2410 | goto out; |
d89d8796 | 2411 | } |
27a84d54 | 2412 | |
d89d8796 NB |
2413 | /* following loop may be a bit non-obvious, and so deserves some |
2414 | * explanation. | |
2415 | * Before entering the loop, bio->bi_next is NULL (as all callers | |
2416 | * ensure that) so we have a list with a single bio. | |
2417 | * We pretend that we have just taken it off a longer list, so | |
bddd87c7 AM |
2418 | * we assign bio_list to a pointer to the bio_list_on_stack, |
2419 | * thus initialising the bio_list of new bios to be | |
27a84d54 | 2420 | * added. ->make_request() may indeed add some more bios |
d89d8796 NB |
2421 | * through a recursive call to generic_make_request. If it |
2422 | * did, we find a non-NULL value in bio_list and re-enter the loop | |
2423 | * from the top. In this case we really did just take the bio | |
bddd87c7 | 2424 | * of the top of the list (no pretending) and so remove it from |
27a84d54 | 2425 | * bio_list, and call into ->make_request() again. |
d89d8796 NB |
2426 | */ |
2427 | BUG_ON(bio->bi_next); | |
f5fe1b51 N |
2428 | bio_list_init(&bio_list_on_stack[0]); |
2429 | current->bio_list = bio_list_on_stack; | |
d89d8796 | 2430 | do { |
37f9579f BVA |
2431 | bool enter_succeeded = true; |
2432 | ||
2433 | if (unlikely(q != bio->bi_disk->queue)) { | |
2434 | if (q) | |
2435 | blk_queue_exit(q); | |
2436 | q = bio->bi_disk->queue; | |
2437 | flags = 0; | |
2438 | if (bio->bi_opf & REQ_NOWAIT) | |
2439 | flags = BLK_MQ_REQ_NOWAIT; | |
2440 | if (blk_queue_enter(q, flags) < 0) { | |
2441 | enter_succeeded = false; | |
2442 | q = NULL; | |
2443 | } | |
2444 | } | |
27a84d54 | 2445 | |
37f9579f | 2446 | if (enter_succeeded) { |
79bd9959 N |
2447 | struct bio_list lower, same; |
2448 | ||
2449 | /* Create a fresh bio_list for all subordinate requests */ | |
f5fe1b51 N |
2450 | bio_list_on_stack[1] = bio_list_on_stack[0]; |
2451 | bio_list_init(&bio_list_on_stack[0]); | |
dece1635 | 2452 | ret = q->make_request_fn(q, bio); |
3ef28e83 | 2453 | |
79bd9959 N |
2454 | /* sort new bios into those for a lower level |
2455 | * and those for the same level | |
2456 | */ | |
2457 | bio_list_init(&lower); | |
2458 | bio_list_init(&same); | |
f5fe1b51 | 2459 | while ((bio = bio_list_pop(&bio_list_on_stack[0])) != NULL) |
74d46992 | 2460 | if (q == bio->bi_disk->queue) |
79bd9959 N |
2461 | bio_list_add(&same, bio); |
2462 | else | |
2463 | bio_list_add(&lower, bio); | |
2464 | /* now assemble so we handle the lowest level first */ | |
f5fe1b51 N |
2465 | bio_list_merge(&bio_list_on_stack[0], &lower); |
2466 | bio_list_merge(&bio_list_on_stack[0], &same); | |
2467 | bio_list_merge(&bio_list_on_stack[0], &bio_list_on_stack[1]); | |
3ef28e83 | 2468 | } else { |
03a07c92 GR |
2469 | if (unlikely(!blk_queue_dying(q) && |
2470 | (bio->bi_opf & REQ_NOWAIT))) | |
2471 | bio_wouldblock_error(bio); | |
2472 | else | |
2473 | bio_io_error(bio); | |
3ef28e83 | 2474 | } |
f5fe1b51 | 2475 | bio = bio_list_pop(&bio_list_on_stack[0]); |
d89d8796 | 2476 | } while (bio); |
bddd87c7 | 2477 | current->bio_list = NULL; /* deactivate */ |
dece1635 JA |
2478 | |
2479 | out: | |
37f9579f BVA |
2480 | if (q) |
2481 | blk_queue_exit(q); | |
dece1635 | 2482 | return ret; |
d89d8796 | 2483 | } |
1da177e4 LT |
2484 | EXPORT_SYMBOL(generic_make_request); |
2485 | ||
f421e1d9 CH |
2486 | /** |
2487 | * direct_make_request - hand a buffer directly to its device driver for I/O | |
2488 | * @bio: The bio describing the location in memory and on the device. | |
2489 | * | |
2490 | * This function behaves like generic_make_request(), but does not protect | |
2491 | * against recursion. Must only be used if the called driver is known | |
2492 | * to not call generic_make_request (or direct_make_request) again from | |
2493 | * its make_request function. (Calling direct_make_request again from | |
2494 | * a workqueue is perfectly fine as that doesn't recurse). | |
2495 | */ | |
2496 | blk_qc_t direct_make_request(struct bio *bio) | |
2497 | { | |
2498 | struct request_queue *q = bio->bi_disk->queue; | |
2499 | bool nowait = bio->bi_opf & REQ_NOWAIT; | |
2500 | blk_qc_t ret; | |
2501 | ||
2502 | if (!generic_make_request_checks(bio)) | |
2503 | return BLK_QC_T_NONE; | |
2504 | ||
3a0a5299 | 2505 | if (unlikely(blk_queue_enter(q, nowait ? BLK_MQ_REQ_NOWAIT : 0))) { |
f421e1d9 CH |
2506 | if (nowait && !blk_queue_dying(q)) |
2507 | bio->bi_status = BLK_STS_AGAIN; | |
2508 | else | |
2509 | bio->bi_status = BLK_STS_IOERR; | |
2510 | bio_endio(bio); | |
2511 | return BLK_QC_T_NONE; | |
2512 | } | |
2513 | ||
2514 | ret = q->make_request_fn(q, bio); | |
2515 | blk_queue_exit(q); | |
2516 | return ret; | |
2517 | } | |
2518 | EXPORT_SYMBOL_GPL(direct_make_request); | |
2519 | ||
1da177e4 | 2520 | /** |
710027a4 | 2521 | * submit_bio - submit a bio to the block device layer for I/O |
1da177e4 LT |
2522 | * @bio: The &struct bio which describes the I/O |
2523 | * | |
2524 | * submit_bio() is very similar in purpose to generic_make_request(), and | |
2525 | * uses that function to do most of the work. Both are fairly rough | |
710027a4 | 2526 | * interfaces; @bio must be presetup and ready for I/O. |
1da177e4 LT |
2527 | * |
2528 | */ | |
4e49ea4a | 2529 | blk_qc_t submit_bio(struct bio *bio) |
1da177e4 | 2530 | { |
bf2de6f5 JA |
2531 | /* |
2532 | * If it's a regular read/write or a barrier with data attached, | |
2533 | * go through the normal accounting stuff before submission. | |
2534 | */ | |
e2a60da7 | 2535 | if (bio_has_data(bio)) { |
4363ac7c MP |
2536 | unsigned int count; |
2537 | ||
95fe6c1a | 2538 | if (unlikely(bio_op(bio) == REQ_OP_WRITE_SAME)) |
7c5a0dcf | 2539 | count = queue_logical_block_size(bio->bi_disk->queue) >> 9; |
4363ac7c MP |
2540 | else |
2541 | count = bio_sectors(bio); | |
2542 | ||
a8ebb056 | 2543 | if (op_is_write(bio_op(bio))) { |
bf2de6f5 JA |
2544 | count_vm_events(PGPGOUT, count); |
2545 | } else { | |
4f024f37 | 2546 | task_io_account_read(bio->bi_iter.bi_size); |
bf2de6f5 JA |
2547 | count_vm_events(PGPGIN, count); |
2548 | } | |
2549 | ||
2550 | if (unlikely(block_dump)) { | |
2551 | char b[BDEVNAME_SIZE]; | |
8dcbdc74 | 2552 | printk(KERN_DEBUG "%s(%d): %s block %Lu on %s (%u sectors)\n", |
ba25f9dc | 2553 | current->comm, task_pid_nr(current), |
a8ebb056 | 2554 | op_is_write(bio_op(bio)) ? "WRITE" : "READ", |
4f024f37 | 2555 | (unsigned long long)bio->bi_iter.bi_sector, |
74d46992 | 2556 | bio_devname(bio, b), count); |
bf2de6f5 | 2557 | } |
1da177e4 LT |
2558 | } |
2559 | ||
dece1635 | 2560 | return generic_make_request(bio); |
1da177e4 | 2561 | } |
1da177e4 LT |
2562 | EXPORT_SYMBOL(submit_bio); |
2563 | ||
ea435e1b CH |
2564 | bool blk_poll(struct request_queue *q, blk_qc_t cookie) |
2565 | { | |
2566 | if (!q->poll_fn || !blk_qc_t_valid(cookie)) | |
2567 | return false; | |
2568 | ||
2569 | if (current->plug) | |
2570 | blk_flush_plug_list(current->plug, false); | |
2571 | return q->poll_fn(q, cookie); | |
2572 | } | |
2573 | EXPORT_SYMBOL_GPL(blk_poll); | |
2574 | ||
82124d60 | 2575 | /** |
bf4e6b4e HR |
2576 | * blk_cloned_rq_check_limits - Helper function to check a cloned request |
2577 | * for new the queue limits | |
82124d60 KU |
2578 | * @q: the queue |
2579 | * @rq: the request being checked | |
2580 | * | |
2581 | * Description: | |
2582 | * @rq may have been made based on weaker limitations of upper-level queues | |
2583 | * in request stacking drivers, and it may violate the limitation of @q. | |
2584 | * Since the block layer and the underlying device driver trust @rq | |
2585 | * after it is inserted to @q, it should be checked against @q before | |
2586 | * the insertion using this generic function. | |
2587 | * | |
82124d60 | 2588 | * Request stacking drivers like request-based dm may change the queue |
bf4e6b4e HR |
2589 | * limits when retrying requests on other queues. Those requests need |
2590 | * to be checked against the new queue limits again during dispatch. | |
82124d60 | 2591 | */ |
bf4e6b4e HR |
2592 | static int blk_cloned_rq_check_limits(struct request_queue *q, |
2593 | struct request *rq) | |
82124d60 | 2594 | { |
8fe0d473 | 2595 | if (blk_rq_sectors(rq) > blk_queue_get_max_sectors(q, req_op(rq))) { |
82124d60 KU |
2596 | printk(KERN_ERR "%s: over max size limit.\n", __func__); |
2597 | return -EIO; | |
2598 | } | |
2599 | ||
2600 | /* | |
2601 | * queue's settings related to segment counting like q->bounce_pfn | |
2602 | * may differ from that of other stacking queues. | |
2603 | * Recalculate it to check the request correctly on this queue's | |
2604 | * limitation. | |
2605 | */ | |
2606 | blk_recalc_rq_segments(rq); | |
8a78362c | 2607 | if (rq->nr_phys_segments > queue_max_segments(q)) { |
82124d60 KU |
2608 | printk(KERN_ERR "%s: over max segments limit.\n", __func__); |
2609 | return -EIO; | |
2610 | } | |
2611 | ||
2612 | return 0; | |
2613 | } | |
82124d60 KU |
2614 | |
2615 | /** | |
2616 | * blk_insert_cloned_request - Helper for stacking drivers to submit a request | |
2617 | * @q: the queue to submit the request | |
2618 | * @rq: the request being queued | |
2619 | */ | |
2a842aca | 2620 | blk_status_t blk_insert_cloned_request(struct request_queue *q, struct request *rq) |
82124d60 KU |
2621 | { |
2622 | unsigned long flags; | |
4853abaa | 2623 | int where = ELEVATOR_INSERT_BACK; |
82124d60 | 2624 | |
bf4e6b4e | 2625 | if (blk_cloned_rq_check_limits(q, rq)) |
2a842aca | 2626 | return BLK_STS_IOERR; |
82124d60 | 2627 | |
b2c9cd37 AM |
2628 | if (rq->rq_disk && |
2629 | should_fail_request(&rq->rq_disk->part0, blk_rq_bytes(rq))) | |
2a842aca | 2630 | return BLK_STS_IOERR; |
82124d60 | 2631 | |
7fb4898e KB |
2632 | if (q->mq_ops) { |
2633 | if (blk_queue_io_stat(q)) | |
2634 | blk_account_io_start(rq, true); | |
157f377b JA |
2635 | /* |
2636 | * Since we have a scheduler attached on the top device, | |
2637 | * bypass a potential scheduler on the bottom device for | |
2638 | * insert. | |
2639 | */ | |
c77ff7fd | 2640 | return blk_mq_request_issue_directly(rq); |
7fb4898e KB |
2641 | } |
2642 | ||
82124d60 | 2643 | spin_lock_irqsave(q->queue_lock, flags); |
3f3299d5 | 2644 | if (unlikely(blk_queue_dying(q))) { |
8ba61435 | 2645 | spin_unlock_irqrestore(q->queue_lock, flags); |
2a842aca | 2646 | return BLK_STS_IOERR; |
8ba61435 | 2647 | } |
82124d60 KU |
2648 | |
2649 | /* | |
2650 | * Submitting request must be dequeued before calling this function | |
2651 | * because it will be linked to another request_queue | |
2652 | */ | |
2653 | BUG_ON(blk_queued_rq(rq)); | |
2654 | ||
f73f44eb | 2655 | if (op_is_flush(rq->cmd_flags)) |
4853abaa JM |
2656 | where = ELEVATOR_INSERT_FLUSH; |
2657 | ||
2658 | add_acct_request(q, rq, where); | |
e67b77c7 JM |
2659 | if (where == ELEVATOR_INSERT_FLUSH) |
2660 | __blk_run_queue(q); | |
82124d60 KU |
2661 | spin_unlock_irqrestore(q->queue_lock, flags); |
2662 | ||
2a842aca | 2663 | return BLK_STS_OK; |
82124d60 KU |
2664 | } |
2665 | EXPORT_SYMBOL_GPL(blk_insert_cloned_request); | |
2666 | ||
80a761fd TH |
2667 | /** |
2668 | * blk_rq_err_bytes - determine number of bytes till the next failure boundary | |
2669 | * @rq: request to examine | |
2670 | * | |
2671 | * Description: | |
2672 | * A request could be merge of IOs which require different failure | |
2673 | * handling. This function determines the number of bytes which | |
2674 | * can be failed from the beginning of the request without | |
2675 | * crossing into area which need to be retried further. | |
2676 | * | |
2677 | * Return: | |
2678 | * The number of bytes to fail. | |
80a761fd TH |
2679 | */ |
2680 | unsigned int blk_rq_err_bytes(const struct request *rq) | |
2681 | { | |
2682 | unsigned int ff = rq->cmd_flags & REQ_FAILFAST_MASK; | |
2683 | unsigned int bytes = 0; | |
2684 | struct bio *bio; | |
2685 | ||
e8064021 | 2686 | if (!(rq->rq_flags & RQF_MIXED_MERGE)) |
80a761fd TH |
2687 | return blk_rq_bytes(rq); |
2688 | ||
2689 | /* | |
2690 | * Currently the only 'mixing' which can happen is between | |
2691 | * different fastfail types. We can safely fail portions | |
2692 | * which have all the failfast bits that the first one has - | |
2693 | * the ones which are at least as eager to fail as the first | |
2694 | * one. | |
2695 | */ | |
2696 | for (bio = rq->bio; bio; bio = bio->bi_next) { | |
1eff9d32 | 2697 | if ((bio->bi_opf & ff) != ff) |
80a761fd | 2698 | break; |
4f024f37 | 2699 | bytes += bio->bi_iter.bi_size; |
80a761fd TH |
2700 | } |
2701 | ||
2702 | /* this could lead to infinite loop */ | |
2703 | BUG_ON(blk_rq_bytes(rq) && !bytes); | |
2704 | return bytes; | |
2705 | } | |
2706 | EXPORT_SYMBOL_GPL(blk_rq_err_bytes); | |
2707 | ||
320ae51f | 2708 | void blk_account_io_completion(struct request *req, unsigned int bytes) |
bc58ba94 | 2709 | { |
c2553b58 | 2710 | if (blk_do_io_stat(req)) { |
ddcf35d3 | 2711 | const int sgrp = op_stat_group(req_op(req)); |
bc58ba94 JA |
2712 | struct hd_struct *part; |
2713 | int cpu; | |
2714 | ||
2715 | cpu = part_stat_lock(); | |
09e099d4 | 2716 | part = req->part; |
ddcf35d3 | 2717 | part_stat_add(cpu, part, sectors[sgrp], bytes >> 9); |
bc58ba94 JA |
2718 | part_stat_unlock(); |
2719 | } | |
2720 | } | |
2721 | ||
522a7775 | 2722 | void blk_account_io_done(struct request *req, u64 now) |
bc58ba94 | 2723 | { |
bc58ba94 | 2724 | /* |
dd4c133f TH |
2725 | * Account IO completion. flush_rq isn't accounted as a |
2726 | * normal IO on queueing nor completion. Accounting the | |
2727 | * containing request is enough. | |
bc58ba94 | 2728 | */ |
e8064021 | 2729 | if (blk_do_io_stat(req) && !(req->rq_flags & RQF_FLUSH_SEQ)) { |
ddcf35d3 | 2730 | const int sgrp = op_stat_group(req_op(req)); |
bc58ba94 JA |
2731 | struct hd_struct *part; |
2732 | int cpu; | |
2733 | ||
2734 | cpu = part_stat_lock(); | |
09e099d4 | 2735 | part = req->part; |
bc58ba94 | 2736 | |
ddcf35d3 | 2737 | part_stat_inc(cpu, part, ios[sgrp]); |
b57e99b4 | 2738 | part_stat_add(cpu, part, nsecs[sgrp], now - req->start_time_ns); |
d62e26b3 | 2739 | part_round_stats(req->q, cpu, part); |
ddcf35d3 | 2740 | part_dec_in_flight(req->q, part, rq_data_dir(req)); |
bc58ba94 | 2741 | |
6c23a968 | 2742 | hd_struct_put(part); |
bc58ba94 JA |
2743 | part_stat_unlock(); |
2744 | } | |
2745 | } | |
2746 | ||
320ae51f JA |
2747 | void blk_account_io_start(struct request *rq, bool new_io) |
2748 | { | |
2749 | struct hd_struct *part; | |
2750 | int rw = rq_data_dir(rq); | |
2751 | int cpu; | |
2752 | ||
2753 | if (!blk_do_io_stat(rq)) | |
2754 | return; | |
2755 | ||
2756 | cpu = part_stat_lock(); | |
2757 | ||
2758 | if (!new_io) { | |
2759 | part = rq->part; | |
2760 | part_stat_inc(cpu, part, merges[rw]); | |
2761 | } else { | |
2762 | part = disk_map_sector_rcu(rq->rq_disk, blk_rq_pos(rq)); | |
2763 | if (!hd_struct_try_get(part)) { | |
2764 | /* | |
2765 | * The partition is already being removed, | |
2766 | * the request will be accounted on the disk only | |
2767 | * | |
2768 | * We take a reference on disk->part0 although that | |
2769 | * partition will never be deleted, so we can treat | |
2770 | * it as any other partition. | |
2771 | */ | |
2772 | part = &rq->rq_disk->part0; | |
2773 | hd_struct_get(part); | |
2774 | } | |
d62e26b3 JA |
2775 | part_round_stats(rq->q, cpu, part); |
2776 | part_inc_in_flight(rq->q, part, rw); | |
320ae51f JA |
2777 | rq->part = part; |
2778 | } | |
2779 | ||
2780 | part_stat_unlock(); | |
2781 | } | |
2782 | ||
9c988374 CH |
2783 | static struct request *elv_next_request(struct request_queue *q) |
2784 | { | |
2785 | struct request *rq; | |
2786 | struct blk_flush_queue *fq = blk_get_flush_queue(q, NULL); | |
2787 | ||
2788 | WARN_ON_ONCE(q->mq_ops); | |
2789 | ||
2790 | while (1) { | |
e4f36b24 | 2791 | list_for_each_entry(rq, &q->queue_head, queuelist) { |
7cedffec BVA |
2792 | #ifdef CONFIG_PM |
2793 | /* | |
2794 | * If a request gets queued in state RPM_SUSPENDED | |
2795 | * then that's a kernel bug. | |
2796 | */ | |
2797 | WARN_ON_ONCE(q->rpm_status == RPM_SUSPENDED); | |
2798 | #endif | |
2799 | return rq; | |
9c988374 CH |
2800 | } |
2801 | ||
2802 | /* | |
2803 | * Flush request is running and flush request isn't queueable | |
2804 | * in the drive, we can hold the queue till flush request is | |
2805 | * finished. Even we don't do this, driver can't dispatch next | |
2806 | * requests and will requeue them. And this can improve | |
2807 | * throughput too. For example, we have request flush1, write1, | |
2808 | * flush 2. flush1 is dispatched, then queue is hold, write1 | |
2809 | * isn't inserted to queue. After flush1 is finished, flush2 | |
2810 | * will be dispatched. Since disk cache is already clean, | |
2811 | * flush2 will be finished very soon, so looks like flush2 is | |
2812 | * folded to flush1. | |
2813 | * Since the queue is hold, a flag is set to indicate the queue | |
2814 | * should be restarted later. Please see flush_end_io() for | |
2815 | * details. | |
2816 | */ | |
2817 | if (fq->flush_pending_idx != fq->flush_running_idx && | |
2818 | !queue_flush_queueable(q)) { | |
2819 | fq->flush_queue_delayed = 1; | |
2820 | return NULL; | |
2821 | } | |
2822 | if (unlikely(blk_queue_bypass(q)) || | |
2823 | !q->elevator->type->ops.sq.elevator_dispatch_fn(q, 0)) | |
2824 | return NULL; | |
2825 | } | |
2826 | } | |
2827 | ||
3bcddeac | 2828 | /** |
9934c8c0 TH |
2829 | * blk_peek_request - peek at the top of a request queue |
2830 | * @q: request queue to peek at | |
2831 | * | |
2832 | * Description: | |
2833 | * Return the request at the top of @q. The returned request | |
2834 | * should be started using blk_start_request() before LLD starts | |
2835 | * processing it. | |
2836 | * | |
2837 | * Return: | |
2838 | * Pointer to the request at the top of @q if available. Null | |
2839 | * otherwise. | |
9934c8c0 TH |
2840 | */ |
2841 | struct request *blk_peek_request(struct request_queue *q) | |
158dbda0 TH |
2842 | { |
2843 | struct request *rq; | |
2844 | int ret; | |
2845 | ||
2fff8a92 | 2846 | lockdep_assert_held(q->queue_lock); |
332ebbf7 | 2847 | WARN_ON_ONCE(q->mq_ops); |
2fff8a92 | 2848 | |
9c988374 | 2849 | while ((rq = elv_next_request(q)) != NULL) { |
e8064021 | 2850 | if (!(rq->rq_flags & RQF_STARTED)) { |
158dbda0 TH |
2851 | /* |
2852 | * This is the first time the device driver | |
2853 | * sees this request (possibly after | |
2854 | * requeueing). Notify IO scheduler. | |
2855 | */ | |
e8064021 | 2856 | if (rq->rq_flags & RQF_SORTED) |
158dbda0 TH |
2857 | elv_activate_rq(q, rq); |
2858 | ||
2859 | /* | |
2860 | * just mark as started even if we don't start | |
2861 | * it, a request that has been delayed should | |
2862 | * not be passed by new incoming requests | |
2863 | */ | |
e8064021 | 2864 | rq->rq_flags |= RQF_STARTED; |
158dbda0 TH |
2865 | trace_block_rq_issue(q, rq); |
2866 | } | |
2867 | ||
2868 | if (!q->boundary_rq || q->boundary_rq == rq) { | |
2869 | q->end_sector = rq_end_sector(rq); | |
2870 | q->boundary_rq = NULL; | |
2871 | } | |
2872 | ||
e8064021 | 2873 | if (rq->rq_flags & RQF_DONTPREP) |
158dbda0 TH |
2874 | break; |
2875 | ||
2e46e8b2 | 2876 | if (q->dma_drain_size && blk_rq_bytes(rq)) { |
158dbda0 TH |
2877 | /* |
2878 | * make sure space for the drain appears we | |
2879 | * know we can do this because max_hw_segments | |
2880 | * has been adjusted to be one fewer than the | |
2881 | * device can handle | |
2882 | */ | |
2883 | rq->nr_phys_segments++; | |
2884 | } | |
2885 | ||
2886 | if (!q->prep_rq_fn) | |
2887 | break; | |
2888 | ||
2889 | ret = q->prep_rq_fn(q, rq); | |
2890 | if (ret == BLKPREP_OK) { | |
2891 | break; | |
2892 | } else if (ret == BLKPREP_DEFER) { | |
2893 | /* | |
2894 | * the request may have been (partially) prepped. | |
2895 | * we need to keep this request in the front to | |
e8064021 | 2896 | * avoid resource deadlock. RQF_STARTED will |
158dbda0 TH |
2897 | * prevent other fs requests from passing this one. |
2898 | */ | |
2e46e8b2 | 2899 | if (q->dma_drain_size && blk_rq_bytes(rq) && |
e8064021 | 2900 | !(rq->rq_flags & RQF_DONTPREP)) { |
158dbda0 TH |
2901 | /* |
2902 | * remove the space for the drain we added | |
2903 | * so that we don't add it again | |
2904 | */ | |
2905 | --rq->nr_phys_segments; | |
2906 | } | |
2907 | ||
2908 | rq = NULL; | |
2909 | break; | |
0fb5b1fb | 2910 | } else if (ret == BLKPREP_KILL || ret == BLKPREP_INVALID) { |
e8064021 | 2911 | rq->rq_flags |= RQF_QUIET; |
c143dc90 JB |
2912 | /* |
2913 | * Mark this request as started so we don't trigger | |
2914 | * any debug logic in the end I/O path. | |
2915 | */ | |
2916 | blk_start_request(rq); | |
2a842aca CH |
2917 | __blk_end_request_all(rq, ret == BLKPREP_INVALID ? |
2918 | BLK_STS_TARGET : BLK_STS_IOERR); | |
158dbda0 TH |
2919 | } else { |
2920 | printk(KERN_ERR "%s: bad return=%d\n", __func__, ret); | |
2921 | break; | |
2922 | } | |
2923 | } | |
2924 | ||
2925 | return rq; | |
2926 | } | |
9934c8c0 | 2927 | EXPORT_SYMBOL(blk_peek_request); |
158dbda0 | 2928 | |
5034435c | 2929 | static void blk_dequeue_request(struct request *rq) |
158dbda0 | 2930 | { |
9934c8c0 TH |
2931 | struct request_queue *q = rq->q; |
2932 | ||
158dbda0 TH |
2933 | BUG_ON(list_empty(&rq->queuelist)); |
2934 | BUG_ON(ELV_ON_HASH(rq)); | |
2935 | ||
2936 | list_del_init(&rq->queuelist); | |
2937 | ||
2938 | /* | |
2939 | * the time frame between a request being removed from the lists | |
2940 | * and to it is freed is accounted as io that is in progress at | |
2941 | * the driver side. | |
2942 | */ | |
522a7775 | 2943 | if (blk_account_rq(rq)) |
0a7ae2ff | 2944 | q->in_flight[rq_is_sync(rq)]++; |
158dbda0 TH |
2945 | } |
2946 | ||
9934c8c0 TH |
2947 | /** |
2948 | * blk_start_request - start request processing on the driver | |
2949 | * @req: request to dequeue | |
2950 | * | |
2951 | * Description: | |
2952 | * Dequeue @req and start timeout timer on it. This hands off the | |
2953 | * request to the driver. | |
9934c8c0 TH |
2954 | */ |
2955 | void blk_start_request(struct request *req) | |
2956 | { | |
2fff8a92 | 2957 | lockdep_assert_held(req->q->queue_lock); |
332ebbf7 | 2958 | WARN_ON_ONCE(req->q->mq_ops); |
2fff8a92 | 2959 | |
9934c8c0 TH |
2960 | blk_dequeue_request(req); |
2961 | ||
cf43e6be | 2962 | if (test_bit(QUEUE_FLAG_STATS, &req->q->queue_flags)) { |
544ccc8d OS |
2963 | req->io_start_time_ns = ktime_get_ns(); |
2964 | #ifdef CONFIG_BLK_DEV_THROTTLING_LOW | |
2965 | req->throtl_size = blk_rq_sectors(req); | |
2966 | #endif | |
cf43e6be | 2967 | req->rq_flags |= RQF_STATS; |
a7905043 | 2968 | rq_qos_issue(req->q, req); |
cf43e6be JA |
2969 | } |
2970 | ||
e14575b3 | 2971 | BUG_ON(blk_rq_is_complete(req)); |
9934c8c0 TH |
2972 | blk_add_timer(req); |
2973 | } | |
2974 | EXPORT_SYMBOL(blk_start_request); | |
2975 | ||
2976 | /** | |
2977 | * blk_fetch_request - fetch a request from a request queue | |
2978 | * @q: request queue to fetch a request from | |
2979 | * | |
2980 | * Description: | |
2981 | * Return the request at the top of @q. The request is started on | |
2982 | * return and LLD can start processing it immediately. | |
2983 | * | |
2984 | * Return: | |
2985 | * Pointer to the request at the top of @q if available. Null | |
2986 | * otherwise. | |
9934c8c0 TH |
2987 | */ |
2988 | struct request *blk_fetch_request(struct request_queue *q) | |
2989 | { | |
2990 | struct request *rq; | |
2991 | ||
2fff8a92 | 2992 | lockdep_assert_held(q->queue_lock); |
332ebbf7 | 2993 | WARN_ON_ONCE(q->mq_ops); |
2fff8a92 | 2994 | |
9934c8c0 TH |
2995 | rq = blk_peek_request(q); |
2996 | if (rq) | |
2997 | blk_start_request(rq); | |
2998 | return rq; | |
2999 | } | |
3000 | EXPORT_SYMBOL(blk_fetch_request); | |
3001 | ||
ef71de8b CH |
3002 | /* |
3003 | * Steal bios from a request and add them to a bio list. | |
3004 | * The request must not have been partially completed before. | |
3005 | */ | |
3006 | void blk_steal_bios(struct bio_list *list, struct request *rq) | |
3007 | { | |
3008 | if (rq->bio) { | |
3009 | if (list->tail) | |
3010 | list->tail->bi_next = rq->bio; | |
3011 | else | |
3012 | list->head = rq->bio; | |
3013 | list->tail = rq->biotail; | |
3014 | ||
3015 | rq->bio = NULL; | |
3016 | rq->biotail = NULL; | |
3017 | } | |
3018 | ||
3019 | rq->__data_len = 0; | |
3020 | } | |
3021 | EXPORT_SYMBOL_GPL(blk_steal_bios); | |
3022 | ||
3bcddeac | 3023 | /** |
2e60e022 | 3024 | * blk_update_request - Special helper function for request stacking drivers |
8ebf9756 | 3025 | * @req: the request being processed |
2a842aca | 3026 | * @error: block status code |
8ebf9756 | 3027 | * @nr_bytes: number of bytes to complete @req |
3bcddeac KU |
3028 | * |
3029 | * Description: | |
8ebf9756 RD |
3030 | * Ends I/O on a number of bytes attached to @req, but doesn't complete |
3031 | * the request structure even if @req doesn't have leftover. | |
3032 | * If @req has leftover, sets it up for the next range of segments. | |
2e60e022 TH |
3033 | * |
3034 | * This special helper function is only for request stacking drivers | |
3035 | * (e.g. request-based dm) so that they can handle partial completion. | |
3036 | * Actual device drivers should use blk_end_request instead. | |
3037 | * | |
3038 | * Passing the result of blk_rq_bytes() as @nr_bytes guarantees | |
3039 | * %false return from this function. | |
3bcddeac | 3040 | * |
1954e9a9 BVA |
3041 | * Note: |
3042 | * The RQF_SPECIAL_PAYLOAD flag is ignored on purpose in both | |
3043 | * blk_rq_bytes() and in blk_update_request(). | |
3044 | * | |
3bcddeac | 3045 | * Return: |
2e60e022 TH |
3046 | * %false - this request doesn't have any more data |
3047 | * %true - this request has more data | |
3bcddeac | 3048 | **/ |
2a842aca CH |
3049 | bool blk_update_request(struct request *req, blk_status_t error, |
3050 | unsigned int nr_bytes) | |
1da177e4 | 3051 | { |
f79ea416 | 3052 | int total_bytes; |
1da177e4 | 3053 | |
2a842aca | 3054 | trace_block_rq_complete(req, blk_status_to_errno(error), nr_bytes); |
4a0efdc9 | 3055 | |
2e60e022 TH |
3056 | if (!req->bio) |
3057 | return false; | |
3058 | ||
2a842aca CH |
3059 | if (unlikely(error && !blk_rq_is_passthrough(req) && |
3060 | !(req->rq_flags & RQF_QUIET))) | |
3061 | print_req_error(req, error); | |
1da177e4 | 3062 | |
bc58ba94 | 3063 | blk_account_io_completion(req, nr_bytes); |
d72d904a | 3064 | |
f79ea416 KO |
3065 | total_bytes = 0; |
3066 | while (req->bio) { | |
3067 | struct bio *bio = req->bio; | |
4f024f37 | 3068 | unsigned bio_bytes = min(bio->bi_iter.bi_size, nr_bytes); |
1da177e4 | 3069 | |
9c24c10a | 3070 | if (bio_bytes == bio->bi_iter.bi_size) |
1da177e4 | 3071 | req->bio = bio->bi_next; |
1da177e4 | 3072 | |
fbbaf700 N |
3073 | /* Completion has already been traced */ |
3074 | bio_clear_flag(bio, BIO_TRACE_COMPLETION); | |
f79ea416 | 3075 | req_bio_endio(req, bio, bio_bytes, error); |
1da177e4 | 3076 | |
f79ea416 KO |
3077 | total_bytes += bio_bytes; |
3078 | nr_bytes -= bio_bytes; | |
1da177e4 | 3079 | |
f79ea416 KO |
3080 | if (!nr_bytes) |
3081 | break; | |
1da177e4 LT |
3082 | } |
3083 | ||
3084 | /* | |
3085 | * completely done | |
3086 | */ | |
2e60e022 TH |
3087 | if (!req->bio) { |
3088 | /* | |
3089 | * Reset counters so that the request stacking driver | |
3090 | * can find how many bytes remain in the request | |
3091 | * later. | |
3092 | */ | |
a2dec7b3 | 3093 | req->__data_len = 0; |
2e60e022 TH |
3094 | return false; |
3095 | } | |
1da177e4 | 3096 | |
a2dec7b3 | 3097 | req->__data_len -= total_bytes; |
2e46e8b2 TH |
3098 | |
3099 | /* update sector only for requests with clear definition of sector */ | |
57292b58 | 3100 | if (!blk_rq_is_passthrough(req)) |
a2dec7b3 | 3101 | req->__sector += total_bytes >> 9; |
2e46e8b2 | 3102 | |
80a761fd | 3103 | /* mixed attributes always follow the first bio */ |
e8064021 | 3104 | if (req->rq_flags & RQF_MIXED_MERGE) { |
80a761fd | 3105 | req->cmd_flags &= ~REQ_FAILFAST_MASK; |
1eff9d32 | 3106 | req->cmd_flags |= req->bio->bi_opf & REQ_FAILFAST_MASK; |
80a761fd TH |
3107 | } |
3108 | ||
ed6565e7 CH |
3109 | if (!(req->rq_flags & RQF_SPECIAL_PAYLOAD)) { |
3110 | /* | |
3111 | * If total number of sectors is less than the first segment | |
3112 | * size, something has gone terribly wrong. | |
3113 | */ | |
3114 | if (blk_rq_bytes(req) < blk_rq_cur_bytes(req)) { | |
3115 | blk_dump_rq_flags(req, "request botched"); | |
3116 | req->__data_len = blk_rq_cur_bytes(req); | |
3117 | } | |
2e46e8b2 | 3118 | |
ed6565e7 CH |
3119 | /* recalculate the number of segments */ |
3120 | blk_recalc_rq_segments(req); | |
3121 | } | |
2e46e8b2 | 3122 | |
2e60e022 | 3123 | return true; |
1da177e4 | 3124 | } |
2e60e022 | 3125 | EXPORT_SYMBOL_GPL(blk_update_request); |
1da177e4 | 3126 | |
2a842aca | 3127 | static bool blk_update_bidi_request(struct request *rq, blk_status_t error, |
2e60e022 TH |
3128 | unsigned int nr_bytes, |
3129 | unsigned int bidi_bytes) | |
5efccd17 | 3130 | { |
2e60e022 TH |
3131 | if (blk_update_request(rq, error, nr_bytes)) |
3132 | return true; | |
5efccd17 | 3133 | |
2e60e022 TH |
3134 | /* Bidi request must be completed as a whole */ |
3135 | if (unlikely(blk_bidi_rq(rq)) && | |
3136 | blk_update_request(rq->next_rq, error, bidi_bytes)) | |
3137 | return true; | |
5efccd17 | 3138 | |
e2e1a148 JA |
3139 | if (blk_queue_add_random(rq->q)) |
3140 | add_disk_randomness(rq->rq_disk); | |
2e60e022 TH |
3141 | |
3142 | return false; | |
1da177e4 LT |
3143 | } |
3144 | ||
28018c24 JB |
3145 | /** |
3146 | * blk_unprep_request - unprepare a request | |
3147 | * @req: the request | |
3148 | * | |
3149 | * This function makes a request ready for complete resubmission (or | |
3150 | * completion). It happens only after all error handling is complete, | |
3151 | * so represents the appropriate moment to deallocate any resources | |
3152 | * that were allocated to the request in the prep_rq_fn. The queue | |
3153 | * lock is held when calling this. | |
3154 | */ | |
3155 | void blk_unprep_request(struct request *req) | |
3156 | { | |
3157 | struct request_queue *q = req->q; | |
3158 | ||
e8064021 | 3159 | req->rq_flags &= ~RQF_DONTPREP; |
28018c24 JB |
3160 | if (q->unprep_rq_fn) |
3161 | q->unprep_rq_fn(q, req); | |
3162 | } | |
3163 | EXPORT_SYMBOL_GPL(blk_unprep_request); | |
3164 | ||
2a842aca | 3165 | void blk_finish_request(struct request *req, blk_status_t error) |
1da177e4 | 3166 | { |
cf43e6be | 3167 | struct request_queue *q = req->q; |
522a7775 | 3168 | u64 now = ktime_get_ns(); |
cf43e6be | 3169 | |
2fff8a92 | 3170 | lockdep_assert_held(req->q->queue_lock); |
332ebbf7 | 3171 | WARN_ON_ONCE(q->mq_ops); |
2fff8a92 | 3172 | |
cf43e6be | 3173 | if (req->rq_flags & RQF_STATS) |
522a7775 | 3174 | blk_stat_add(req, now); |
cf43e6be | 3175 | |
e8064021 | 3176 | if (req->rq_flags & RQF_QUEUED) |
cf43e6be | 3177 | blk_queue_end_tag(q, req); |
b8286239 | 3178 | |
ba396a6c | 3179 | BUG_ON(blk_queued_rq(req)); |
1da177e4 | 3180 | |
57292b58 | 3181 | if (unlikely(laptop_mode) && !blk_rq_is_passthrough(req)) |
dc3b17cc | 3182 | laptop_io_completion(req->q->backing_dev_info); |
1da177e4 | 3183 | |
e78042e5 MA |
3184 | blk_delete_timer(req); |
3185 | ||
e8064021 | 3186 | if (req->rq_flags & RQF_DONTPREP) |
28018c24 JB |
3187 | blk_unprep_request(req); |
3188 | ||
522a7775 | 3189 | blk_account_io_done(req, now); |
b8286239 | 3190 | |
87760e5e | 3191 | if (req->end_io) { |
a7905043 | 3192 | rq_qos_done(q, req); |
8ffdc655 | 3193 | req->end_io(req, error); |
87760e5e | 3194 | } else { |
b8286239 KU |
3195 | if (blk_bidi_rq(req)) |
3196 | __blk_put_request(req->next_rq->q, req->next_rq); | |
3197 | ||
cf43e6be | 3198 | __blk_put_request(q, req); |
b8286239 | 3199 | } |
1da177e4 | 3200 | } |
12120077 | 3201 | EXPORT_SYMBOL(blk_finish_request); |
1da177e4 | 3202 | |
3b11313a | 3203 | /** |
2e60e022 TH |
3204 | * blk_end_bidi_request - Complete a bidi request |
3205 | * @rq: the request to complete | |
2a842aca | 3206 | * @error: block status code |
2e60e022 TH |
3207 | * @nr_bytes: number of bytes to complete @rq |
3208 | * @bidi_bytes: number of bytes to complete @rq->next_rq | |
a0cd1285 JA |
3209 | * |
3210 | * Description: | |
e3a04fe3 | 3211 | * Ends I/O on a number of bytes attached to @rq and @rq->next_rq. |
2e60e022 TH |
3212 | * Drivers that supports bidi can safely call this member for any |
3213 | * type of request, bidi or uni. In the later case @bidi_bytes is | |
3214 | * just ignored. | |
336cdb40 KU |
3215 | * |
3216 | * Return: | |
2e60e022 TH |
3217 | * %false - we are done with this request |
3218 | * %true - still buffers pending for this request | |
a0cd1285 | 3219 | **/ |
2a842aca | 3220 | static bool blk_end_bidi_request(struct request *rq, blk_status_t error, |
32fab448 KU |
3221 | unsigned int nr_bytes, unsigned int bidi_bytes) |
3222 | { | |
336cdb40 | 3223 | struct request_queue *q = rq->q; |
2e60e022 | 3224 | unsigned long flags; |
32fab448 | 3225 | |
332ebbf7 BVA |
3226 | WARN_ON_ONCE(q->mq_ops); |
3227 | ||
2e60e022 TH |
3228 | if (blk_update_bidi_request(rq, error, nr_bytes, bidi_bytes)) |
3229 | return true; | |
32fab448 | 3230 | |
336cdb40 | 3231 | spin_lock_irqsave(q->queue_lock, flags); |
2e60e022 | 3232 | blk_finish_request(rq, error); |
336cdb40 KU |
3233 | spin_unlock_irqrestore(q->queue_lock, flags); |
3234 | ||
2e60e022 | 3235 | return false; |
32fab448 KU |
3236 | } |
3237 | ||
336cdb40 | 3238 | /** |
2e60e022 TH |
3239 | * __blk_end_bidi_request - Complete a bidi request with queue lock held |
3240 | * @rq: the request to complete | |
2a842aca | 3241 | * @error: block status code |
e3a04fe3 KU |
3242 | * @nr_bytes: number of bytes to complete @rq |
3243 | * @bidi_bytes: number of bytes to complete @rq->next_rq | |
336cdb40 KU |
3244 | * |
3245 | * Description: | |
2e60e022 TH |
3246 | * Identical to blk_end_bidi_request() except that queue lock is |
3247 | * assumed to be locked on entry and remains so on return. | |
336cdb40 KU |
3248 | * |
3249 | * Return: | |
2e60e022 TH |
3250 | * %false - we are done with this request |
3251 | * %true - still buffers pending for this request | |
336cdb40 | 3252 | **/ |
2a842aca | 3253 | static bool __blk_end_bidi_request(struct request *rq, blk_status_t error, |
b1f74493 | 3254 | unsigned int nr_bytes, unsigned int bidi_bytes) |
336cdb40 | 3255 | { |
2fff8a92 | 3256 | lockdep_assert_held(rq->q->queue_lock); |
332ebbf7 | 3257 | WARN_ON_ONCE(rq->q->mq_ops); |
2fff8a92 | 3258 | |
2e60e022 TH |
3259 | if (blk_update_bidi_request(rq, error, nr_bytes, bidi_bytes)) |
3260 | return true; | |
336cdb40 | 3261 | |
2e60e022 | 3262 | blk_finish_request(rq, error); |
336cdb40 | 3263 | |
2e60e022 | 3264 | return false; |
336cdb40 | 3265 | } |
e19a3ab0 KU |
3266 | |
3267 | /** | |
3268 | * blk_end_request - Helper function for drivers to complete the request. | |
3269 | * @rq: the request being processed | |
2a842aca | 3270 | * @error: block status code |
e19a3ab0 KU |
3271 | * @nr_bytes: number of bytes to complete |
3272 | * | |
3273 | * Description: | |
3274 | * Ends I/O on a number of bytes attached to @rq. | |
3275 | * If @rq has leftover, sets it up for the next range of segments. | |
3276 | * | |
3277 | * Return: | |
b1f74493 FT |
3278 | * %false - we are done with this request |
3279 | * %true - still buffers pending for this request | |
e19a3ab0 | 3280 | **/ |
2a842aca CH |
3281 | bool blk_end_request(struct request *rq, blk_status_t error, |
3282 | unsigned int nr_bytes) | |
e19a3ab0 | 3283 | { |
332ebbf7 | 3284 | WARN_ON_ONCE(rq->q->mq_ops); |
b1f74493 | 3285 | return blk_end_bidi_request(rq, error, nr_bytes, 0); |
e19a3ab0 | 3286 | } |
56ad1740 | 3287 | EXPORT_SYMBOL(blk_end_request); |
336cdb40 KU |
3288 | |
3289 | /** | |
b1f74493 FT |
3290 | * blk_end_request_all - Helper function for drives to finish the request. |
3291 | * @rq: the request to finish | |
2a842aca | 3292 | * @error: block status code |
336cdb40 KU |
3293 | * |
3294 | * Description: | |
b1f74493 FT |
3295 | * Completely finish @rq. |
3296 | */ | |
2a842aca | 3297 | void blk_end_request_all(struct request *rq, blk_status_t error) |
336cdb40 | 3298 | { |
b1f74493 FT |
3299 | bool pending; |
3300 | unsigned int bidi_bytes = 0; | |
336cdb40 | 3301 | |
b1f74493 FT |
3302 | if (unlikely(blk_bidi_rq(rq))) |
3303 | bidi_bytes = blk_rq_bytes(rq->next_rq); | |
336cdb40 | 3304 | |
b1f74493 FT |
3305 | pending = blk_end_bidi_request(rq, error, blk_rq_bytes(rq), bidi_bytes); |
3306 | BUG_ON(pending); | |
3307 | } | |
56ad1740 | 3308 | EXPORT_SYMBOL(blk_end_request_all); |
336cdb40 | 3309 | |
e3a04fe3 | 3310 | /** |
b1f74493 FT |
3311 | * __blk_end_request - Helper function for drivers to complete the request. |
3312 | * @rq: the request being processed | |
2a842aca | 3313 | * @error: block status code |
b1f74493 | 3314 | * @nr_bytes: number of bytes to complete |
e3a04fe3 KU |
3315 | * |
3316 | * Description: | |
b1f74493 | 3317 | * Must be called with queue lock held unlike blk_end_request(). |
e3a04fe3 KU |
3318 | * |
3319 | * Return: | |
b1f74493 FT |
3320 | * %false - we are done with this request |
3321 | * %true - still buffers pending for this request | |
e3a04fe3 | 3322 | **/ |
2a842aca CH |
3323 | bool __blk_end_request(struct request *rq, blk_status_t error, |
3324 | unsigned int nr_bytes) | |
e3a04fe3 | 3325 | { |
2fff8a92 | 3326 | lockdep_assert_held(rq->q->queue_lock); |
332ebbf7 | 3327 | WARN_ON_ONCE(rq->q->mq_ops); |
2fff8a92 | 3328 | |
b1f74493 | 3329 | return __blk_end_bidi_request(rq, error, nr_bytes, 0); |
e3a04fe3 | 3330 | } |
56ad1740 | 3331 | EXPORT_SYMBOL(__blk_end_request); |
e3a04fe3 | 3332 | |
32fab448 | 3333 | /** |
b1f74493 FT |
3334 | * __blk_end_request_all - Helper function for drives to finish the request. |
3335 | * @rq: the request to finish | |
2a842aca | 3336 | * @error: block status code |
32fab448 KU |
3337 | * |
3338 | * Description: | |
b1f74493 | 3339 | * Completely finish @rq. Must be called with queue lock held. |
32fab448 | 3340 | */ |
2a842aca | 3341 | void __blk_end_request_all(struct request *rq, blk_status_t error) |
32fab448 | 3342 | { |
b1f74493 FT |
3343 | bool pending; |
3344 | unsigned int bidi_bytes = 0; | |
3345 | ||
2fff8a92 | 3346 | lockdep_assert_held(rq->q->queue_lock); |
332ebbf7 | 3347 | WARN_ON_ONCE(rq->q->mq_ops); |
2fff8a92 | 3348 | |
b1f74493 FT |
3349 | if (unlikely(blk_bidi_rq(rq))) |
3350 | bidi_bytes = blk_rq_bytes(rq->next_rq); | |
3351 | ||
3352 | pending = __blk_end_bidi_request(rq, error, blk_rq_bytes(rq), bidi_bytes); | |
3353 | BUG_ON(pending); | |
32fab448 | 3354 | } |
56ad1740 | 3355 | EXPORT_SYMBOL(__blk_end_request_all); |
32fab448 | 3356 | |
e19a3ab0 | 3357 | /** |
b1f74493 FT |
3358 | * __blk_end_request_cur - Helper function to finish the current request chunk. |
3359 | * @rq: the request to finish the current chunk for | |
2a842aca | 3360 | * @error: block status code |
e19a3ab0 KU |
3361 | * |
3362 | * Description: | |
b1f74493 FT |
3363 | * Complete the current consecutively mapped chunk from @rq. Must |
3364 | * be called with queue lock held. | |
e19a3ab0 KU |
3365 | * |
3366 | * Return: | |
b1f74493 FT |
3367 | * %false - we are done with this request |
3368 | * %true - still buffers pending for this request | |
3369 | */ | |
2a842aca | 3370 | bool __blk_end_request_cur(struct request *rq, blk_status_t error) |
e19a3ab0 | 3371 | { |
b1f74493 | 3372 | return __blk_end_request(rq, error, blk_rq_cur_bytes(rq)); |
e19a3ab0 | 3373 | } |
56ad1740 | 3374 | EXPORT_SYMBOL(__blk_end_request_cur); |
e19a3ab0 | 3375 | |
86db1e29 JA |
3376 | void blk_rq_bio_prep(struct request_queue *q, struct request *rq, |
3377 | struct bio *bio) | |
1da177e4 | 3378 | { |
b4f42e28 | 3379 | if (bio_has_data(bio)) |
fb2dce86 | 3380 | rq->nr_phys_segments = bio_phys_segments(q, bio); |
445251d0 JA |
3381 | else if (bio_op(bio) == REQ_OP_DISCARD) |
3382 | rq->nr_phys_segments = 1; | |
b4f42e28 | 3383 | |
4f024f37 | 3384 | rq->__data_len = bio->bi_iter.bi_size; |
1da177e4 | 3385 | rq->bio = rq->biotail = bio; |
1da177e4 | 3386 | |
74d46992 CH |
3387 | if (bio->bi_disk) |
3388 | rq->rq_disk = bio->bi_disk; | |
66846572 | 3389 | } |
1da177e4 | 3390 | |
2d4dc890 IL |
3391 | #if ARCH_IMPLEMENTS_FLUSH_DCACHE_PAGE |
3392 | /** | |
3393 | * rq_flush_dcache_pages - Helper function to flush all pages in a request | |
3394 | * @rq: the request to be flushed | |
3395 | * | |
3396 | * Description: | |
3397 | * Flush all pages in @rq. | |
3398 | */ | |
3399 | void rq_flush_dcache_pages(struct request *rq) | |
3400 | { | |
3401 | struct req_iterator iter; | |
7988613b | 3402 | struct bio_vec bvec; |
2d4dc890 IL |
3403 | |
3404 | rq_for_each_segment(bvec, rq, iter) | |
7988613b | 3405 | flush_dcache_page(bvec.bv_page); |
2d4dc890 IL |
3406 | } |
3407 | EXPORT_SYMBOL_GPL(rq_flush_dcache_pages); | |
3408 | #endif | |
3409 | ||
ef9e3fac KU |
3410 | /** |
3411 | * blk_lld_busy - Check if underlying low-level drivers of a device are busy | |
3412 | * @q : the queue of the device being checked | |
3413 | * | |
3414 | * Description: | |
3415 | * Check if underlying low-level drivers of a device are busy. | |
3416 | * If the drivers want to export their busy state, they must set own | |
3417 | * exporting function using blk_queue_lld_busy() first. | |
3418 | * | |
3419 | * Basically, this function is used only by request stacking drivers | |
3420 | * to stop dispatching requests to underlying devices when underlying | |
3421 | * devices are busy. This behavior helps more I/O merging on the queue | |
3422 | * of the request stacking driver and prevents I/O throughput regression | |
3423 | * on burst I/O load. | |
3424 | * | |
3425 | * Return: | |
3426 | * 0 - Not busy (The request stacking driver should dispatch request) | |
3427 | * 1 - Busy (The request stacking driver should stop dispatching request) | |
3428 | */ | |
3429 | int blk_lld_busy(struct request_queue *q) | |
3430 | { | |
3431 | if (q->lld_busy_fn) | |
3432 | return q->lld_busy_fn(q); | |
3433 | ||
3434 | return 0; | |
3435 | } | |
3436 | EXPORT_SYMBOL_GPL(blk_lld_busy); | |
3437 | ||
78d8e58a MS |
3438 | /** |
3439 | * blk_rq_unprep_clone - Helper function to free all bios in a cloned request | |
3440 | * @rq: the clone request to be cleaned up | |
3441 | * | |
3442 | * Description: | |
3443 | * Free all bios in @rq for a cloned request. | |
3444 | */ | |
3445 | void blk_rq_unprep_clone(struct request *rq) | |
3446 | { | |
3447 | struct bio *bio; | |
3448 | ||
3449 | while ((bio = rq->bio) != NULL) { | |
3450 | rq->bio = bio->bi_next; | |
3451 | ||
3452 | bio_put(bio); | |
3453 | } | |
3454 | } | |
3455 | EXPORT_SYMBOL_GPL(blk_rq_unprep_clone); | |
3456 | ||
3457 | /* | |
3458 | * Copy attributes of the original request to the clone request. | |
3459 | * The actual data parts (e.g. ->cmd, ->sense) are not copied. | |
3460 | */ | |
3461 | static void __blk_rq_prep_clone(struct request *dst, struct request *src) | |
b0fd271d KU |
3462 | { |
3463 | dst->cpu = src->cpu; | |
b0fd271d KU |
3464 | dst->__sector = blk_rq_pos(src); |
3465 | dst->__data_len = blk_rq_bytes(src); | |
297ba57d BVA |
3466 | if (src->rq_flags & RQF_SPECIAL_PAYLOAD) { |
3467 | dst->rq_flags |= RQF_SPECIAL_PAYLOAD; | |
3468 | dst->special_vec = src->special_vec; | |
3469 | } | |
b0fd271d KU |
3470 | dst->nr_phys_segments = src->nr_phys_segments; |
3471 | dst->ioprio = src->ioprio; | |
3472 | dst->extra_len = src->extra_len; | |
78d8e58a MS |
3473 | } |
3474 | ||
3475 | /** | |
3476 | * blk_rq_prep_clone - Helper function to setup clone request | |
3477 | * @rq: the request to be setup | |
3478 | * @rq_src: original request to be cloned | |
3479 | * @bs: bio_set that bios for clone are allocated from | |
3480 | * @gfp_mask: memory allocation mask for bio | |
3481 | * @bio_ctr: setup function to be called for each clone bio. | |
3482 | * Returns %0 for success, non %0 for failure. | |
3483 | * @data: private data to be passed to @bio_ctr | |
3484 | * | |
3485 | * Description: | |
3486 | * Clones bios in @rq_src to @rq, and copies attributes of @rq_src to @rq. | |
3487 | * The actual data parts of @rq_src (e.g. ->cmd, ->sense) | |
3488 | * are not copied, and copying such parts is the caller's responsibility. | |
3489 | * Also, pages which the original bios are pointing to are not copied | |
3490 | * and the cloned bios just point same pages. | |
3491 | * So cloned bios must be completed before original bios, which means | |
3492 | * the caller must complete @rq before @rq_src. | |
3493 | */ | |
3494 | int blk_rq_prep_clone(struct request *rq, struct request *rq_src, | |
3495 | struct bio_set *bs, gfp_t gfp_mask, | |
3496 | int (*bio_ctr)(struct bio *, struct bio *, void *), | |
3497 | void *data) | |
3498 | { | |
3499 | struct bio *bio, *bio_src; | |
3500 | ||
3501 | if (!bs) | |
f4f8154a | 3502 | bs = &fs_bio_set; |
78d8e58a MS |
3503 | |
3504 | __rq_for_each_bio(bio_src, rq_src) { | |
3505 | bio = bio_clone_fast(bio_src, gfp_mask, bs); | |
3506 | if (!bio) | |
3507 | goto free_and_out; | |
3508 | ||
3509 | if (bio_ctr && bio_ctr(bio, bio_src, data)) | |
3510 | goto free_and_out; | |
3511 | ||
3512 | if (rq->bio) { | |
3513 | rq->biotail->bi_next = bio; | |
3514 | rq->biotail = bio; | |
3515 | } else | |
3516 | rq->bio = rq->biotail = bio; | |
3517 | } | |
3518 | ||
3519 | __blk_rq_prep_clone(rq, rq_src); | |
3520 | ||
3521 | return 0; | |
3522 | ||
3523 | free_and_out: | |
3524 | if (bio) | |
3525 | bio_put(bio); | |
3526 | blk_rq_unprep_clone(rq); | |
3527 | ||
3528 | return -ENOMEM; | |
b0fd271d KU |
3529 | } |
3530 | EXPORT_SYMBOL_GPL(blk_rq_prep_clone); | |
3531 | ||
59c3d45e | 3532 | int kblockd_schedule_work(struct work_struct *work) |
1da177e4 LT |
3533 | { |
3534 | return queue_work(kblockd_workqueue, work); | |
3535 | } | |
1da177e4 LT |
3536 | EXPORT_SYMBOL(kblockd_schedule_work); |
3537 | ||
ee63cfa7 JA |
3538 | int kblockd_schedule_work_on(int cpu, struct work_struct *work) |
3539 | { | |
3540 | return queue_work_on(cpu, kblockd_workqueue, work); | |
3541 | } | |
3542 | EXPORT_SYMBOL(kblockd_schedule_work_on); | |
3543 | ||
818cd1cb JA |
3544 | int kblockd_mod_delayed_work_on(int cpu, struct delayed_work *dwork, |
3545 | unsigned long delay) | |
3546 | { | |
3547 | return mod_delayed_work_on(cpu, kblockd_workqueue, dwork, delay); | |
3548 | } | |
3549 | EXPORT_SYMBOL(kblockd_mod_delayed_work_on); | |
3550 | ||
75df7136 SJ |
3551 | /** |
3552 | * blk_start_plug - initialize blk_plug and track it inside the task_struct | |
3553 | * @plug: The &struct blk_plug that needs to be initialized | |
3554 | * | |
3555 | * Description: | |
3556 | * Tracking blk_plug inside the task_struct will help with auto-flushing the | |
3557 | * pending I/O should the task end up blocking between blk_start_plug() and | |
3558 | * blk_finish_plug(). This is important from a performance perspective, but | |
3559 | * also ensures that we don't deadlock. For instance, if the task is blocking | |
3560 | * for a memory allocation, memory reclaim could end up wanting to free a | |
3561 | * page belonging to that request that is currently residing in our private | |
3562 | * plug. By flushing the pending I/O when the process goes to sleep, we avoid | |
3563 | * this kind of deadlock. | |
3564 | */ | |
73c10101 JA |
3565 | void blk_start_plug(struct blk_plug *plug) |
3566 | { | |
3567 | struct task_struct *tsk = current; | |
3568 | ||
dd6cf3e1 SL |
3569 | /* |
3570 | * If this is a nested plug, don't actually assign it. | |
3571 | */ | |
3572 | if (tsk->plug) | |
3573 | return; | |
3574 | ||
73c10101 | 3575 | INIT_LIST_HEAD(&plug->list); |
320ae51f | 3576 | INIT_LIST_HEAD(&plug->mq_list); |
048c9374 | 3577 | INIT_LIST_HEAD(&plug->cb_list); |
73c10101 | 3578 | /* |
dd6cf3e1 SL |
3579 | * Store ordering should not be needed here, since a potential |
3580 | * preempt will imply a full memory barrier | |
73c10101 | 3581 | */ |
dd6cf3e1 | 3582 | tsk->plug = plug; |
73c10101 JA |
3583 | } |
3584 | EXPORT_SYMBOL(blk_start_plug); | |
3585 | ||
3586 | static int plug_rq_cmp(void *priv, struct list_head *a, struct list_head *b) | |
3587 | { | |
3588 | struct request *rqa = container_of(a, struct request, queuelist); | |
3589 | struct request *rqb = container_of(b, struct request, queuelist); | |
3590 | ||
975927b9 JM |
3591 | return !(rqa->q < rqb->q || |
3592 | (rqa->q == rqb->q && blk_rq_pos(rqa) < blk_rq_pos(rqb))); | |
73c10101 JA |
3593 | } |
3594 | ||
49cac01e JA |
3595 | /* |
3596 | * If 'from_schedule' is true, then postpone the dispatch of requests | |
3597 | * until a safe kblockd context. We due this to avoid accidental big | |
3598 | * additional stack usage in driver dispatch, in places where the originally | |
3599 | * plugger did not intend it. | |
3600 | */ | |
f6603783 | 3601 | static void queue_unplugged(struct request_queue *q, unsigned int depth, |
49cac01e | 3602 | bool from_schedule) |
99e22598 | 3603 | __releases(q->queue_lock) |
94b5eb28 | 3604 | { |
2fff8a92 BVA |
3605 | lockdep_assert_held(q->queue_lock); |
3606 | ||
49cac01e | 3607 | trace_block_unplug(q, depth, !from_schedule); |
99e22598 | 3608 | |
70460571 | 3609 | if (from_schedule) |
24ecfbe2 | 3610 | blk_run_queue_async(q); |
70460571 | 3611 | else |
24ecfbe2 | 3612 | __blk_run_queue(q); |
50864670 | 3613 | spin_unlock_irq(q->queue_lock); |
94b5eb28 JA |
3614 | } |
3615 | ||
74018dc3 | 3616 | static void flush_plug_callbacks(struct blk_plug *plug, bool from_schedule) |
048c9374 N |
3617 | { |
3618 | LIST_HEAD(callbacks); | |
3619 | ||
2a7d5559 SL |
3620 | while (!list_empty(&plug->cb_list)) { |
3621 | list_splice_init(&plug->cb_list, &callbacks); | |
048c9374 | 3622 | |
2a7d5559 SL |
3623 | while (!list_empty(&callbacks)) { |
3624 | struct blk_plug_cb *cb = list_first_entry(&callbacks, | |
048c9374 N |
3625 | struct blk_plug_cb, |
3626 | list); | |
2a7d5559 | 3627 | list_del(&cb->list); |
74018dc3 | 3628 | cb->callback(cb, from_schedule); |
2a7d5559 | 3629 | } |
048c9374 N |
3630 | } |
3631 | } | |
3632 | ||
9cbb1750 N |
3633 | struct blk_plug_cb *blk_check_plugged(blk_plug_cb_fn unplug, void *data, |
3634 | int size) | |
3635 | { | |
3636 | struct blk_plug *plug = current->plug; | |
3637 | struct blk_plug_cb *cb; | |
3638 | ||
3639 | if (!plug) | |
3640 | return NULL; | |
3641 | ||
3642 | list_for_each_entry(cb, &plug->cb_list, list) | |
3643 | if (cb->callback == unplug && cb->data == data) | |
3644 | return cb; | |
3645 | ||
3646 | /* Not currently on the callback list */ | |
3647 | BUG_ON(size < sizeof(*cb)); | |
3648 | cb = kzalloc(size, GFP_ATOMIC); | |
3649 | if (cb) { | |
3650 | cb->data = data; | |
3651 | cb->callback = unplug; | |
3652 | list_add(&cb->list, &plug->cb_list); | |
3653 | } | |
3654 | return cb; | |
3655 | } | |
3656 | EXPORT_SYMBOL(blk_check_plugged); | |
3657 | ||
49cac01e | 3658 | void blk_flush_plug_list(struct blk_plug *plug, bool from_schedule) |
73c10101 JA |
3659 | { |
3660 | struct request_queue *q; | |
73c10101 | 3661 | struct request *rq; |
109b8129 | 3662 | LIST_HEAD(list); |
94b5eb28 | 3663 | unsigned int depth; |
73c10101 | 3664 | |
74018dc3 | 3665 | flush_plug_callbacks(plug, from_schedule); |
320ae51f JA |
3666 | |
3667 | if (!list_empty(&plug->mq_list)) | |
3668 | blk_mq_flush_plug_list(plug, from_schedule); | |
3669 | ||
73c10101 JA |
3670 | if (list_empty(&plug->list)) |
3671 | return; | |
3672 | ||
109b8129 N |
3673 | list_splice_init(&plug->list, &list); |
3674 | ||
422765c2 | 3675 | list_sort(NULL, &list, plug_rq_cmp); |
73c10101 JA |
3676 | |
3677 | q = NULL; | |
94b5eb28 | 3678 | depth = 0; |
18811272 | 3679 | |
109b8129 N |
3680 | while (!list_empty(&list)) { |
3681 | rq = list_entry_rq(list.next); | |
73c10101 | 3682 | list_del_init(&rq->queuelist); |
73c10101 JA |
3683 | BUG_ON(!rq->q); |
3684 | if (rq->q != q) { | |
99e22598 JA |
3685 | /* |
3686 | * This drops the queue lock | |
3687 | */ | |
3688 | if (q) | |
49cac01e | 3689 | queue_unplugged(q, depth, from_schedule); |
73c10101 | 3690 | q = rq->q; |
94b5eb28 | 3691 | depth = 0; |
50864670 | 3692 | spin_lock_irq(q->queue_lock); |
73c10101 | 3693 | } |
8ba61435 TH |
3694 | |
3695 | /* | |
3696 | * Short-circuit if @q is dead | |
3697 | */ | |
3f3299d5 | 3698 | if (unlikely(blk_queue_dying(q))) { |
2a842aca | 3699 | __blk_end_request_all(rq, BLK_STS_IOERR); |
8ba61435 TH |
3700 | continue; |
3701 | } | |
3702 | ||
73c10101 JA |
3703 | /* |
3704 | * rq is already accounted, so use raw insert | |
3705 | */ | |
f73f44eb | 3706 | if (op_is_flush(rq->cmd_flags)) |
401a18e9 JA |
3707 | __elv_add_request(q, rq, ELEVATOR_INSERT_FLUSH); |
3708 | else | |
3709 | __elv_add_request(q, rq, ELEVATOR_INSERT_SORT_MERGE); | |
94b5eb28 JA |
3710 | |
3711 | depth++; | |
73c10101 JA |
3712 | } |
3713 | ||
99e22598 JA |
3714 | /* |
3715 | * This drops the queue lock | |
3716 | */ | |
3717 | if (q) | |
49cac01e | 3718 | queue_unplugged(q, depth, from_schedule); |
73c10101 | 3719 | } |
73c10101 JA |
3720 | |
3721 | void blk_finish_plug(struct blk_plug *plug) | |
3722 | { | |
dd6cf3e1 SL |
3723 | if (plug != current->plug) |
3724 | return; | |
f6603783 | 3725 | blk_flush_plug_list(plug, false); |
73c10101 | 3726 | |
dd6cf3e1 | 3727 | current->plug = NULL; |
73c10101 | 3728 | } |
88b996cd | 3729 | EXPORT_SYMBOL(blk_finish_plug); |
73c10101 | 3730 | |
1da177e4 LT |
3731 | int __init blk_dev_init(void) |
3732 | { | |
ef295ecf CH |
3733 | BUILD_BUG_ON(REQ_OP_LAST >= (1 << REQ_OP_BITS)); |
3734 | BUILD_BUG_ON(REQ_OP_BITS + REQ_FLAG_BITS > 8 * | |
0762b23d | 3735 | FIELD_SIZEOF(struct request, cmd_flags)); |
ef295ecf CH |
3736 | BUILD_BUG_ON(REQ_OP_BITS + REQ_FLAG_BITS > 8 * |
3737 | FIELD_SIZEOF(struct bio, bi_opf)); | |
9eb55b03 | 3738 | |
89b90be2 TH |
3739 | /* used for unplugging and affects IO latency/throughput - HIGHPRI */ |
3740 | kblockd_workqueue = alloc_workqueue("kblockd", | |
28747fcd | 3741 | WQ_MEM_RECLAIM | WQ_HIGHPRI, 0); |
1da177e4 LT |
3742 | if (!kblockd_workqueue) |
3743 | panic("Failed to create kblockd\n"); | |
3744 | ||
3745 | request_cachep = kmem_cache_create("blkdev_requests", | |
20c2df83 | 3746 | sizeof(struct request), 0, SLAB_PANIC, NULL); |
1da177e4 | 3747 | |
c2789bd4 | 3748 | blk_requestq_cachep = kmem_cache_create("request_queue", |
165125e1 | 3749 | sizeof(struct request_queue), 0, SLAB_PANIC, NULL); |
1da177e4 | 3750 | |
18fbda91 OS |
3751 | #ifdef CONFIG_DEBUG_FS |
3752 | blk_debugfs_root = debugfs_create_dir("block", NULL); | |
3753 | #endif | |
3754 | ||
d38ecf93 | 3755 | return 0; |
1da177e4 | 3756 | } |