Commit | Line | Data |
---|---|---|
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> |
55782138 LZ |
37 | |
38 | #define CREATE_TRACE_POINTS | |
39 | #include <trace/events/block.h> | |
1da177e4 | 40 | |
8324aa91 | 41 | #include "blk.h" |
43a5e4e2 | 42 | #include "blk-mq.h" |
bd166ef1 | 43 | #include "blk-mq-sched.h" |
87760e5e | 44 | #include "blk-wbt.h" |
8324aa91 | 45 | |
18fbda91 OS |
46 | #ifdef CONFIG_DEBUG_FS |
47 | struct dentry *blk_debugfs_root; | |
48 | #endif | |
49 | ||
d07335e5 | 50 | EXPORT_TRACEPOINT_SYMBOL_GPL(block_bio_remap); |
b0da3f0d | 51 | EXPORT_TRACEPOINT_SYMBOL_GPL(block_rq_remap); |
0a82a8d1 | 52 | EXPORT_TRACEPOINT_SYMBOL_GPL(block_bio_complete); |
3291fa57 | 53 | EXPORT_TRACEPOINT_SYMBOL_GPL(block_split); |
cbae8d45 | 54 | EXPORT_TRACEPOINT_SYMBOL_GPL(block_unplug); |
0bfc2455 | 55 | |
a73f730d TH |
56 | DEFINE_IDA(blk_queue_ida); |
57 | ||
1da177e4 LT |
58 | /* |
59 | * For the allocated request tables | |
60 | */ | |
d674d414 | 61 | struct kmem_cache *request_cachep; |
1da177e4 LT |
62 | |
63 | /* | |
64 | * For queue allocation | |
65 | */ | |
6728cb0e | 66 | struct kmem_cache *blk_requestq_cachep; |
1da177e4 | 67 | |
1da177e4 LT |
68 | /* |
69 | * Controlling structure to kblockd | |
70 | */ | |
ff856bad | 71 | static struct workqueue_struct *kblockd_workqueue; |
1da177e4 | 72 | |
d40f75a0 TH |
73 | static void blk_clear_congested(struct request_list *rl, int sync) |
74 | { | |
d40f75a0 TH |
75 | #ifdef CONFIG_CGROUP_WRITEBACK |
76 | clear_wb_congested(rl->blkg->wb_congested, sync); | |
77 | #else | |
482cf79c TH |
78 | /* |
79 | * If !CGROUP_WRITEBACK, all blkg's map to bdi->wb and we shouldn't | |
80 | * flip its congestion state for events on other blkcgs. | |
81 | */ | |
82 | if (rl == &rl->q->root_rl) | |
dc3b17cc | 83 | clear_wb_congested(rl->q->backing_dev_info->wb.congested, sync); |
d40f75a0 TH |
84 | #endif |
85 | } | |
86 | ||
87 | static void blk_set_congested(struct request_list *rl, int sync) | |
88 | { | |
d40f75a0 TH |
89 | #ifdef CONFIG_CGROUP_WRITEBACK |
90 | set_wb_congested(rl->blkg->wb_congested, sync); | |
91 | #else | |
482cf79c TH |
92 | /* see blk_clear_congested() */ |
93 | if (rl == &rl->q->root_rl) | |
dc3b17cc | 94 | set_wb_congested(rl->q->backing_dev_info->wb.congested, sync); |
d40f75a0 TH |
95 | #endif |
96 | } | |
97 | ||
8324aa91 | 98 | void blk_queue_congestion_threshold(struct request_queue *q) |
1da177e4 LT |
99 | { |
100 | int nr; | |
101 | ||
102 | nr = q->nr_requests - (q->nr_requests / 8) + 1; | |
103 | if (nr > q->nr_requests) | |
104 | nr = q->nr_requests; | |
105 | q->nr_congestion_on = nr; | |
106 | ||
107 | nr = q->nr_requests - (q->nr_requests / 8) - (q->nr_requests / 16) - 1; | |
108 | if (nr < 1) | |
109 | nr = 1; | |
110 | q->nr_congestion_off = nr; | |
111 | } | |
112 | ||
2a4aa30c | 113 | void blk_rq_init(struct request_queue *q, struct request *rq) |
1da177e4 | 114 | { |
1afb20f3 FT |
115 | memset(rq, 0, sizeof(*rq)); |
116 | ||
1da177e4 | 117 | INIT_LIST_HEAD(&rq->queuelist); |
242f9dcb | 118 | INIT_LIST_HEAD(&rq->timeout_list); |
c7c22e4d | 119 | rq->cpu = -1; |
63a71386 | 120 | rq->q = q; |
a2dec7b3 | 121 | rq->__sector = (sector_t) -1; |
2e662b65 JA |
122 | INIT_HLIST_NODE(&rq->hash); |
123 | RB_CLEAR_NODE(&rq->rb_node); | |
63a71386 | 124 | rq->tag = -1; |
bd166ef1 | 125 | rq->internal_tag = -1; |
b243ddcb | 126 | rq->start_time = jiffies; |
9195291e | 127 | set_start_time_ns(rq); |
09e099d4 | 128 | rq->part = NULL; |
1da177e4 | 129 | } |
2a4aa30c | 130 | EXPORT_SYMBOL(blk_rq_init); |
1da177e4 | 131 | |
2a842aca CH |
132 | static const struct { |
133 | int errno; | |
134 | const char *name; | |
135 | } blk_errors[] = { | |
136 | [BLK_STS_OK] = { 0, "" }, | |
137 | [BLK_STS_NOTSUPP] = { -EOPNOTSUPP, "operation not supported" }, | |
138 | [BLK_STS_TIMEOUT] = { -ETIMEDOUT, "timeout" }, | |
139 | [BLK_STS_NOSPC] = { -ENOSPC, "critical space allocation" }, | |
140 | [BLK_STS_TRANSPORT] = { -ENOLINK, "recoverable transport" }, | |
141 | [BLK_STS_TARGET] = { -EREMOTEIO, "critical target" }, | |
142 | [BLK_STS_NEXUS] = { -EBADE, "critical nexus" }, | |
143 | [BLK_STS_MEDIUM] = { -ENODATA, "critical medium" }, | |
144 | [BLK_STS_PROTECTION] = { -EILSEQ, "protection" }, | |
145 | [BLK_STS_RESOURCE] = { -ENOMEM, "kernel resource" }, | |
03a07c92 | 146 | [BLK_STS_AGAIN] = { -EAGAIN, "nonblocking retry" }, |
2a842aca | 147 | |
4e4cbee9 CH |
148 | /* device mapper special case, should not leak out: */ |
149 | [BLK_STS_DM_REQUEUE] = { -EREMCHG, "dm internal retry" }, | |
150 | ||
2a842aca CH |
151 | /* everything else not covered above: */ |
152 | [BLK_STS_IOERR] = { -EIO, "I/O" }, | |
153 | }; | |
154 | ||
155 | blk_status_t errno_to_blk_status(int errno) | |
156 | { | |
157 | int i; | |
158 | ||
159 | for (i = 0; i < ARRAY_SIZE(blk_errors); i++) { | |
160 | if (blk_errors[i].errno == errno) | |
161 | return (__force blk_status_t)i; | |
162 | } | |
163 | ||
164 | return BLK_STS_IOERR; | |
165 | } | |
166 | EXPORT_SYMBOL_GPL(errno_to_blk_status); | |
167 | ||
168 | int blk_status_to_errno(blk_status_t status) | |
169 | { | |
170 | int idx = (__force int)status; | |
171 | ||
34bd9c1c | 172 | if (WARN_ON_ONCE(idx >= ARRAY_SIZE(blk_errors))) |
2a842aca CH |
173 | return -EIO; |
174 | return blk_errors[idx].errno; | |
175 | } | |
176 | EXPORT_SYMBOL_GPL(blk_status_to_errno); | |
177 | ||
178 | static void print_req_error(struct request *req, blk_status_t status) | |
179 | { | |
180 | int idx = (__force int)status; | |
181 | ||
34bd9c1c | 182 | if (WARN_ON_ONCE(idx >= ARRAY_SIZE(blk_errors))) |
2a842aca CH |
183 | return; |
184 | ||
185 | printk_ratelimited(KERN_ERR "%s: %s error, dev %s, sector %llu\n", | |
186 | __func__, blk_errors[idx].name, req->rq_disk ? | |
187 | req->rq_disk->disk_name : "?", | |
188 | (unsigned long long)blk_rq_pos(req)); | |
189 | } | |
190 | ||
5bb23a68 | 191 | static void req_bio_endio(struct request *rq, struct bio *bio, |
2a842aca | 192 | unsigned int nbytes, blk_status_t error) |
1da177e4 | 193 | { |
78d8e58a | 194 | if (error) |
4e4cbee9 | 195 | bio->bi_status = error; |
797e7dbb | 196 | |
e8064021 | 197 | if (unlikely(rq->rq_flags & RQF_QUIET)) |
b7c44ed9 | 198 | bio_set_flag(bio, BIO_QUIET); |
08bafc03 | 199 | |
f79ea416 | 200 | bio_advance(bio, nbytes); |
7ba1ba12 | 201 | |
143a87f4 | 202 | /* don't actually finish bio if it's part of flush sequence */ |
e8064021 | 203 | if (bio->bi_iter.bi_size == 0 && !(rq->rq_flags & RQF_FLUSH_SEQ)) |
4246a0b6 | 204 | bio_endio(bio); |
1da177e4 | 205 | } |
1da177e4 | 206 | |
1da177e4 LT |
207 | void blk_dump_rq_flags(struct request *rq, char *msg) |
208 | { | |
aebf526b CH |
209 | printk(KERN_INFO "%s: dev %s: flags=%llx\n", msg, |
210 | rq->rq_disk ? rq->rq_disk->disk_name : "?", | |
5953316d | 211 | (unsigned long long) rq->cmd_flags); |
1da177e4 | 212 | |
83096ebf TH |
213 | printk(KERN_INFO " sector %llu, nr/cnr %u/%u\n", |
214 | (unsigned long long)blk_rq_pos(rq), | |
215 | blk_rq_sectors(rq), blk_rq_cur_sectors(rq)); | |
b4f42e28 JA |
216 | printk(KERN_INFO " bio %p, biotail %p, len %u\n", |
217 | rq->bio, rq->biotail, blk_rq_bytes(rq)); | |
1da177e4 | 218 | } |
1da177e4 LT |
219 | EXPORT_SYMBOL(blk_dump_rq_flags); |
220 | ||
3cca6dc1 | 221 | static void blk_delay_work(struct work_struct *work) |
1da177e4 | 222 | { |
3cca6dc1 | 223 | struct request_queue *q; |
1da177e4 | 224 | |
3cca6dc1 JA |
225 | q = container_of(work, struct request_queue, delay_work.work); |
226 | spin_lock_irq(q->queue_lock); | |
24ecfbe2 | 227 | __blk_run_queue(q); |
3cca6dc1 | 228 | spin_unlock_irq(q->queue_lock); |
1da177e4 | 229 | } |
1da177e4 LT |
230 | |
231 | /** | |
3cca6dc1 JA |
232 | * blk_delay_queue - restart queueing after defined interval |
233 | * @q: The &struct request_queue in question | |
234 | * @msecs: Delay in msecs | |
1da177e4 LT |
235 | * |
236 | * Description: | |
3cca6dc1 JA |
237 | * Sometimes queueing needs to be postponed for a little while, to allow |
238 | * resources to come back. This function will make sure that queueing is | |
2fff8a92 | 239 | * restarted around the specified time. |
3cca6dc1 JA |
240 | */ |
241 | void blk_delay_queue(struct request_queue *q, unsigned long msecs) | |
2ad8b1ef | 242 | { |
2fff8a92 | 243 | lockdep_assert_held(q->queue_lock); |
332ebbf7 | 244 | WARN_ON_ONCE(q->mq_ops); |
2fff8a92 | 245 | |
70460571 BVA |
246 | if (likely(!blk_queue_dead(q))) |
247 | queue_delayed_work(kblockd_workqueue, &q->delay_work, | |
248 | msecs_to_jiffies(msecs)); | |
2ad8b1ef | 249 | } |
3cca6dc1 | 250 | EXPORT_SYMBOL(blk_delay_queue); |
2ad8b1ef | 251 | |
21491412 JA |
252 | /** |
253 | * blk_start_queue_async - asynchronously restart a previously stopped queue | |
254 | * @q: The &struct request_queue in question | |
255 | * | |
256 | * Description: | |
257 | * blk_start_queue_async() will clear the stop flag on the queue, and | |
258 | * ensure that the request_fn for the queue is run from an async | |
259 | * context. | |
260 | **/ | |
261 | void blk_start_queue_async(struct request_queue *q) | |
262 | { | |
2fff8a92 | 263 | lockdep_assert_held(q->queue_lock); |
332ebbf7 | 264 | WARN_ON_ONCE(q->mq_ops); |
2fff8a92 | 265 | |
21491412 JA |
266 | queue_flag_clear(QUEUE_FLAG_STOPPED, q); |
267 | blk_run_queue_async(q); | |
268 | } | |
269 | EXPORT_SYMBOL(blk_start_queue_async); | |
270 | ||
1da177e4 LT |
271 | /** |
272 | * blk_start_queue - restart a previously stopped queue | |
165125e1 | 273 | * @q: The &struct request_queue in question |
1da177e4 LT |
274 | * |
275 | * Description: | |
276 | * blk_start_queue() will clear the stop flag on the queue, and call | |
277 | * the request_fn for the queue if it was in a stopped state when | |
2fff8a92 | 278 | * entered. Also see blk_stop_queue(). |
1da177e4 | 279 | **/ |
165125e1 | 280 | void blk_start_queue(struct request_queue *q) |
1da177e4 | 281 | { |
2fff8a92 | 282 | lockdep_assert_held(q->queue_lock); |
4ddd56b0 | 283 | WARN_ON(!in_interrupt() && !irqs_disabled()); |
332ebbf7 | 284 | WARN_ON_ONCE(q->mq_ops); |
a038e253 | 285 | |
75ad23bc | 286 | queue_flag_clear(QUEUE_FLAG_STOPPED, q); |
24ecfbe2 | 287 | __blk_run_queue(q); |
1da177e4 | 288 | } |
1da177e4 LT |
289 | EXPORT_SYMBOL(blk_start_queue); |
290 | ||
291 | /** | |
292 | * blk_stop_queue - stop a queue | |
165125e1 | 293 | * @q: The &struct request_queue in question |
1da177e4 LT |
294 | * |
295 | * Description: | |
296 | * The Linux block layer assumes that a block driver will consume all | |
297 | * entries on the request queue when the request_fn strategy is called. | |
298 | * Often this will not happen, because of hardware limitations (queue | |
299 | * depth settings). If a device driver gets a 'queue full' response, | |
300 | * or if it simply chooses not to queue more I/O at one point, it can | |
301 | * call this function to prevent the request_fn from being called until | |
302 | * the driver has signalled it's ready to go again. This happens by calling | |
2fff8a92 | 303 | * blk_start_queue() to restart queue operations. |
1da177e4 | 304 | **/ |
165125e1 | 305 | void blk_stop_queue(struct request_queue *q) |
1da177e4 | 306 | { |
2fff8a92 | 307 | lockdep_assert_held(q->queue_lock); |
332ebbf7 | 308 | WARN_ON_ONCE(q->mq_ops); |
2fff8a92 | 309 | |
136b5721 | 310 | cancel_delayed_work(&q->delay_work); |
75ad23bc | 311 | queue_flag_set(QUEUE_FLAG_STOPPED, q); |
1da177e4 LT |
312 | } |
313 | EXPORT_SYMBOL(blk_stop_queue); | |
314 | ||
315 | /** | |
316 | * blk_sync_queue - cancel any pending callbacks on a queue | |
317 | * @q: the queue | |
318 | * | |
319 | * Description: | |
320 | * The block layer may perform asynchronous callback activity | |
321 | * on a queue, such as calling the unplug function after a timeout. | |
322 | * A block device may call blk_sync_queue to ensure that any | |
323 | * such activity is cancelled, thus allowing it to release resources | |
59c51591 | 324 | * that the callbacks might use. The caller must already have made sure |
1da177e4 LT |
325 | * that its ->make_request_fn will not re-add plugging prior to calling |
326 | * this function. | |
327 | * | |
da527770 | 328 | * This function does not cancel any asynchronous activity arising |
da3dae54 | 329 | * out of elevator or throttling code. That would require elevator_exit() |
5efd6113 | 330 | * and blkcg_exit_queue() to be called with queue lock initialized. |
da527770 | 331 | * |
1da177e4 LT |
332 | */ |
333 | void blk_sync_queue(struct request_queue *q) | |
334 | { | |
70ed28b9 | 335 | del_timer_sync(&q->timeout); |
4e9b6f20 | 336 | cancel_work_sync(&q->timeout_work); |
f04c1fe7 ML |
337 | |
338 | if (q->mq_ops) { | |
339 | struct blk_mq_hw_ctx *hctx; | |
340 | int i; | |
341 | ||
aba7afc5 | 342 | cancel_delayed_work_sync(&q->requeue_work); |
21c6e939 | 343 | queue_for_each_hw_ctx(q, hctx, i) |
9f993737 | 344 | cancel_delayed_work_sync(&hctx->run_work); |
f04c1fe7 ML |
345 | } else { |
346 | cancel_delayed_work_sync(&q->delay_work); | |
347 | } | |
1da177e4 LT |
348 | } |
349 | EXPORT_SYMBOL(blk_sync_queue); | |
350 | ||
c9254f2d BVA |
351 | /** |
352 | * blk_set_preempt_only - set QUEUE_FLAG_PREEMPT_ONLY | |
353 | * @q: request queue pointer | |
354 | * | |
355 | * Returns the previous value of the PREEMPT_ONLY flag - 0 if the flag was not | |
356 | * set and 1 if the flag was already set. | |
357 | */ | |
358 | int blk_set_preempt_only(struct request_queue *q) | |
359 | { | |
360 | unsigned long flags; | |
361 | int res; | |
362 | ||
363 | spin_lock_irqsave(q->queue_lock, flags); | |
364 | res = queue_flag_test_and_set(QUEUE_FLAG_PREEMPT_ONLY, q); | |
365 | spin_unlock_irqrestore(q->queue_lock, flags); | |
366 | ||
367 | return res; | |
368 | } | |
369 | EXPORT_SYMBOL_GPL(blk_set_preempt_only); | |
370 | ||
371 | void blk_clear_preempt_only(struct request_queue *q) | |
372 | { | |
373 | unsigned long flags; | |
374 | ||
375 | spin_lock_irqsave(q->queue_lock, flags); | |
376 | queue_flag_clear(QUEUE_FLAG_PREEMPT_ONLY, q); | |
377 | spin_unlock_irqrestore(q->queue_lock, flags); | |
378 | } | |
379 | EXPORT_SYMBOL_GPL(blk_clear_preempt_only); | |
380 | ||
c246e80d BVA |
381 | /** |
382 | * __blk_run_queue_uncond - run a queue whether or not it has been stopped | |
383 | * @q: The queue to run | |
384 | * | |
385 | * Description: | |
386 | * Invoke request handling on a queue if there are any pending requests. | |
387 | * May be used to restart request handling after a request has completed. | |
388 | * This variant runs the queue whether or not the queue has been | |
389 | * stopped. Must be called with the queue lock held and interrupts | |
390 | * disabled. See also @blk_run_queue. | |
391 | */ | |
392 | inline void __blk_run_queue_uncond(struct request_queue *q) | |
393 | { | |
2fff8a92 | 394 | lockdep_assert_held(q->queue_lock); |
332ebbf7 | 395 | WARN_ON_ONCE(q->mq_ops); |
2fff8a92 | 396 | |
c246e80d BVA |
397 | if (unlikely(blk_queue_dead(q))) |
398 | return; | |
399 | ||
24faf6f6 BVA |
400 | /* |
401 | * Some request_fn implementations, e.g. scsi_request_fn(), unlock | |
402 | * the queue lock internally. As a result multiple threads may be | |
403 | * running such a request function concurrently. Keep track of the | |
404 | * number of active request_fn invocations such that blk_drain_queue() | |
405 | * can wait until all these request_fn calls have finished. | |
406 | */ | |
407 | q->request_fn_active++; | |
c246e80d | 408 | q->request_fn(q); |
24faf6f6 | 409 | q->request_fn_active--; |
c246e80d | 410 | } |
a7928c15 | 411 | EXPORT_SYMBOL_GPL(__blk_run_queue_uncond); |
c246e80d | 412 | |
1da177e4 | 413 | /** |
80a4b58e | 414 | * __blk_run_queue - run a single device queue |
1da177e4 | 415 | * @q: The queue to run |
80a4b58e JA |
416 | * |
417 | * Description: | |
2fff8a92 | 418 | * See @blk_run_queue. |
1da177e4 | 419 | */ |
24ecfbe2 | 420 | void __blk_run_queue(struct request_queue *q) |
1da177e4 | 421 | { |
2fff8a92 | 422 | lockdep_assert_held(q->queue_lock); |
332ebbf7 | 423 | WARN_ON_ONCE(q->mq_ops); |
2fff8a92 | 424 | |
a538cd03 TH |
425 | if (unlikely(blk_queue_stopped(q))) |
426 | return; | |
427 | ||
c246e80d | 428 | __blk_run_queue_uncond(q); |
75ad23bc NP |
429 | } |
430 | EXPORT_SYMBOL(__blk_run_queue); | |
dac07ec1 | 431 | |
24ecfbe2 CH |
432 | /** |
433 | * blk_run_queue_async - run a single device queue in workqueue context | |
434 | * @q: The queue to run | |
435 | * | |
436 | * Description: | |
437 | * Tells kblockd to perform the equivalent of @blk_run_queue on behalf | |
2fff8a92 BVA |
438 | * of us. |
439 | * | |
440 | * Note: | |
441 | * Since it is not allowed to run q->delay_work after blk_cleanup_queue() | |
442 | * has canceled q->delay_work, callers must hold the queue lock to avoid | |
443 | * race conditions between blk_cleanup_queue() and blk_run_queue_async(). | |
24ecfbe2 CH |
444 | */ |
445 | void blk_run_queue_async(struct request_queue *q) | |
446 | { | |
2fff8a92 | 447 | lockdep_assert_held(q->queue_lock); |
332ebbf7 | 448 | WARN_ON_ONCE(q->mq_ops); |
2fff8a92 | 449 | |
70460571 | 450 | if (likely(!blk_queue_stopped(q) && !blk_queue_dead(q))) |
e7c2f967 | 451 | mod_delayed_work(kblockd_workqueue, &q->delay_work, 0); |
24ecfbe2 | 452 | } |
c21e6beb | 453 | EXPORT_SYMBOL(blk_run_queue_async); |
24ecfbe2 | 454 | |
75ad23bc NP |
455 | /** |
456 | * blk_run_queue - run a single device queue | |
457 | * @q: The queue to run | |
80a4b58e JA |
458 | * |
459 | * Description: | |
460 | * Invoke request handling on this queue, if it has pending work to do. | |
a7f55792 | 461 | * May be used to restart queueing when a request has completed. |
75ad23bc NP |
462 | */ |
463 | void blk_run_queue(struct request_queue *q) | |
464 | { | |
465 | unsigned long flags; | |
466 | ||
332ebbf7 BVA |
467 | WARN_ON_ONCE(q->mq_ops); |
468 | ||
75ad23bc | 469 | spin_lock_irqsave(q->queue_lock, flags); |
24ecfbe2 | 470 | __blk_run_queue(q); |
1da177e4 LT |
471 | spin_unlock_irqrestore(q->queue_lock, flags); |
472 | } | |
473 | EXPORT_SYMBOL(blk_run_queue); | |
474 | ||
165125e1 | 475 | void blk_put_queue(struct request_queue *q) |
483f4afc AV |
476 | { |
477 | kobject_put(&q->kobj); | |
478 | } | |
d86e0e83 | 479 | EXPORT_SYMBOL(blk_put_queue); |
483f4afc | 480 | |
e3c78ca5 | 481 | /** |
807592a4 | 482 | * __blk_drain_queue - drain requests from request_queue |
e3c78ca5 | 483 | * @q: queue to drain |
c9a929dd | 484 | * @drain_all: whether to drain all requests or only the ones w/ ELVPRIV |
e3c78ca5 | 485 | * |
c9a929dd TH |
486 | * Drain requests from @q. If @drain_all is set, all requests are drained. |
487 | * If not, only ELVPRIV requests are drained. The caller is responsible | |
488 | * for ensuring that no new requests which need to be drained are queued. | |
e3c78ca5 | 489 | */ |
807592a4 BVA |
490 | static void __blk_drain_queue(struct request_queue *q, bool drain_all) |
491 | __releases(q->queue_lock) | |
492 | __acquires(q->queue_lock) | |
e3c78ca5 | 493 | { |
458f27a9 AH |
494 | int i; |
495 | ||
807592a4 | 496 | lockdep_assert_held(q->queue_lock); |
332ebbf7 | 497 | WARN_ON_ONCE(q->mq_ops); |
807592a4 | 498 | |
e3c78ca5 | 499 | while (true) { |
481a7d64 | 500 | bool drain = false; |
e3c78ca5 | 501 | |
b855b04a TH |
502 | /* |
503 | * The caller might be trying to drain @q before its | |
504 | * elevator is initialized. | |
505 | */ | |
506 | if (q->elevator) | |
507 | elv_drain_elevator(q); | |
508 | ||
5efd6113 | 509 | blkcg_drain_queue(q); |
e3c78ca5 | 510 | |
4eabc941 TH |
511 | /* |
512 | * This function might be called on a queue which failed | |
b855b04a TH |
513 | * driver init after queue creation or is not yet fully |
514 | * active yet. Some drivers (e.g. fd and loop) get unhappy | |
515 | * in such cases. Kick queue iff dispatch queue has | |
516 | * something on it and @q has request_fn set. | |
4eabc941 | 517 | */ |
b855b04a | 518 | if (!list_empty(&q->queue_head) && q->request_fn) |
4eabc941 | 519 | __blk_run_queue(q); |
c9a929dd | 520 | |
8a5ecdd4 | 521 | drain |= q->nr_rqs_elvpriv; |
24faf6f6 | 522 | drain |= q->request_fn_active; |
481a7d64 TH |
523 | |
524 | /* | |
525 | * Unfortunately, requests are queued at and tracked from | |
526 | * multiple places and there's no single counter which can | |
527 | * be drained. Check all the queues and counters. | |
528 | */ | |
529 | if (drain_all) { | |
e97c293c | 530 | struct blk_flush_queue *fq = blk_get_flush_queue(q, NULL); |
481a7d64 TH |
531 | drain |= !list_empty(&q->queue_head); |
532 | for (i = 0; i < 2; i++) { | |
8a5ecdd4 | 533 | drain |= q->nr_rqs[i]; |
481a7d64 | 534 | drain |= q->in_flight[i]; |
7c94e1c1 ML |
535 | if (fq) |
536 | drain |= !list_empty(&fq->flush_queue[i]); | |
481a7d64 TH |
537 | } |
538 | } | |
e3c78ca5 | 539 | |
481a7d64 | 540 | if (!drain) |
e3c78ca5 | 541 | break; |
807592a4 BVA |
542 | |
543 | spin_unlock_irq(q->queue_lock); | |
544 | ||
e3c78ca5 | 545 | msleep(10); |
807592a4 BVA |
546 | |
547 | spin_lock_irq(q->queue_lock); | |
e3c78ca5 | 548 | } |
458f27a9 AH |
549 | |
550 | /* | |
551 | * With queue marked dead, any woken up waiter will fail the | |
552 | * allocation path, so the wakeup chaining is lost and we're | |
553 | * left with hung waiters. We need to wake up those waiters. | |
554 | */ | |
555 | if (q->request_fn) { | |
a051661c TH |
556 | struct request_list *rl; |
557 | ||
a051661c TH |
558 | blk_queue_for_each_rl(rl, q) |
559 | for (i = 0; i < ARRAY_SIZE(rl->wait); i++) | |
560 | wake_up_all(&rl->wait[i]); | |
458f27a9 | 561 | } |
e3c78ca5 TH |
562 | } |
563 | ||
d732580b TH |
564 | /** |
565 | * blk_queue_bypass_start - enter queue bypass mode | |
566 | * @q: queue of interest | |
567 | * | |
568 | * In bypass mode, only the dispatch FIFO queue of @q is used. This | |
569 | * function makes @q enter bypass mode and drains all requests which were | |
6ecf23af | 570 | * throttled or issued before. On return, it's guaranteed that no request |
80fd9979 TH |
571 | * is being throttled or has ELVPRIV set and blk_queue_bypass() %true |
572 | * inside queue or RCU read lock. | |
d732580b TH |
573 | */ |
574 | void blk_queue_bypass_start(struct request_queue *q) | |
575 | { | |
332ebbf7 BVA |
576 | WARN_ON_ONCE(q->mq_ops); |
577 | ||
d732580b | 578 | spin_lock_irq(q->queue_lock); |
776687bc | 579 | q->bypass_depth++; |
d732580b TH |
580 | queue_flag_set(QUEUE_FLAG_BYPASS, q); |
581 | spin_unlock_irq(q->queue_lock); | |
582 | ||
776687bc TH |
583 | /* |
584 | * Queues start drained. Skip actual draining till init is | |
585 | * complete. This avoids lenghty delays during queue init which | |
586 | * can happen many times during boot. | |
587 | */ | |
588 | if (blk_queue_init_done(q)) { | |
807592a4 BVA |
589 | spin_lock_irq(q->queue_lock); |
590 | __blk_drain_queue(q, false); | |
591 | spin_unlock_irq(q->queue_lock); | |
592 | ||
b82d4b19 TH |
593 | /* ensure blk_queue_bypass() is %true inside RCU read lock */ |
594 | synchronize_rcu(); | |
595 | } | |
d732580b TH |
596 | } |
597 | EXPORT_SYMBOL_GPL(blk_queue_bypass_start); | |
598 | ||
599 | /** | |
600 | * blk_queue_bypass_end - leave queue bypass mode | |
601 | * @q: queue of interest | |
602 | * | |
603 | * Leave bypass mode and restore the normal queueing behavior. | |
332ebbf7 BVA |
604 | * |
605 | * Note: although blk_queue_bypass_start() is only called for blk-sq queues, | |
606 | * this function is called for both blk-sq and blk-mq queues. | |
d732580b TH |
607 | */ |
608 | void blk_queue_bypass_end(struct request_queue *q) | |
609 | { | |
610 | spin_lock_irq(q->queue_lock); | |
611 | if (!--q->bypass_depth) | |
612 | queue_flag_clear(QUEUE_FLAG_BYPASS, q); | |
613 | WARN_ON_ONCE(q->bypass_depth < 0); | |
614 | spin_unlock_irq(q->queue_lock); | |
615 | } | |
616 | EXPORT_SYMBOL_GPL(blk_queue_bypass_end); | |
617 | ||
aed3ea94 JA |
618 | void blk_set_queue_dying(struct request_queue *q) |
619 | { | |
1b856086 BVA |
620 | spin_lock_irq(q->queue_lock); |
621 | queue_flag_set(QUEUE_FLAG_DYING, q); | |
622 | spin_unlock_irq(q->queue_lock); | |
aed3ea94 | 623 | |
d3cfb2a0 ML |
624 | /* |
625 | * When queue DYING flag is set, we need to block new req | |
626 | * entering queue, so we call blk_freeze_queue_start() to | |
627 | * prevent I/O from crossing blk_queue_enter(). | |
628 | */ | |
629 | blk_freeze_queue_start(q); | |
630 | ||
aed3ea94 JA |
631 | if (q->mq_ops) |
632 | blk_mq_wake_waiters(q); | |
633 | else { | |
634 | struct request_list *rl; | |
635 | ||
bbfc3c5d | 636 | spin_lock_irq(q->queue_lock); |
aed3ea94 JA |
637 | blk_queue_for_each_rl(rl, q) { |
638 | if (rl->rq_pool) { | |
639 | wake_up(&rl->wait[BLK_RW_SYNC]); | |
640 | wake_up(&rl->wait[BLK_RW_ASYNC]); | |
641 | } | |
642 | } | |
bbfc3c5d | 643 | spin_unlock_irq(q->queue_lock); |
aed3ea94 | 644 | } |
055f6e18 ML |
645 | |
646 | /* Make blk_queue_enter() reexamine the DYING flag. */ | |
647 | wake_up_all(&q->mq_freeze_wq); | |
aed3ea94 JA |
648 | } |
649 | EXPORT_SYMBOL_GPL(blk_set_queue_dying); | |
650 | ||
c9a929dd TH |
651 | /** |
652 | * blk_cleanup_queue - shutdown a request queue | |
653 | * @q: request queue to shutdown | |
654 | * | |
c246e80d BVA |
655 | * Mark @q DYING, drain all pending requests, mark @q DEAD, destroy and |
656 | * put it. All future requests will be failed immediately with -ENODEV. | |
c94a96ac | 657 | */ |
6728cb0e | 658 | void blk_cleanup_queue(struct request_queue *q) |
483f4afc | 659 | { |
c9a929dd | 660 | spinlock_t *lock = q->queue_lock; |
e3335de9 | 661 | |
3f3299d5 | 662 | /* mark @q DYING, no new request or merges will be allowed afterwards */ |
483f4afc | 663 | mutex_lock(&q->sysfs_lock); |
aed3ea94 | 664 | blk_set_queue_dying(q); |
c9a929dd | 665 | spin_lock_irq(lock); |
6ecf23af | 666 | |
80fd9979 | 667 | /* |
3f3299d5 | 668 | * A dying queue is permanently in bypass mode till released. Note |
80fd9979 TH |
669 | * that, unlike blk_queue_bypass_start(), we aren't performing |
670 | * synchronize_rcu() after entering bypass mode to avoid the delay | |
671 | * as some drivers create and destroy a lot of queues while | |
672 | * probing. This is still safe because blk_release_queue() will be | |
673 | * called only after the queue refcnt drops to zero and nothing, | |
674 | * RCU or not, would be traversing the queue by then. | |
675 | */ | |
6ecf23af TH |
676 | q->bypass_depth++; |
677 | queue_flag_set(QUEUE_FLAG_BYPASS, q); | |
678 | ||
c9a929dd TH |
679 | queue_flag_set(QUEUE_FLAG_NOMERGES, q); |
680 | queue_flag_set(QUEUE_FLAG_NOXMERGES, q); | |
3f3299d5 | 681 | queue_flag_set(QUEUE_FLAG_DYING, q); |
c9a929dd TH |
682 | spin_unlock_irq(lock); |
683 | mutex_unlock(&q->sysfs_lock); | |
684 | ||
c246e80d BVA |
685 | /* |
686 | * Drain all requests queued before DYING marking. Set DEAD flag to | |
687 | * prevent that q->request_fn() gets invoked after draining finished. | |
688 | */ | |
3ef28e83 | 689 | blk_freeze_queue(q); |
9c1051aa OS |
690 | spin_lock_irq(lock); |
691 | if (!q->mq_ops) | |
43a5e4e2 | 692 | __blk_drain_queue(q, true); |
c246e80d | 693 | queue_flag_set(QUEUE_FLAG_DEAD, q); |
807592a4 | 694 | spin_unlock_irq(lock); |
c9a929dd | 695 | |
5a48fc14 DW |
696 | /* for synchronous bio-based driver finish in-flight integrity i/o */ |
697 | blk_flush_integrity(); | |
698 | ||
c9a929dd | 699 | /* @q won't process any more request, flush async actions */ |
dc3b17cc | 700 | del_timer_sync(&q->backing_dev_info->laptop_mode_wb_timer); |
c9a929dd TH |
701 | blk_sync_queue(q); |
702 | ||
45a9c9d9 BVA |
703 | if (q->mq_ops) |
704 | blk_mq_free_queue(q); | |
3ef28e83 | 705 | percpu_ref_exit(&q->q_usage_counter); |
45a9c9d9 | 706 | |
5e5cfac0 AH |
707 | spin_lock_irq(lock); |
708 | if (q->queue_lock != &q->__queue_lock) | |
709 | q->queue_lock = &q->__queue_lock; | |
710 | spin_unlock_irq(lock); | |
711 | ||
c9a929dd | 712 | /* @q is and will stay empty, shutdown and put */ |
483f4afc AV |
713 | blk_put_queue(q); |
714 | } | |
1da177e4 LT |
715 | EXPORT_SYMBOL(blk_cleanup_queue); |
716 | ||
271508db | 717 | /* Allocate memory local to the request queue */ |
6d247d7f | 718 | static void *alloc_request_simple(gfp_t gfp_mask, void *data) |
271508db | 719 | { |
6d247d7f CH |
720 | struct request_queue *q = data; |
721 | ||
722 | return kmem_cache_alloc_node(request_cachep, gfp_mask, q->node); | |
271508db DR |
723 | } |
724 | ||
6d247d7f | 725 | static void free_request_simple(void *element, void *data) |
271508db DR |
726 | { |
727 | kmem_cache_free(request_cachep, element); | |
728 | } | |
729 | ||
6d247d7f CH |
730 | static void *alloc_request_size(gfp_t gfp_mask, void *data) |
731 | { | |
732 | struct request_queue *q = data; | |
733 | struct request *rq; | |
734 | ||
735 | rq = kmalloc_node(sizeof(struct request) + q->cmd_size, gfp_mask, | |
736 | q->node); | |
737 | if (rq && q->init_rq_fn && q->init_rq_fn(q, rq, gfp_mask) < 0) { | |
738 | kfree(rq); | |
739 | rq = NULL; | |
740 | } | |
741 | return rq; | |
742 | } | |
743 | ||
744 | static void free_request_size(void *element, void *data) | |
745 | { | |
746 | struct request_queue *q = data; | |
747 | ||
748 | if (q->exit_rq_fn) | |
749 | q->exit_rq_fn(q, element); | |
750 | kfree(element); | |
751 | } | |
752 | ||
5b788ce3 TH |
753 | int blk_init_rl(struct request_list *rl, struct request_queue *q, |
754 | gfp_t gfp_mask) | |
1da177e4 | 755 | { |
85acb3ba | 756 | if (unlikely(rl->rq_pool) || q->mq_ops) |
1abec4fd MS |
757 | return 0; |
758 | ||
5b788ce3 | 759 | rl->q = q; |
1faa16d2 JA |
760 | rl->count[BLK_RW_SYNC] = rl->count[BLK_RW_ASYNC] = 0; |
761 | rl->starved[BLK_RW_SYNC] = rl->starved[BLK_RW_ASYNC] = 0; | |
1faa16d2 JA |
762 | init_waitqueue_head(&rl->wait[BLK_RW_SYNC]); |
763 | init_waitqueue_head(&rl->wait[BLK_RW_ASYNC]); | |
1da177e4 | 764 | |
6d247d7f CH |
765 | if (q->cmd_size) { |
766 | rl->rq_pool = mempool_create_node(BLKDEV_MIN_RQ, | |
767 | alloc_request_size, free_request_size, | |
768 | q, gfp_mask, q->node); | |
769 | } else { | |
770 | rl->rq_pool = mempool_create_node(BLKDEV_MIN_RQ, | |
771 | alloc_request_simple, free_request_simple, | |
772 | q, gfp_mask, q->node); | |
773 | } | |
1da177e4 LT |
774 | if (!rl->rq_pool) |
775 | return -ENOMEM; | |
776 | ||
b425e504 BVA |
777 | if (rl != &q->root_rl) |
778 | WARN_ON_ONCE(!blk_get_queue(q)); | |
779 | ||
1da177e4 LT |
780 | return 0; |
781 | } | |
782 | ||
b425e504 | 783 | void blk_exit_rl(struct request_queue *q, struct request_list *rl) |
5b788ce3 | 784 | { |
b425e504 | 785 | if (rl->rq_pool) { |
5b788ce3 | 786 | mempool_destroy(rl->rq_pool); |
b425e504 BVA |
787 | if (rl != &q->root_rl) |
788 | blk_put_queue(q); | |
789 | } | |
5b788ce3 TH |
790 | } |
791 | ||
165125e1 | 792 | struct request_queue *blk_alloc_queue(gfp_t gfp_mask) |
1da177e4 | 793 | { |
c304a51b | 794 | return blk_alloc_queue_node(gfp_mask, NUMA_NO_NODE); |
1946089a CL |
795 | } |
796 | EXPORT_SYMBOL(blk_alloc_queue); | |
1da177e4 | 797 | |
6f3b0e8b | 798 | int blk_queue_enter(struct request_queue *q, bool nowait) |
3ef28e83 DW |
799 | { |
800 | while (true) { | |
801 | int ret; | |
802 | ||
803 | if (percpu_ref_tryget_live(&q->q_usage_counter)) | |
804 | return 0; | |
805 | ||
6f3b0e8b | 806 | if (nowait) |
3ef28e83 DW |
807 | return -EBUSY; |
808 | ||
5ed61d3f | 809 | /* |
1671d522 | 810 | * read pair of barrier in blk_freeze_queue_start(), |
5ed61d3f | 811 | * we need to order reading __PERCPU_REF_DEAD flag of |
d3cfb2a0 ML |
812 | * .q_usage_counter and reading .mq_freeze_depth or |
813 | * queue dying flag, otherwise the following wait may | |
814 | * never return if the two reads are reordered. | |
5ed61d3f ML |
815 | */ |
816 | smp_rmb(); | |
817 | ||
3ef28e83 DW |
818 | ret = wait_event_interruptible(q->mq_freeze_wq, |
819 | !atomic_read(&q->mq_freeze_depth) || | |
820 | blk_queue_dying(q)); | |
821 | if (blk_queue_dying(q)) | |
822 | return -ENODEV; | |
823 | if (ret) | |
824 | return ret; | |
825 | } | |
826 | } | |
827 | ||
828 | void blk_queue_exit(struct request_queue *q) | |
829 | { | |
830 | percpu_ref_put(&q->q_usage_counter); | |
831 | } | |
832 | ||
833 | static void blk_queue_usage_counter_release(struct percpu_ref *ref) | |
834 | { | |
835 | struct request_queue *q = | |
836 | container_of(ref, struct request_queue, q_usage_counter); | |
837 | ||
838 | wake_up_all(&q->mq_freeze_wq); | |
839 | } | |
840 | ||
287922eb CH |
841 | static void blk_rq_timed_out_timer(unsigned long data) |
842 | { | |
843 | struct request_queue *q = (struct request_queue *)data; | |
844 | ||
845 | kblockd_schedule_work(&q->timeout_work); | |
846 | } | |
847 | ||
165125e1 | 848 | struct request_queue *blk_alloc_queue_node(gfp_t gfp_mask, int node_id) |
1946089a | 849 | { |
165125e1 | 850 | struct request_queue *q; |
1946089a | 851 | |
8324aa91 | 852 | q = kmem_cache_alloc_node(blk_requestq_cachep, |
94f6030c | 853 | gfp_mask | __GFP_ZERO, node_id); |
1da177e4 LT |
854 | if (!q) |
855 | return NULL; | |
856 | ||
00380a40 | 857 | q->id = ida_simple_get(&blk_queue_ida, 0, 0, gfp_mask); |
a73f730d | 858 | if (q->id < 0) |
3d2936f4 | 859 | goto fail_q; |
a73f730d | 860 | |
93b27e72 | 861 | q->bio_split = bioset_create(BIO_POOL_SIZE, 0, BIOSET_NEED_BVECS); |
54efd50b KO |
862 | if (!q->bio_split) |
863 | goto fail_id; | |
864 | ||
d03f6cdc JK |
865 | q->backing_dev_info = bdi_alloc_node(gfp_mask, node_id); |
866 | if (!q->backing_dev_info) | |
867 | goto fail_split; | |
868 | ||
a83b576c JA |
869 | q->stats = blk_alloc_queue_stats(); |
870 | if (!q->stats) | |
871 | goto fail_stats; | |
872 | ||
dc3b17cc | 873 | q->backing_dev_info->ra_pages = |
09cbfeaf | 874 | (VM_MAX_READAHEAD * 1024) / PAGE_SIZE; |
dc3b17cc JK |
875 | q->backing_dev_info->capabilities = BDI_CAP_CGROUP_WRITEBACK; |
876 | q->backing_dev_info->name = "block"; | |
5151412d | 877 | q->node = node_id; |
0989a025 | 878 | |
dc3b17cc | 879 | setup_timer(&q->backing_dev_info->laptop_mode_wb_timer, |
31373d09 | 880 | laptop_mode_timer_fn, (unsigned long) q); |
242f9dcb | 881 | setup_timer(&q->timeout, blk_rq_timed_out_timer, (unsigned long) q); |
4e9b6f20 | 882 | INIT_WORK(&q->timeout_work, NULL); |
b855b04a | 883 | INIT_LIST_HEAD(&q->queue_head); |
242f9dcb | 884 | INIT_LIST_HEAD(&q->timeout_list); |
a612fddf | 885 | INIT_LIST_HEAD(&q->icq_list); |
4eef3049 | 886 | #ifdef CONFIG_BLK_CGROUP |
e8989fae | 887 | INIT_LIST_HEAD(&q->blkg_list); |
4eef3049 | 888 | #endif |
3cca6dc1 | 889 | INIT_DELAYED_WORK(&q->delay_work, blk_delay_work); |
483f4afc | 890 | |
8324aa91 | 891 | kobject_init(&q->kobj, &blk_queue_ktype); |
1da177e4 | 892 | |
5acb3cc2 WL |
893 | #ifdef CONFIG_BLK_DEV_IO_TRACE |
894 | mutex_init(&q->blk_trace_mutex); | |
895 | #endif | |
483f4afc | 896 | mutex_init(&q->sysfs_lock); |
e7e72bf6 | 897 | spin_lock_init(&q->__queue_lock); |
483f4afc | 898 | |
c94a96ac VG |
899 | /* |
900 | * By default initialize queue_lock to internal lock and driver can | |
901 | * override it later if need be. | |
902 | */ | |
903 | q->queue_lock = &q->__queue_lock; | |
904 | ||
b82d4b19 TH |
905 | /* |
906 | * A queue starts its life with bypass turned on to avoid | |
907 | * unnecessary bypass on/off overhead and nasty surprises during | |
749fefe6 TH |
908 | * init. The initial bypass will be finished when the queue is |
909 | * registered by blk_register_queue(). | |
b82d4b19 TH |
910 | */ |
911 | q->bypass_depth = 1; | |
912 | __set_bit(QUEUE_FLAG_BYPASS, &q->queue_flags); | |
913 | ||
320ae51f JA |
914 | init_waitqueue_head(&q->mq_freeze_wq); |
915 | ||
3ef28e83 DW |
916 | /* |
917 | * Init percpu_ref in atomic mode so that it's faster to shutdown. | |
918 | * See blk_register_queue() for details. | |
919 | */ | |
920 | if (percpu_ref_init(&q->q_usage_counter, | |
921 | blk_queue_usage_counter_release, | |
922 | PERCPU_REF_INIT_ATOMIC, GFP_KERNEL)) | |
fff4996b | 923 | goto fail_bdi; |
f51b802c | 924 | |
3ef28e83 DW |
925 | if (blkcg_init_queue(q)) |
926 | goto fail_ref; | |
927 | ||
1da177e4 | 928 | return q; |
a73f730d | 929 | |
3ef28e83 DW |
930 | fail_ref: |
931 | percpu_ref_exit(&q->q_usage_counter); | |
fff4996b | 932 | fail_bdi: |
a83b576c JA |
933 | blk_free_queue_stats(q->stats); |
934 | fail_stats: | |
d03f6cdc | 935 | bdi_put(q->backing_dev_info); |
54efd50b KO |
936 | fail_split: |
937 | bioset_free(q->bio_split); | |
a73f730d TH |
938 | fail_id: |
939 | ida_simple_remove(&blk_queue_ida, q->id); | |
940 | fail_q: | |
941 | kmem_cache_free(blk_requestq_cachep, q); | |
942 | return NULL; | |
1da177e4 | 943 | } |
1946089a | 944 | EXPORT_SYMBOL(blk_alloc_queue_node); |
1da177e4 LT |
945 | |
946 | /** | |
947 | * blk_init_queue - prepare a request queue for use with a block device | |
948 | * @rfn: The function to be called to process requests that have been | |
949 | * placed on the queue. | |
950 | * @lock: Request queue spin lock | |
951 | * | |
952 | * Description: | |
953 | * If a block device wishes to use the standard request handling procedures, | |
954 | * which sorts requests and coalesces adjacent requests, then it must | |
955 | * call blk_init_queue(). The function @rfn will be called when there | |
956 | * are requests on the queue that need to be processed. If the device | |
957 | * supports plugging, then @rfn may not be called immediately when requests | |
958 | * are available on the queue, but may be called at some time later instead. | |
959 | * Plugged queues are generally unplugged when a buffer belonging to one | |
960 | * of the requests on the queue is needed, or due to memory pressure. | |
961 | * | |
962 | * @rfn is not required, or even expected, to remove all requests off the | |
963 | * queue, but only as many as it can handle at a time. If it does leave | |
964 | * requests on the queue, it is responsible for arranging that the requests | |
965 | * get dealt with eventually. | |
966 | * | |
967 | * The queue spin lock must be held while manipulating the requests on the | |
a038e253 PBG |
968 | * request queue; this lock will be taken also from interrupt context, so irq |
969 | * disabling is needed for it. | |
1da177e4 | 970 | * |
710027a4 | 971 | * Function returns a pointer to the initialized request queue, or %NULL if |
1da177e4 LT |
972 | * it didn't succeed. |
973 | * | |
974 | * Note: | |
975 | * blk_init_queue() must be paired with a blk_cleanup_queue() call | |
976 | * when the block device is deactivated (such as at module unload). | |
977 | **/ | |
1946089a | 978 | |
165125e1 | 979 | struct request_queue *blk_init_queue(request_fn_proc *rfn, spinlock_t *lock) |
1da177e4 | 980 | { |
c304a51b | 981 | return blk_init_queue_node(rfn, lock, NUMA_NO_NODE); |
1946089a CL |
982 | } |
983 | EXPORT_SYMBOL(blk_init_queue); | |
984 | ||
165125e1 | 985 | struct request_queue * |
1946089a CL |
986 | blk_init_queue_node(request_fn_proc *rfn, spinlock_t *lock, int node_id) |
987 | { | |
5ea708d1 | 988 | struct request_queue *q; |
1da177e4 | 989 | |
5ea708d1 CH |
990 | q = blk_alloc_queue_node(GFP_KERNEL, node_id); |
991 | if (!q) | |
c86d1b8a MS |
992 | return NULL; |
993 | ||
5ea708d1 CH |
994 | q->request_fn = rfn; |
995 | if (lock) | |
996 | q->queue_lock = lock; | |
997 | if (blk_init_allocated_queue(q) < 0) { | |
998 | blk_cleanup_queue(q); | |
999 | return NULL; | |
1000 | } | |
18741986 | 1001 | |
7982e90c | 1002 | return q; |
01effb0d MS |
1003 | } |
1004 | EXPORT_SYMBOL(blk_init_queue_node); | |
1005 | ||
dece1635 | 1006 | static blk_qc_t blk_queue_bio(struct request_queue *q, struct bio *bio); |
336b7e1f | 1007 | |
1da177e4 | 1008 | |
5ea708d1 CH |
1009 | int blk_init_allocated_queue(struct request_queue *q) |
1010 | { | |
332ebbf7 BVA |
1011 | WARN_ON_ONCE(q->mq_ops); |
1012 | ||
6d247d7f | 1013 | q->fq = blk_alloc_flush_queue(q, NUMA_NO_NODE, q->cmd_size); |
ba483388 | 1014 | if (!q->fq) |
5ea708d1 | 1015 | return -ENOMEM; |
7982e90c | 1016 | |
6d247d7f CH |
1017 | if (q->init_rq_fn && q->init_rq_fn(q, q->fq->flush_rq, GFP_KERNEL)) |
1018 | goto out_free_flush_queue; | |
7982e90c | 1019 | |
a051661c | 1020 | if (blk_init_rl(&q->root_rl, q, GFP_KERNEL)) |
6d247d7f | 1021 | goto out_exit_flush_rq; |
1da177e4 | 1022 | |
287922eb | 1023 | INIT_WORK(&q->timeout_work, blk_timeout_work); |
60ea8226 | 1024 | q->queue_flags |= QUEUE_FLAG_DEFAULT; |
c94a96ac | 1025 | |
f3b144aa JA |
1026 | /* |
1027 | * This also sets hw/phys segments, boundary and size | |
1028 | */ | |
c20e8de2 | 1029 | blk_queue_make_request(q, blk_queue_bio); |
1da177e4 | 1030 | |
44ec9542 AS |
1031 | q->sg_reserved_size = INT_MAX; |
1032 | ||
eb1c160b TS |
1033 | /* Protect q->elevator from elevator_change */ |
1034 | mutex_lock(&q->sysfs_lock); | |
1035 | ||
b82d4b19 | 1036 | /* init elevator */ |
eb1c160b TS |
1037 | if (elevator_init(q, NULL)) { |
1038 | mutex_unlock(&q->sysfs_lock); | |
6d247d7f | 1039 | goto out_exit_flush_rq; |
eb1c160b TS |
1040 | } |
1041 | ||
1042 | mutex_unlock(&q->sysfs_lock); | |
5ea708d1 | 1043 | return 0; |
eb1c160b | 1044 | |
6d247d7f CH |
1045 | out_exit_flush_rq: |
1046 | if (q->exit_rq_fn) | |
1047 | q->exit_rq_fn(q, q->fq->flush_rq); | |
1048 | out_free_flush_queue: | |
ba483388 | 1049 | blk_free_flush_queue(q->fq); |
5ea708d1 | 1050 | return -ENOMEM; |
1da177e4 | 1051 | } |
5151412d | 1052 | EXPORT_SYMBOL(blk_init_allocated_queue); |
1da177e4 | 1053 | |
09ac46c4 | 1054 | bool blk_get_queue(struct request_queue *q) |
1da177e4 | 1055 | { |
3f3299d5 | 1056 | if (likely(!blk_queue_dying(q))) { |
09ac46c4 TH |
1057 | __blk_get_queue(q); |
1058 | return true; | |
1da177e4 LT |
1059 | } |
1060 | ||
09ac46c4 | 1061 | return false; |
1da177e4 | 1062 | } |
d86e0e83 | 1063 | EXPORT_SYMBOL(blk_get_queue); |
1da177e4 | 1064 | |
5b788ce3 | 1065 | static inline void blk_free_request(struct request_list *rl, struct request *rq) |
1da177e4 | 1066 | { |
e8064021 | 1067 | if (rq->rq_flags & RQF_ELVPRIV) { |
5b788ce3 | 1068 | elv_put_request(rl->q, rq); |
f1f8cc94 | 1069 | if (rq->elv.icq) |
11a3122f | 1070 | put_io_context(rq->elv.icq->ioc); |
f1f8cc94 TH |
1071 | } |
1072 | ||
5b788ce3 | 1073 | mempool_free(rq, rl->rq_pool); |
1da177e4 LT |
1074 | } |
1075 | ||
1da177e4 LT |
1076 | /* |
1077 | * ioc_batching returns true if the ioc is a valid batching request and | |
1078 | * should be given priority access to a request. | |
1079 | */ | |
165125e1 | 1080 | static inline int ioc_batching(struct request_queue *q, struct io_context *ioc) |
1da177e4 LT |
1081 | { |
1082 | if (!ioc) | |
1083 | return 0; | |
1084 | ||
1085 | /* | |
1086 | * Make sure the process is able to allocate at least 1 request | |
1087 | * even if the batch times out, otherwise we could theoretically | |
1088 | * lose wakeups. | |
1089 | */ | |
1090 | return ioc->nr_batch_requests == q->nr_batching || | |
1091 | (ioc->nr_batch_requests > 0 | |
1092 | && time_before(jiffies, ioc->last_waited + BLK_BATCH_TIME)); | |
1093 | } | |
1094 | ||
1095 | /* | |
1096 | * ioc_set_batching sets ioc to be a new "batcher" if it is not one. This | |
1097 | * will cause the process to be a "batcher" on all queues in the system. This | |
1098 | * is the behaviour we want though - once it gets a wakeup it should be given | |
1099 | * a nice run. | |
1100 | */ | |
165125e1 | 1101 | static void ioc_set_batching(struct request_queue *q, struct io_context *ioc) |
1da177e4 LT |
1102 | { |
1103 | if (!ioc || ioc_batching(q, ioc)) | |
1104 | return; | |
1105 | ||
1106 | ioc->nr_batch_requests = q->nr_batching; | |
1107 | ioc->last_waited = jiffies; | |
1108 | } | |
1109 | ||
5b788ce3 | 1110 | static void __freed_request(struct request_list *rl, int sync) |
1da177e4 | 1111 | { |
5b788ce3 | 1112 | struct request_queue *q = rl->q; |
1da177e4 | 1113 | |
d40f75a0 TH |
1114 | if (rl->count[sync] < queue_congestion_off_threshold(q)) |
1115 | blk_clear_congested(rl, sync); | |
1da177e4 | 1116 | |
1faa16d2 JA |
1117 | if (rl->count[sync] + 1 <= q->nr_requests) { |
1118 | if (waitqueue_active(&rl->wait[sync])) | |
1119 | wake_up(&rl->wait[sync]); | |
1da177e4 | 1120 | |
5b788ce3 | 1121 | blk_clear_rl_full(rl, sync); |
1da177e4 LT |
1122 | } |
1123 | } | |
1124 | ||
1125 | /* | |
1126 | * A request has just been released. Account for it, update the full and | |
1127 | * congestion status, wake up any waiters. Called under q->queue_lock. | |
1128 | */ | |
e8064021 CH |
1129 | static void freed_request(struct request_list *rl, bool sync, |
1130 | req_flags_t rq_flags) | |
1da177e4 | 1131 | { |
5b788ce3 | 1132 | struct request_queue *q = rl->q; |
1da177e4 | 1133 | |
8a5ecdd4 | 1134 | q->nr_rqs[sync]--; |
1faa16d2 | 1135 | rl->count[sync]--; |
e8064021 | 1136 | if (rq_flags & RQF_ELVPRIV) |
8a5ecdd4 | 1137 | q->nr_rqs_elvpriv--; |
1da177e4 | 1138 | |
5b788ce3 | 1139 | __freed_request(rl, sync); |
1da177e4 | 1140 | |
1faa16d2 | 1141 | if (unlikely(rl->starved[sync ^ 1])) |
5b788ce3 | 1142 | __freed_request(rl, sync ^ 1); |
1da177e4 LT |
1143 | } |
1144 | ||
e3a2b3f9 JA |
1145 | int blk_update_nr_requests(struct request_queue *q, unsigned int nr) |
1146 | { | |
1147 | struct request_list *rl; | |
d40f75a0 | 1148 | int on_thresh, off_thresh; |
e3a2b3f9 | 1149 | |
332ebbf7 BVA |
1150 | WARN_ON_ONCE(q->mq_ops); |
1151 | ||
e3a2b3f9 JA |
1152 | spin_lock_irq(q->queue_lock); |
1153 | q->nr_requests = nr; | |
1154 | blk_queue_congestion_threshold(q); | |
d40f75a0 TH |
1155 | on_thresh = queue_congestion_on_threshold(q); |
1156 | off_thresh = queue_congestion_off_threshold(q); | |
e3a2b3f9 | 1157 | |
d40f75a0 TH |
1158 | blk_queue_for_each_rl(rl, q) { |
1159 | if (rl->count[BLK_RW_SYNC] >= on_thresh) | |
1160 | blk_set_congested(rl, BLK_RW_SYNC); | |
1161 | else if (rl->count[BLK_RW_SYNC] < off_thresh) | |
1162 | blk_clear_congested(rl, BLK_RW_SYNC); | |
e3a2b3f9 | 1163 | |
d40f75a0 TH |
1164 | if (rl->count[BLK_RW_ASYNC] >= on_thresh) |
1165 | blk_set_congested(rl, BLK_RW_ASYNC); | |
1166 | else if (rl->count[BLK_RW_ASYNC] < off_thresh) | |
1167 | blk_clear_congested(rl, BLK_RW_ASYNC); | |
e3a2b3f9 | 1168 | |
e3a2b3f9 JA |
1169 | if (rl->count[BLK_RW_SYNC] >= q->nr_requests) { |
1170 | blk_set_rl_full(rl, BLK_RW_SYNC); | |
1171 | } else { | |
1172 | blk_clear_rl_full(rl, BLK_RW_SYNC); | |
1173 | wake_up(&rl->wait[BLK_RW_SYNC]); | |
1174 | } | |
1175 | ||
1176 | if (rl->count[BLK_RW_ASYNC] >= q->nr_requests) { | |
1177 | blk_set_rl_full(rl, BLK_RW_ASYNC); | |
1178 | } else { | |
1179 | blk_clear_rl_full(rl, BLK_RW_ASYNC); | |
1180 | wake_up(&rl->wait[BLK_RW_ASYNC]); | |
1181 | } | |
1182 | } | |
1183 | ||
1184 | spin_unlock_irq(q->queue_lock); | |
1185 | return 0; | |
1186 | } | |
1187 | ||
da8303c6 | 1188 | /** |
a06e05e6 | 1189 | * __get_request - get a free request |
5b788ce3 | 1190 | * @rl: request list to allocate from |
ef295ecf | 1191 | * @op: operation and flags |
da8303c6 | 1192 | * @bio: bio to allocate request for (can be %NULL) |
6a15674d | 1193 | * @flags: BLQ_MQ_REQ_* flags |
da8303c6 TH |
1194 | * |
1195 | * Get a free request from @q. This function may fail under memory | |
1196 | * pressure or if @q is dead. | |
1197 | * | |
da3dae54 | 1198 | * Must be called with @q->queue_lock held and, |
a492f075 JL |
1199 | * Returns ERR_PTR on failure, with @q->queue_lock held. |
1200 | * Returns request pointer on success, with @q->queue_lock *not held*. | |
1da177e4 | 1201 | */ |
ef295ecf | 1202 | static struct request *__get_request(struct request_list *rl, unsigned int op, |
6a15674d | 1203 | struct bio *bio, unsigned int flags) |
1da177e4 | 1204 | { |
5b788ce3 | 1205 | struct request_queue *q = rl->q; |
b679281a | 1206 | struct request *rq; |
7f4b35d1 TH |
1207 | struct elevator_type *et = q->elevator->type; |
1208 | struct io_context *ioc = rq_ioc(bio); | |
f1f8cc94 | 1209 | struct io_cq *icq = NULL; |
ef295ecf | 1210 | const bool is_sync = op_is_sync(op); |
75eb6c37 | 1211 | int may_queue; |
6a15674d BVA |
1212 | gfp_t gfp_mask = flags & BLK_MQ_REQ_NOWAIT ? GFP_ATOMIC : |
1213 | __GFP_DIRECT_RECLAIM; | |
e8064021 | 1214 | req_flags_t rq_flags = RQF_ALLOCED; |
88ee5ef1 | 1215 | |
2fff8a92 BVA |
1216 | lockdep_assert_held(q->queue_lock); |
1217 | ||
3f3299d5 | 1218 | if (unlikely(blk_queue_dying(q))) |
a492f075 | 1219 | return ERR_PTR(-ENODEV); |
da8303c6 | 1220 | |
ef295ecf | 1221 | may_queue = elv_may_queue(q, op); |
88ee5ef1 JA |
1222 | if (may_queue == ELV_MQUEUE_NO) |
1223 | goto rq_starved; | |
1224 | ||
1faa16d2 JA |
1225 | if (rl->count[is_sync]+1 >= queue_congestion_on_threshold(q)) { |
1226 | if (rl->count[is_sync]+1 >= q->nr_requests) { | |
88ee5ef1 JA |
1227 | /* |
1228 | * The queue will fill after this allocation, so set | |
1229 | * it as full, and mark this process as "batching". | |
1230 | * This process will be allowed to complete a batch of | |
1231 | * requests, others will be blocked. | |
1232 | */ | |
5b788ce3 | 1233 | if (!blk_rl_full(rl, is_sync)) { |
88ee5ef1 | 1234 | ioc_set_batching(q, ioc); |
5b788ce3 | 1235 | blk_set_rl_full(rl, is_sync); |
88ee5ef1 JA |
1236 | } else { |
1237 | if (may_queue != ELV_MQUEUE_MUST | |
1238 | && !ioc_batching(q, ioc)) { | |
1239 | /* | |
1240 | * The queue is full and the allocating | |
1241 | * process is not a "batcher", and not | |
1242 | * exempted by the IO scheduler | |
1243 | */ | |
a492f075 | 1244 | return ERR_PTR(-ENOMEM); |
88ee5ef1 JA |
1245 | } |
1246 | } | |
1da177e4 | 1247 | } |
d40f75a0 | 1248 | blk_set_congested(rl, is_sync); |
1da177e4 LT |
1249 | } |
1250 | ||
082cf69e JA |
1251 | /* |
1252 | * Only allow batching queuers to allocate up to 50% over the defined | |
1253 | * limit of requests, otherwise we could have thousands of requests | |
1254 | * allocated with any setting of ->nr_requests | |
1255 | */ | |
1faa16d2 | 1256 | if (rl->count[is_sync] >= (3 * q->nr_requests / 2)) |
a492f075 | 1257 | return ERR_PTR(-ENOMEM); |
fd782a4a | 1258 | |
8a5ecdd4 | 1259 | q->nr_rqs[is_sync]++; |
1faa16d2 JA |
1260 | rl->count[is_sync]++; |
1261 | rl->starved[is_sync] = 0; | |
cb98fc8b | 1262 | |
f1f8cc94 TH |
1263 | /* |
1264 | * Decide whether the new request will be managed by elevator. If | |
e8064021 | 1265 | * so, mark @rq_flags and increment elvpriv. Non-zero elvpriv will |
f1f8cc94 TH |
1266 | * prevent the current elevator from being destroyed until the new |
1267 | * request is freed. This guarantees icq's won't be destroyed and | |
1268 | * makes creating new ones safe. | |
1269 | * | |
e6f7f93d CH |
1270 | * Flush requests do not use the elevator so skip initialization. |
1271 | * This allows a request to share the flush and elevator data. | |
1272 | * | |
f1f8cc94 TH |
1273 | * Also, lookup icq while holding queue_lock. If it doesn't exist, |
1274 | * it will be created after releasing queue_lock. | |
1275 | */ | |
e6f7f93d | 1276 | if (!op_is_flush(op) && !blk_queue_bypass(q)) { |
e8064021 | 1277 | rq_flags |= RQF_ELVPRIV; |
8a5ecdd4 | 1278 | q->nr_rqs_elvpriv++; |
f1f8cc94 TH |
1279 | if (et->icq_cache && ioc) |
1280 | icq = ioc_lookup_icq(ioc, q); | |
9d5a4e94 | 1281 | } |
cb98fc8b | 1282 | |
f253b86b | 1283 | if (blk_queue_io_stat(q)) |
e8064021 | 1284 | rq_flags |= RQF_IO_STAT; |
1da177e4 LT |
1285 | spin_unlock_irq(q->queue_lock); |
1286 | ||
29e2b09a | 1287 | /* allocate and init request */ |
5b788ce3 | 1288 | rq = mempool_alloc(rl->rq_pool, gfp_mask); |
29e2b09a | 1289 | if (!rq) |
b679281a | 1290 | goto fail_alloc; |
1da177e4 | 1291 | |
29e2b09a | 1292 | blk_rq_init(q, rq); |
a051661c | 1293 | blk_rq_set_rl(rq, rl); |
ef295ecf | 1294 | rq->cmd_flags = op; |
e8064021 | 1295 | rq->rq_flags = rq_flags; |
1b6d65a0 BVA |
1296 | if (flags & BLK_MQ_REQ_PREEMPT) |
1297 | rq->rq_flags |= RQF_PREEMPT; | |
29e2b09a | 1298 | |
aaf7c680 | 1299 | /* init elvpriv */ |
e8064021 | 1300 | if (rq_flags & RQF_ELVPRIV) { |
aaf7c680 | 1301 | if (unlikely(et->icq_cache && !icq)) { |
7f4b35d1 TH |
1302 | if (ioc) |
1303 | icq = ioc_create_icq(ioc, q, gfp_mask); | |
aaf7c680 TH |
1304 | if (!icq) |
1305 | goto fail_elvpriv; | |
29e2b09a | 1306 | } |
aaf7c680 TH |
1307 | |
1308 | rq->elv.icq = icq; | |
1309 | if (unlikely(elv_set_request(q, rq, bio, gfp_mask))) | |
1310 | goto fail_elvpriv; | |
1311 | ||
1312 | /* @rq->elv.icq holds io_context until @rq is freed */ | |
29e2b09a TH |
1313 | if (icq) |
1314 | get_io_context(icq->ioc); | |
1315 | } | |
aaf7c680 | 1316 | out: |
88ee5ef1 JA |
1317 | /* |
1318 | * ioc may be NULL here, and ioc_batching will be false. That's | |
1319 | * OK, if the queue is under the request limit then requests need | |
1320 | * not count toward the nr_batch_requests limit. There will always | |
1321 | * be some limit enforced by BLK_BATCH_TIME. | |
1322 | */ | |
1da177e4 LT |
1323 | if (ioc_batching(q, ioc)) |
1324 | ioc->nr_batch_requests--; | |
6728cb0e | 1325 | |
e6a40b09 | 1326 | trace_block_getrq(q, bio, op); |
1da177e4 | 1327 | return rq; |
b679281a | 1328 | |
aaf7c680 TH |
1329 | fail_elvpriv: |
1330 | /* | |
1331 | * elvpriv init failed. ioc, icq and elvpriv aren't mempool backed | |
1332 | * and may fail indefinitely under memory pressure and thus | |
1333 | * shouldn't stall IO. Treat this request as !elvpriv. This will | |
1334 | * disturb iosched and blkcg but weird is bettern than dead. | |
1335 | */ | |
7b2b10e0 | 1336 | printk_ratelimited(KERN_WARNING "%s: dev %s: request aux data allocation failed, iosched may be disturbed\n", |
dc3b17cc | 1337 | __func__, dev_name(q->backing_dev_info->dev)); |
aaf7c680 | 1338 | |
e8064021 | 1339 | rq->rq_flags &= ~RQF_ELVPRIV; |
aaf7c680 TH |
1340 | rq->elv.icq = NULL; |
1341 | ||
1342 | spin_lock_irq(q->queue_lock); | |
8a5ecdd4 | 1343 | q->nr_rqs_elvpriv--; |
aaf7c680 TH |
1344 | spin_unlock_irq(q->queue_lock); |
1345 | goto out; | |
1346 | ||
b679281a TH |
1347 | fail_alloc: |
1348 | /* | |
1349 | * Allocation failed presumably due to memory. Undo anything we | |
1350 | * might have messed up. | |
1351 | * | |
1352 | * Allocating task should really be put onto the front of the wait | |
1353 | * queue, but this is pretty rare. | |
1354 | */ | |
1355 | spin_lock_irq(q->queue_lock); | |
e8064021 | 1356 | freed_request(rl, is_sync, rq_flags); |
b679281a TH |
1357 | |
1358 | /* | |
1359 | * in the very unlikely event that allocation failed and no | |
1360 | * requests for this direction was pending, mark us starved so that | |
1361 | * freeing of a request in the other direction will notice | |
1362 | * us. another possible fix would be to split the rq mempool into | |
1363 | * READ and WRITE | |
1364 | */ | |
1365 | rq_starved: | |
1366 | if (unlikely(rl->count[is_sync] == 0)) | |
1367 | rl->starved[is_sync] = 1; | |
a492f075 | 1368 | return ERR_PTR(-ENOMEM); |
1da177e4 LT |
1369 | } |
1370 | ||
da8303c6 | 1371 | /** |
a06e05e6 | 1372 | * get_request - get a free request |
da8303c6 | 1373 | * @q: request_queue to allocate request from |
ef295ecf | 1374 | * @op: operation and flags |
da8303c6 | 1375 | * @bio: bio to allocate request for (can be %NULL) |
6a15674d | 1376 | * @flags: BLK_MQ_REQ_* flags. |
da8303c6 | 1377 | * |
d0164adc MG |
1378 | * Get a free request from @q. If %__GFP_DIRECT_RECLAIM is set in @gfp_mask, |
1379 | * this function keeps retrying under memory pressure and fails iff @q is dead. | |
d6344532 | 1380 | * |
da3dae54 | 1381 | * Must be called with @q->queue_lock held and, |
a492f075 JL |
1382 | * Returns ERR_PTR on failure, with @q->queue_lock held. |
1383 | * Returns request pointer on success, with @q->queue_lock *not held*. | |
1da177e4 | 1384 | */ |
ef295ecf | 1385 | static struct request *get_request(struct request_queue *q, unsigned int op, |
6a15674d | 1386 | struct bio *bio, unsigned int flags) |
1da177e4 | 1387 | { |
ef295ecf | 1388 | const bool is_sync = op_is_sync(op); |
a06e05e6 | 1389 | DEFINE_WAIT(wait); |
a051661c | 1390 | struct request_list *rl; |
1da177e4 | 1391 | struct request *rq; |
a051661c | 1392 | |
2fff8a92 | 1393 | lockdep_assert_held(q->queue_lock); |
332ebbf7 | 1394 | WARN_ON_ONCE(q->mq_ops); |
2fff8a92 | 1395 | |
a051661c | 1396 | rl = blk_get_rl(q, bio); /* transferred to @rq on success */ |
a06e05e6 | 1397 | retry: |
6a15674d | 1398 | rq = __get_request(rl, op, bio, flags); |
a492f075 | 1399 | if (!IS_ERR(rq)) |
a06e05e6 | 1400 | return rq; |
1da177e4 | 1401 | |
03a07c92 GR |
1402 | if (op & REQ_NOWAIT) { |
1403 | blk_put_rl(rl); | |
1404 | return ERR_PTR(-EAGAIN); | |
1405 | } | |
1406 | ||
6a15674d | 1407 | if ((flags & BLK_MQ_REQ_NOWAIT) || unlikely(blk_queue_dying(q))) { |
a051661c | 1408 | blk_put_rl(rl); |
a492f075 | 1409 | return rq; |
a051661c | 1410 | } |
1da177e4 | 1411 | |
a06e05e6 TH |
1412 | /* wait on @rl and retry */ |
1413 | prepare_to_wait_exclusive(&rl->wait[is_sync], &wait, | |
1414 | TASK_UNINTERRUPTIBLE); | |
1da177e4 | 1415 | |
e6a40b09 | 1416 | trace_block_sleeprq(q, bio, op); |
1da177e4 | 1417 | |
a06e05e6 TH |
1418 | spin_unlock_irq(q->queue_lock); |
1419 | io_schedule(); | |
d6344532 | 1420 | |
a06e05e6 TH |
1421 | /* |
1422 | * After sleeping, we become a "batching" process and will be able | |
1423 | * to allocate at least one request, and up to a big batch of them | |
1424 | * for a small period time. See ioc_batching, ioc_set_batching | |
1425 | */ | |
a06e05e6 | 1426 | ioc_set_batching(q, current->io_context); |
05caf8db | 1427 | |
a06e05e6 TH |
1428 | spin_lock_irq(q->queue_lock); |
1429 | finish_wait(&rl->wait[is_sync], &wait); | |
1da177e4 | 1430 | |
a06e05e6 | 1431 | goto retry; |
1da177e4 LT |
1432 | } |
1433 | ||
6a15674d | 1434 | /* flags: BLK_MQ_REQ_PREEMPT and/or BLK_MQ_REQ_NOWAIT. */ |
cd6ce148 | 1435 | static struct request *blk_old_get_request(struct request_queue *q, |
6a15674d | 1436 | unsigned int op, unsigned int flags) |
1da177e4 LT |
1437 | { |
1438 | struct request *rq; | |
6a15674d BVA |
1439 | gfp_t gfp_mask = flags & BLK_MQ_REQ_NOWAIT ? GFP_ATOMIC : |
1440 | __GFP_DIRECT_RECLAIM; | |
055f6e18 | 1441 | int ret = 0; |
1da177e4 | 1442 | |
332ebbf7 BVA |
1443 | WARN_ON_ONCE(q->mq_ops); |
1444 | ||
7f4b35d1 TH |
1445 | /* create ioc upfront */ |
1446 | create_io_context(gfp_mask, q->node); | |
1447 | ||
055f6e18 ML |
1448 | ret = blk_queue_enter(q, !(gfp_mask & __GFP_DIRECT_RECLAIM) || |
1449 | (op & REQ_NOWAIT)); | |
1450 | if (ret) | |
1451 | return ERR_PTR(ret); | |
d6344532 | 1452 | spin_lock_irq(q->queue_lock); |
6a15674d | 1453 | rq = get_request(q, op, NULL, flags); |
0c4de0f3 | 1454 | if (IS_ERR(rq)) { |
da8303c6 | 1455 | spin_unlock_irq(q->queue_lock); |
055f6e18 | 1456 | blk_queue_exit(q); |
0c4de0f3 CH |
1457 | return rq; |
1458 | } | |
1da177e4 | 1459 | |
0c4de0f3 CH |
1460 | /* q->queue_lock is unlocked at this point */ |
1461 | rq->__data_len = 0; | |
1462 | rq->__sector = (sector_t) -1; | |
1463 | rq->bio = rq->biotail = NULL; | |
1da177e4 LT |
1464 | return rq; |
1465 | } | |
320ae51f | 1466 | |
6a15674d BVA |
1467 | /** |
1468 | * blk_get_request_flags - allocate a request | |
1469 | * @q: request queue to allocate a request for | |
1470 | * @op: operation (REQ_OP_*) and REQ_* flags, e.g. REQ_SYNC. | |
1471 | * @flags: BLK_MQ_REQ_* flags, e.g. BLK_MQ_REQ_NOWAIT. | |
1472 | */ | |
1473 | struct request *blk_get_request_flags(struct request_queue *q, unsigned int op, | |
1474 | unsigned int flags) | |
320ae51f | 1475 | { |
d280bab3 BVA |
1476 | struct request *req; |
1477 | ||
6a15674d | 1478 | WARN_ON_ONCE(op & REQ_NOWAIT); |
1b6d65a0 | 1479 | WARN_ON_ONCE(flags & ~(BLK_MQ_REQ_NOWAIT | BLK_MQ_REQ_PREEMPT)); |
6a15674d | 1480 | |
d280bab3 | 1481 | if (q->mq_ops) { |
6a15674d | 1482 | req = blk_mq_alloc_request(q, op, flags); |
d280bab3 BVA |
1483 | if (!IS_ERR(req) && q->mq_ops->initialize_rq_fn) |
1484 | q->mq_ops->initialize_rq_fn(req); | |
1485 | } else { | |
6a15674d | 1486 | req = blk_old_get_request(q, op, flags); |
d280bab3 BVA |
1487 | if (!IS_ERR(req) && q->initialize_rq_fn) |
1488 | q->initialize_rq_fn(req); | |
1489 | } | |
1490 | ||
1491 | return req; | |
320ae51f | 1492 | } |
6a15674d BVA |
1493 | EXPORT_SYMBOL(blk_get_request_flags); |
1494 | ||
1495 | struct request *blk_get_request(struct request_queue *q, unsigned int op, | |
1496 | gfp_t gfp_mask) | |
1497 | { | |
1498 | return blk_get_request_flags(q, op, gfp_mask & __GFP_DIRECT_RECLAIM ? | |
1499 | 0 : BLK_MQ_REQ_NOWAIT); | |
1500 | } | |
1da177e4 LT |
1501 | EXPORT_SYMBOL(blk_get_request); |
1502 | ||
1503 | /** | |
1504 | * blk_requeue_request - put a request back on queue | |
1505 | * @q: request queue where request should be inserted | |
1506 | * @rq: request to be inserted | |
1507 | * | |
1508 | * Description: | |
1509 | * Drivers often keep queueing requests until the hardware cannot accept | |
1510 | * more, when that condition happens we need to put the request back | |
1511 | * on the queue. Must be called with queue lock held. | |
1512 | */ | |
165125e1 | 1513 | void blk_requeue_request(struct request_queue *q, struct request *rq) |
1da177e4 | 1514 | { |
2fff8a92 | 1515 | lockdep_assert_held(q->queue_lock); |
332ebbf7 | 1516 | WARN_ON_ONCE(q->mq_ops); |
2fff8a92 | 1517 | |
242f9dcb JA |
1518 | blk_delete_timer(rq); |
1519 | blk_clear_rq_complete(rq); | |
5f3ea37c | 1520 | trace_block_rq_requeue(q, rq); |
87760e5e | 1521 | wbt_requeue(q->rq_wb, &rq->issue_stat); |
2056a782 | 1522 | |
e8064021 | 1523 | if (rq->rq_flags & RQF_QUEUED) |
1da177e4 LT |
1524 | blk_queue_end_tag(q, rq); |
1525 | ||
ba396a6c JB |
1526 | BUG_ON(blk_queued_rq(rq)); |
1527 | ||
1da177e4 LT |
1528 | elv_requeue_request(q, rq); |
1529 | } | |
1da177e4 LT |
1530 | EXPORT_SYMBOL(blk_requeue_request); |
1531 | ||
73c10101 JA |
1532 | static void add_acct_request(struct request_queue *q, struct request *rq, |
1533 | int where) | |
1534 | { | |
320ae51f | 1535 | blk_account_io_start(rq, true); |
7eaceacc | 1536 | __elv_add_request(q, rq, where); |
73c10101 JA |
1537 | } |
1538 | ||
d62e26b3 | 1539 | static void part_round_stats_single(struct request_queue *q, int cpu, |
b8d62b3a JA |
1540 | struct hd_struct *part, unsigned long now, |
1541 | unsigned int inflight) | |
074a7aca | 1542 | { |
b8d62b3a | 1543 | if (inflight) { |
074a7aca | 1544 | __part_stat_add(cpu, part, time_in_queue, |
b8d62b3a | 1545 | inflight * (now - part->stamp)); |
074a7aca TH |
1546 | __part_stat_add(cpu, part, io_ticks, (now - part->stamp)); |
1547 | } | |
1548 | part->stamp = now; | |
1549 | } | |
1550 | ||
1551 | /** | |
496aa8a9 | 1552 | * part_round_stats() - Round off the performance stats on a struct disk_stats. |
d62e26b3 | 1553 | * @q: target block queue |
496aa8a9 RD |
1554 | * @cpu: cpu number for stats access |
1555 | * @part: target partition | |
1da177e4 LT |
1556 | * |
1557 | * The average IO queue length and utilisation statistics are maintained | |
1558 | * by observing the current state of the queue length and the amount of | |
1559 | * time it has been in this state for. | |
1560 | * | |
1561 | * Normally, that accounting is done on IO completion, but that can result | |
1562 | * in more than a second's worth of IO being accounted for within any one | |
1563 | * second, leading to >100% utilisation. To deal with that, we call this | |
1564 | * function to do a round-off before returning the results when reading | |
1565 | * /proc/diskstats. This accounts immediately for all queue usage up to | |
1566 | * the current jiffies and restarts the counters again. | |
1567 | */ | |
d62e26b3 | 1568 | void part_round_stats(struct request_queue *q, int cpu, struct hd_struct *part) |
6f2576af | 1569 | { |
b8d62b3a | 1570 | struct hd_struct *part2 = NULL; |
6f2576af | 1571 | unsigned long now = jiffies; |
b8d62b3a JA |
1572 | unsigned int inflight[2]; |
1573 | int stats = 0; | |
1574 | ||
1575 | if (part->stamp != now) | |
1576 | stats |= 1; | |
1577 | ||
1578 | if (part->partno) { | |
1579 | part2 = &part_to_disk(part)->part0; | |
1580 | if (part2->stamp != now) | |
1581 | stats |= 2; | |
1582 | } | |
1583 | ||
1584 | if (!stats) | |
1585 | return; | |
1586 | ||
1587 | part_in_flight(q, part, inflight); | |
6f2576af | 1588 | |
b8d62b3a JA |
1589 | if (stats & 2) |
1590 | part_round_stats_single(q, cpu, part2, now, inflight[1]); | |
1591 | if (stats & 1) | |
1592 | part_round_stats_single(q, cpu, part, now, inflight[0]); | |
6f2576af | 1593 | } |
074a7aca | 1594 | EXPORT_SYMBOL_GPL(part_round_stats); |
6f2576af | 1595 | |
47fafbc7 | 1596 | #ifdef CONFIG_PM |
c8158819 LM |
1597 | static void blk_pm_put_request(struct request *rq) |
1598 | { | |
e8064021 | 1599 | if (rq->q->dev && !(rq->rq_flags & RQF_PM) && !--rq->q->nr_pending) |
c8158819 LM |
1600 | pm_runtime_mark_last_busy(rq->q->dev); |
1601 | } | |
1602 | #else | |
1603 | static inline void blk_pm_put_request(struct request *rq) {} | |
1604 | #endif | |
1605 | ||
165125e1 | 1606 | void __blk_put_request(struct request_queue *q, struct request *req) |
1da177e4 | 1607 | { |
e8064021 CH |
1608 | req_flags_t rq_flags = req->rq_flags; |
1609 | ||
1da177e4 LT |
1610 | if (unlikely(!q)) |
1611 | return; | |
1da177e4 | 1612 | |
6f5ba581 CH |
1613 | if (q->mq_ops) { |
1614 | blk_mq_free_request(req); | |
1615 | return; | |
1616 | } | |
1617 | ||
2fff8a92 BVA |
1618 | lockdep_assert_held(q->queue_lock); |
1619 | ||
c8158819 LM |
1620 | blk_pm_put_request(req); |
1621 | ||
8922e16c TH |
1622 | elv_completed_request(q, req); |
1623 | ||
1cd96c24 BH |
1624 | /* this is a bio leak */ |
1625 | WARN_ON(req->bio != NULL); | |
1626 | ||
87760e5e JA |
1627 | wbt_done(q->rq_wb, &req->issue_stat); |
1628 | ||
1da177e4 LT |
1629 | /* |
1630 | * Request may not have originated from ll_rw_blk. if not, | |
1631 | * it didn't come out of our reserved rq pools | |
1632 | */ | |
e8064021 | 1633 | if (rq_flags & RQF_ALLOCED) { |
a051661c | 1634 | struct request_list *rl = blk_rq_rl(req); |
ef295ecf | 1635 | bool sync = op_is_sync(req->cmd_flags); |
1da177e4 | 1636 | |
1da177e4 | 1637 | BUG_ON(!list_empty(&req->queuelist)); |
360f92c2 | 1638 | BUG_ON(ELV_ON_HASH(req)); |
1da177e4 | 1639 | |
a051661c | 1640 | blk_free_request(rl, req); |
e8064021 | 1641 | freed_request(rl, sync, rq_flags); |
a051661c | 1642 | blk_put_rl(rl); |
055f6e18 | 1643 | blk_queue_exit(q); |
1da177e4 LT |
1644 | } |
1645 | } | |
6e39b69e MC |
1646 | EXPORT_SYMBOL_GPL(__blk_put_request); |
1647 | ||
1da177e4 LT |
1648 | void blk_put_request(struct request *req) |
1649 | { | |
165125e1 | 1650 | struct request_queue *q = req->q; |
8922e16c | 1651 | |
320ae51f JA |
1652 | if (q->mq_ops) |
1653 | blk_mq_free_request(req); | |
1654 | else { | |
1655 | unsigned long flags; | |
1656 | ||
1657 | spin_lock_irqsave(q->queue_lock, flags); | |
1658 | __blk_put_request(q, req); | |
1659 | spin_unlock_irqrestore(q->queue_lock, flags); | |
1660 | } | |
1da177e4 | 1661 | } |
1da177e4 LT |
1662 | EXPORT_SYMBOL(blk_put_request); |
1663 | ||
320ae51f JA |
1664 | bool bio_attempt_back_merge(struct request_queue *q, struct request *req, |
1665 | struct bio *bio) | |
73c10101 | 1666 | { |
1eff9d32 | 1667 | const int ff = bio->bi_opf & REQ_FAILFAST_MASK; |
73c10101 | 1668 | |
73c10101 JA |
1669 | if (!ll_back_merge_fn(q, req, bio)) |
1670 | return false; | |
1671 | ||
8c1cf6bb | 1672 | trace_block_bio_backmerge(q, req, bio); |
73c10101 JA |
1673 | |
1674 | if ((req->cmd_flags & REQ_FAILFAST_MASK) != ff) | |
1675 | blk_rq_set_mixed_merge(req); | |
1676 | ||
1677 | req->biotail->bi_next = bio; | |
1678 | req->biotail = bio; | |
4f024f37 | 1679 | req->__data_len += bio->bi_iter.bi_size; |
73c10101 JA |
1680 | req->ioprio = ioprio_best(req->ioprio, bio_prio(bio)); |
1681 | ||
320ae51f | 1682 | blk_account_io_start(req, false); |
73c10101 JA |
1683 | return true; |
1684 | } | |
1685 | ||
320ae51f JA |
1686 | bool bio_attempt_front_merge(struct request_queue *q, struct request *req, |
1687 | struct bio *bio) | |
73c10101 | 1688 | { |
1eff9d32 | 1689 | const int ff = bio->bi_opf & REQ_FAILFAST_MASK; |
73c10101 | 1690 | |
73c10101 JA |
1691 | if (!ll_front_merge_fn(q, req, bio)) |
1692 | return false; | |
1693 | ||
8c1cf6bb | 1694 | trace_block_bio_frontmerge(q, req, bio); |
73c10101 JA |
1695 | |
1696 | if ((req->cmd_flags & REQ_FAILFAST_MASK) != ff) | |
1697 | blk_rq_set_mixed_merge(req); | |
1698 | ||
73c10101 JA |
1699 | bio->bi_next = req->bio; |
1700 | req->bio = bio; | |
1701 | ||
4f024f37 KO |
1702 | req->__sector = bio->bi_iter.bi_sector; |
1703 | req->__data_len += bio->bi_iter.bi_size; | |
73c10101 JA |
1704 | req->ioprio = ioprio_best(req->ioprio, bio_prio(bio)); |
1705 | ||
320ae51f | 1706 | blk_account_io_start(req, false); |
73c10101 JA |
1707 | return true; |
1708 | } | |
1709 | ||
1e739730 CH |
1710 | bool bio_attempt_discard_merge(struct request_queue *q, struct request *req, |
1711 | struct bio *bio) | |
1712 | { | |
1713 | unsigned short segments = blk_rq_nr_discard_segments(req); | |
1714 | ||
1715 | if (segments >= queue_max_discard_segments(q)) | |
1716 | goto no_merge; | |
1717 | if (blk_rq_sectors(req) + bio_sectors(bio) > | |
1718 | blk_rq_get_max_sectors(req, blk_rq_pos(req))) | |
1719 | goto no_merge; | |
1720 | ||
1721 | req->biotail->bi_next = bio; | |
1722 | req->biotail = bio; | |
1723 | req->__data_len += bio->bi_iter.bi_size; | |
1724 | req->ioprio = ioprio_best(req->ioprio, bio_prio(bio)); | |
1725 | req->nr_phys_segments = segments + 1; | |
1726 | ||
1727 | blk_account_io_start(req, false); | |
1728 | return true; | |
1729 | no_merge: | |
1730 | req_set_nomerge(q, req); | |
1731 | return false; | |
1732 | } | |
1733 | ||
bd87b589 | 1734 | /** |
320ae51f | 1735 | * blk_attempt_plug_merge - try to merge with %current's plugged list |
bd87b589 TH |
1736 | * @q: request_queue new bio is being queued at |
1737 | * @bio: new bio being queued | |
1738 | * @request_count: out parameter for number of traversed plugged requests | |
ccc2600b RD |
1739 | * @same_queue_rq: pointer to &struct request that gets filled in when |
1740 | * another request associated with @q is found on the plug list | |
1741 | * (optional, may be %NULL) | |
bd87b589 TH |
1742 | * |
1743 | * Determine whether @bio being queued on @q can be merged with a request | |
1744 | * on %current's plugged list. Returns %true if merge was successful, | |
1745 | * otherwise %false. | |
1746 | * | |
07c2bd37 TH |
1747 | * Plugging coalesces IOs from the same issuer for the same purpose without |
1748 | * going through @q->queue_lock. As such it's more of an issuing mechanism | |
1749 | * than scheduling, and the request, while may have elvpriv data, is not | |
1750 | * added on the elevator at this point. In addition, we don't have | |
1751 | * reliable access to the elevator outside queue lock. Only check basic | |
1752 | * merging parameters without querying the elevator. | |
da41a589 RE |
1753 | * |
1754 | * Caller must ensure !blk_queue_nomerges(q) beforehand. | |
73c10101 | 1755 | */ |
320ae51f | 1756 | bool blk_attempt_plug_merge(struct request_queue *q, struct bio *bio, |
5b3f341f SL |
1757 | unsigned int *request_count, |
1758 | struct request **same_queue_rq) | |
73c10101 JA |
1759 | { |
1760 | struct blk_plug *plug; | |
1761 | struct request *rq; | |
92f399c7 | 1762 | struct list_head *plug_list; |
73c10101 | 1763 | |
bd87b589 | 1764 | plug = current->plug; |
73c10101 | 1765 | if (!plug) |
34fe7c05 | 1766 | return false; |
56ebdaf2 | 1767 | *request_count = 0; |
73c10101 | 1768 | |
92f399c7 SL |
1769 | if (q->mq_ops) |
1770 | plug_list = &plug->mq_list; | |
1771 | else | |
1772 | plug_list = &plug->list; | |
1773 | ||
1774 | list_for_each_entry_reverse(rq, plug_list, queuelist) { | |
34fe7c05 | 1775 | bool merged = false; |
73c10101 | 1776 | |
5b3f341f | 1777 | if (rq->q == q) { |
1b2e19f1 | 1778 | (*request_count)++; |
5b3f341f SL |
1779 | /* |
1780 | * Only blk-mq multiple hardware queues case checks the | |
1781 | * rq in the same queue, there should be only one such | |
1782 | * rq in a queue | |
1783 | **/ | |
1784 | if (same_queue_rq) | |
1785 | *same_queue_rq = rq; | |
1786 | } | |
56ebdaf2 | 1787 | |
07c2bd37 | 1788 | if (rq->q != q || !blk_rq_merge_ok(rq, bio)) |
73c10101 JA |
1789 | continue; |
1790 | ||
34fe7c05 CH |
1791 | switch (blk_try_merge(rq, bio)) { |
1792 | case ELEVATOR_BACK_MERGE: | |
1793 | merged = bio_attempt_back_merge(q, rq, bio); | |
1794 | break; | |
1795 | case ELEVATOR_FRONT_MERGE: | |
1796 | merged = bio_attempt_front_merge(q, rq, bio); | |
1797 | break; | |
1e739730 CH |
1798 | case ELEVATOR_DISCARD_MERGE: |
1799 | merged = bio_attempt_discard_merge(q, rq, bio); | |
1800 | break; | |
34fe7c05 CH |
1801 | default: |
1802 | break; | |
73c10101 | 1803 | } |
34fe7c05 CH |
1804 | |
1805 | if (merged) | |
1806 | return true; | |
73c10101 | 1807 | } |
34fe7c05 CH |
1808 | |
1809 | return false; | |
73c10101 JA |
1810 | } |
1811 | ||
0809e3ac JM |
1812 | unsigned int blk_plug_queued_count(struct request_queue *q) |
1813 | { | |
1814 | struct blk_plug *plug; | |
1815 | struct request *rq; | |
1816 | struct list_head *plug_list; | |
1817 | unsigned int ret = 0; | |
1818 | ||
1819 | plug = current->plug; | |
1820 | if (!plug) | |
1821 | goto out; | |
1822 | ||
1823 | if (q->mq_ops) | |
1824 | plug_list = &plug->mq_list; | |
1825 | else | |
1826 | plug_list = &plug->list; | |
1827 | ||
1828 | list_for_each_entry(rq, plug_list, queuelist) { | |
1829 | if (rq->q == q) | |
1830 | ret++; | |
1831 | } | |
1832 | out: | |
1833 | return ret; | |
1834 | } | |
1835 | ||
da8d7f07 | 1836 | void blk_init_request_from_bio(struct request *req, struct bio *bio) |
52d9e675 | 1837 | { |
0be0dee6 BVA |
1838 | struct io_context *ioc = rq_ioc(bio); |
1839 | ||
1eff9d32 | 1840 | if (bio->bi_opf & REQ_RAHEAD) |
a82afdfc | 1841 | req->cmd_flags |= REQ_FAILFAST_MASK; |
b31dc66a | 1842 | |
4f024f37 | 1843 | req->__sector = bio->bi_iter.bi_sector; |
5dc8b362 AM |
1844 | if (ioprio_valid(bio_prio(bio))) |
1845 | req->ioprio = bio_prio(bio); | |
0be0dee6 BVA |
1846 | else if (ioc) |
1847 | req->ioprio = ioc->ioprio; | |
1848 | else | |
1849 | req->ioprio = IOPRIO_PRIO_VALUE(IOPRIO_CLASS_NONE, 0); | |
cb6934f8 | 1850 | req->write_hint = bio->bi_write_hint; |
bc1c56fd | 1851 | blk_rq_bio_prep(req->q, req, bio); |
52d9e675 | 1852 | } |
da8d7f07 | 1853 | EXPORT_SYMBOL_GPL(blk_init_request_from_bio); |
52d9e675 | 1854 | |
dece1635 | 1855 | static blk_qc_t blk_queue_bio(struct request_queue *q, struct bio *bio) |
1da177e4 | 1856 | { |
73c10101 | 1857 | struct blk_plug *plug; |
34fe7c05 | 1858 | int where = ELEVATOR_INSERT_SORT; |
e4d750c9 | 1859 | struct request *req, *free; |
56ebdaf2 | 1860 | unsigned int request_count = 0; |
87760e5e | 1861 | unsigned int wb_acct; |
1da177e4 | 1862 | |
1da177e4 LT |
1863 | /* |
1864 | * low level driver can indicate that it wants pages above a | |
1865 | * certain limit bounced to low memory (ie for highmem, or even | |
1866 | * ISA dma in theory) | |
1867 | */ | |
1868 | blk_queue_bounce(q, &bio); | |
1869 | ||
af67c31f | 1870 | blk_queue_split(q, &bio); |
23688bf4 | 1871 | |
e23947bd | 1872 | if (!bio_integrity_prep(bio)) |
dece1635 | 1873 | return BLK_QC_T_NONE; |
ffecfd1a | 1874 | |
f73f44eb | 1875 | if (op_is_flush(bio->bi_opf)) { |
73c10101 | 1876 | spin_lock_irq(q->queue_lock); |
ae1b1539 | 1877 | where = ELEVATOR_INSERT_FLUSH; |
28e7d184 TH |
1878 | goto get_rq; |
1879 | } | |
1880 | ||
73c10101 JA |
1881 | /* |
1882 | * Check if we can merge with the plugged list before grabbing | |
1883 | * any locks. | |
1884 | */ | |
0809e3ac JM |
1885 | if (!blk_queue_nomerges(q)) { |
1886 | if (blk_attempt_plug_merge(q, bio, &request_count, NULL)) | |
dece1635 | 1887 | return BLK_QC_T_NONE; |
0809e3ac JM |
1888 | } else |
1889 | request_count = blk_plug_queued_count(q); | |
1da177e4 | 1890 | |
73c10101 | 1891 | spin_lock_irq(q->queue_lock); |
2056a782 | 1892 | |
34fe7c05 CH |
1893 | switch (elv_merge(q, &req, bio)) { |
1894 | case ELEVATOR_BACK_MERGE: | |
1895 | if (!bio_attempt_back_merge(q, req, bio)) | |
1896 | break; | |
1897 | elv_bio_merged(q, req, bio); | |
1898 | free = attempt_back_merge(q, req); | |
1899 | if (free) | |
1900 | __blk_put_request(q, free); | |
1901 | else | |
1902 | elv_merged_request(q, req, ELEVATOR_BACK_MERGE); | |
1903 | goto out_unlock; | |
1904 | case ELEVATOR_FRONT_MERGE: | |
1905 | if (!bio_attempt_front_merge(q, req, bio)) | |
1906 | break; | |
1907 | elv_bio_merged(q, req, bio); | |
1908 | free = attempt_front_merge(q, req); | |
1909 | if (free) | |
1910 | __blk_put_request(q, free); | |
1911 | else | |
1912 | elv_merged_request(q, req, ELEVATOR_FRONT_MERGE); | |
1913 | goto out_unlock; | |
1914 | default: | |
1915 | break; | |
1da177e4 LT |
1916 | } |
1917 | ||
450991bc | 1918 | get_rq: |
87760e5e JA |
1919 | wb_acct = wbt_wait(q->rq_wb, bio, q->queue_lock); |
1920 | ||
1da177e4 | 1921 | /* |
450991bc | 1922 | * Grab a free request. This is might sleep but can not fail. |
d6344532 | 1923 | * Returns with the queue unlocked. |
450991bc | 1924 | */ |
055f6e18 | 1925 | blk_queue_enter_live(q); |
6a15674d | 1926 | req = get_request(q, bio->bi_opf, bio, 0); |
a492f075 | 1927 | if (IS_ERR(req)) { |
055f6e18 | 1928 | blk_queue_exit(q); |
87760e5e | 1929 | __wbt_done(q->rq_wb, wb_acct); |
4e4cbee9 CH |
1930 | if (PTR_ERR(req) == -ENOMEM) |
1931 | bio->bi_status = BLK_STS_RESOURCE; | |
1932 | else | |
1933 | bio->bi_status = BLK_STS_IOERR; | |
4246a0b6 | 1934 | bio_endio(bio); |
da8303c6 TH |
1935 | goto out_unlock; |
1936 | } | |
d6344532 | 1937 | |
87760e5e JA |
1938 | wbt_track(&req->issue_stat, wb_acct); |
1939 | ||
450991bc NP |
1940 | /* |
1941 | * After dropping the lock and possibly sleeping here, our request | |
1942 | * may now be mergeable after it had proven unmergeable (above). | |
1943 | * We don't worry about that case for efficiency. It won't happen | |
1944 | * often, and the elevators are able to handle it. | |
1da177e4 | 1945 | */ |
da8d7f07 | 1946 | blk_init_request_from_bio(req, bio); |
1da177e4 | 1947 | |
9562ad9a | 1948 | if (test_bit(QUEUE_FLAG_SAME_COMP, &q->queue_flags)) |
11ccf116 | 1949 | req->cpu = raw_smp_processor_id(); |
73c10101 JA |
1950 | |
1951 | plug = current->plug; | |
721a9602 | 1952 | if (plug) { |
dc6d36c9 JA |
1953 | /* |
1954 | * If this is the first request added after a plug, fire | |
7aef2e78 | 1955 | * of a plug trace. |
0a6219a9 ML |
1956 | * |
1957 | * @request_count may become stale because of schedule | |
1958 | * out, so check plug list again. | |
dc6d36c9 | 1959 | */ |
0a6219a9 | 1960 | if (!request_count || list_empty(&plug->list)) |
dc6d36c9 | 1961 | trace_block_plug(q); |
3540d5e8 | 1962 | else { |
50d24c34 SL |
1963 | struct request *last = list_entry_rq(plug->list.prev); |
1964 | if (request_count >= BLK_MAX_REQUEST_COUNT || | |
1965 | blk_rq_bytes(last) >= BLK_PLUG_FLUSH_SIZE) { | |
3540d5e8 | 1966 | blk_flush_plug_list(plug, false); |
019ceb7d SL |
1967 | trace_block_plug(q); |
1968 | } | |
73c10101 | 1969 | } |
73c10101 | 1970 | list_add_tail(&req->queuelist, &plug->list); |
320ae51f | 1971 | blk_account_io_start(req, true); |
73c10101 JA |
1972 | } else { |
1973 | spin_lock_irq(q->queue_lock); | |
1974 | add_acct_request(q, req, where); | |
24ecfbe2 | 1975 | __blk_run_queue(q); |
73c10101 JA |
1976 | out_unlock: |
1977 | spin_unlock_irq(q->queue_lock); | |
1978 | } | |
dece1635 JA |
1979 | |
1980 | return BLK_QC_T_NONE; | |
1da177e4 LT |
1981 | } |
1982 | ||
1da177e4 LT |
1983 | static void handle_bad_sector(struct bio *bio) |
1984 | { | |
1985 | char b[BDEVNAME_SIZE]; | |
1986 | ||
1987 | printk(KERN_INFO "attempt to access beyond end of device\n"); | |
6296b960 | 1988 | printk(KERN_INFO "%s: rw=%d, want=%Lu, limit=%Lu\n", |
74d46992 | 1989 | bio_devname(bio, b), bio->bi_opf, |
f73a1c7d | 1990 | (unsigned long long)bio_end_sector(bio), |
74d46992 | 1991 | (long long)get_capacity(bio->bi_disk)); |
1da177e4 LT |
1992 | } |
1993 | ||
c17bb495 AM |
1994 | #ifdef CONFIG_FAIL_MAKE_REQUEST |
1995 | ||
1996 | static DECLARE_FAULT_ATTR(fail_make_request); | |
1997 | ||
1998 | static int __init setup_fail_make_request(char *str) | |
1999 | { | |
2000 | return setup_fault_attr(&fail_make_request, str); | |
2001 | } | |
2002 | __setup("fail_make_request=", setup_fail_make_request); | |
2003 | ||
b2c9cd37 | 2004 | static bool should_fail_request(struct hd_struct *part, unsigned int bytes) |
c17bb495 | 2005 | { |
b2c9cd37 | 2006 | return part->make_it_fail && should_fail(&fail_make_request, bytes); |
c17bb495 AM |
2007 | } |
2008 | ||
2009 | static int __init fail_make_request_debugfs(void) | |
2010 | { | |
dd48c085 AM |
2011 | struct dentry *dir = fault_create_debugfs_attr("fail_make_request", |
2012 | NULL, &fail_make_request); | |
2013 | ||
21f9fcd8 | 2014 | return PTR_ERR_OR_ZERO(dir); |
c17bb495 AM |
2015 | } |
2016 | ||
2017 | late_initcall(fail_make_request_debugfs); | |
2018 | ||
2019 | #else /* CONFIG_FAIL_MAKE_REQUEST */ | |
2020 | ||
b2c9cd37 AM |
2021 | static inline bool should_fail_request(struct hd_struct *part, |
2022 | unsigned int bytes) | |
c17bb495 | 2023 | { |
b2c9cd37 | 2024 | return false; |
c17bb495 AM |
2025 | } |
2026 | ||
2027 | #endif /* CONFIG_FAIL_MAKE_REQUEST */ | |
2028 | ||
74d46992 CH |
2029 | /* |
2030 | * Remap block n of partition p to block n+start(p) of the disk. | |
2031 | */ | |
2032 | static inline int blk_partition_remap(struct bio *bio) | |
2033 | { | |
2034 | struct hd_struct *p; | |
2035 | int ret = 0; | |
2036 | ||
2037 | /* | |
2038 | * Zone reset does not include bi_size so bio_sectors() is always 0. | |
2039 | * Include a test for the reset op code and perform the remap if needed. | |
2040 | */ | |
2041 | if (!bio->bi_partno || | |
2042 | (!bio_sectors(bio) && bio_op(bio) != REQ_OP_ZONE_RESET)) | |
2043 | return 0; | |
2044 | ||
2045 | rcu_read_lock(); | |
2046 | p = __disk_get_part(bio->bi_disk, bio->bi_partno); | |
2047 | if (likely(p && !should_fail_request(p, bio->bi_iter.bi_size))) { | |
2048 | bio->bi_iter.bi_sector += p->start_sect; | |
2049 | bio->bi_partno = 0; | |
2050 | trace_block_bio_remap(bio->bi_disk->queue, bio, part_devt(p), | |
2051 | bio->bi_iter.bi_sector - p->start_sect); | |
2052 | } else { | |
2053 | printk("%s: fail for partition %d\n", __func__, bio->bi_partno); | |
2054 | ret = -EIO; | |
2055 | } | |
2056 | rcu_read_unlock(); | |
2057 | ||
2058 | return ret; | |
2059 | } | |
2060 | ||
c07e2b41 JA |
2061 | /* |
2062 | * Check whether this bio extends beyond the end of the device. | |
2063 | */ | |
2064 | static inline int bio_check_eod(struct bio *bio, unsigned int nr_sectors) | |
2065 | { | |
2066 | sector_t maxsector; | |
2067 | ||
2068 | if (!nr_sectors) | |
2069 | return 0; | |
2070 | ||
2071 | /* Test device or partition size, when known. */ | |
74d46992 | 2072 | maxsector = get_capacity(bio->bi_disk); |
c07e2b41 | 2073 | if (maxsector) { |
4f024f37 | 2074 | sector_t sector = bio->bi_iter.bi_sector; |
c07e2b41 JA |
2075 | |
2076 | if (maxsector < nr_sectors || maxsector - nr_sectors < sector) { | |
2077 | /* | |
2078 | * This may well happen - the kernel calls bread() | |
2079 | * without checking the size of the device, e.g., when | |
2080 | * mounting a device. | |
2081 | */ | |
2082 | handle_bad_sector(bio); | |
2083 | return 1; | |
2084 | } | |
2085 | } | |
2086 | ||
2087 | return 0; | |
2088 | } | |
2089 | ||
27a84d54 CH |
2090 | static noinline_for_stack bool |
2091 | generic_make_request_checks(struct bio *bio) | |
1da177e4 | 2092 | { |
165125e1 | 2093 | struct request_queue *q; |
5a7bbad2 | 2094 | int nr_sectors = bio_sectors(bio); |
4e4cbee9 | 2095 | blk_status_t status = BLK_STS_IOERR; |
5a7bbad2 | 2096 | char b[BDEVNAME_SIZE]; |
1da177e4 LT |
2097 | |
2098 | might_sleep(); | |
1da177e4 | 2099 | |
c07e2b41 JA |
2100 | if (bio_check_eod(bio, nr_sectors)) |
2101 | goto end_io; | |
1da177e4 | 2102 | |
74d46992 | 2103 | q = bio->bi_disk->queue; |
5a7bbad2 CH |
2104 | if (unlikely(!q)) { |
2105 | printk(KERN_ERR | |
2106 | "generic_make_request: Trying to access " | |
2107 | "nonexistent block-device %s (%Lu)\n", | |
74d46992 | 2108 | bio_devname(bio, b), (long long)bio->bi_iter.bi_sector); |
5a7bbad2 CH |
2109 | goto end_io; |
2110 | } | |
c17bb495 | 2111 | |
03a07c92 GR |
2112 | /* |
2113 | * For a REQ_NOWAIT based request, return -EOPNOTSUPP | |
2114 | * if queue is not a request based queue. | |
2115 | */ | |
2116 | ||
2117 | if ((bio->bi_opf & REQ_NOWAIT) && !queue_is_rq_based(q)) | |
2118 | goto not_supported; | |
2119 | ||
74d46992 | 2120 | if (should_fail_request(&bio->bi_disk->part0, bio->bi_iter.bi_size)) |
5a7bbad2 | 2121 | goto end_io; |
2056a782 | 2122 | |
74d46992 CH |
2123 | if (blk_partition_remap(bio)) |
2124 | goto end_io; | |
2056a782 | 2125 | |
5a7bbad2 CH |
2126 | if (bio_check_eod(bio, nr_sectors)) |
2127 | goto end_io; | |
1e87901e | 2128 | |
5a7bbad2 CH |
2129 | /* |
2130 | * Filter flush bio's early so that make_request based | |
2131 | * drivers without flush support don't have to worry | |
2132 | * about them. | |
2133 | */ | |
f3a8ab7d | 2134 | if (op_is_flush(bio->bi_opf) && |
c888a8f9 | 2135 | !test_bit(QUEUE_FLAG_WC, &q->queue_flags)) { |
1eff9d32 | 2136 | bio->bi_opf &= ~(REQ_PREFLUSH | REQ_FUA); |
5a7bbad2 | 2137 | if (!nr_sectors) { |
4e4cbee9 | 2138 | status = BLK_STS_OK; |
51fd77bd JA |
2139 | goto end_io; |
2140 | } | |
5a7bbad2 | 2141 | } |
5ddfe969 | 2142 | |
288dab8a CH |
2143 | switch (bio_op(bio)) { |
2144 | case REQ_OP_DISCARD: | |
2145 | if (!blk_queue_discard(q)) | |
2146 | goto not_supported; | |
2147 | break; | |
2148 | case REQ_OP_SECURE_ERASE: | |
2149 | if (!blk_queue_secure_erase(q)) | |
2150 | goto not_supported; | |
2151 | break; | |
2152 | case REQ_OP_WRITE_SAME: | |
74d46992 | 2153 | if (!q->limits.max_write_same_sectors) |
288dab8a | 2154 | goto not_supported; |
58886785 | 2155 | break; |
2d253440 ST |
2156 | case REQ_OP_ZONE_REPORT: |
2157 | case REQ_OP_ZONE_RESET: | |
74d46992 | 2158 | if (!blk_queue_is_zoned(q)) |
2d253440 | 2159 | goto not_supported; |
288dab8a | 2160 | break; |
a6f0788e | 2161 | case REQ_OP_WRITE_ZEROES: |
74d46992 | 2162 | if (!q->limits.max_write_zeroes_sectors) |
a6f0788e CK |
2163 | goto not_supported; |
2164 | break; | |
288dab8a CH |
2165 | default: |
2166 | break; | |
5a7bbad2 | 2167 | } |
01edede4 | 2168 | |
7f4b35d1 TH |
2169 | /* |
2170 | * Various block parts want %current->io_context and lazy ioc | |
2171 | * allocation ends up trading a lot of pain for a small amount of | |
2172 | * memory. Just allocate it upfront. This may fail and block | |
2173 | * layer knows how to live with it. | |
2174 | */ | |
2175 | create_io_context(GFP_ATOMIC, q->node); | |
2176 | ||
ae118896 TH |
2177 | if (!blkcg_bio_issue_check(q, bio)) |
2178 | return false; | |
27a84d54 | 2179 | |
fbbaf700 N |
2180 | if (!bio_flagged(bio, BIO_TRACE_COMPLETION)) { |
2181 | trace_block_bio_queue(q, bio); | |
2182 | /* Now that enqueuing has been traced, we need to trace | |
2183 | * completion as well. | |
2184 | */ | |
2185 | bio_set_flag(bio, BIO_TRACE_COMPLETION); | |
2186 | } | |
27a84d54 | 2187 | return true; |
a7384677 | 2188 | |
288dab8a | 2189 | not_supported: |
4e4cbee9 | 2190 | status = BLK_STS_NOTSUPP; |
a7384677 | 2191 | end_io: |
4e4cbee9 | 2192 | bio->bi_status = status; |
4246a0b6 | 2193 | bio_endio(bio); |
27a84d54 | 2194 | return false; |
1da177e4 LT |
2195 | } |
2196 | ||
27a84d54 CH |
2197 | /** |
2198 | * generic_make_request - hand a buffer to its device driver for I/O | |
2199 | * @bio: The bio describing the location in memory and on the device. | |
2200 | * | |
2201 | * generic_make_request() is used to make I/O requests of block | |
2202 | * devices. It is passed a &struct bio, which describes the I/O that needs | |
2203 | * to be done. | |
2204 | * | |
2205 | * generic_make_request() does not return any status. The | |
2206 | * success/failure status of the request, along with notification of | |
2207 | * completion, is delivered asynchronously through the bio->bi_end_io | |
2208 | * function described (one day) else where. | |
2209 | * | |
2210 | * The caller of generic_make_request must make sure that bi_io_vec | |
2211 | * are set to describe the memory buffer, and that bi_dev and bi_sector are | |
2212 | * set to describe the device address, and the | |
2213 | * bi_end_io and optionally bi_private are set to describe how | |
2214 | * completion notification should be signaled. | |
2215 | * | |
2216 | * generic_make_request and the drivers it calls may use bi_next if this | |
2217 | * bio happens to be merged with someone else, and may resubmit the bio to | |
2218 | * a lower device by calling into generic_make_request recursively, which | |
2219 | * means the bio should NOT be touched after the call to ->make_request_fn. | |
d89d8796 | 2220 | */ |
dece1635 | 2221 | blk_qc_t generic_make_request(struct bio *bio) |
d89d8796 | 2222 | { |
f5fe1b51 N |
2223 | /* |
2224 | * bio_list_on_stack[0] contains bios submitted by the current | |
2225 | * make_request_fn. | |
2226 | * bio_list_on_stack[1] contains bios that were submitted before | |
2227 | * the current make_request_fn, but that haven't been processed | |
2228 | * yet. | |
2229 | */ | |
2230 | struct bio_list bio_list_on_stack[2]; | |
dece1635 | 2231 | blk_qc_t ret = BLK_QC_T_NONE; |
bddd87c7 | 2232 | |
27a84d54 | 2233 | if (!generic_make_request_checks(bio)) |
dece1635 | 2234 | goto out; |
27a84d54 CH |
2235 | |
2236 | /* | |
2237 | * We only want one ->make_request_fn to be active at a time, else | |
2238 | * stack usage with stacked devices could be a problem. So use | |
2239 | * current->bio_list to keep a list of requests submited by a | |
2240 | * make_request_fn function. current->bio_list is also used as a | |
2241 | * flag to say if generic_make_request is currently active in this | |
2242 | * task or not. If it is NULL, then no make_request is active. If | |
2243 | * it is non-NULL, then a make_request is active, and new requests | |
2244 | * should be added at the tail | |
2245 | */ | |
bddd87c7 | 2246 | if (current->bio_list) { |
f5fe1b51 | 2247 | bio_list_add(¤t->bio_list[0], bio); |
dece1635 | 2248 | goto out; |
d89d8796 | 2249 | } |
27a84d54 | 2250 | |
d89d8796 NB |
2251 | /* following loop may be a bit non-obvious, and so deserves some |
2252 | * explanation. | |
2253 | * Before entering the loop, bio->bi_next is NULL (as all callers | |
2254 | * ensure that) so we have a list with a single bio. | |
2255 | * We pretend that we have just taken it off a longer list, so | |
bddd87c7 AM |
2256 | * we assign bio_list to a pointer to the bio_list_on_stack, |
2257 | * thus initialising the bio_list of new bios to be | |
27a84d54 | 2258 | * added. ->make_request() may indeed add some more bios |
d89d8796 NB |
2259 | * through a recursive call to generic_make_request. If it |
2260 | * did, we find a non-NULL value in bio_list and re-enter the loop | |
2261 | * from the top. In this case we really did just take the bio | |
bddd87c7 | 2262 | * of the top of the list (no pretending) and so remove it from |
27a84d54 | 2263 | * bio_list, and call into ->make_request() again. |
d89d8796 NB |
2264 | */ |
2265 | BUG_ON(bio->bi_next); | |
f5fe1b51 N |
2266 | bio_list_init(&bio_list_on_stack[0]); |
2267 | current->bio_list = bio_list_on_stack; | |
d89d8796 | 2268 | do { |
74d46992 | 2269 | struct request_queue *q = bio->bi_disk->queue; |
27a84d54 | 2270 | |
03a07c92 | 2271 | if (likely(blk_queue_enter(q, bio->bi_opf & REQ_NOWAIT) == 0)) { |
79bd9959 N |
2272 | struct bio_list lower, same; |
2273 | ||
2274 | /* Create a fresh bio_list for all subordinate requests */ | |
f5fe1b51 N |
2275 | bio_list_on_stack[1] = bio_list_on_stack[0]; |
2276 | bio_list_init(&bio_list_on_stack[0]); | |
dece1635 | 2277 | ret = q->make_request_fn(q, bio); |
3ef28e83 DW |
2278 | |
2279 | blk_queue_exit(q); | |
27a84d54 | 2280 | |
79bd9959 N |
2281 | /* sort new bios into those for a lower level |
2282 | * and those for the same level | |
2283 | */ | |
2284 | bio_list_init(&lower); | |
2285 | bio_list_init(&same); | |
f5fe1b51 | 2286 | while ((bio = bio_list_pop(&bio_list_on_stack[0])) != NULL) |
74d46992 | 2287 | if (q == bio->bi_disk->queue) |
79bd9959 N |
2288 | bio_list_add(&same, bio); |
2289 | else | |
2290 | bio_list_add(&lower, bio); | |
2291 | /* now assemble so we handle the lowest level first */ | |
f5fe1b51 N |
2292 | bio_list_merge(&bio_list_on_stack[0], &lower); |
2293 | bio_list_merge(&bio_list_on_stack[0], &same); | |
2294 | bio_list_merge(&bio_list_on_stack[0], &bio_list_on_stack[1]); | |
3ef28e83 | 2295 | } else { |
03a07c92 GR |
2296 | if (unlikely(!blk_queue_dying(q) && |
2297 | (bio->bi_opf & REQ_NOWAIT))) | |
2298 | bio_wouldblock_error(bio); | |
2299 | else | |
2300 | bio_io_error(bio); | |
3ef28e83 | 2301 | } |
f5fe1b51 | 2302 | bio = bio_list_pop(&bio_list_on_stack[0]); |
d89d8796 | 2303 | } while (bio); |
bddd87c7 | 2304 | current->bio_list = NULL; /* deactivate */ |
dece1635 JA |
2305 | |
2306 | out: | |
2307 | return ret; | |
d89d8796 | 2308 | } |
1da177e4 LT |
2309 | EXPORT_SYMBOL(generic_make_request); |
2310 | ||
f421e1d9 CH |
2311 | /** |
2312 | * direct_make_request - hand a buffer directly to its device driver for I/O | |
2313 | * @bio: The bio describing the location in memory and on the device. | |
2314 | * | |
2315 | * This function behaves like generic_make_request(), but does not protect | |
2316 | * against recursion. Must only be used if the called driver is known | |
2317 | * to not call generic_make_request (or direct_make_request) again from | |
2318 | * its make_request function. (Calling direct_make_request again from | |
2319 | * a workqueue is perfectly fine as that doesn't recurse). | |
2320 | */ | |
2321 | blk_qc_t direct_make_request(struct bio *bio) | |
2322 | { | |
2323 | struct request_queue *q = bio->bi_disk->queue; | |
2324 | bool nowait = bio->bi_opf & REQ_NOWAIT; | |
2325 | blk_qc_t ret; | |
2326 | ||
2327 | if (!generic_make_request_checks(bio)) | |
2328 | return BLK_QC_T_NONE; | |
2329 | ||
2330 | if (unlikely(blk_queue_enter(q, nowait))) { | |
2331 | if (nowait && !blk_queue_dying(q)) | |
2332 | bio->bi_status = BLK_STS_AGAIN; | |
2333 | else | |
2334 | bio->bi_status = BLK_STS_IOERR; | |
2335 | bio_endio(bio); | |
2336 | return BLK_QC_T_NONE; | |
2337 | } | |
2338 | ||
2339 | ret = q->make_request_fn(q, bio); | |
2340 | blk_queue_exit(q); | |
2341 | return ret; | |
2342 | } | |
2343 | EXPORT_SYMBOL_GPL(direct_make_request); | |
2344 | ||
1da177e4 | 2345 | /** |
710027a4 | 2346 | * submit_bio - submit a bio to the block device layer for I/O |
1da177e4 LT |
2347 | * @bio: The &struct bio which describes the I/O |
2348 | * | |
2349 | * submit_bio() is very similar in purpose to generic_make_request(), and | |
2350 | * uses that function to do most of the work. Both are fairly rough | |
710027a4 | 2351 | * interfaces; @bio must be presetup and ready for I/O. |
1da177e4 LT |
2352 | * |
2353 | */ | |
4e49ea4a | 2354 | blk_qc_t submit_bio(struct bio *bio) |
1da177e4 | 2355 | { |
bf2de6f5 JA |
2356 | /* |
2357 | * If it's a regular read/write or a barrier with data attached, | |
2358 | * go through the normal accounting stuff before submission. | |
2359 | */ | |
e2a60da7 | 2360 | if (bio_has_data(bio)) { |
4363ac7c MP |
2361 | unsigned int count; |
2362 | ||
95fe6c1a | 2363 | if (unlikely(bio_op(bio) == REQ_OP_WRITE_SAME)) |
74d46992 | 2364 | count = queue_logical_block_size(bio->bi_disk->queue); |
4363ac7c MP |
2365 | else |
2366 | count = bio_sectors(bio); | |
2367 | ||
a8ebb056 | 2368 | if (op_is_write(bio_op(bio))) { |
bf2de6f5 JA |
2369 | count_vm_events(PGPGOUT, count); |
2370 | } else { | |
4f024f37 | 2371 | task_io_account_read(bio->bi_iter.bi_size); |
bf2de6f5 JA |
2372 | count_vm_events(PGPGIN, count); |
2373 | } | |
2374 | ||
2375 | if (unlikely(block_dump)) { | |
2376 | char b[BDEVNAME_SIZE]; | |
8dcbdc74 | 2377 | printk(KERN_DEBUG "%s(%d): %s block %Lu on %s (%u sectors)\n", |
ba25f9dc | 2378 | current->comm, task_pid_nr(current), |
a8ebb056 | 2379 | op_is_write(bio_op(bio)) ? "WRITE" : "READ", |
4f024f37 | 2380 | (unsigned long long)bio->bi_iter.bi_sector, |
74d46992 | 2381 | bio_devname(bio, b), count); |
bf2de6f5 | 2382 | } |
1da177e4 LT |
2383 | } |
2384 | ||
dece1635 | 2385 | return generic_make_request(bio); |
1da177e4 | 2386 | } |
1da177e4 LT |
2387 | EXPORT_SYMBOL(submit_bio); |
2388 | ||
ea435e1b CH |
2389 | bool blk_poll(struct request_queue *q, blk_qc_t cookie) |
2390 | { | |
2391 | if (!q->poll_fn || !blk_qc_t_valid(cookie)) | |
2392 | return false; | |
2393 | ||
2394 | if (current->plug) | |
2395 | blk_flush_plug_list(current->plug, false); | |
2396 | return q->poll_fn(q, cookie); | |
2397 | } | |
2398 | EXPORT_SYMBOL_GPL(blk_poll); | |
2399 | ||
82124d60 | 2400 | /** |
bf4e6b4e HR |
2401 | * blk_cloned_rq_check_limits - Helper function to check a cloned request |
2402 | * for new the queue limits | |
82124d60 KU |
2403 | * @q: the queue |
2404 | * @rq: the request being checked | |
2405 | * | |
2406 | * Description: | |
2407 | * @rq may have been made based on weaker limitations of upper-level queues | |
2408 | * in request stacking drivers, and it may violate the limitation of @q. | |
2409 | * Since the block layer and the underlying device driver trust @rq | |
2410 | * after it is inserted to @q, it should be checked against @q before | |
2411 | * the insertion using this generic function. | |
2412 | * | |
82124d60 | 2413 | * Request stacking drivers like request-based dm may change the queue |
bf4e6b4e HR |
2414 | * limits when retrying requests on other queues. Those requests need |
2415 | * to be checked against the new queue limits again during dispatch. | |
82124d60 | 2416 | */ |
bf4e6b4e HR |
2417 | static int blk_cloned_rq_check_limits(struct request_queue *q, |
2418 | struct request *rq) | |
82124d60 | 2419 | { |
8fe0d473 | 2420 | if (blk_rq_sectors(rq) > blk_queue_get_max_sectors(q, req_op(rq))) { |
82124d60 KU |
2421 | printk(KERN_ERR "%s: over max size limit.\n", __func__); |
2422 | return -EIO; | |
2423 | } | |
2424 | ||
2425 | /* | |
2426 | * queue's settings related to segment counting like q->bounce_pfn | |
2427 | * may differ from that of other stacking queues. | |
2428 | * Recalculate it to check the request correctly on this queue's | |
2429 | * limitation. | |
2430 | */ | |
2431 | blk_recalc_rq_segments(rq); | |
8a78362c | 2432 | if (rq->nr_phys_segments > queue_max_segments(q)) { |
82124d60 KU |
2433 | printk(KERN_ERR "%s: over max segments limit.\n", __func__); |
2434 | return -EIO; | |
2435 | } | |
2436 | ||
2437 | return 0; | |
2438 | } | |
82124d60 KU |
2439 | |
2440 | /** | |
2441 | * blk_insert_cloned_request - Helper for stacking drivers to submit a request | |
2442 | * @q: the queue to submit the request | |
2443 | * @rq: the request being queued | |
2444 | */ | |
2a842aca | 2445 | blk_status_t blk_insert_cloned_request(struct request_queue *q, struct request *rq) |
82124d60 KU |
2446 | { |
2447 | unsigned long flags; | |
4853abaa | 2448 | int where = ELEVATOR_INSERT_BACK; |
82124d60 | 2449 | |
bf4e6b4e | 2450 | if (blk_cloned_rq_check_limits(q, rq)) |
2a842aca | 2451 | return BLK_STS_IOERR; |
82124d60 | 2452 | |
b2c9cd37 AM |
2453 | if (rq->rq_disk && |
2454 | should_fail_request(&rq->rq_disk->part0, blk_rq_bytes(rq))) | |
2a842aca | 2455 | return BLK_STS_IOERR; |
82124d60 | 2456 | |
7fb4898e KB |
2457 | if (q->mq_ops) { |
2458 | if (blk_queue_io_stat(q)) | |
2459 | blk_account_io_start(rq, true); | |
157f377b JA |
2460 | /* |
2461 | * Since we have a scheduler attached on the top device, | |
2462 | * bypass a potential scheduler on the bottom device for | |
2463 | * insert. | |
2464 | */ | |
b0850297 | 2465 | blk_mq_request_bypass_insert(rq, true); |
2a842aca | 2466 | return BLK_STS_OK; |
7fb4898e KB |
2467 | } |
2468 | ||
82124d60 | 2469 | spin_lock_irqsave(q->queue_lock, flags); |
3f3299d5 | 2470 | if (unlikely(blk_queue_dying(q))) { |
8ba61435 | 2471 | spin_unlock_irqrestore(q->queue_lock, flags); |
2a842aca | 2472 | return BLK_STS_IOERR; |
8ba61435 | 2473 | } |
82124d60 KU |
2474 | |
2475 | /* | |
2476 | * Submitting request must be dequeued before calling this function | |
2477 | * because it will be linked to another request_queue | |
2478 | */ | |
2479 | BUG_ON(blk_queued_rq(rq)); | |
2480 | ||
f73f44eb | 2481 | if (op_is_flush(rq->cmd_flags)) |
4853abaa JM |
2482 | where = ELEVATOR_INSERT_FLUSH; |
2483 | ||
2484 | add_acct_request(q, rq, where); | |
e67b77c7 JM |
2485 | if (where == ELEVATOR_INSERT_FLUSH) |
2486 | __blk_run_queue(q); | |
82124d60 KU |
2487 | spin_unlock_irqrestore(q->queue_lock, flags); |
2488 | ||
2a842aca | 2489 | return BLK_STS_OK; |
82124d60 KU |
2490 | } |
2491 | EXPORT_SYMBOL_GPL(blk_insert_cloned_request); | |
2492 | ||
80a761fd TH |
2493 | /** |
2494 | * blk_rq_err_bytes - determine number of bytes till the next failure boundary | |
2495 | * @rq: request to examine | |
2496 | * | |
2497 | * Description: | |
2498 | * A request could be merge of IOs which require different failure | |
2499 | * handling. This function determines the number of bytes which | |
2500 | * can be failed from the beginning of the request without | |
2501 | * crossing into area which need to be retried further. | |
2502 | * | |
2503 | * Return: | |
2504 | * The number of bytes to fail. | |
80a761fd TH |
2505 | */ |
2506 | unsigned int blk_rq_err_bytes(const struct request *rq) | |
2507 | { | |
2508 | unsigned int ff = rq->cmd_flags & REQ_FAILFAST_MASK; | |
2509 | unsigned int bytes = 0; | |
2510 | struct bio *bio; | |
2511 | ||
e8064021 | 2512 | if (!(rq->rq_flags & RQF_MIXED_MERGE)) |
80a761fd TH |
2513 | return blk_rq_bytes(rq); |
2514 | ||
2515 | /* | |
2516 | * Currently the only 'mixing' which can happen is between | |
2517 | * different fastfail types. We can safely fail portions | |
2518 | * which have all the failfast bits that the first one has - | |
2519 | * the ones which are at least as eager to fail as the first | |
2520 | * one. | |
2521 | */ | |
2522 | for (bio = rq->bio; bio; bio = bio->bi_next) { | |
1eff9d32 | 2523 | if ((bio->bi_opf & ff) != ff) |
80a761fd | 2524 | break; |
4f024f37 | 2525 | bytes += bio->bi_iter.bi_size; |
80a761fd TH |
2526 | } |
2527 | ||
2528 | /* this could lead to infinite loop */ | |
2529 | BUG_ON(blk_rq_bytes(rq) && !bytes); | |
2530 | return bytes; | |
2531 | } | |
2532 | EXPORT_SYMBOL_GPL(blk_rq_err_bytes); | |
2533 | ||
320ae51f | 2534 | void blk_account_io_completion(struct request *req, unsigned int bytes) |
bc58ba94 | 2535 | { |
c2553b58 | 2536 | if (blk_do_io_stat(req)) { |
bc58ba94 JA |
2537 | const int rw = rq_data_dir(req); |
2538 | struct hd_struct *part; | |
2539 | int cpu; | |
2540 | ||
2541 | cpu = part_stat_lock(); | |
09e099d4 | 2542 | part = req->part; |
bc58ba94 JA |
2543 | part_stat_add(cpu, part, sectors[rw], bytes >> 9); |
2544 | part_stat_unlock(); | |
2545 | } | |
2546 | } | |
2547 | ||
320ae51f | 2548 | void blk_account_io_done(struct request *req) |
bc58ba94 | 2549 | { |
bc58ba94 | 2550 | /* |
dd4c133f TH |
2551 | * Account IO completion. flush_rq isn't accounted as a |
2552 | * normal IO on queueing nor completion. Accounting the | |
2553 | * containing request is enough. | |
bc58ba94 | 2554 | */ |
e8064021 | 2555 | if (blk_do_io_stat(req) && !(req->rq_flags & RQF_FLUSH_SEQ)) { |
bc58ba94 JA |
2556 | unsigned long duration = jiffies - req->start_time; |
2557 | const int rw = rq_data_dir(req); | |
2558 | struct hd_struct *part; | |
2559 | int cpu; | |
2560 | ||
2561 | cpu = part_stat_lock(); | |
09e099d4 | 2562 | part = req->part; |
bc58ba94 JA |
2563 | |
2564 | part_stat_inc(cpu, part, ios[rw]); | |
2565 | part_stat_add(cpu, part, ticks[rw], duration); | |
d62e26b3 JA |
2566 | part_round_stats(req->q, cpu, part); |
2567 | part_dec_in_flight(req->q, part, rw); | |
bc58ba94 | 2568 | |
6c23a968 | 2569 | hd_struct_put(part); |
bc58ba94 JA |
2570 | part_stat_unlock(); |
2571 | } | |
2572 | } | |
2573 | ||
47fafbc7 | 2574 | #ifdef CONFIG_PM |
c8158819 LM |
2575 | /* |
2576 | * Don't process normal requests when queue is suspended | |
2577 | * or in the process of suspending/resuming | |
2578 | */ | |
e4f36b24 | 2579 | static bool blk_pm_allow_request(struct request *rq) |
c8158819 | 2580 | { |
e4f36b24 CH |
2581 | switch (rq->q->rpm_status) { |
2582 | case RPM_RESUMING: | |
2583 | case RPM_SUSPENDING: | |
2584 | return rq->rq_flags & RQF_PM; | |
2585 | case RPM_SUSPENDED: | |
2586 | return false; | |
2587 | } | |
2588 | ||
2589 | return true; | |
c8158819 LM |
2590 | } |
2591 | #else | |
e4f36b24 | 2592 | static bool blk_pm_allow_request(struct request *rq) |
c8158819 | 2593 | { |
e4f36b24 | 2594 | return true; |
c8158819 LM |
2595 | } |
2596 | #endif | |
2597 | ||
320ae51f JA |
2598 | void blk_account_io_start(struct request *rq, bool new_io) |
2599 | { | |
2600 | struct hd_struct *part; | |
2601 | int rw = rq_data_dir(rq); | |
2602 | int cpu; | |
2603 | ||
2604 | if (!blk_do_io_stat(rq)) | |
2605 | return; | |
2606 | ||
2607 | cpu = part_stat_lock(); | |
2608 | ||
2609 | if (!new_io) { | |
2610 | part = rq->part; | |
2611 | part_stat_inc(cpu, part, merges[rw]); | |
2612 | } else { | |
2613 | part = disk_map_sector_rcu(rq->rq_disk, blk_rq_pos(rq)); | |
2614 | if (!hd_struct_try_get(part)) { | |
2615 | /* | |
2616 | * The partition is already being removed, | |
2617 | * the request will be accounted on the disk only | |
2618 | * | |
2619 | * We take a reference on disk->part0 although that | |
2620 | * partition will never be deleted, so we can treat | |
2621 | * it as any other partition. | |
2622 | */ | |
2623 | part = &rq->rq_disk->part0; | |
2624 | hd_struct_get(part); | |
2625 | } | |
d62e26b3 JA |
2626 | part_round_stats(rq->q, cpu, part); |
2627 | part_inc_in_flight(rq->q, part, rw); | |
320ae51f JA |
2628 | rq->part = part; |
2629 | } | |
2630 | ||
2631 | part_stat_unlock(); | |
2632 | } | |
2633 | ||
9c988374 CH |
2634 | static struct request *elv_next_request(struct request_queue *q) |
2635 | { | |
2636 | struct request *rq; | |
2637 | struct blk_flush_queue *fq = blk_get_flush_queue(q, NULL); | |
2638 | ||
2639 | WARN_ON_ONCE(q->mq_ops); | |
2640 | ||
2641 | while (1) { | |
e4f36b24 CH |
2642 | list_for_each_entry(rq, &q->queue_head, queuelist) { |
2643 | if (blk_pm_allow_request(rq)) | |
2644 | return rq; | |
2645 | ||
2646 | if (rq->rq_flags & RQF_SOFTBARRIER) | |
2647 | break; | |
9c988374 CH |
2648 | } |
2649 | ||
2650 | /* | |
2651 | * Flush request is running and flush request isn't queueable | |
2652 | * in the drive, we can hold the queue till flush request is | |
2653 | * finished. Even we don't do this, driver can't dispatch next | |
2654 | * requests and will requeue them. And this can improve | |
2655 | * throughput too. For example, we have request flush1, write1, | |
2656 | * flush 2. flush1 is dispatched, then queue is hold, write1 | |
2657 | * isn't inserted to queue. After flush1 is finished, flush2 | |
2658 | * will be dispatched. Since disk cache is already clean, | |
2659 | * flush2 will be finished very soon, so looks like flush2 is | |
2660 | * folded to flush1. | |
2661 | * Since the queue is hold, a flag is set to indicate the queue | |
2662 | * should be restarted later. Please see flush_end_io() for | |
2663 | * details. | |
2664 | */ | |
2665 | if (fq->flush_pending_idx != fq->flush_running_idx && | |
2666 | !queue_flush_queueable(q)) { | |
2667 | fq->flush_queue_delayed = 1; | |
2668 | return NULL; | |
2669 | } | |
2670 | if (unlikely(blk_queue_bypass(q)) || | |
2671 | !q->elevator->type->ops.sq.elevator_dispatch_fn(q, 0)) | |
2672 | return NULL; | |
2673 | } | |
2674 | } | |
2675 | ||
3bcddeac | 2676 | /** |
9934c8c0 TH |
2677 | * blk_peek_request - peek at the top of a request queue |
2678 | * @q: request queue to peek at | |
2679 | * | |
2680 | * Description: | |
2681 | * Return the request at the top of @q. The returned request | |
2682 | * should be started using blk_start_request() before LLD starts | |
2683 | * processing it. | |
2684 | * | |
2685 | * Return: | |
2686 | * Pointer to the request at the top of @q if available. Null | |
2687 | * otherwise. | |
9934c8c0 TH |
2688 | */ |
2689 | struct request *blk_peek_request(struct request_queue *q) | |
158dbda0 TH |
2690 | { |
2691 | struct request *rq; | |
2692 | int ret; | |
2693 | ||
2fff8a92 | 2694 | lockdep_assert_held(q->queue_lock); |
332ebbf7 | 2695 | WARN_ON_ONCE(q->mq_ops); |
2fff8a92 | 2696 | |
9c988374 | 2697 | while ((rq = elv_next_request(q)) != NULL) { |
e8064021 | 2698 | if (!(rq->rq_flags & RQF_STARTED)) { |
158dbda0 TH |
2699 | /* |
2700 | * This is the first time the device driver | |
2701 | * sees this request (possibly after | |
2702 | * requeueing). Notify IO scheduler. | |
2703 | */ | |
e8064021 | 2704 | if (rq->rq_flags & RQF_SORTED) |
158dbda0 TH |
2705 | elv_activate_rq(q, rq); |
2706 | ||
2707 | /* | |
2708 | * just mark as started even if we don't start | |
2709 | * it, a request that has been delayed should | |
2710 | * not be passed by new incoming requests | |
2711 | */ | |
e8064021 | 2712 | rq->rq_flags |= RQF_STARTED; |
158dbda0 TH |
2713 | trace_block_rq_issue(q, rq); |
2714 | } | |
2715 | ||
2716 | if (!q->boundary_rq || q->boundary_rq == rq) { | |
2717 | q->end_sector = rq_end_sector(rq); | |
2718 | q->boundary_rq = NULL; | |
2719 | } | |
2720 | ||
e8064021 | 2721 | if (rq->rq_flags & RQF_DONTPREP) |
158dbda0 TH |
2722 | break; |
2723 | ||
2e46e8b2 | 2724 | if (q->dma_drain_size && blk_rq_bytes(rq)) { |
158dbda0 TH |
2725 | /* |
2726 | * make sure space for the drain appears we | |
2727 | * know we can do this because max_hw_segments | |
2728 | * has been adjusted to be one fewer than the | |
2729 | * device can handle | |
2730 | */ | |
2731 | rq->nr_phys_segments++; | |
2732 | } | |
2733 | ||
2734 | if (!q->prep_rq_fn) | |
2735 | break; | |
2736 | ||
2737 | ret = q->prep_rq_fn(q, rq); | |
2738 | if (ret == BLKPREP_OK) { | |
2739 | break; | |
2740 | } else if (ret == BLKPREP_DEFER) { | |
2741 | /* | |
2742 | * the request may have been (partially) prepped. | |
2743 | * we need to keep this request in the front to | |
e8064021 | 2744 | * avoid resource deadlock. RQF_STARTED will |
158dbda0 TH |
2745 | * prevent other fs requests from passing this one. |
2746 | */ | |
2e46e8b2 | 2747 | if (q->dma_drain_size && blk_rq_bytes(rq) && |
e8064021 | 2748 | !(rq->rq_flags & RQF_DONTPREP)) { |
158dbda0 TH |
2749 | /* |
2750 | * remove the space for the drain we added | |
2751 | * so that we don't add it again | |
2752 | */ | |
2753 | --rq->nr_phys_segments; | |
2754 | } | |
2755 | ||
2756 | rq = NULL; | |
2757 | break; | |
0fb5b1fb | 2758 | } else if (ret == BLKPREP_KILL || ret == BLKPREP_INVALID) { |
e8064021 | 2759 | rq->rq_flags |= RQF_QUIET; |
c143dc90 JB |
2760 | /* |
2761 | * Mark this request as started so we don't trigger | |
2762 | * any debug logic in the end I/O path. | |
2763 | */ | |
2764 | blk_start_request(rq); | |
2a842aca CH |
2765 | __blk_end_request_all(rq, ret == BLKPREP_INVALID ? |
2766 | BLK_STS_TARGET : BLK_STS_IOERR); | |
158dbda0 TH |
2767 | } else { |
2768 | printk(KERN_ERR "%s: bad return=%d\n", __func__, ret); | |
2769 | break; | |
2770 | } | |
2771 | } | |
2772 | ||
2773 | return rq; | |
2774 | } | |
9934c8c0 | 2775 | EXPORT_SYMBOL(blk_peek_request); |
158dbda0 | 2776 | |
5034435c | 2777 | static void blk_dequeue_request(struct request *rq) |
158dbda0 | 2778 | { |
9934c8c0 TH |
2779 | struct request_queue *q = rq->q; |
2780 | ||
158dbda0 TH |
2781 | BUG_ON(list_empty(&rq->queuelist)); |
2782 | BUG_ON(ELV_ON_HASH(rq)); | |
2783 | ||
2784 | list_del_init(&rq->queuelist); | |
2785 | ||
2786 | /* | |
2787 | * the time frame between a request being removed from the lists | |
2788 | * and to it is freed is accounted as io that is in progress at | |
2789 | * the driver side. | |
2790 | */ | |
9195291e | 2791 | if (blk_account_rq(rq)) { |
0a7ae2ff | 2792 | q->in_flight[rq_is_sync(rq)]++; |
9195291e DS |
2793 | set_io_start_time_ns(rq); |
2794 | } | |
158dbda0 TH |
2795 | } |
2796 | ||
9934c8c0 TH |
2797 | /** |
2798 | * blk_start_request - start request processing on the driver | |
2799 | * @req: request to dequeue | |
2800 | * | |
2801 | * Description: | |
2802 | * Dequeue @req and start timeout timer on it. This hands off the | |
2803 | * request to the driver. | |
9934c8c0 TH |
2804 | */ |
2805 | void blk_start_request(struct request *req) | |
2806 | { | |
2fff8a92 | 2807 | lockdep_assert_held(req->q->queue_lock); |
332ebbf7 | 2808 | WARN_ON_ONCE(req->q->mq_ops); |
2fff8a92 | 2809 | |
9934c8c0 TH |
2810 | blk_dequeue_request(req); |
2811 | ||
cf43e6be | 2812 | if (test_bit(QUEUE_FLAG_STATS, &req->q->queue_flags)) { |
88eeca49 | 2813 | blk_stat_set_issue(&req->issue_stat, blk_rq_sectors(req)); |
cf43e6be | 2814 | req->rq_flags |= RQF_STATS; |
87760e5e | 2815 | wbt_issue(req->q->rq_wb, &req->issue_stat); |
cf43e6be JA |
2816 | } |
2817 | ||
4912aa6c | 2818 | BUG_ON(test_bit(REQ_ATOM_COMPLETE, &req->atomic_flags)); |
9934c8c0 TH |
2819 | blk_add_timer(req); |
2820 | } | |
2821 | EXPORT_SYMBOL(blk_start_request); | |
2822 | ||
2823 | /** | |
2824 | * blk_fetch_request - fetch a request from a request queue | |
2825 | * @q: request queue to fetch a request from | |
2826 | * | |
2827 | * Description: | |
2828 | * Return the request at the top of @q. The request is started on | |
2829 | * return and LLD can start processing it immediately. | |
2830 | * | |
2831 | * Return: | |
2832 | * Pointer to the request at the top of @q if available. Null | |
2833 | * otherwise. | |
9934c8c0 TH |
2834 | */ |
2835 | struct request *blk_fetch_request(struct request_queue *q) | |
2836 | { | |
2837 | struct request *rq; | |
2838 | ||
2fff8a92 | 2839 | lockdep_assert_held(q->queue_lock); |
332ebbf7 | 2840 | WARN_ON_ONCE(q->mq_ops); |
2fff8a92 | 2841 | |
9934c8c0 TH |
2842 | rq = blk_peek_request(q); |
2843 | if (rq) | |
2844 | blk_start_request(rq); | |
2845 | return rq; | |
2846 | } | |
2847 | EXPORT_SYMBOL(blk_fetch_request); | |
2848 | ||
ef71de8b CH |
2849 | /* |
2850 | * Steal bios from a request and add them to a bio list. | |
2851 | * The request must not have been partially completed before. | |
2852 | */ | |
2853 | void blk_steal_bios(struct bio_list *list, struct request *rq) | |
2854 | { | |
2855 | if (rq->bio) { | |
2856 | if (list->tail) | |
2857 | list->tail->bi_next = rq->bio; | |
2858 | else | |
2859 | list->head = rq->bio; | |
2860 | list->tail = rq->biotail; | |
2861 | ||
2862 | rq->bio = NULL; | |
2863 | rq->biotail = NULL; | |
2864 | } | |
2865 | ||
2866 | rq->__data_len = 0; | |
2867 | } | |
2868 | EXPORT_SYMBOL_GPL(blk_steal_bios); | |
2869 | ||
3bcddeac | 2870 | /** |
2e60e022 | 2871 | * blk_update_request - Special helper function for request stacking drivers |
8ebf9756 | 2872 | * @req: the request being processed |
2a842aca | 2873 | * @error: block status code |
8ebf9756 | 2874 | * @nr_bytes: number of bytes to complete @req |
3bcddeac KU |
2875 | * |
2876 | * Description: | |
8ebf9756 RD |
2877 | * Ends I/O on a number of bytes attached to @req, but doesn't complete |
2878 | * the request structure even if @req doesn't have leftover. | |
2879 | * If @req has leftover, sets it up for the next range of segments. | |
2e60e022 TH |
2880 | * |
2881 | * This special helper function is only for request stacking drivers | |
2882 | * (e.g. request-based dm) so that they can handle partial completion. | |
2883 | * Actual device drivers should use blk_end_request instead. | |
2884 | * | |
2885 | * Passing the result of blk_rq_bytes() as @nr_bytes guarantees | |
2886 | * %false return from this function. | |
3bcddeac KU |
2887 | * |
2888 | * Return: | |
2e60e022 TH |
2889 | * %false - this request doesn't have any more data |
2890 | * %true - this request has more data | |
3bcddeac | 2891 | **/ |
2a842aca CH |
2892 | bool blk_update_request(struct request *req, blk_status_t error, |
2893 | unsigned int nr_bytes) | |
1da177e4 | 2894 | { |
f79ea416 | 2895 | int total_bytes; |
1da177e4 | 2896 | |
2a842aca | 2897 | trace_block_rq_complete(req, blk_status_to_errno(error), nr_bytes); |
4a0efdc9 | 2898 | |
2e60e022 TH |
2899 | if (!req->bio) |
2900 | return false; | |
2901 | ||
2a842aca CH |
2902 | if (unlikely(error && !blk_rq_is_passthrough(req) && |
2903 | !(req->rq_flags & RQF_QUIET))) | |
2904 | print_req_error(req, error); | |
1da177e4 | 2905 | |
bc58ba94 | 2906 | blk_account_io_completion(req, nr_bytes); |
d72d904a | 2907 | |
f79ea416 KO |
2908 | total_bytes = 0; |
2909 | while (req->bio) { | |
2910 | struct bio *bio = req->bio; | |
4f024f37 | 2911 | unsigned bio_bytes = min(bio->bi_iter.bi_size, nr_bytes); |
1da177e4 | 2912 | |
4f024f37 | 2913 | if (bio_bytes == bio->bi_iter.bi_size) |
1da177e4 | 2914 | req->bio = bio->bi_next; |
1da177e4 | 2915 | |
fbbaf700 N |
2916 | /* Completion has already been traced */ |
2917 | bio_clear_flag(bio, BIO_TRACE_COMPLETION); | |
f79ea416 | 2918 | req_bio_endio(req, bio, bio_bytes, error); |
1da177e4 | 2919 | |
f79ea416 KO |
2920 | total_bytes += bio_bytes; |
2921 | nr_bytes -= bio_bytes; | |
1da177e4 | 2922 | |
f79ea416 KO |
2923 | if (!nr_bytes) |
2924 | break; | |
1da177e4 LT |
2925 | } |
2926 | ||
2927 | /* | |
2928 | * completely done | |
2929 | */ | |
2e60e022 TH |
2930 | if (!req->bio) { |
2931 | /* | |
2932 | * Reset counters so that the request stacking driver | |
2933 | * can find how many bytes remain in the request | |
2934 | * later. | |
2935 | */ | |
a2dec7b3 | 2936 | req->__data_len = 0; |
2e60e022 TH |
2937 | return false; |
2938 | } | |
1da177e4 | 2939 | |
a2dec7b3 | 2940 | req->__data_len -= total_bytes; |
2e46e8b2 TH |
2941 | |
2942 | /* update sector only for requests with clear definition of sector */ | |
57292b58 | 2943 | if (!blk_rq_is_passthrough(req)) |
a2dec7b3 | 2944 | req->__sector += total_bytes >> 9; |
2e46e8b2 | 2945 | |
80a761fd | 2946 | /* mixed attributes always follow the first bio */ |
e8064021 | 2947 | if (req->rq_flags & RQF_MIXED_MERGE) { |
80a761fd | 2948 | req->cmd_flags &= ~REQ_FAILFAST_MASK; |
1eff9d32 | 2949 | req->cmd_flags |= req->bio->bi_opf & REQ_FAILFAST_MASK; |
80a761fd TH |
2950 | } |
2951 | ||
ed6565e7 CH |
2952 | if (!(req->rq_flags & RQF_SPECIAL_PAYLOAD)) { |
2953 | /* | |
2954 | * If total number of sectors is less than the first segment | |
2955 | * size, something has gone terribly wrong. | |
2956 | */ | |
2957 | if (blk_rq_bytes(req) < blk_rq_cur_bytes(req)) { | |
2958 | blk_dump_rq_flags(req, "request botched"); | |
2959 | req->__data_len = blk_rq_cur_bytes(req); | |
2960 | } | |
2e46e8b2 | 2961 | |
ed6565e7 CH |
2962 | /* recalculate the number of segments */ |
2963 | blk_recalc_rq_segments(req); | |
2964 | } | |
2e46e8b2 | 2965 | |
2e60e022 | 2966 | return true; |
1da177e4 | 2967 | } |
2e60e022 | 2968 | EXPORT_SYMBOL_GPL(blk_update_request); |
1da177e4 | 2969 | |
2a842aca | 2970 | static bool blk_update_bidi_request(struct request *rq, blk_status_t error, |
2e60e022 TH |
2971 | unsigned int nr_bytes, |
2972 | unsigned int bidi_bytes) | |
5efccd17 | 2973 | { |
2e60e022 TH |
2974 | if (blk_update_request(rq, error, nr_bytes)) |
2975 | return true; | |
5efccd17 | 2976 | |
2e60e022 TH |
2977 | /* Bidi request must be completed as a whole */ |
2978 | if (unlikely(blk_bidi_rq(rq)) && | |
2979 | blk_update_request(rq->next_rq, error, bidi_bytes)) | |
2980 | return true; | |
5efccd17 | 2981 | |
e2e1a148 JA |
2982 | if (blk_queue_add_random(rq->q)) |
2983 | add_disk_randomness(rq->rq_disk); | |
2e60e022 TH |
2984 | |
2985 | return false; | |
1da177e4 LT |
2986 | } |
2987 | ||
28018c24 JB |
2988 | /** |
2989 | * blk_unprep_request - unprepare a request | |
2990 | * @req: the request | |
2991 | * | |
2992 | * This function makes a request ready for complete resubmission (or | |
2993 | * completion). It happens only after all error handling is complete, | |
2994 | * so represents the appropriate moment to deallocate any resources | |
2995 | * that were allocated to the request in the prep_rq_fn. The queue | |
2996 | * lock is held when calling this. | |
2997 | */ | |
2998 | void blk_unprep_request(struct request *req) | |
2999 | { | |
3000 | struct request_queue *q = req->q; | |
3001 | ||
e8064021 | 3002 | req->rq_flags &= ~RQF_DONTPREP; |
28018c24 JB |
3003 | if (q->unprep_rq_fn) |
3004 | q->unprep_rq_fn(q, req); | |
3005 | } | |
3006 | EXPORT_SYMBOL_GPL(blk_unprep_request); | |
3007 | ||
2a842aca | 3008 | void blk_finish_request(struct request *req, blk_status_t error) |
1da177e4 | 3009 | { |
cf43e6be JA |
3010 | struct request_queue *q = req->q; |
3011 | ||
2fff8a92 | 3012 | lockdep_assert_held(req->q->queue_lock); |
332ebbf7 | 3013 | WARN_ON_ONCE(q->mq_ops); |
2fff8a92 | 3014 | |
cf43e6be | 3015 | if (req->rq_flags & RQF_STATS) |
34dbad5d | 3016 | blk_stat_add(req); |
cf43e6be | 3017 | |
e8064021 | 3018 | if (req->rq_flags & RQF_QUEUED) |
cf43e6be | 3019 | blk_queue_end_tag(q, req); |
b8286239 | 3020 | |
ba396a6c | 3021 | BUG_ON(blk_queued_rq(req)); |
1da177e4 | 3022 | |
57292b58 | 3023 | if (unlikely(laptop_mode) && !blk_rq_is_passthrough(req)) |
dc3b17cc | 3024 | laptop_io_completion(req->q->backing_dev_info); |
1da177e4 | 3025 | |
e78042e5 MA |
3026 | blk_delete_timer(req); |
3027 | ||
e8064021 | 3028 | if (req->rq_flags & RQF_DONTPREP) |
28018c24 JB |
3029 | blk_unprep_request(req); |
3030 | ||
bc58ba94 | 3031 | blk_account_io_done(req); |
b8286239 | 3032 | |
87760e5e JA |
3033 | if (req->end_io) { |
3034 | wbt_done(req->q->rq_wb, &req->issue_stat); | |
8ffdc655 | 3035 | req->end_io(req, error); |
87760e5e | 3036 | } else { |
b8286239 KU |
3037 | if (blk_bidi_rq(req)) |
3038 | __blk_put_request(req->next_rq->q, req->next_rq); | |
3039 | ||
cf43e6be | 3040 | __blk_put_request(q, req); |
b8286239 | 3041 | } |
1da177e4 | 3042 | } |
12120077 | 3043 | EXPORT_SYMBOL(blk_finish_request); |
1da177e4 | 3044 | |
3b11313a | 3045 | /** |
2e60e022 TH |
3046 | * blk_end_bidi_request - Complete a bidi request |
3047 | * @rq: the request to complete | |
2a842aca | 3048 | * @error: block status code |
2e60e022 TH |
3049 | * @nr_bytes: number of bytes to complete @rq |
3050 | * @bidi_bytes: number of bytes to complete @rq->next_rq | |
a0cd1285 JA |
3051 | * |
3052 | * Description: | |
e3a04fe3 | 3053 | * Ends I/O on a number of bytes attached to @rq and @rq->next_rq. |
2e60e022 TH |
3054 | * Drivers that supports bidi can safely call this member for any |
3055 | * type of request, bidi or uni. In the later case @bidi_bytes is | |
3056 | * just ignored. | |
336cdb40 KU |
3057 | * |
3058 | * Return: | |
2e60e022 TH |
3059 | * %false - we are done with this request |
3060 | * %true - still buffers pending for this request | |
a0cd1285 | 3061 | **/ |
2a842aca | 3062 | static bool blk_end_bidi_request(struct request *rq, blk_status_t error, |
32fab448 KU |
3063 | unsigned int nr_bytes, unsigned int bidi_bytes) |
3064 | { | |
336cdb40 | 3065 | struct request_queue *q = rq->q; |
2e60e022 | 3066 | unsigned long flags; |
32fab448 | 3067 | |
332ebbf7 BVA |
3068 | WARN_ON_ONCE(q->mq_ops); |
3069 | ||
2e60e022 TH |
3070 | if (blk_update_bidi_request(rq, error, nr_bytes, bidi_bytes)) |
3071 | return true; | |
32fab448 | 3072 | |
336cdb40 | 3073 | spin_lock_irqsave(q->queue_lock, flags); |
2e60e022 | 3074 | blk_finish_request(rq, error); |
336cdb40 KU |
3075 | spin_unlock_irqrestore(q->queue_lock, flags); |
3076 | ||
2e60e022 | 3077 | return false; |
32fab448 KU |
3078 | } |
3079 | ||
336cdb40 | 3080 | /** |
2e60e022 TH |
3081 | * __blk_end_bidi_request - Complete a bidi request with queue lock held |
3082 | * @rq: the request to complete | |
2a842aca | 3083 | * @error: block status code |
e3a04fe3 KU |
3084 | * @nr_bytes: number of bytes to complete @rq |
3085 | * @bidi_bytes: number of bytes to complete @rq->next_rq | |
336cdb40 KU |
3086 | * |
3087 | * Description: | |
2e60e022 TH |
3088 | * Identical to blk_end_bidi_request() except that queue lock is |
3089 | * assumed to be locked on entry and remains so on return. | |
336cdb40 KU |
3090 | * |
3091 | * Return: | |
2e60e022 TH |
3092 | * %false - we are done with this request |
3093 | * %true - still buffers pending for this request | |
336cdb40 | 3094 | **/ |
2a842aca | 3095 | static bool __blk_end_bidi_request(struct request *rq, blk_status_t error, |
b1f74493 | 3096 | unsigned int nr_bytes, unsigned int bidi_bytes) |
336cdb40 | 3097 | { |
2fff8a92 | 3098 | lockdep_assert_held(rq->q->queue_lock); |
332ebbf7 | 3099 | WARN_ON_ONCE(rq->q->mq_ops); |
2fff8a92 | 3100 | |
2e60e022 TH |
3101 | if (blk_update_bidi_request(rq, error, nr_bytes, bidi_bytes)) |
3102 | return true; | |
336cdb40 | 3103 | |
2e60e022 | 3104 | blk_finish_request(rq, error); |
336cdb40 | 3105 | |
2e60e022 | 3106 | return false; |
336cdb40 | 3107 | } |
e19a3ab0 KU |
3108 | |
3109 | /** | |
3110 | * blk_end_request - Helper function for drivers to complete the request. | |
3111 | * @rq: the request being processed | |
2a842aca | 3112 | * @error: block status code |
e19a3ab0 KU |
3113 | * @nr_bytes: number of bytes to complete |
3114 | * | |
3115 | * Description: | |
3116 | * Ends I/O on a number of bytes attached to @rq. | |
3117 | * If @rq has leftover, sets it up for the next range of segments. | |
3118 | * | |
3119 | * Return: | |
b1f74493 FT |
3120 | * %false - we are done with this request |
3121 | * %true - still buffers pending for this request | |
e19a3ab0 | 3122 | **/ |
2a842aca CH |
3123 | bool blk_end_request(struct request *rq, blk_status_t error, |
3124 | unsigned int nr_bytes) | |
e19a3ab0 | 3125 | { |
332ebbf7 | 3126 | WARN_ON_ONCE(rq->q->mq_ops); |
b1f74493 | 3127 | return blk_end_bidi_request(rq, error, nr_bytes, 0); |
e19a3ab0 | 3128 | } |
56ad1740 | 3129 | EXPORT_SYMBOL(blk_end_request); |
336cdb40 KU |
3130 | |
3131 | /** | |
b1f74493 FT |
3132 | * blk_end_request_all - Helper function for drives to finish the request. |
3133 | * @rq: the request to finish | |
2a842aca | 3134 | * @error: block status code |
336cdb40 KU |
3135 | * |
3136 | * Description: | |
b1f74493 FT |
3137 | * Completely finish @rq. |
3138 | */ | |
2a842aca | 3139 | void blk_end_request_all(struct request *rq, blk_status_t error) |
336cdb40 | 3140 | { |
b1f74493 FT |
3141 | bool pending; |
3142 | unsigned int bidi_bytes = 0; | |
336cdb40 | 3143 | |
b1f74493 FT |
3144 | if (unlikely(blk_bidi_rq(rq))) |
3145 | bidi_bytes = blk_rq_bytes(rq->next_rq); | |
336cdb40 | 3146 | |
b1f74493 FT |
3147 | pending = blk_end_bidi_request(rq, error, blk_rq_bytes(rq), bidi_bytes); |
3148 | BUG_ON(pending); | |
3149 | } | |
56ad1740 | 3150 | EXPORT_SYMBOL(blk_end_request_all); |
336cdb40 | 3151 | |
e3a04fe3 | 3152 | /** |
b1f74493 FT |
3153 | * __blk_end_request - Helper function for drivers to complete the request. |
3154 | * @rq: the request being processed | |
2a842aca | 3155 | * @error: block status code |
b1f74493 | 3156 | * @nr_bytes: number of bytes to complete |
e3a04fe3 KU |
3157 | * |
3158 | * Description: | |
b1f74493 | 3159 | * Must be called with queue lock held unlike blk_end_request(). |
e3a04fe3 KU |
3160 | * |
3161 | * Return: | |
b1f74493 FT |
3162 | * %false - we are done with this request |
3163 | * %true - still buffers pending for this request | |
e3a04fe3 | 3164 | **/ |
2a842aca CH |
3165 | bool __blk_end_request(struct request *rq, blk_status_t error, |
3166 | unsigned int nr_bytes) | |
e3a04fe3 | 3167 | { |
2fff8a92 | 3168 | lockdep_assert_held(rq->q->queue_lock); |
332ebbf7 | 3169 | WARN_ON_ONCE(rq->q->mq_ops); |
2fff8a92 | 3170 | |
b1f74493 | 3171 | return __blk_end_bidi_request(rq, error, nr_bytes, 0); |
e3a04fe3 | 3172 | } |
56ad1740 | 3173 | EXPORT_SYMBOL(__blk_end_request); |
e3a04fe3 | 3174 | |
32fab448 | 3175 | /** |
b1f74493 FT |
3176 | * __blk_end_request_all - Helper function for drives to finish the request. |
3177 | * @rq: the request to finish | |
2a842aca | 3178 | * @error: block status code |
32fab448 KU |
3179 | * |
3180 | * Description: | |
b1f74493 | 3181 | * Completely finish @rq. Must be called with queue lock held. |
32fab448 | 3182 | */ |
2a842aca | 3183 | void __blk_end_request_all(struct request *rq, blk_status_t error) |
32fab448 | 3184 | { |
b1f74493 FT |
3185 | bool pending; |
3186 | unsigned int bidi_bytes = 0; | |
3187 | ||
2fff8a92 | 3188 | lockdep_assert_held(rq->q->queue_lock); |
332ebbf7 | 3189 | WARN_ON_ONCE(rq->q->mq_ops); |
2fff8a92 | 3190 | |
b1f74493 FT |
3191 | if (unlikely(blk_bidi_rq(rq))) |
3192 | bidi_bytes = blk_rq_bytes(rq->next_rq); | |
3193 | ||
3194 | pending = __blk_end_bidi_request(rq, error, blk_rq_bytes(rq), bidi_bytes); | |
3195 | BUG_ON(pending); | |
32fab448 | 3196 | } |
56ad1740 | 3197 | EXPORT_SYMBOL(__blk_end_request_all); |
32fab448 | 3198 | |
e19a3ab0 | 3199 | /** |
b1f74493 FT |
3200 | * __blk_end_request_cur - Helper function to finish the current request chunk. |
3201 | * @rq: the request to finish the current chunk for | |
2a842aca | 3202 | * @error: block status code |
e19a3ab0 KU |
3203 | * |
3204 | * Description: | |
b1f74493 FT |
3205 | * Complete the current consecutively mapped chunk from @rq. Must |
3206 | * be called with queue lock held. | |
e19a3ab0 KU |
3207 | * |
3208 | * Return: | |
b1f74493 FT |
3209 | * %false - we are done with this request |
3210 | * %true - still buffers pending for this request | |
3211 | */ | |
2a842aca | 3212 | bool __blk_end_request_cur(struct request *rq, blk_status_t error) |
e19a3ab0 | 3213 | { |
b1f74493 | 3214 | return __blk_end_request(rq, error, blk_rq_cur_bytes(rq)); |
e19a3ab0 | 3215 | } |
56ad1740 | 3216 | EXPORT_SYMBOL(__blk_end_request_cur); |
e19a3ab0 | 3217 | |
86db1e29 JA |
3218 | void blk_rq_bio_prep(struct request_queue *q, struct request *rq, |
3219 | struct bio *bio) | |
1da177e4 | 3220 | { |
b4f42e28 | 3221 | if (bio_has_data(bio)) |
fb2dce86 | 3222 | rq->nr_phys_segments = bio_phys_segments(q, bio); |
b4f42e28 | 3223 | |
4f024f37 | 3224 | rq->__data_len = bio->bi_iter.bi_size; |
1da177e4 | 3225 | rq->bio = rq->biotail = bio; |
1da177e4 | 3226 | |
74d46992 CH |
3227 | if (bio->bi_disk) |
3228 | rq->rq_disk = bio->bi_disk; | |
66846572 | 3229 | } |
1da177e4 | 3230 | |
2d4dc890 IL |
3231 | #if ARCH_IMPLEMENTS_FLUSH_DCACHE_PAGE |
3232 | /** | |
3233 | * rq_flush_dcache_pages - Helper function to flush all pages in a request | |
3234 | * @rq: the request to be flushed | |
3235 | * | |
3236 | * Description: | |
3237 | * Flush all pages in @rq. | |
3238 | */ | |
3239 | void rq_flush_dcache_pages(struct request *rq) | |
3240 | { | |
3241 | struct req_iterator iter; | |
7988613b | 3242 | struct bio_vec bvec; |
2d4dc890 IL |
3243 | |
3244 | rq_for_each_segment(bvec, rq, iter) | |
7988613b | 3245 | flush_dcache_page(bvec.bv_page); |
2d4dc890 IL |
3246 | } |
3247 | EXPORT_SYMBOL_GPL(rq_flush_dcache_pages); | |
3248 | #endif | |
3249 | ||
ef9e3fac KU |
3250 | /** |
3251 | * blk_lld_busy - Check if underlying low-level drivers of a device are busy | |
3252 | * @q : the queue of the device being checked | |
3253 | * | |
3254 | * Description: | |
3255 | * Check if underlying low-level drivers of a device are busy. | |
3256 | * If the drivers want to export their busy state, they must set own | |
3257 | * exporting function using blk_queue_lld_busy() first. | |
3258 | * | |
3259 | * Basically, this function is used only by request stacking drivers | |
3260 | * to stop dispatching requests to underlying devices when underlying | |
3261 | * devices are busy. This behavior helps more I/O merging on the queue | |
3262 | * of the request stacking driver and prevents I/O throughput regression | |
3263 | * on burst I/O load. | |
3264 | * | |
3265 | * Return: | |
3266 | * 0 - Not busy (The request stacking driver should dispatch request) | |
3267 | * 1 - Busy (The request stacking driver should stop dispatching request) | |
3268 | */ | |
3269 | int blk_lld_busy(struct request_queue *q) | |
3270 | { | |
3271 | if (q->lld_busy_fn) | |
3272 | return q->lld_busy_fn(q); | |
3273 | ||
3274 | return 0; | |
3275 | } | |
3276 | EXPORT_SYMBOL_GPL(blk_lld_busy); | |
3277 | ||
78d8e58a MS |
3278 | /** |
3279 | * blk_rq_unprep_clone - Helper function to free all bios in a cloned request | |
3280 | * @rq: the clone request to be cleaned up | |
3281 | * | |
3282 | * Description: | |
3283 | * Free all bios in @rq for a cloned request. | |
3284 | */ | |
3285 | void blk_rq_unprep_clone(struct request *rq) | |
3286 | { | |
3287 | struct bio *bio; | |
3288 | ||
3289 | while ((bio = rq->bio) != NULL) { | |
3290 | rq->bio = bio->bi_next; | |
3291 | ||
3292 | bio_put(bio); | |
3293 | } | |
3294 | } | |
3295 | EXPORT_SYMBOL_GPL(blk_rq_unprep_clone); | |
3296 | ||
3297 | /* | |
3298 | * Copy attributes of the original request to the clone request. | |
3299 | * The actual data parts (e.g. ->cmd, ->sense) are not copied. | |
3300 | */ | |
3301 | static void __blk_rq_prep_clone(struct request *dst, struct request *src) | |
b0fd271d KU |
3302 | { |
3303 | dst->cpu = src->cpu; | |
b0fd271d KU |
3304 | dst->__sector = blk_rq_pos(src); |
3305 | dst->__data_len = blk_rq_bytes(src); | |
3306 | dst->nr_phys_segments = src->nr_phys_segments; | |
3307 | dst->ioprio = src->ioprio; | |
3308 | dst->extra_len = src->extra_len; | |
78d8e58a MS |
3309 | } |
3310 | ||
3311 | /** | |
3312 | * blk_rq_prep_clone - Helper function to setup clone request | |
3313 | * @rq: the request to be setup | |
3314 | * @rq_src: original request to be cloned | |
3315 | * @bs: bio_set that bios for clone are allocated from | |
3316 | * @gfp_mask: memory allocation mask for bio | |
3317 | * @bio_ctr: setup function to be called for each clone bio. | |
3318 | * Returns %0 for success, non %0 for failure. | |
3319 | * @data: private data to be passed to @bio_ctr | |
3320 | * | |
3321 | * Description: | |
3322 | * Clones bios in @rq_src to @rq, and copies attributes of @rq_src to @rq. | |
3323 | * The actual data parts of @rq_src (e.g. ->cmd, ->sense) | |
3324 | * are not copied, and copying such parts is the caller's responsibility. | |
3325 | * Also, pages which the original bios are pointing to are not copied | |
3326 | * and the cloned bios just point same pages. | |
3327 | * So cloned bios must be completed before original bios, which means | |
3328 | * the caller must complete @rq before @rq_src. | |
3329 | */ | |
3330 | int blk_rq_prep_clone(struct request *rq, struct request *rq_src, | |
3331 | struct bio_set *bs, gfp_t gfp_mask, | |
3332 | int (*bio_ctr)(struct bio *, struct bio *, void *), | |
3333 | void *data) | |
3334 | { | |
3335 | struct bio *bio, *bio_src; | |
3336 | ||
3337 | if (!bs) | |
3338 | bs = fs_bio_set; | |
3339 | ||
3340 | __rq_for_each_bio(bio_src, rq_src) { | |
3341 | bio = bio_clone_fast(bio_src, gfp_mask, bs); | |
3342 | if (!bio) | |
3343 | goto free_and_out; | |
3344 | ||
3345 | if (bio_ctr && bio_ctr(bio, bio_src, data)) | |
3346 | goto free_and_out; | |
3347 | ||
3348 | if (rq->bio) { | |
3349 | rq->biotail->bi_next = bio; | |
3350 | rq->biotail = bio; | |
3351 | } else | |
3352 | rq->bio = rq->biotail = bio; | |
3353 | } | |
3354 | ||
3355 | __blk_rq_prep_clone(rq, rq_src); | |
3356 | ||
3357 | return 0; | |
3358 | ||
3359 | free_and_out: | |
3360 | if (bio) | |
3361 | bio_put(bio); | |
3362 | blk_rq_unprep_clone(rq); | |
3363 | ||
3364 | return -ENOMEM; | |
b0fd271d KU |
3365 | } |
3366 | EXPORT_SYMBOL_GPL(blk_rq_prep_clone); | |
3367 | ||
59c3d45e | 3368 | int kblockd_schedule_work(struct work_struct *work) |
1da177e4 LT |
3369 | { |
3370 | return queue_work(kblockd_workqueue, work); | |
3371 | } | |
1da177e4 LT |
3372 | EXPORT_SYMBOL(kblockd_schedule_work); |
3373 | ||
ee63cfa7 JA |
3374 | int kblockd_schedule_work_on(int cpu, struct work_struct *work) |
3375 | { | |
3376 | return queue_work_on(cpu, kblockd_workqueue, work); | |
3377 | } | |
3378 | EXPORT_SYMBOL(kblockd_schedule_work_on); | |
3379 | ||
818cd1cb JA |
3380 | int kblockd_mod_delayed_work_on(int cpu, struct delayed_work *dwork, |
3381 | unsigned long delay) | |
3382 | { | |
3383 | return mod_delayed_work_on(cpu, kblockd_workqueue, dwork, delay); | |
3384 | } | |
3385 | EXPORT_SYMBOL(kblockd_mod_delayed_work_on); | |
3386 | ||
59c3d45e JA |
3387 | int kblockd_schedule_delayed_work(struct delayed_work *dwork, |
3388 | unsigned long delay) | |
e43473b7 VG |
3389 | { |
3390 | return queue_delayed_work(kblockd_workqueue, dwork, delay); | |
3391 | } | |
3392 | EXPORT_SYMBOL(kblockd_schedule_delayed_work); | |
3393 | ||
8ab14595 JA |
3394 | int kblockd_schedule_delayed_work_on(int cpu, struct delayed_work *dwork, |
3395 | unsigned long delay) | |
3396 | { | |
3397 | return queue_delayed_work_on(cpu, kblockd_workqueue, dwork, delay); | |
3398 | } | |
3399 | EXPORT_SYMBOL(kblockd_schedule_delayed_work_on); | |
3400 | ||
75df7136 SJ |
3401 | /** |
3402 | * blk_start_plug - initialize blk_plug and track it inside the task_struct | |
3403 | * @plug: The &struct blk_plug that needs to be initialized | |
3404 | * | |
3405 | * Description: | |
3406 | * Tracking blk_plug inside the task_struct will help with auto-flushing the | |
3407 | * pending I/O should the task end up blocking between blk_start_plug() and | |
3408 | * blk_finish_plug(). This is important from a performance perspective, but | |
3409 | * also ensures that we don't deadlock. For instance, if the task is blocking | |
3410 | * for a memory allocation, memory reclaim could end up wanting to free a | |
3411 | * page belonging to that request that is currently residing in our private | |
3412 | * plug. By flushing the pending I/O when the process goes to sleep, we avoid | |
3413 | * this kind of deadlock. | |
3414 | */ | |
73c10101 JA |
3415 | void blk_start_plug(struct blk_plug *plug) |
3416 | { | |
3417 | struct task_struct *tsk = current; | |
3418 | ||
dd6cf3e1 SL |
3419 | /* |
3420 | * If this is a nested plug, don't actually assign it. | |
3421 | */ | |
3422 | if (tsk->plug) | |
3423 | return; | |
3424 | ||
73c10101 | 3425 | INIT_LIST_HEAD(&plug->list); |
320ae51f | 3426 | INIT_LIST_HEAD(&plug->mq_list); |
048c9374 | 3427 | INIT_LIST_HEAD(&plug->cb_list); |
73c10101 | 3428 | /* |
dd6cf3e1 SL |
3429 | * Store ordering should not be needed here, since a potential |
3430 | * preempt will imply a full memory barrier | |
73c10101 | 3431 | */ |
dd6cf3e1 | 3432 | tsk->plug = plug; |
73c10101 JA |
3433 | } |
3434 | EXPORT_SYMBOL(blk_start_plug); | |
3435 | ||
3436 | static int plug_rq_cmp(void *priv, struct list_head *a, struct list_head *b) | |
3437 | { | |
3438 | struct request *rqa = container_of(a, struct request, queuelist); | |
3439 | struct request *rqb = container_of(b, struct request, queuelist); | |
3440 | ||
975927b9 JM |
3441 | return !(rqa->q < rqb->q || |
3442 | (rqa->q == rqb->q && blk_rq_pos(rqa) < blk_rq_pos(rqb))); | |
73c10101 JA |
3443 | } |
3444 | ||
49cac01e JA |
3445 | /* |
3446 | * If 'from_schedule' is true, then postpone the dispatch of requests | |
3447 | * until a safe kblockd context. We due this to avoid accidental big | |
3448 | * additional stack usage in driver dispatch, in places where the originally | |
3449 | * plugger did not intend it. | |
3450 | */ | |
f6603783 | 3451 | static void queue_unplugged(struct request_queue *q, unsigned int depth, |
49cac01e | 3452 | bool from_schedule) |
99e22598 | 3453 | __releases(q->queue_lock) |
94b5eb28 | 3454 | { |
2fff8a92 BVA |
3455 | lockdep_assert_held(q->queue_lock); |
3456 | ||
49cac01e | 3457 | trace_block_unplug(q, depth, !from_schedule); |
99e22598 | 3458 | |
70460571 | 3459 | if (from_schedule) |
24ecfbe2 | 3460 | blk_run_queue_async(q); |
70460571 | 3461 | else |
24ecfbe2 | 3462 | __blk_run_queue(q); |
70460571 | 3463 | spin_unlock(q->queue_lock); |
94b5eb28 JA |
3464 | } |
3465 | ||
74018dc3 | 3466 | static void flush_plug_callbacks(struct blk_plug *plug, bool from_schedule) |
048c9374 N |
3467 | { |
3468 | LIST_HEAD(callbacks); | |
3469 | ||
2a7d5559 SL |
3470 | while (!list_empty(&plug->cb_list)) { |
3471 | list_splice_init(&plug->cb_list, &callbacks); | |
048c9374 | 3472 | |
2a7d5559 SL |
3473 | while (!list_empty(&callbacks)) { |
3474 | struct blk_plug_cb *cb = list_first_entry(&callbacks, | |
048c9374 N |
3475 | struct blk_plug_cb, |
3476 | list); | |
2a7d5559 | 3477 | list_del(&cb->list); |
74018dc3 | 3478 | cb->callback(cb, from_schedule); |
2a7d5559 | 3479 | } |
048c9374 N |
3480 | } |
3481 | } | |
3482 | ||
9cbb1750 N |
3483 | struct blk_plug_cb *blk_check_plugged(blk_plug_cb_fn unplug, void *data, |
3484 | int size) | |
3485 | { | |
3486 | struct blk_plug *plug = current->plug; | |
3487 | struct blk_plug_cb *cb; | |
3488 | ||
3489 | if (!plug) | |
3490 | return NULL; | |
3491 | ||
3492 | list_for_each_entry(cb, &plug->cb_list, list) | |
3493 | if (cb->callback == unplug && cb->data == data) | |
3494 | return cb; | |
3495 | ||
3496 | /* Not currently on the callback list */ | |
3497 | BUG_ON(size < sizeof(*cb)); | |
3498 | cb = kzalloc(size, GFP_ATOMIC); | |
3499 | if (cb) { | |
3500 | cb->data = data; | |
3501 | cb->callback = unplug; | |
3502 | list_add(&cb->list, &plug->cb_list); | |
3503 | } | |
3504 | return cb; | |
3505 | } | |
3506 | EXPORT_SYMBOL(blk_check_plugged); | |
3507 | ||
49cac01e | 3508 | void blk_flush_plug_list(struct blk_plug *plug, bool from_schedule) |
73c10101 JA |
3509 | { |
3510 | struct request_queue *q; | |
3511 | unsigned long flags; | |
3512 | struct request *rq; | |
109b8129 | 3513 | LIST_HEAD(list); |
94b5eb28 | 3514 | unsigned int depth; |
73c10101 | 3515 | |
74018dc3 | 3516 | flush_plug_callbacks(plug, from_schedule); |
320ae51f JA |
3517 | |
3518 | if (!list_empty(&plug->mq_list)) | |
3519 | blk_mq_flush_plug_list(plug, from_schedule); | |
3520 | ||
73c10101 JA |
3521 | if (list_empty(&plug->list)) |
3522 | return; | |
3523 | ||
109b8129 N |
3524 | list_splice_init(&plug->list, &list); |
3525 | ||
422765c2 | 3526 | list_sort(NULL, &list, plug_rq_cmp); |
73c10101 JA |
3527 | |
3528 | q = NULL; | |
94b5eb28 | 3529 | depth = 0; |
18811272 JA |
3530 | |
3531 | /* | |
3532 | * Save and disable interrupts here, to avoid doing it for every | |
3533 | * queue lock we have to take. | |
3534 | */ | |
73c10101 | 3535 | local_irq_save(flags); |
109b8129 N |
3536 | while (!list_empty(&list)) { |
3537 | rq = list_entry_rq(list.next); | |
73c10101 | 3538 | list_del_init(&rq->queuelist); |
73c10101 JA |
3539 | BUG_ON(!rq->q); |
3540 | if (rq->q != q) { | |
99e22598 JA |
3541 | /* |
3542 | * This drops the queue lock | |
3543 | */ | |
3544 | if (q) | |
49cac01e | 3545 | queue_unplugged(q, depth, from_schedule); |
73c10101 | 3546 | q = rq->q; |
94b5eb28 | 3547 | depth = 0; |
73c10101 JA |
3548 | spin_lock(q->queue_lock); |
3549 | } | |
8ba61435 TH |
3550 | |
3551 | /* | |
3552 | * Short-circuit if @q is dead | |
3553 | */ | |
3f3299d5 | 3554 | if (unlikely(blk_queue_dying(q))) { |
2a842aca | 3555 | __blk_end_request_all(rq, BLK_STS_IOERR); |
8ba61435 TH |
3556 | continue; |
3557 | } | |
3558 | ||
73c10101 JA |
3559 | /* |
3560 | * rq is already accounted, so use raw insert | |
3561 | */ | |
f73f44eb | 3562 | if (op_is_flush(rq->cmd_flags)) |
401a18e9 JA |
3563 | __elv_add_request(q, rq, ELEVATOR_INSERT_FLUSH); |
3564 | else | |
3565 | __elv_add_request(q, rq, ELEVATOR_INSERT_SORT_MERGE); | |
94b5eb28 JA |
3566 | |
3567 | depth++; | |
73c10101 JA |
3568 | } |
3569 | ||
99e22598 JA |
3570 | /* |
3571 | * This drops the queue lock | |
3572 | */ | |
3573 | if (q) | |
49cac01e | 3574 | queue_unplugged(q, depth, from_schedule); |
73c10101 | 3575 | |
73c10101 JA |
3576 | local_irq_restore(flags); |
3577 | } | |
73c10101 JA |
3578 | |
3579 | void blk_finish_plug(struct blk_plug *plug) | |
3580 | { | |
dd6cf3e1 SL |
3581 | if (plug != current->plug) |
3582 | return; | |
f6603783 | 3583 | blk_flush_plug_list(plug, false); |
73c10101 | 3584 | |
dd6cf3e1 | 3585 | current->plug = NULL; |
73c10101 | 3586 | } |
88b996cd | 3587 | EXPORT_SYMBOL(blk_finish_plug); |
73c10101 | 3588 | |
47fafbc7 | 3589 | #ifdef CONFIG_PM |
6c954667 LM |
3590 | /** |
3591 | * blk_pm_runtime_init - Block layer runtime PM initialization routine | |
3592 | * @q: the queue of the device | |
3593 | * @dev: the device the queue belongs to | |
3594 | * | |
3595 | * Description: | |
3596 | * Initialize runtime-PM-related fields for @q and start auto suspend for | |
3597 | * @dev. Drivers that want to take advantage of request-based runtime PM | |
3598 | * should call this function after @dev has been initialized, and its | |
3599 | * request queue @q has been allocated, and runtime PM for it can not happen | |
3600 | * yet(either due to disabled/forbidden or its usage_count > 0). In most | |
3601 | * cases, driver should call this function before any I/O has taken place. | |
3602 | * | |
3603 | * This function takes care of setting up using auto suspend for the device, | |
3604 | * the autosuspend delay is set to -1 to make runtime suspend impossible | |
3605 | * until an updated value is either set by user or by driver. Drivers do | |
3606 | * not need to touch other autosuspend settings. | |
3607 | * | |
3608 | * The block layer runtime PM is request based, so only works for drivers | |
3609 | * that use request as their IO unit instead of those directly use bio's. | |
3610 | */ | |
3611 | void blk_pm_runtime_init(struct request_queue *q, struct device *dev) | |
3612 | { | |
765e40b6 CH |
3613 | /* not support for RQF_PM and ->rpm_status in blk-mq yet */ |
3614 | if (q->mq_ops) | |
3615 | return; | |
3616 | ||
6c954667 LM |
3617 | q->dev = dev; |
3618 | q->rpm_status = RPM_ACTIVE; | |
3619 | pm_runtime_set_autosuspend_delay(q->dev, -1); | |
3620 | pm_runtime_use_autosuspend(q->dev); | |
3621 | } | |
3622 | EXPORT_SYMBOL(blk_pm_runtime_init); | |
3623 | ||
3624 | /** | |
3625 | * blk_pre_runtime_suspend - Pre runtime suspend check | |
3626 | * @q: the queue of the device | |
3627 | * | |
3628 | * Description: | |
3629 | * This function will check if runtime suspend is allowed for the device | |
3630 | * by examining if there are any requests pending in the queue. If there | |
3631 | * are requests pending, the device can not be runtime suspended; otherwise, | |
3632 | * the queue's status will be updated to SUSPENDING and the driver can | |
3633 | * proceed to suspend the device. | |
3634 | * | |
3635 | * For the not allowed case, we mark last busy for the device so that | |
3636 | * runtime PM core will try to autosuspend it some time later. | |
3637 | * | |
3638 | * This function should be called near the start of the device's | |
3639 | * runtime_suspend callback. | |
3640 | * | |
3641 | * Return: | |
3642 | * 0 - OK to runtime suspend the device | |
3643 | * -EBUSY - Device should not be runtime suspended | |
3644 | */ | |
3645 | int blk_pre_runtime_suspend(struct request_queue *q) | |
3646 | { | |
3647 | int ret = 0; | |
3648 | ||
4fd41a85 KX |
3649 | if (!q->dev) |
3650 | return ret; | |
3651 | ||
6c954667 LM |
3652 | spin_lock_irq(q->queue_lock); |
3653 | if (q->nr_pending) { | |
3654 | ret = -EBUSY; | |
3655 | pm_runtime_mark_last_busy(q->dev); | |
3656 | } else { | |
3657 | q->rpm_status = RPM_SUSPENDING; | |
3658 | } | |
3659 | spin_unlock_irq(q->queue_lock); | |
3660 | return ret; | |
3661 | } | |
3662 | EXPORT_SYMBOL(blk_pre_runtime_suspend); | |
3663 | ||
3664 | /** | |
3665 | * blk_post_runtime_suspend - Post runtime suspend processing | |
3666 | * @q: the queue of the device | |
3667 | * @err: return value of the device's runtime_suspend function | |
3668 | * | |
3669 | * Description: | |
3670 | * Update the queue's runtime status according to the return value of the | |
3671 | * device's runtime suspend function and mark last busy for the device so | |
3672 | * that PM core will try to auto suspend the device at a later time. | |
3673 | * | |
3674 | * This function should be called near the end of the device's | |
3675 | * runtime_suspend callback. | |
3676 | */ | |
3677 | void blk_post_runtime_suspend(struct request_queue *q, int err) | |
3678 | { | |
4fd41a85 KX |
3679 | if (!q->dev) |
3680 | return; | |
3681 | ||
6c954667 LM |
3682 | spin_lock_irq(q->queue_lock); |
3683 | if (!err) { | |
3684 | q->rpm_status = RPM_SUSPENDED; | |
3685 | } else { | |
3686 | q->rpm_status = RPM_ACTIVE; | |
3687 | pm_runtime_mark_last_busy(q->dev); | |
3688 | } | |
3689 | spin_unlock_irq(q->queue_lock); | |
3690 | } | |
3691 | EXPORT_SYMBOL(blk_post_runtime_suspend); | |
3692 | ||
3693 | /** | |
3694 | * blk_pre_runtime_resume - Pre runtime resume processing | |
3695 | * @q: the queue of the device | |
3696 | * | |
3697 | * Description: | |
3698 | * Update the queue's runtime status to RESUMING in preparation for the | |
3699 | * runtime resume of the device. | |
3700 | * | |
3701 | * This function should be called near the start of the device's | |
3702 | * runtime_resume callback. | |
3703 | */ | |
3704 | void blk_pre_runtime_resume(struct request_queue *q) | |
3705 | { | |
4fd41a85 KX |
3706 | if (!q->dev) |
3707 | return; | |
3708 | ||
6c954667 LM |
3709 | spin_lock_irq(q->queue_lock); |
3710 | q->rpm_status = RPM_RESUMING; | |
3711 | spin_unlock_irq(q->queue_lock); | |
3712 | } | |
3713 | EXPORT_SYMBOL(blk_pre_runtime_resume); | |
3714 | ||
3715 | /** | |
3716 | * blk_post_runtime_resume - Post runtime resume processing | |
3717 | * @q: the queue of the device | |
3718 | * @err: return value of the device's runtime_resume function | |
3719 | * | |
3720 | * Description: | |
3721 | * Update the queue's runtime status according to the return value of the | |
3722 | * device's runtime_resume function. If it is successfully resumed, process | |
3723 | * the requests that are queued into the device's queue when it is resuming | |
3724 | * and then mark last busy and initiate autosuspend for it. | |
3725 | * | |
3726 | * This function should be called near the end of the device's | |
3727 | * runtime_resume callback. | |
3728 | */ | |
3729 | void blk_post_runtime_resume(struct request_queue *q, int err) | |
3730 | { | |
4fd41a85 KX |
3731 | if (!q->dev) |
3732 | return; | |
3733 | ||
6c954667 LM |
3734 | spin_lock_irq(q->queue_lock); |
3735 | if (!err) { | |
3736 | q->rpm_status = RPM_ACTIVE; | |
3737 | __blk_run_queue(q); | |
3738 | pm_runtime_mark_last_busy(q->dev); | |
c60855cd | 3739 | pm_request_autosuspend(q->dev); |
6c954667 LM |
3740 | } else { |
3741 | q->rpm_status = RPM_SUSPENDED; | |
3742 | } | |
3743 | spin_unlock_irq(q->queue_lock); | |
3744 | } | |
3745 | EXPORT_SYMBOL(blk_post_runtime_resume); | |
d07ab6d1 MW |
3746 | |
3747 | /** | |
3748 | * blk_set_runtime_active - Force runtime status of the queue to be active | |
3749 | * @q: the queue of the device | |
3750 | * | |
3751 | * If the device is left runtime suspended during system suspend the resume | |
3752 | * hook typically resumes the device and corrects runtime status | |
3753 | * accordingly. However, that does not affect the queue runtime PM status | |
3754 | * which is still "suspended". This prevents processing requests from the | |
3755 | * queue. | |
3756 | * | |
3757 | * This function can be used in driver's resume hook to correct queue | |
3758 | * runtime PM status and re-enable peeking requests from the queue. It | |
3759 | * should be called before first request is added to the queue. | |
3760 | */ | |
3761 | void blk_set_runtime_active(struct request_queue *q) | |
3762 | { | |
3763 | spin_lock_irq(q->queue_lock); | |
3764 | q->rpm_status = RPM_ACTIVE; | |
3765 | pm_runtime_mark_last_busy(q->dev); | |
3766 | pm_request_autosuspend(q->dev); | |
3767 | spin_unlock_irq(q->queue_lock); | |
3768 | } | |
3769 | EXPORT_SYMBOL(blk_set_runtime_active); | |
6c954667 LM |
3770 | #endif |
3771 | ||
1da177e4 LT |
3772 | int __init blk_dev_init(void) |
3773 | { | |
ef295ecf CH |
3774 | BUILD_BUG_ON(REQ_OP_LAST >= (1 << REQ_OP_BITS)); |
3775 | BUILD_BUG_ON(REQ_OP_BITS + REQ_FLAG_BITS > 8 * | |
0762b23d | 3776 | FIELD_SIZEOF(struct request, cmd_flags)); |
ef295ecf CH |
3777 | BUILD_BUG_ON(REQ_OP_BITS + REQ_FLAG_BITS > 8 * |
3778 | FIELD_SIZEOF(struct bio, bi_opf)); | |
9eb55b03 | 3779 | |
89b90be2 TH |
3780 | /* used for unplugging and affects IO latency/throughput - HIGHPRI */ |
3781 | kblockd_workqueue = alloc_workqueue("kblockd", | |
28747fcd | 3782 | WQ_MEM_RECLAIM | WQ_HIGHPRI, 0); |
1da177e4 LT |
3783 | if (!kblockd_workqueue) |
3784 | panic("Failed to create kblockd\n"); | |
3785 | ||
3786 | request_cachep = kmem_cache_create("blkdev_requests", | |
20c2df83 | 3787 | sizeof(struct request), 0, SLAB_PANIC, NULL); |
1da177e4 | 3788 | |
c2789bd4 | 3789 | blk_requestq_cachep = kmem_cache_create("request_queue", |
165125e1 | 3790 | sizeof(struct request_queue), 0, SLAB_PANIC, NULL); |
1da177e4 | 3791 | |
18fbda91 OS |
3792 | #ifdef CONFIG_DEBUG_FS |
3793 | blk_debugfs_root = debugfs_create_dir("block", NULL); | |
3794 | #endif | |
3795 | ||
d38ecf93 | 3796 | return 0; |
1da177e4 | 3797 | } |