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> | |
19 | #include <linux/highmem.h> | |
20 | #include <linux/mm.h> | |
21 | #include <linux/kernel_stat.h> | |
22 | #include <linux/string.h> | |
23 | #include <linux/init.h> | |
1da177e4 LT |
24 | #include <linux/completion.h> |
25 | #include <linux/slab.h> | |
26 | #include <linux/swap.h> | |
27 | #include <linux/writeback.h> | |
faccbd4b | 28 | #include <linux/task_io_accounting_ops.h> |
c17bb495 | 29 | #include <linux/fault-inject.h> |
73c10101 | 30 | #include <linux/list_sort.h> |
e3c78ca5 | 31 | #include <linux/delay.h> |
aaf7c680 | 32 | #include <linux/ratelimit.h> |
6c954667 | 33 | #include <linux/pm_runtime.h> |
55782138 LZ |
34 | |
35 | #define CREATE_TRACE_POINTS | |
36 | #include <trace/events/block.h> | |
1da177e4 | 37 | |
8324aa91 | 38 | #include "blk.h" |
5efd6113 | 39 | #include "blk-cgroup.h" |
8324aa91 | 40 | |
d07335e5 | 41 | EXPORT_TRACEPOINT_SYMBOL_GPL(block_bio_remap); |
b0da3f0d | 42 | EXPORT_TRACEPOINT_SYMBOL_GPL(block_rq_remap); |
0a82a8d1 | 43 | EXPORT_TRACEPOINT_SYMBOL_GPL(block_bio_complete); |
cbae8d45 | 44 | EXPORT_TRACEPOINT_SYMBOL_GPL(block_unplug); |
0bfc2455 | 45 | |
a73f730d TH |
46 | DEFINE_IDA(blk_queue_ida); |
47 | ||
1da177e4 LT |
48 | /* |
49 | * For the allocated request tables | |
50 | */ | |
5ece6c52 | 51 | static struct kmem_cache *request_cachep; |
1da177e4 LT |
52 | |
53 | /* | |
54 | * For queue allocation | |
55 | */ | |
6728cb0e | 56 | struct kmem_cache *blk_requestq_cachep; |
1da177e4 | 57 | |
1da177e4 LT |
58 | /* |
59 | * Controlling structure to kblockd | |
60 | */ | |
ff856bad | 61 | static struct workqueue_struct *kblockd_workqueue; |
1da177e4 | 62 | |
26b8256e JA |
63 | static void drive_stat_acct(struct request *rq, int new_io) |
64 | { | |
28f13702 | 65 | struct hd_struct *part; |
26b8256e | 66 | int rw = rq_data_dir(rq); |
c9959059 | 67 | int cpu; |
26b8256e | 68 | |
c2553b58 | 69 | if (!blk_do_io_stat(rq)) |
26b8256e JA |
70 | return; |
71 | ||
074a7aca | 72 | cpu = part_stat_lock(); |
c9959059 | 73 | |
09e099d4 JM |
74 | if (!new_io) { |
75 | part = rq->part; | |
074a7aca | 76 | part_stat_inc(cpu, part, merges[rw]); |
09e099d4 JM |
77 | } else { |
78 | part = disk_map_sector_rcu(rq->rq_disk, blk_rq_pos(rq)); | |
6c23a968 | 79 | if (!hd_struct_try_get(part)) { |
09e099d4 JM |
80 | /* |
81 | * The partition is already being removed, | |
82 | * the request will be accounted on the disk only | |
83 | * | |
84 | * We take a reference on disk->part0 although that | |
85 | * partition will never be deleted, so we can treat | |
86 | * it as any other partition. | |
87 | */ | |
88 | part = &rq->rq_disk->part0; | |
6c23a968 | 89 | hd_struct_get(part); |
09e099d4 | 90 | } |
074a7aca | 91 | part_round_stats(cpu, part); |
316d315b | 92 | part_inc_in_flight(part, rw); |
09e099d4 | 93 | rq->part = part; |
26b8256e | 94 | } |
e71bf0d0 | 95 | |
074a7aca | 96 | part_stat_unlock(); |
26b8256e JA |
97 | } |
98 | ||
8324aa91 | 99 | void blk_queue_congestion_threshold(struct request_queue *q) |
1da177e4 LT |
100 | { |
101 | int nr; | |
102 | ||
103 | nr = q->nr_requests - (q->nr_requests / 8) + 1; | |
104 | if (nr > q->nr_requests) | |
105 | nr = q->nr_requests; | |
106 | q->nr_congestion_on = nr; | |
107 | ||
108 | nr = q->nr_requests - (q->nr_requests / 8) - (q->nr_requests / 16) - 1; | |
109 | if (nr < 1) | |
110 | nr = 1; | |
111 | q->nr_congestion_off = nr; | |
112 | } | |
113 | ||
1da177e4 LT |
114 | /** |
115 | * blk_get_backing_dev_info - get the address of a queue's backing_dev_info | |
116 | * @bdev: device | |
117 | * | |
118 | * Locates the passed device's request queue and returns the address of its | |
119 | * backing_dev_info | |
120 | * | |
121 | * Will return NULL if the request queue cannot be located. | |
122 | */ | |
123 | struct backing_dev_info *blk_get_backing_dev_info(struct block_device *bdev) | |
124 | { | |
125 | struct backing_dev_info *ret = NULL; | |
165125e1 | 126 | struct request_queue *q = bdev_get_queue(bdev); |
1da177e4 LT |
127 | |
128 | if (q) | |
129 | ret = &q->backing_dev_info; | |
130 | return ret; | |
131 | } | |
1da177e4 LT |
132 | EXPORT_SYMBOL(blk_get_backing_dev_info); |
133 | ||
2a4aa30c | 134 | void blk_rq_init(struct request_queue *q, struct request *rq) |
1da177e4 | 135 | { |
1afb20f3 FT |
136 | memset(rq, 0, sizeof(*rq)); |
137 | ||
1da177e4 | 138 | INIT_LIST_HEAD(&rq->queuelist); |
242f9dcb | 139 | INIT_LIST_HEAD(&rq->timeout_list); |
c7c22e4d | 140 | rq->cpu = -1; |
63a71386 | 141 | rq->q = q; |
a2dec7b3 | 142 | rq->__sector = (sector_t) -1; |
2e662b65 JA |
143 | INIT_HLIST_NODE(&rq->hash); |
144 | RB_CLEAR_NODE(&rq->rb_node); | |
d7e3c324 | 145 | rq->cmd = rq->__cmd; |
e2494e1b | 146 | rq->cmd_len = BLK_MAX_CDB; |
63a71386 | 147 | rq->tag = -1; |
b243ddcb | 148 | rq->start_time = jiffies; |
9195291e | 149 | set_start_time_ns(rq); |
09e099d4 | 150 | rq->part = NULL; |
1da177e4 | 151 | } |
2a4aa30c | 152 | EXPORT_SYMBOL(blk_rq_init); |
1da177e4 | 153 | |
5bb23a68 N |
154 | static void req_bio_endio(struct request *rq, struct bio *bio, |
155 | unsigned int nbytes, int error) | |
1da177e4 | 156 | { |
143a87f4 TH |
157 | if (error) |
158 | clear_bit(BIO_UPTODATE, &bio->bi_flags); | |
159 | else if (!test_bit(BIO_UPTODATE, &bio->bi_flags)) | |
160 | error = -EIO; | |
797e7dbb | 161 | |
143a87f4 TH |
162 | if (unlikely(rq->cmd_flags & REQ_QUIET)) |
163 | set_bit(BIO_QUIET, &bio->bi_flags); | |
08bafc03 | 164 | |
f79ea416 | 165 | bio_advance(bio, nbytes); |
7ba1ba12 | 166 | |
143a87f4 TH |
167 | /* don't actually finish bio if it's part of flush sequence */ |
168 | if (bio->bi_size == 0 && !(rq->cmd_flags & REQ_FLUSH_SEQ)) | |
169 | bio_endio(bio, error); | |
1da177e4 | 170 | } |
1da177e4 | 171 | |
1da177e4 LT |
172 | void blk_dump_rq_flags(struct request *rq, char *msg) |
173 | { | |
174 | int bit; | |
175 | ||
5953316d | 176 | printk(KERN_INFO "%s: dev %s: type=%x, flags=%llx\n", msg, |
4aff5e23 | 177 | rq->rq_disk ? rq->rq_disk->disk_name : "?", rq->cmd_type, |
5953316d | 178 | (unsigned long long) rq->cmd_flags); |
1da177e4 | 179 | |
83096ebf TH |
180 | printk(KERN_INFO " sector %llu, nr/cnr %u/%u\n", |
181 | (unsigned long long)blk_rq_pos(rq), | |
182 | blk_rq_sectors(rq), blk_rq_cur_sectors(rq)); | |
731ec497 | 183 | printk(KERN_INFO " bio %p, biotail %p, buffer %p, len %u\n", |
2e46e8b2 | 184 | rq->bio, rq->biotail, rq->buffer, blk_rq_bytes(rq)); |
1da177e4 | 185 | |
33659ebb | 186 | if (rq->cmd_type == REQ_TYPE_BLOCK_PC) { |
6728cb0e | 187 | printk(KERN_INFO " cdb: "); |
d34c87e4 | 188 | for (bit = 0; bit < BLK_MAX_CDB; bit++) |
1da177e4 LT |
189 | printk("%02x ", rq->cmd[bit]); |
190 | printk("\n"); | |
191 | } | |
192 | } | |
1da177e4 LT |
193 | EXPORT_SYMBOL(blk_dump_rq_flags); |
194 | ||
3cca6dc1 | 195 | static void blk_delay_work(struct work_struct *work) |
1da177e4 | 196 | { |
3cca6dc1 | 197 | struct request_queue *q; |
1da177e4 | 198 | |
3cca6dc1 JA |
199 | q = container_of(work, struct request_queue, delay_work.work); |
200 | spin_lock_irq(q->queue_lock); | |
24ecfbe2 | 201 | __blk_run_queue(q); |
3cca6dc1 | 202 | spin_unlock_irq(q->queue_lock); |
1da177e4 | 203 | } |
1da177e4 LT |
204 | |
205 | /** | |
3cca6dc1 JA |
206 | * blk_delay_queue - restart queueing after defined interval |
207 | * @q: The &struct request_queue in question | |
208 | * @msecs: Delay in msecs | |
1da177e4 LT |
209 | * |
210 | * Description: | |
3cca6dc1 JA |
211 | * Sometimes queueing needs to be postponed for a little while, to allow |
212 | * resources to come back. This function will make sure that queueing is | |
70460571 | 213 | * restarted around the specified time. Queue lock must be held. |
3cca6dc1 JA |
214 | */ |
215 | void blk_delay_queue(struct request_queue *q, unsigned long msecs) | |
2ad8b1ef | 216 | { |
70460571 BVA |
217 | if (likely(!blk_queue_dead(q))) |
218 | queue_delayed_work(kblockd_workqueue, &q->delay_work, | |
219 | msecs_to_jiffies(msecs)); | |
2ad8b1ef | 220 | } |
3cca6dc1 | 221 | EXPORT_SYMBOL(blk_delay_queue); |
2ad8b1ef | 222 | |
1da177e4 LT |
223 | /** |
224 | * blk_start_queue - restart a previously stopped queue | |
165125e1 | 225 | * @q: The &struct request_queue in question |
1da177e4 LT |
226 | * |
227 | * Description: | |
228 | * blk_start_queue() will clear the stop flag on the queue, and call | |
229 | * the request_fn for the queue if it was in a stopped state when | |
230 | * entered. Also see blk_stop_queue(). Queue lock must be held. | |
231 | **/ | |
165125e1 | 232 | void blk_start_queue(struct request_queue *q) |
1da177e4 | 233 | { |
a038e253 PBG |
234 | WARN_ON(!irqs_disabled()); |
235 | ||
75ad23bc | 236 | queue_flag_clear(QUEUE_FLAG_STOPPED, q); |
24ecfbe2 | 237 | __blk_run_queue(q); |
1da177e4 | 238 | } |
1da177e4 LT |
239 | EXPORT_SYMBOL(blk_start_queue); |
240 | ||
241 | /** | |
242 | * blk_stop_queue - stop a queue | |
165125e1 | 243 | * @q: The &struct request_queue in question |
1da177e4 LT |
244 | * |
245 | * Description: | |
246 | * The Linux block layer assumes that a block driver will consume all | |
247 | * entries on the request queue when the request_fn strategy is called. | |
248 | * Often this will not happen, because of hardware limitations (queue | |
249 | * depth settings). If a device driver gets a 'queue full' response, | |
250 | * or if it simply chooses not to queue more I/O at one point, it can | |
251 | * call this function to prevent the request_fn from being called until | |
252 | * the driver has signalled it's ready to go again. This happens by calling | |
253 | * blk_start_queue() to restart queue operations. Queue lock must be held. | |
254 | **/ | |
165125e1 | 255 | void blk_stop_queue(struct request_queue *q) |
1da177e4 | 256 | { |
136b5721 | 257 | cancel_delayed_work(&q->delay_work); |
75ad23bc | 258 | queue_flag_set(QUEUE_FLAG_STOPPED, q); |
1da177e4 LT |
259 | } |
260 | EXPORT_SYMBOL(blk_stop_queue); | |
261 | ||
262 | /** | |
263 | * blk_sync_queue - cancel any pending callbacks on a queue | |
264 | * @q: the queue | |
265 | * | |
266 | * Description: | |
267 | * The block layer may perform asynchronous callback activity | |
268 | * on a queue, such as calling the unplug function after a timeout. | |
269 | * A block device may call blk_sync_queue to ensure that any | |
270 | * such activity is cancelled, thus allowing it to release resources | |
59c51591 | 271 | * that the callbacks might use. The caller must already have made sure |
1da177e4 LT |
272 | * that its ->make_request_fn will not re-add plugging prior to calling |
273 | * this function. | |
274 | * | |
da527770 VG |
275 | * This function does not cancel any asynchronous activity arising |
276 | * out of elevator or throttling code. That would require elevaotor_exit() | |
5efd6113 | 277 | * and blkcg_exit_queue() to be called with queue lock initialized. |
da527770 | 278 | * |
1da177e4 LT |
279 | */ |
280 | void blk_sync_queue(struct request_queue *q) | |
281 | { | |
70ed28b9 | 282 | del_timer_sync(&q->timeout); |
3cca6dc1 | 283 | cancel_delayed_work_sync(&q->delay_work); |
1da177e4 LT |
284 | } |
285 | EXPORT_SYMBOL(blk_sync_queue); | |
286 | ||
c246e80d BVA |
287 | /** |
288 | * __blk_run_queue_uncond - run a queue whether or not it has been stopped | |
289 | * @q: The queue to run | |
290 | * | |
291 | * Description: | |
292 | * Invoke request handling on a queue if there are any pending requests. | |
293 | * May be used to restart request handling after a request has completed. | |
294 | * This variant runs the queue whether or not the queue has been | |
295 | * stopped. Must be called with the queue lock held and interrupts | |
296 | * disabled. See also @blk_run_queue. | |
297 | */ | |
298 | inline void __blk_run_queue_uncond(struct request_queue *q) | |
299 | { | |
300 | if (unlikely(blk_queue_dead(q))) | |
301 | return; | |
302 | ||
24faf6f6 BVA |
303 | /* |
304 | * Some request_fn implementations, e.g. scsi_request_fn(), unlock | |
305 | * the queue lock internally. As a result multiple threads may be | |
306 | * running such a request function concurrently. Keep track of the | |
307 | * number of active request_fn invocations such that blk_drain_queue() | |
308 | * can wait until all these request_fn calls have finished. | |
309 | */ | |
310 | q->request_fn_active++; | |
c246e80d | 311 | q->request_fn(q); |
24faf6f6 | 312 | q->request_fn_active--; |
c246e80d BVA |
313 | } |
314 | ||
1da177e4 | 315 | /** |
80a4b58e | 316 | * __blk_run_queue - run a single device queue |
1da177e4 | 317 | * @q: The queue to run |
80a4b58e JA |
318 | * |
319 | * Description: | |
320 | * See @blk_run_queue. This variant must be called with the queue lock | |
24ecfbe2 | 321 | * held and interrupts disabled. |
1da177e4 | 322 | */ |
24ecfbe2 | 323 | void __blk_run_queue(struct request_queue *q) |
1da177e4 | 324 | { |
a538cd03 TH |
325 | if (unlikely(blk_queue_stopped(q))) |
326 | return; | |
327 | ||
c246e80d | 328 | __blk_run_queue_uncond(q); |
75ad23bc NP |
329 | } |
330 | EXPORT_SYMBOL(__blk_run_queue); | |
dac07ec1 | 331 | |
24ecfbe2 CH |
332 | /** |
333 | * blk_run_queue_async - run a single device queue in workqueue context | |
334 | * @q: The queue to run | |
335 | * | |
336 | * Description: | |
337 | * Tells kblockd to perform the equivalent of @blk_run_queue on behalf | |
70460571 | 338 | * of us. The caller must hold the queue lock. |
24ecfbe2 CH |
339 | */ |
340 | void blk_run_queue_async(struct request_queue *q) | |
341 | { | |
70460571 | 342 | if (likely(!blk_queue_stopped(q) && !blk_queue_dead(q))) |
e7c2f967 | 343 | mod_delayed_work(kblockd_workqueue, &q->delay_work, 0); |
24ecfbe2 | 344 | } |
c21e6beb | 345 | EXPORT_SYMBOL(blk_run_queue_async); |
24ecfbe2 | 346 | |
75ad23bc NP |
347 | /** |
348 | * blk_run_queue - run a single device queue | |
349 | * @q: The queue to run | |
80a4b58e JA |
350 | * |
351 | * Description: | |
352 | * Invoke request handling on this queue, if it has pending work to do. | |
a7f55792 | 353 | * May be used to restart queueing when a request has completed. |
75ad23bc NP |
354 | */ |
355 | void blk_run_queue(struct request_queue *q) | |
356 | { | |
357 | unsigned long flags; | |
358 | ||
359 | spin_lock_irqsave(q->queue_lock, flags); | |
24ecfbe2 | 360 | __blk_run_queue(q); |
1da177e4 LT |
361 | spin_unlock_irqrestore(q->queue_lock, flags); |
362 | } | |
363 | EXPORT_SYMBOL(blk_run_queue); | |
364 | ||
165125e1 | 365 | void blk_put_queue(struct request_queue *q) |
483f4afc AV |
366 | { |
367 | kobject_put(&q->kobj); | |
368 | } | |
d86e0e83 | 369 | EXPORT_SYMBOL(blk_put_queue); |
483f4afc | 370 | |
e3c78ca5 | 371 | /** |
807592a4 | 372 | * __blk_drain_queue - drain requests from request_queue |
e3c78ca5 | 373 | * @q: queue to drain |
c9a929dd | 374 | * @drain_all: whether to drain all requests or only the ones w/ ELVPRIV |
e3c78ca5 | 375 | * |
c9a929dd TH |
376 | * Drain requests from @q. If @drain_all is set, all requests are drained. |
377 | * If not, only ELVPRIV requests are drained. The caller is responsible | |
378 | * for ensuring that no new requests which need to be drained are queued. | |
e3c78ca5 | 379 | */ |
807592a4 BVA |
380 | static void __blk_drain_queue(struct request_queue *q, bool drain_all) |
381 | __releases(q->queue_lock) | |
382 | __acquires(q->queue_lock) | |
e3c78ca5 | 383 | { |
458f27a9 AH |
384 | int i; |
385 | ||
807592a4 BVA |
386 | lockdep_assert_held(q->queue_lock); |
387 | ||
e3c78ca5 | 388 | while (true) { |
481a7d64 | 389 | bool drain = false; |
e3c78ca5 | 390 | |
b855b04a TH |
391 | /* |
392 | * The caller might be trying to drain @q before its | |
393 | * elevator is initialized. | |
394 | */ | |
395 | if (q->elevator) | |
396 | elv_drain_elevator(q); | |
397 | ||
5efd6113 | 398 | blkcg_drain_queue(q); |
e3c78ca5 | 399 | |
4eabc941 TH |
400 | /* |
401 | * This function might be called on a queue which failed | |
b855b04a TH |
402 | * driver init after queue creation or is not yet fully |
403 | * active yet. Some drivers (e.g. fd and loop) get unhappy | |
404 | * in such cases. Kick queue iff dispatch queue has | |
405 | * something on it and @q has request_fn set. | |
4eabc941 | 406 | */ |
b855b04a | 407 | if (!list_empty(&q->queue_head) && q->request_fn) |
4eabc941 | 408 | __blk_run_queue(q); |
c9a929dd | 409 | |
8a5ecdd4 | 410 | drain |= q->nr_rqs_elvpriv; |
24faf6f6 | 411 | drain |= q->request_fn_active; |
481a7d64 TH |
412 | |
413 | /* | |
414 | * Unfortunately, requests are queued at and tracked from | |
415 | * multiple places and there's no single counter which can | |
416 | * be drained. Check all the queues and counters. | |
417 | */ | |
418 | if (drain_all) { | |
419 | drain |= !list_empty(&q->queue_head); | |
420 | for (i = 0; i < 2; i++) { | |
8a5ecdd4 | 421 | drain |= q->nr_rqs[i]; |
481a7d64 TH |
422 | drain |= q->in_flight[i]; |
423 | drain |= !list_empty(&q->flush_queue[i]); | |
424 | } | |
425 | } | |
e3c78ca5 | 426 | |
481a7d64 | 427 | if (!drain) |
e3c78ca5 | 428 | break; |
807592a4 BVA |
429 | |
430 | spin_unlock_irq(q->queue_lock); | |
431 | ||
e3c78ca5 | 432 | msleep(10); |
807592a4 BVA |
433 | |
434 | spin_lock_irq(q->queue_lock); | |
e3c78ca5 | 435 | } |
458f27a9 AH |
436 | |
437 | /* | |
438 | * With queue marked dead, any woken up waiter will fail the | |
439 | * allocation path, so the wakeup chaining is lost and we're | |
440 | * left with hung waiters. We need to wake up those waiters. | |
441 | */ | |
442 | if (q->request_fn) { | |
a051661c TH |
443 | struct request_list *rl; |
444 | ||
a051661c TH |
445 | blk_queue_for_each_rl(rl, q) |
446 | for (i = 0; i < ARRAY_SIZE(rl->wait); i++) | |
447 | wake_up_all(&rl->wait[i]); | |
458f27a9 | 448 | } |
e3c78ca5 TH |
449 | } |
450 | ||
d732580b TH |
451 | /** |
452 | * blk_queue_bypass_start - enter queue bypass mode | |
453 | * @q: queue of interest | |
454 | * | |
455 | * In bypass mode, only the dispatch FIFO queue of @q is used. This | |
456 | * function makes @q enter bypass mode and drains all requests which were | |
6ecf23af | 457 | * throttled or issued before. On return, it's guaranteed that no request |
80fd9979 TH |
458 | * is being throttled or has ELVPRIV set and blk_queue_bypass() %true |
459 | * inside queue or RCU read lock. | |
d732580b TH |
460 | */ |
461 | void blk_queue_bypass_start(struct request_queue *q) | |
462 | { | |
b82d4b19 TH |
463 | bool drain; |
464 | ||
d732580b | 465 | spin_lock_irq(q->queue_lock); |
b82d4b19 | 466 | drain = !q->bypass_depth++; |
d732580b TH |
467 | queue_flag_set(QUEUE_FLAG_BYPASS, q); |
468 | spin_unlock_irq(q->queue_lock); | |
469 | ||
b82d4b19 | 470 | if (drain) { |
807592a4 BVA |
471 | spin_lock_irq(q->queue_lock); |
472 | __blk_drain_queue(q, false); | |
473 | spin_unlock_irq(q->queue_lock); | |
474 | ||
b82d4b19 TH |
475 | /* ensure blk_queue_bypass() is %true inside RCU read lock */ |
476 | synchronize_rcu(); | |
477 | } | |
d732580b TH |
478 | } |
479 | EXPORT_SYMBOL_GPL(blk_queue_bypass_start); | |
480 | ||
481 | /** | |
482 | * blk_queue_bypass_end - leave queue bypass mode | |
483 | * @q: queue of interest | |
484 | * | |
485 | * Leave bypass mode and restore the normal queueing behavior. | |
486 | */ | |
487 | void blk_queue_bypass_end(struct request_queue *q) | |
488 | { | |
489 | spin_lock_irq(q->queue_lock); | |
490 | if (!--q->bypass_depth) | |
491 | queue_flag_clear(QUEUE_FLAG_BYPASS, q); | |
492 | WARN_ON_ONCE(q->bypass_depth < 0); | |
493 | spin_unlock_irq(q->queue_lock); | |
494 | } | |
495 | EXPORT_SYMBOL_GPL(blk_queue_bypass_end); | |
496 | ||
c9a929dd TH |
497 | /** |
498 | * blk_cleanup_queue - shutdown a request queue | |
499 | * @q: request queue to shutdown | |
500 | * | |
c246e80d BVA |
501 | * Mark @q DYING, drain all pending requests, mark @q DEAD, destroy and |
502 | * put it. All future requests will be failed immediately with -ENODEV. | |
c94a96ac | 503 | */ |
6728cb0e | 504 | void blk_cleanup_queue(struct request_queue *q) |
483f4afc | 505 | { |
c9a929dd | 506 | spinlock_t *lock = q->queue_lock; |
e3335de9 | 507 | |
3f3299d5 | 508 | /* mark @q DYING, no new request or merges will be allowed afterwards */ |
483f4afc | 509 | mutex_lock(&q->sysfs_lock); |
3f3299d5 | 510 | queue_flag_set_unlocked(QUEUE_FLAG_DYING, q); |
c9a929dd | 511 | spin_lock_irq(lock); |
6ecf23af | 512 | |
80fd9979 | 513 | /* |
3f3299d5 | 514 | * A dying queue is permanently in bypass mode till released. Note |
80fd9979 TH |
515 | * that, unlike blk_queue_bypass_start(), we aren't performing |
516 | * synchronize_rcu() after entering bypass mode to avoid the delay | |
517 | * as some drivers create and destroy a lot of queues while | |
518 | * probing. This is still safe because blk_release_queue() will be | |
519 | * called only after the queue refcnt drops to zero and nothing, | |
520 | * RCU or not, would be traversing the queue by then. | |
521 | */ | |
6ecf23af TH |
522 | q->bypass_depth++; |
523 | queue_flag_set(QUEUE_FLAG_BYPASS, q); | |
524 | ||
c9a929dd TH |
525 | queue_flag_set(QUEUE_FLAG_NOMERGES, q); |
526 | queue_flag_set(QUEUE_FLAG_NOXMERGES, q); | |
3f3299d5 | 527 | queue_flag_set(QUEUE_FLAG_DYING, q); |
c9a929dd TH |
528 | spin_unlock_irq(lock); |
529 | mutex_unlock(&q->sysfs_lock); | |
530 | ||
c246e80d BVA |
531 | /* |
532 | * Drain all requests queued before DYING marking. Set DEAD flag to | |
533 | * prevent that q->request_fn() gets invoked after draining finished. | |
534 | */ | |
807592a4 BVA |
535 | spin_lock_irq(lock); |
536 | __blk_drain_queue(q, true); | |
c246e80d | 537 | queue_flag_set(QUEUE_FLAG_DEAD, q); |
807592a4 | 538 | spin_unlock_irq(lock); |
c9a929dd TH |
539 | |
540 | /* @q won't process any more request, flush async actions */ | |
541 | del_timer_sync(&q->backing_dev_info.laptop_mode_wb_timer); | |
542 | blk_sync_queue(q); | |
543 | ||
5e5cfac0 AH |
544 | spin_lock_irq(lock); |
545 | if (q->queue_lock != &q->__queue_lock) | |
546 | q->queue_lock = &q->__queue_lock; | |
547 | spin_unlock_irq(lock); | |
548 | ||
c9a929dd | 549 | /* @q is and will stay empty, shutdown and put */ |
483f4afc AV |
550 | blk_put_queue(q); |
551 | } | |
1da177e4 LT |
552 | EXPORT_SYMBOL(blk_cleanup_queue); |
553 | ||
5b788ce3 TH |
554 | int blk_init_rl(struct request_list *rl, struct request_queue *q, |
555 | gfp_t gfp_mask) | |
1da177e4 | 556 | { |
1abec4fd MS |
557 | if (unlikely(rl->rq_pool)) |
558 | return 0; | |
559 | ||
5b788ce3 | 560 | rl->q = q; |
1faa16d2 JA |
561 | rl->count[BLK_RW_SYNC] = rl->count[BLK_RW_ASYNC] = 0; |
562 | rl->starved[BLK_RW_SYNC] = rl->starved[BLK_RW_ASYNC] = 0; | |
1faa16d2 JA |
563 | init_waitqueue_head(&rl->wait[BLK_RW_SYNC]); |
564 | init_waitqueue_head(&rl->wait[BLK_RW_ASYNC]); | |
1da177e4 | 565 | |
1946089a | 566 | rl->rq_pool = mempool_create_node(BLKDEV_MIN_RQ, mempool_alloc_slab, |
a91a5ac6 | 567 | mempool_free_slab, request_cachep, |
5b788ce3 | 568 | gfp_mask, q->node); |
1da177e4 LT |
569 | if (!rl->rq_pool) |
570 | return -ENOMEM; | |
571 | ||
572 | return 0; | |
573 | } | |
574 | ||
5b788ce3 TH |
575 | void blk_exit_rl(struct request_list *rl) |
576 | { | |
577 | if (rl->rq_pool) | |
578 | mempool_destroy(rl->rq_pool); | |
579 | } | |
580 | ||
165125e1 | 581 | struct request_queue *blk_alloc_queue(gfp_t gfp_mask) |
1da177e4 | 582 | { |
c304a51b | 583 | return blk_alloc_queue_node(gfp_mask, NUMA_NO_NODE); |
1946089a CL |
584 | } |
585 | EXPORT_SYMBOL(blk_alloc_queue); | |
1da177e4 | 586 | |
165125e1 | 587 | struct request_queue *blk_alloc_queue_node(gfp_t gfp_mask, int node_id) |
1946089a | 588 | { |
165125e1 | 589 | struct request_queue *q; |
e0bf68dd | 590 | int err; |
1946089a | 591 | |
8324aa91 | 592 | q = kmem_cache_alloc_node(blk_requestq_cachep, |
94f6030c | 593 | gfp_mask | __GFP_ZERO, node_id); |
1da177e4 LT |
594 | if (!q) |
595 | return NULL; | |
596 | ||
00380a40 | 597 | q->id = ida_simple_get(&blk_queue_ida, 0, 0, gfp_mask); |
a73f730d TH |
598 | if (q->id < 0) |
599 | goto fail_q; | |
600 | ||
0989a025 JA |
601 | q->backing_dev_info.ra_pages = |
602 | (VM_MAX_READAHEAD * 1024) / PAGE_CACHE_SIZE; | |
603 | q->backing_dev_info.state = 0; | |
604 | q->backing_dev_info.capabilities = BDI_CAP_MAP_COPY; | |
d993831f | 605 | q->backing_dev_info.name = "block"; |
5151412d | 606 | q->node = node_id; |
0989a025 | 607 | |
e0bf68dd | 608 | err = bdi_init(&q->backing_dev_info); |
a73f730d TH |
609 | if (err) |
610 | goto fail_id; | |
e0bf68dd | 611 | |
31373d09 MG |
612 | setup_timer(&q->backing_dev_info.laptop_mode_wb_timer, |
613 | laptop_mode_timer_fn, (unsigned long) q); | |
242f9dcb | 614 | setup_timer(&q->timeout, blk_rq_timed_out_timer, (unsigned long) q); |
b855b04a | 615 | INIT_LIST_HEAD(&q->queue_head); |
242f9dcb | 616 | INIT_LIST_HEAD(&q->timeout_list); |
a612fddf | 617 | INIT_LIST_HEAD(&q->icq_list); |
4eef3049 | 618 | #ifdef CONFIG_BLK_CGROUP |
e8989fae | 619 | INIT_LIST_HEAD(&q->blkg_list); |
4eef3049 | 620 | #endif |
ae1b1539 TH |
621 | INIT_LIST_HEAD(&q->flush_queue[0]); |
622 | INIT_LIST_HEAD(&q->flush_queue[1]); | |
623 | INIT_LIST_HEAD(&q->flush_data_in_flight); | |
3cca6dc1 | 624 | INIT_DELAYED_WORK(&q->delay_work, blk_delay_work); |
483f4afc | 625 | |
8324aa91 | 626 | kobject_init(&q->kobj, &blk_queue_ktype); |
1da177e4 | 627 | |
483f4afc | 628 | mutex_init(&q->sysfs_lock); |
e7e72bf6 | 629 | spin_lock_init(&q->__queue_lock); |
483f4afc | 630 | |
c94a96ac VG |
631 | /* |
632 | * By default initialize queue_lock to internal lock and driver can | |
633 | * override it later if need be. | |
634 | */ | |
635 | q->queue_lock = &q->__queue_lock; | |
636 | ||
b82d4b19 TH |
637 | /* |
638 | * A queue starts its life with bypass turned on to avoid | |
639 | * unnecessary bypass on/off overhead and nasty surprises during | |
749fefe6 TH |
640 | * init. The initial bypass will be finished when the queue is |
641 | * registered by blk_register_queue(). | |
b82d4b19 TH |
642 | */ |
643 | q->bypass_depth = 1; | |
644 | __set_bit(QUEUE_FLAG_BYPASS, &q->queue_flags); | |
645 | ||
5efd6113 | 646 | if (blkcg_init_queue(q)) |
f51b802c TH |
647 | goto fail_id; |
648 | ||
1da177e4 | 649 | return q; |
a73f730d TH |
650 | |
651 | fail_id: | |
652 | ida_simple_remove(&blk_queue_ida, q->id); | |
653 | fail_q: | |
654 | kmem_cache_free(blk_requestq_cachep, q); | |
655 | return NULL; | |
1da177e4 | 656 | } |
1946089a | 657 | EXPORT_SYMBOL(blk_alloc_queue_node); |
1da177e4 LT |
658 | |
659 | /** | |
660 | * blk_init_queue - prepare a request queue for use with a block device | |
661 | * @rfn: The function to be called to process requests that have been | |
662 | * placed on the queue. | |
663 | * @lock: Request queue spin lock | |
664 | * | |
665 | * Description: | |
666 | * If a block device wishes to use the standard request handling procedures, | |
667 | * which sorts requests and coalesces adjacent requests, then it must | |
668 | * call blk_init_queue(). The function @rfn will be called when there | |
669 | * are requests on the queue that need to be processed. If the device | |
670 | * supports plugging, then @rfn may not be called immediately when requests | |
671 | * are available on the queue, but may be called at some time later instead. | |
672 | * Plugged queues are generally unplugged when a buffer belonging to one | |
673 | * of the requests on the queue is needed, or due to memory pressure. | |
674 | * | |
675 | * @rfn is not required, or even expected, to remove all requests off the | |
676 | * queue, but only as many as it can handle at a time. If it does leave | |
677 | * requests on the queue, it is responsible for arranging that the requests | |
678 | * get dealt with eventually. | |
679 | * | |
680 | * The queue spin lock must be held while manipulating the requests on the | |
a038e253 PBG |
681 | * request queue; this lock will be taken also from interrupt context, so irq |
682 | * disabling is needed for it. | |
1da177e4 | 683 | * |
710027a4 | 684 | * Function returns a pointer to the initialized request queue, or %NULL if |
1da177e4 LT |
685 | * it didn't succeed. |
686 | * | |
687 | * Note: | |
688 | * blk_init_queue() must be paired with a blk_cleanup_queue() call | |
689 | * when the block device is deactivated (such as at module unload). | |
690 | **/ | |
1946089a | 691 | |
165125e1 | 692 | struct request_queue *blk_init_queue(request_fn_proc *rfn, spinlock_t *lock) |
1da177e4 | 693 | { |
c304a51b | 694 | return blk_init_queue_node(rfn, lock, NUMA_NO_NODE); |
1946089a CL |
695 | } |
696 | EXPORT_SYMBOL(blk_init_queue); | |
697 | ||
165125e1 | 698 | struct request_queue * |
1946089a CL |
699 | blk_init_queue_node(request_fn_proc *rfn, spinlock_t *lock, int node_id) |
700 | { | |
c86d1b8a | 701 | struct request_queue *uninit_q, *q; |
1da177e4 | 702 | |
c86d1b8a MS |
703 | uninit_q = blk_alloc_queue_node(GFP_KERNEL, node_id); |
704 | if (!uninit_q) | |
705 | return NULL; | |
706 | ||
5151412d | 707 | q = blk_init_allocated_queue(uninit_q, rfn, lock); |
c86d1b8a MS |
708 | if (!q) |
709 | blk_cleanup_queue(uninit_q); | |
710 | ||
711 | return q; | |
01effb0d MS |
712 | } |
713 | EXPORT_SYMBOL(blk_init_queue_node); | |
714 | ||
715 | struct request_queue * | |
716 | blk_init_allocated_queue(struct request_queue *q, request_fn_proc *rfn, | |
717 | spinlock_t *lock) | |
01effb0d | 718 | { |
1da177e4 LT |
719 | if (!q) |
720 | return NULL; | |
721 | ||
a051661c | 722 | if (blk_init_rl(&q->root_rl, q, GFP_KERNEL)) |
8669aafd | 723 | return NULL; |
1da177e4 LT |
724 | |
725 | q->request_fn = rfn; | |
1da177e4 | 726 | q->prep_rq_fn = NULL; |
28018c24 | 727 | q->unprep_rq_fn = NULL; |
60ea8226 | 728 | q->queue_flags |= QUEUE_FLAG_DEFAULT; |
c94a96ac VG |
729 | |
730 | /* Override internal queue lock with supplied lock pointer */ | |
731 | if (lock) | |
732 | q->queue_lock = lock; | |
1da177e4 | 733 | |
f3b144aa JA |
734 | /* |
735 | * This also sets hw/phys segments, boundary and size | |
736 | */ | |
c20e8de2 | 737 | blk_queue_make_request(q, blk_queue_bio); |
1da177e4 | 738 | |
44ec9542 AS |
739 | q->sg_reserved_size = INT_MAX; |
740 | ||
b82d4b19 TH |
741 | /* init elevator */ |
742 | if (elevator_init(q, NULL)) | |
743 | return NULL; | |
b82d4b19 | 744 | return q; |
1da177e4 | 745 | } |
5151412d | 746 | EXPORT_SYMBOL(blk_init_allocated_queue); |
1da177e4 | 747 | |
09ac46c4 | 748 | bool blk_get_queue(struct request_queue *q) |
1da177e4 | 749 | { |
3f3299d5 | 750 | if (likely(!blk_queue_dying(q))) { |
09ac46c4 TH |
751 | __blk_get_queue(q); |
752 | return true; | |
1da177e4 LT |
753 | } |
754 | ||
09ac46c4 | 755 | return false; |
1da177e4 | 756 | } |
d86e0e83 | 757 | EXPORT_SYMBOL(blk_get_queue); |
1da177e4 | 758 | |
5b788ce3 | 759 | static inline void blk_free_request(struct request_list *rl, struct request *rq) |
1da177e4 | 760 | { |
f1f8cc94 | 761 | if (rq->cmd_flags & REQ_ELVPRIV) { |
5b788ce3 | 762 | elv_put_request(rl->q, rq); |
f1f8cc94 | 763 | if (rq->elv.icq) |
11a3122f | 764 | put_io_context(rq->elv.icq->ioc); |
f1f8cc94 TH |
765 | } |
766 | ||
5b788ce3 | 767 | mempool_free(rq, rl->rq_pool); |
1da177e4 LT |
768 | } |
769 | ||
1da177e4 LT |
770 | /* |
771 | * ioc_batching returns true if the ioc is a valid batching request and | |
772 | * should be given priority access to a request. | |
773 | */ | |
165125e1 | 774 | static inline int ioc_batching(struct request_queue *q, struct io_context *ioc) |
1da177e4 LT |
775 | { |
776 | if (!ioc) | |
777 | return 0; | |
778 | ||
779 | /* | |
780 | * Make sure the process is able to allocate at least 1 request | |
781 | * even if the batch times out, otherwise we could theoretically | |
782 | * lose wakeups. | |
783 | */ | |
784 | return ioc->nr_batch_requests == q->nr_batching || | |
785 | (ioc->nr_batch_requests > 0 | |
786 | && time_before(jiffies, ioc->last_waited + BLK_BATCH_TIME)); | |
787 | } | |
788 | ||
789 | /* | |
790 | * ioc_set_batching sets ioc to be a new "batcher" if it is not one. This | |
791 | * will cause the process to be a "batcher" on all queues in the system. This | |
792 | * is the behaviour we want though - once it gets a wakeup it should be given | |
793 | * a nice run. | |
794 | */ | |
165125e1 | 795 | static void ioc_set_batching(struct request_queue *q, struct io_context *ioc) |
1da177e4 LT |
796 | { |
797 | if (!ioc || ioc_batching(q, ioc)) | |
798 | return; | |
799 | ||
800 | ioc->nr_batch_requests = q->nr_batching; | |
801 | ioc->last_waited = jiffies; | |
802 | } | |
803 | ||
5b788ce3 | 804 | static void __freed_request(struct request_list *rl, int sync) |
1da177e4 | 805 | { |
5b788ce3 | 806 | struct request_queue *q = rl->q; |
1da177e4 | 807 | |
a051661c TH |
808 | /* |
809 | * bdi isn't aware of blkcg yet. As all async IOs end up root | |
810 | * blkcg anyway, just use root blkcg state. | |
811 | */ | |
812 | if (rl == &q->root_rl && | |
813 | rl->count[sync] < queue_congestion_off_threshold(q)) | |
1faa16d2 | 814 | blk_clear_queue_congested(q, sync); |
1da177e4 | 815 | |
1faa16d2 JA |
816 | if (rl->count[sync] + 1 <= q->nr_requests) { |
817 | if (waitqueue_active(&rl->wait[sync])) | |
818 | wake_up(&rl->wait[sync]); | |
1da177e4 | 819 | |
5b788ce3 | 820 | blk_clear_rl_full(rl, sync); |
1da177e4 LT |
821 | } |
822 | } | |
823 | ||
824 | /* | |
825 | * A request has just been released. Account for it, update the full and | |
826 | * congestion status, wake up any waiters. Called under q->queue_lock. | |
827 | */ | |
5b788ce3 | 828 | static void freed_request(struct request_list *rl, unsigned int flags) |
1da177e4 | 829 | { |
5b788ce3 | 830 | struct request_queue *q = rl->q; |
75eb6c37 | 831 | int sync = rw_is_sync(flags); |
1da177e4 | 832 | |
8a5ecdd4 | 833 | q->nr_rqs[sync]--; |
1faa16d2 | 834 | rl->count[sync]--; |
75eb6c37 | 835 | if (flags & REQ_ELVPRIV) |
8a5ecdd4 | 836 | q->nr_rqs_elvpriv--; |
1da177e4 | 837 | |
5b788ce3 | 838 | __freed_request(rl, sync); |
1da177e4 | 839 | |
1faa16d2 | 840 | if (unlikely(rl->starved[sync ^ 1])) |
5b788ce3 | 841 | __freed_request(rl, sync ^ 1); |
1da177e4 LT |
842 | } |
843 | ||
9d5a4e94 MS |
844 | /* |
845 | * Determine if elevator data should be initialized when allocating the | |
846 | * request associated with @bio. | |
847 | */ | |
848 | static bool blk_rq_should_init_elevator(struct bio *bio) | |
849 | { | |
850 | if (!bio) | |
851 | return true; | |
852 | ||
853 | /* | |
854 | * Flush requests do not use the elevator so skip initialization. | |
855 | * This allows a request to share the flush and elevator data. | |
856 | */ | |
857 | if (bio->bi_rw & (REQ_FLUSH | REQ_FUA)) | |
858 | return false; | |
859 | ||
860 | return true; | |
861 | } | |
862 | ||
852c788f TH |
863 | /** |
864 | * rq_ioc - determine io_context for request allocation | |
865 | * @bio: request being allocated is for this bio (can be %NULL) | |
866 | * | |
867 | * Determine io_context to use for request allocation for @bio. May return | |
868 | * %NULL if %current->io_context doesn't exist. | |
869 | */ | |
870 | static struct io_context *rq_ioc(struct bio *bio) | |
871 | { | |
872 | #ifdef CONFIG_BLK_CGROUP | |
873 | if (bio && bio->bi_ioc) | |
874 | return bio->bi_ioc; | |
875 | #endif | |
876 | return current->io_context; | |
877 | } | |
878 | ||
da8303c6 | 879 | /** |
a06e05e6 | 880 | * __get_request - get a free request |
5b788ce3 | 881 | * @rl: request list to allocate from |
da8303c6 TH |
882 | * @rw_flags: RW and SYNC flags |
883 | * @bio: bio to allocate request for (can be %NULL) | |
884 | * @gfp_mask: allocation mask | |
885 | * | |
886 | * Get a free request from @q. This function may fail under memory | |
887 | * pressure or if @q is dead. | |
888 | * | |
889 | * Must be callled with @q->queue_lock held and, | |
890 | * Returns %NULL on failure, with @q->queue_lock held. | |
891 | * Returns !%NULL on success, with @q->queue_lock *not held*. | |
1da177e4 | 892 | */ |
5b788ce3 | 893 | static struct request *__get_request(struct request_list *rl, int rw_flags, |
a06e05e6 | 894 | struct bio *bio, gfp_t gfp_mask) |
1da177e4 | 895 | { |
5b788ce3 | 896 | struct request_queue *q = rl->q; |
b679281a | 897 | struct request *rq; |
7f4b35d1 TH |
898 | struct elevator_type *et = q->elevator->type; |
899 | struct io_context *ioc = rq_ioc(bio); | |
f1f8cc94 | 900 | struct io_cq *icq = NULL; |
1faa16d2 | 901 | const bool is_sync = rw_is_sync(rw_flags) != 0; |
75eb6c37 | 902 | int may_queue; |
88ee5ef1 | 903 | |
3f3299d5 | 904 | if (unlikely(blk_queue_dying(q))) |
da8303c6 TH |
905 | return NULL; |
906 | ||
7749a8d4 | 907 | may_queue = elv_may_queue(q, rw_flags); |
88ee5ef1 JA |
908 | if (may_queue == ELV_MQUEUE_NO) |
909 | goto rq_starved; | |
910 | ||
1faa16d2 JA |
911 | if (rl->count[is_sync]+1 >= queue_congestion_on_threshold(q)) { |
912 | if (rl->count[is_sync]+1 >= q->nr_requests) { | |
88ee5ef1 JA |
913 | /* |
914 | * The queue will fill after this allocation, so set | |
915 | * it as full, and mark this process as "batching". | |
916 | * This process will be allowed to complete a batch of | |
917 | * requests, others will be blocked. | |
918 | */ | |
5b788ce3 | 919 | if (!blk_rl_full(rl, is_sync)) { |
88ee5ef1 | 920 | ioc_set_batching(q, ioc); |
5b788ce3 | 921 | blk_set_rl_full(rl, is_sync); |
88ee5ef1 JA |
922 | } else { |
923 | if (may_queue != ELV_MQUEUE_MUST | |
924 | && !ioc_batching(q, ioc)) { | |
925 | /* | |
926 | * The queue is full and the allocating | |
927 | * process is not a "batcher", and not | |
928 | * exempted by the IO scheduler | |
929 | */ | |
b679281a | 930 | return NULL; |
88ee5ef1 JA |
931 | } |
932 | } | |
1da177e4 | 933 | } |
a051661c TH |
934 | /* |
935 | * bdi isn't aware of blkcg yet. As all async IOs end up | |
936 | * root blkcg anyway, just use root blkcg state. | |
937 | */ | |
938 | if (rl == &q->root_rl) | |
939 | blk_set_queue_congested(q, is_sync); | |
1da177e4 LT |
940 | } |
941 | ||
082cf69e JA |
942 | /* |
943 | * Only allow batching queuers to allocate up to 50% over the defined | |
944 | * limit of requests, otherwise we could have thousands of requests | |
945 | * allocated with any setting of ->nr_requests | |
946 | */ | |
1faa16d2 | 947 | if (rl->count[is_sync] >= (3 * q->nr_requests / 2)) |
b679281a | 948 | return NULL; |
fd782a4a | 949 | |
8a5ecdd4 | 950 | q->nr_rqs[is_sync]++; |
1faa16d2 JA |
951 | rl->count[is_sync]++; |
952 | rl->starved[is_sync] = 0; | |
cb98fc8b | 953 | |
f1f8cc94 TH |
954 | /* |
955 | * Decide whether the new request will be managed by elevator. If | |
956 | * so, mark @rw_flags and increment elvpriv. Non-zero elvpriv will | |
957 | * prevent the current elevator from being destroyed until the new | |
958 | * request is freed. This guarantees icq's won't be destroyed and | |
959 | * makes creating new ones safe. | |
960 | * | |
961 | * Also, lookup icq while holding queue_lock. If it doesn't exist, | |
962 | * it will be created after releasing queue_lock. | |
963 | */ | |
d732580b | 964 | if (blk_rq_should_init_elevator(bio) && !blk_queue_bypass(q)) { |
75eb6c37 | 965 | rw_flags |= REQ_ELVPRIV; |
8a5ecdd4 | 966 | q->nr_rqs_elvpriv++; |
f1f8cc94 TH |
967 | if (et->icq_cache && ioc) |
968 | icq = ioc_lookup_icq(ioc, q); | |
9d5a4e94 | 969 | } |
cb98fc8b | 970 | |
f253b86b JA |
971 | if (blk_queue_io_stat(q)) |
972 | rw_flags |= REQ_IO_STAT; | |
1da177e4 LT |
973 | spin_unlock_irq(q->queue_lock); |
974 | ||
29e2b09a | 975 | /* allocate and init request */ |
5b788ce3 | 976 | rq = mempool_alloc(rl->rq_pool, gfp_mask); |
29e2b09a | 977 | if (!rq) |
b679281a | 978 | goto fail_alloc; |
1da177e4 | 979 | |
29e2b09a | 980 | blk_rq_init(q, rq); |
a051661c | 981 | blk_rq_set_rl(rq, rl); |
29e2b09a TH |
982 | rq->cmd_flags = rw_flags | REQ_ALLOCED; |
983 | ||
aaf7c680 | 984 | /* init elvpriv */ |
29e2b09a | 985 | if (rw_flags & REQ_ELVPRIV) { |
aaf7c680 | 986 | if (unlikely(et->icq_cache && !icq)) { |
7f4b35d1 TH |
987 | if (ioc) |
988 | icq = ioc_create_icq(ioc, q, gfp_mask); | |
aaf7c680 TH |
989 | if (!icq) |
990 | goto fail_elvpriv; | |
29e2b09a | 991 | } |
aaf7c680 TH |
992 | |
993 | rq->elv.icq = icq; | |
994 | if (unlikely(elv_set_request(q, rq, bio, gfp_mask))) | |
995 | goto fail_elvpriv; | |
996 | ||
997 | /* @rq->elv.icq holds io_context until @rq is freed */ | |
29e2b09a TH |
998 | if (icq) |
999 | get_io_context(icq->ioc); | |
1000 | } | |
aaf7c680 | 1001 | out: |
88ee5ef1 JA |
1002 | /* |
1003 | * ioc may be NULL here, and ioc_batching will be false. That's | |
1004 | * OK, if the queue is under the request limit then requests need | |
1005 | * not count toward the nr_batch_requests limit. There will always | |
1006 | * be some limit enforced by BLK_BATCH_TIME. | |
1007 | */ | |
1da177e4 LT |
1008 | if (ioc_batching(q, ioc)) |
1009 | ioc->nr_batch_requests--; | |
6728cb0e | 1010 | |
1faa16d2 | 1011 | trace_block_getrq(q, bio, rw_flags & 1); |
1da177e4 | 1012 | return rq; |
b679281a | 1013 | |
aaf7c680 TH |
1014 | fail_elvpriv: |
1015 | /* | |
1016 | * elvpriv init failed. ioc, icq and elvpriv aren't mempool backed | |
1017 | * and may fail indefinitely under memory pressure and thus | |
1018 | * shouldn't stall IO. Treat this request as !elvpriv. This will | |
1019 | * disturb iosched and blkcg but weird is bettern than dead. | |
1020 | */ | |
1021 | printk_ratelimited(KERN_WARNING "%s: request aux data allocation failed, iosched may be disturbed\n", | |
1022 | dev_name(q->backing_dev_info.dev)); | |
1023 | ||
1024 | rq->cmd_flags &= ~REQ_ELVPRIV; | |
1025 | rq->elv.icq = NULL; | |
1026 | ||
1027 | spin_lock_irq(q->queue_lock); | |
8a5ecdd4 | 1028 | q->nr_rqs_elvpriv--; |
aaf7c680 TH |
1029 | spin_unlock_irq(q->queue_lock); |
1030 | goto out; | |
1031 | ||
b679281a TH |
1032 | fail_alloc: |
1033 | /* | |
1034 | * Allocation failed presumably due to memory. Undo anything we | |
1035 | * might have messed up. | |
1036 | * | |
1037 | * Allocating task should really be put onto the front of the wait | |
1038 | * queue, but this is pretty rare. | |
1039 | */ | |
1040 | spin_lock_irq(q->queue_lock); | |
5b788ce3 | 1041 | freed_request(rl, rw_flags); |
b679281a TH |
1042 | |
1043 | /* | |
1044 | * in the very unlikely event that allocation failed and no | |
1045 | * requests for this direction was pending, mark us starved so that | |
1046 | * freeing of a request in the other direction will notice | |
1047 | * us. another possible fix would be to split the rq mempool into | |
1048 | * READ and WRITE | |
1049 | */ | |
1050 | rq_starved: | |
1051 | if (unlikely(rl->count[is_sync] == 0)) | |
1052 | rl->starved[is_sync] = 1; | |
1053 | return NULL; | |
1da177e4 LT |
1054 | } |
1055 | ||
da8303c6 | 1056 | /** |
a06e05e6 | 1057 | * get_request - get a free request |
da8303c6 TH |
1058 | * @q: request_queue to allocate request from |
1059 | * @rw_flags: RW and SYNC flags | |
1060 | * @bio: bio to allocate request for (can be %NULL) | |
a06e05e6 | 1061 | * @gfp_mask: allocation mask |
da8303c6 | 1062 | * |
a06e05e6 TH |
1063 | * Get a free request from @q. If %__GFP_WAIT is set in @gfp_mask, this |
1064 | * function keeps retrying under memory pressure and fails iff @q is dead. | |
d6344532 | 1065 | * |
da8303c6 TH |
1066 | * Must be callled with @q->queue_lock held and, |
1067 | * Returns %NULL on failure, with @q->queue_lock held. | |
1068 | * Returns !%NULL on success, with @q->queue_lock *not held*. | |
1da177e4 | 1069 | */ |
a06e05e6 TH |
1070 | static struct request *get_request(struct request_queue *q, int rw_flags, |
1071 | struct bio *bio, gfp_t gfp_mask) | |
1da177e4 | 1072 | { |
1faa16d2 | 1073 | const bool is_sync = rw_is_sync(rw_flags) != 0; |
a06e05e6 | 1074 | DEFINE_WAIT(wait); |
a051661c | 1075 | struct request_list *rl; |
1da177e4 | 1076 | struct request *rq; |
a051661c TH |
1077 | |
1078 | rl = blk_get_rl(q, bio); /* transferred to @rq on success */ | |
a06e05e6 | 1079 | retry: |
a051661c | 1080 | rq = __get_request(rl, rw_flags, bio, gfp_mask); |
a06e05e6 TH |
1081 | if (rq) |
1082 | return rq; | |
1da177e4 | 1083 | |
3f3299d5 | 1084 | if (!(gfp_mask & __GFP_WAIT) || unlikely(blk_queue_dying(q))) { |
a051661c | 1085 | blk_put_rl(rl); |
a06e05e6 | 1086 | return NULL; |
a051661c | 1087 | } |
1da177e4 | 1088 | |
a06e05e6 TH |
1089 | /* wait on @rl and retry */ |
1090 | prepare_to_wait_exclusive(&rl->wait[is_sync], &wait, | |
1091 | TASK_UNINTERRUPTIBLE); | |
1da177e4 | 1092 | |
a06e05e6 | 1093 | trace_block_sleeprq(q, bio, rw_flags & 1); |
1da177e4 | 1094 | |
a06e05e6 TH |
1095 | spin_unlock_irq(q->queue_lock); |
1096 | io_schedule(); | |
d6344532 | 1097 | |
a06e05e6 TH |
1098 | /* |
1099 | * After sleeping, we become a "batching" process and will be able | |
1100 | * to allocate at least one request, and up to a big batch of them | |
1101 | * for a small period time. See ioc_batching, ioc_set_batching | |
1102 | */ | |
a06e05e6 | 1103 | ioc_set_batching(q, current->io_context); |
05caf8db | 1104 | |
a06e05e6 TH |
1105 | spin_lock_irq(q->queue_lock); |
1106 | finish_wait(&rl->wait[is_sync], &wait); | |
1da177e4 | 1107 | |
a06e05e6 | 1108 | goto retry; |
1da177e4 LT |
1109 | } |
1110 | ||
165125e1 | 1111 | struct request *blk_get_request(struct request_queue *q, int rw, gfp_t gfp_mask) |
1da177e4 LT |
1112 | { |
1113 | struct request *rq; | |
1114 | ||
1115 | BUG_ON(rw != READ && rw != WRITE); | |
1116 | ||
7f4b35d1 TH |
1117 | /* create ioc upfront */ |
1118 | create_io_context(gfp_mask, q->node); | |
1119 | ||
d6344532 | 1120 | spin_lock_irq(q->queue_lock); |
a06e05e6 | 1121 | rq = get_request(q, rw, NULL, gfp_mask); |
da8303c6 TH |
1122 | if (!rq) |
1123 | spin_unlock_irq(q->queue_lock); | |
d6344532 | 1124 | /* q->queue_lock is unlocked at this point */ |
1da177e4 LT |
1125 | |
1126 | return rq; | |
1127 | } | |
1da177e4 LT |
1128 | EXPORT_SYMBOL(blk_get_request); |
1129 | ||
dc72ef4a | 1130 | /** |
79eb63e9 | 1131 | * blk_make_request - given a bio, allocate a corresponding struct request. |
8ebf9756 | 1132 | * @q: target request queue |
79eb63e9 BH |
1133 | * @bio: The bio describing the memory mappings that will be submitted for IO. |
1134 | * It may be a chained-bio properly constructed by block/bio layer. | |
8ebf9756 | 1135 | * @gfp_mask: gfp flags to be used for memory allocation |
dc72ef4a | 1136 | * |
79eb63e9 BH |
1137 | * blk_make_request is the parallel of generic_make_request for BLOCK_PC |
1138 | * type commands. Where the struct request needs to be farther initialized by | |
1139 | * the caller. It is passed a &struct bio, which describes the memory info of | |
1140 | * the I/O transfer. | |
dc72ef4a | 1141 | * |
79eb63e9 BH |
1142 | * The caller of blk_make_request must make sure that bi_io_vec |
1143 | * are set to describe the memory buffers. That bio_data_dir() will return | |
1144 | * the needed direction of the request. (And all bio's in the passed bio-chain | |
1145 | * are properly set accordingly) | |
1146 | * | |
1147 | * If called under none-sleepable conditions, mapped bio buffers must not | |
1148 | * need bouncing, by calling the appropriate masked or flagged allocator, | |
1149 | * suitable for the target device. Otherwise the call to blk_queue_bounce will | |
1150 | * BUG. | |
53674ac5 JA |
1151 | * |
1152 | * WARNING: When allocating/cloning a bio-chain, careful consideration should be | |
1153 | * given to how you allocate bios. In particular, you cannot use __GFP_WAIT for | |
1154 | * anything but the first bio in the chain. Otherwise you risk waiting for IO | |
1155 | * completion of a bio that hasn't been submitted yet, thus resulting in a | |
1156 | * deadlock. Alternatively bios should be allocated using bio_kmalloc() instead | |
1157 | * of bio_alloc(), as that avoids the mempool deadlock. | |
1158 | * If possible a big IO should be split into smaller parts when allocation | |
1159 | * fails. Partial allocation should not be an error, or you risk a live-lock. | |
dc72ef4a | 1160 | */ |
79eb63e9 BH |
1161 | struct request *blk_make_request(struct request_queue *q, struct bio *bio, |
1162 | gfp_t gfp_mask) | |
dc72ef4a | 1163 | { |
79eb63e9 BH |
1164 | struct request *rq = blk_get_request(q, bio_data_dir(bio), gfp_mask); |
1165 | ||
1166 | if (unlikely(!rq)) | |
1167 | return ERR_PTR(-ENOMEM); | |
1168 | ||
1169 | for_each_bio(bio) { | |
1170 | struct bio *bounce_bio = bio; | |
1171 | int ret; | |
1172 | ||
1173 | blk_queue_bounce(q, &bounce_bio); | |
1174 | ret = blk_rq_append_bio(q, rq, bounce_bio); | |
1175 | if (unlikely(ret)) { | |
1176 | blk_put_request(rq); | |
1177 | return ERR_PTR(ret); | |
1178 | } | |
1179 | } | |
1180 | ||
1181 | return rq; | |
dc72ef4a | 1182 | } |
79eb63e9 | 1183 | EXPORT_SYMBOL(blk_make_request); |
dc72ef4a | 1184 | |
1da177e4 LT |
1185 | /** |
1186 | * blk_requeue_request - put a request back on queue | |
1187 | * @q: request queue where request should be inserted | |
1188 | * @rq: request to be inserted | |
1189 | * | |
1190 | * Description: | |
1191 | * Drivers often keep queueing requests until the hardware cannot accept | |
1192 | * more, when that condition happens we need to put the request back | |
1193 | * on the queue. Must be called with queue lock held. | |
1194 | */ | |
165125e1 | 1195 | void blk_requeue_request(struct request_queue *q, struct request *rq) |
1da177e4 | 1196 | { |
242f9dcb JA |
1197 | blk_delete_timer(rq); |
1198 | blk_clear_rq_complete(rq); | |
5f3ea37c | 1199 | trace_block_rq_requeue(q, rq); |
2056a782 | 1200 | |
1da177e4 LT |
1201 | if (blk_rq_tagged(rq)) |
1202 | blk_queue_end_tag(q, rq); | |
1203 | ||
ba396a6c JB |
1204 | BUG_ON(blk_queued_rq(rq)); |
1205 | ||
1da177e4 LT |
1206 | elv_requeue_request(q, rq); |
1207 | } | |
1da177e4 LT |
1208 | EXPORT_SYMBOL(blk_requeue_request); |
1209 | ||
73c10101 JA |
1210 | static void add_acct_request(struct request_queue *q, struct request *rq, |
1211 | int where) | |
1212 | { | |
1213 | drive_stat_acct(rq, 1); | |
7eaceacc | 1214 | __elv_add_request(q, rq, where); |
73c10101 JA |
1215 | } |
1216 | ||
074a7aca TH |
1217 | static void part_round_stats_single(int cpu, struct hd_struct *part, |
1218 | unsigned long now) | |
1219 | { | |
1220 | if (now == part->stamp) | |
1221 | return; | |
1222 | ||
316d315b | 1223 | if (part_in_flight(part)) { |
074a7aca | 1224 | __part_stat_add(cpu, part, time_in_queue, |
316d315b | 1225 | part_in_flight(part) * (now - part->stamp)); |
074a7aca TH |
1226 | __part_stat_add(cpu, part, io_ticks, (now - part->stamp)); |
1227 | } | |
1228 | part->stamp = now; | |
1229 | } | |
1230 | ||
1231 | /** | |
496aa8a9 RD |
1232 | * part_round_stats() - Round off the performance stats on a struct disk_stats. |
1233 | * @cpu: cpu number for stats access | |
1234 | * @part: target partition | |
1da177e4 LT |
1235 | * |
1236 | * The average IO queue length and utilisation statistics are maintained | |
1237 | * by observing the current state of the queue length and the amount of | |
1238 | * time it has been in this state for. | |
1239 | * | |
1240 | * Normally, that accounting is done on IO completion, but that can result | |
1241 | * in more than a second's worth of IO being accounted for within any one | |
1242 | * second, leading to >100% utilisation. To deal with that, we call this | |
1243 | * function to do a round-off before returning the results when reading | |
1244 | * /proc/diskstats. This accounts immediately for all queue usage up to | |
1245 | * the current jiffies and restarts the counters again. | |
1246 | */ | |
c9959059 | 1247 | void part_round_stats(int cpu, struct hd_struct *part) |
6f2576af JM |
1248 | { |
1249 | unsigned long now = jiffies; | |
1250 | ||
074a7aca TH |
1251 | if (part->partno) |
1252 | part_round_stats_single(cpu, &part_to_disk(part)->part0, now); | |
1253 | part_round_stats_single(cpu, part, now); | |
6f2576af | 1254 | } |
074a7aca | 1255 | EXPORT_SYMBOL_GPL(part_round_stats); |
6f2576af | 1256 | |
c8158819 LM |
1257 | #ifdef CONFIG_PM_RUNTIME |
1258 | static void blk_pm_put_request(struct request *rq) | |
1259 | { | |
1260 | if (rq->q->dev && !(rq->cmd_flags & REQ_PM) && !--rq->q->nr_pending) | |
1261 | pm_runtime_mark_last_busy(rq->q->dev); | |
1262 | } | |
1263 | #else | |
1264 | static inline void blk_pm_put_request(struct request *rq) {} | |
1265 | #endif | |
1266 | ||
1da177e4 LT |
1267 | /* |
1268 | * queue lock must be held | |
1269 | */ | |
165125e1 | 1270 | void __blk_put_request(struct request_queue *q, struct request *req) |
1da177e4 | 1271 | { |
1da177e4 LT |
1272 | if (unlikely(!q)) |
1273 | return; | |
1da177e4 | 1274 | |
c8158819 LM |
1275 | blk_pm_put_request(req); |
1276 | ||
8922e16c TH |
1277 | elv_completed_request(q, req); |
1278 | ||
1cd96c24 BH |
1279 | /* this is a bio leak */ |
1280 | WARN_ON(req->bio != NULL); | |
1281 | ||
1da177e4 LT |
1282 | /* |
1283 | * Request may not have originated from ll_rw_blk. if not, | |
1284 | * it didn't come out of our reserved rq pools | |
1285 | */ | |
49171e5c | 1286 | if (req->cmd_flags & REQ_ALLOCED) { |
75eb6c37 | 1287 | unsigned int flags = req->cmd_flags; |
a051661c | 1288 | struct request_list *rl = blk_rq_rl(req); |
1da177e4 | 1289 | |
1da177e4 | 1290 | BUG_ON(!list_empty(&req->queuelist)); |
9817064b | 1291 | BUG_ON(!hlist_unhashed(&req->hash)); |
1da177e4 | 1292 | |
a051661c TH |
1293 | blk_free_request(rl, req); |
1294 | freed_request(rl, flags); | |
1295 | blk_put_rl(rl); | |
1da177e4 LT |
1296 | } |
1297 | } | |
6e39b69e MC |
1298 | EXPORT_SYMBOL_GPL(__blk_put_request); |
1299 | ||
1da177e4 LT |
1300 | void blk_put_request(struct request *req) |
1301 | { | |
8922e16c | 1302 | unsigned long flags; |
165125e1 | 1303 | struct request_queue *q = req->q; |
8922e16c | 1304 | |
52a93ba8 FT |
1305 | spin_lock_irqsave(q->queue_lock, flags); |
1306 | __blk_put_request(q, req); | |
1307 | spin_unlock_irqrestore(q->queue_lock, flags); | |
1da177e4 | 1308 | } |
1da177e4 LT |
1309 | EXPORT_SYMBOL(blk_put_request); |
1310 | ||
66ac0280 CH |
1311 | /** |
1312 | * blk_add_request_payload - add a payload to a request | |
1313 | * @rq: request to update | |
1314 | * @page: page backing the payload | |
1315 | * @len: length of the payload. | |
1316 | * | |
1317 | * This allows to later add a payload to an already submitted request by | |
1318 | * a block driver. The driver needs to take care of freeing the payload | |
1319 | * itself. | |
1320 | * | |
1321 | * Note that this is a quite horrible hack and nothing but handling of | |
1322 | * discard requests should ever use it. | |
1323 | */ | |
1324 | void blk_add_request_payload(struct request *rq, struct page *page, | |
1325 | unsigned int len) | |
1326 | { | |
1327 | struct bio *bio = rq->bio; | |
1328 | ||
1329 | bio->bi_io_vec->bv_page = page; | |
1330 | bio->bi_io_vec->bv_offset = 0; | |
1331 | bio->bi_io_vec->bv_len = len; | |
1332 | ||
1333 | bio->bi_size = len; | |
1334 | bio->bi_vcnt = 1; | |
1335 | bio->bi_phys_segments = 1; | |
1336 | ||
1337 | rq->__data_len = rq->resid_len = len; | |
1338 | rq->nr_phys_segments = 1; | |
1339 | rq->buffer = bio_data(bio); | |
1340 | } | |
1341 | EXPORT_SYMBOL_GPL(blk_add_request_payload); | |
1342 | ||
73c10101 JA |
1343 | static bool bio_attempt_back_merge(struct request_queue *q, struct request *req, |
1344 | struct bio *bio) | |
1345 | { | |
1346 | const int ff = bio->bi_rw & REQ_FAILFAST_MASK; | |
1347 | ||
73c10101 JA |
1348 | if (!ll_back_merge_fn(q, req, bio)) |
1349 | return false; | |
1350 | ||
8c1cf6bb | 1351 | trace_block_bio_backmerge(q, req, bio); |
73c10101 JA |
1352 | |
1353 | if ((req->cmd_flags & REQ_FAILFAST_MASK) != ff) | |
1354 | blk_rq_set_mixed_merge(req); | |
1355 | ||
1356 | req->biotail->bi_next = bio; | |
1357 | req->biotail = bio; | |
1358 | req->__data_len += bio->bi_size; | |
1359 | req->ioprio = ioprio_best(req->ioprio, bio_prio(bio)); | |
1360 | ||
1361 | drive_stat_acct(req, 0); | |
1362 | return true; | |
1363 | } | |
1364 | ||
1365 | static bool bio_attempt_front_merge(struct request_queue *q, | |
1366 | struct request *req, struct bio *bio) | |
1367 | { | |
1368 | const int ff = bio->bi_rw & REQ_FAILFAST_MASK; | |
73c10101 | 1369 | |
73c10101 JA |
1370 | if (!ll_front_merge_fn(q, req, bio)) |
1371 | return false; | |
1372 | ||
8c1cf6bb | 1373 | trace_block_bio_frontmerge(q, req, bio); |
73c10101 JA |
1374 | |
1375 | if ((req->cmd_flags & REQ_FAILFAST_MASK) != ff) | |
1376 | blk_rq_set_mixed_merge(req); | |
1377 | ||
73c10101 JA |
1378 | bio->bi_next = req->bio; |
1379 | req->bio = bio; | |
1380 | ||
1381 | /* | |
1382 | * may not be valid. if the low level driver said | |
1383 | * it didn't need a bounce buffer then it better | |
1384 | * not touch req->buffer either... | |
1385 | */ | |
1386 | req->buffer = bio_data(bio); | |
1387 | req->__sector = bio->bi_sector; | |
1388 | req->__data_len += bio->bi_size; | |
1389 | req->ioprio = ioprio_best(req->ioprio, bio_prio(bio)); | |
1390 | ||
1391 | drive_stat_acct(req, 0); | |
1392 | return true; | |
1393 | } | |
1394 | ||
bd87b589 TH |
1395 | /** |
1396 | * attempt_plug_merge - try to merge with %current's plugged list | |
1397 | * @q: request_queue new bio is being queued at | |
1398 | * @bio: new bio being queued | |
1399 | * @request_count: out parameter for number of traversed plugged requests | |
1400 | * | |
1401 | * Determine whether @bio being queued on @q can be merged with a request | |
1402 | * on %current's plugged list. Returns %true if merge was successful, | |
1403 | * otherwise %false. | |
1404 | * | |
07c2bd37 TH |
1405 | * Plugging coalesces IOs from the same issuer for the same purpose without |
1406 | * going through @q->queue_lock. As such it's more of an issuing mechanism | |
1407 | * than scheduling, and the request, while may have elvpriv data, is not | |
1408 | * added on the elevator at this point. In addition, we don't have | |
1409 | * reliable access to the elevator outside queue lock. Only check basic | |
1410 | * merging parameters without querying the elevator. | |
73c10101 | 1411 | */ |
bd87b589 TH |
1412 | static bool attempt_plug_merge(struct request_queue *q, struct bio *bio, |
1413 | unsigned int *request_count) | |
73c10101 JA |
1414 | { |
1415 | struct blk_plug *plug; | |
1416 | struct request *rq; | |
1417 | bool ret = false; | |
1418 | ||
bd87b589 | 1419 | plug = current->plug; |
73c10101 JA |
1420 | if (!plug) |
1421 | goto out; | |
56ebdaf2 | 1422 | *request_count = 0; |
73c10101 JA |
1423 | |
1424 | list_for_each_entry_reverse(rq, &plug->list, queuelist) { | |
1425 | int el_ret; | |
1426 | ||
1b2e19f1 SL |
1427 | if (rq->q == q) |
1428 | (*request_count)++; | |
56ebdaf2 | 1429 | |
07c2bd37 | 1430 | if (rq->q != q || !blk_rq_merge_ok(rq, bio)) |
73c10101 JA |
1431 | continue; |
1432 | ||
050c8ea8 | 1433 | el_ret = blk_try_merge(rq, bio); |
73c10101 JA |
1434 | if (el_ret == ELEVATOR_BACK_MERGE) { |
1435 | ret = bio_attempt_back_merge(q, rq, bio); | |
1436 | if (ret) | |
1437 | break; | |
1438 | } else if (el_ret == ELEVATOR_FRONT_MERGE) { | |
1439 | ret = bio_attempt_front_merge(q, rq, bio); | |
1440 | if (ret) | |
1441 | break; | |
1442 | } | |
1443 | } | |
1444 | out: | |
1445 | return ret; | |
1446 | } | |
1447 | ||
86db1e29 | 1448 | void init_request_from_bio(struct request *req, struct bio *bio) |
52d9e675 | 1449 | { |
4aff5e23 | 1450 | req->cmd_type = REQ_TYPE_FS; |
52d9e675 | 1451 | |
7b6d91da CH |
1452 | req->cmd_flags |= bio->bi_rw & REQ_COMMON_MASK; |
1453 | if (bio->bi_rw & REQ_RAHEAD) | |
a82afdfc | 1454 | req->cmd_flags |= REQ_FAILFAST_MASK; |
b31dc66a | 1455 | |
52d9e675 | 1456 | req->errors = 0; |
a2dec7b3 | 1457 | req->__sector = bio->bi_sector; |
52d9e675 | 1458 | req->ioprio = bio_prio(bio); |
bc1c56fd | 1459 | blk_rq_bio_prep(req->q, req, bio); |
52d9e675 TH |
1460 | } |
1461 | ||
5a7bbad2 | 1462 | void blk_queue_bio(struct request_queue *q, struct bio *bio) |
1da177e4 | 1463 | { |
5e00d1b5 | 1464 | const bool sync = !!(bio->bi_rw & REQ_SYNC); |
73c10101 JA |
1465 | struct blk_plug *plug; |
1466 | int el_ret, rw_flags, where = ELEVATOR_INSERT_SORT; | |
1467 | struct request *req; | |
56ebdaf2 | 1468 | unsigned int request_count = 0; |
1da177e4 | 1469 | |
1da177e4 LT |
1470 | /* |
1471 | * low level driver can indicate that it wants pages above a | |
1472 | * certain limit bounced to low memory (ie for highmem, or even | |
1473 | * ISA dma in theory) | |
1474 | */ | |
1475 | blk_queue_bounce(q, &bio); | |
1476 | ||
ffecfd1a DW |
1477 | if (bio_integrity_enabled(bio) && bio_integrity_prep(bio)) { |
1478 | bio_endio(bio, -EIO); | |
1479 | return; | |
1480 | } | |
1481 | ||
4fed947c | 1482 | if (bio->bi_rw & (REQ_FLUSH | REQ_FUA)) { |
73c10101 | 1483 | spin_lock_irq(q->queue_lock); |
ae1b1539 | 1484 | where = ELEVATOR_INSERT_FLUSH; |
28e7d184 TH |
1485 | goto get_rq; |
1486 | } | |
1487 | ||
73c10101 JA |
1488 | /* |
1489 | * Check if we can merge with the plugged list before grabbing | |
1490 | * any locks. | |
1491 | */ | |
bd87b589 | 1492 | if (attempt_plug_merge(q, bio, &request_count)) |
5a7bbad2 | 1493 | return; |
1da177e4 | 1494 | |
73c10101 | 1495 | spin_lock_irq(q->queue_lock); |
2056a782 | 1496 | |
73c10101 JA |
1497 | el_ret = elv_merge(q, &req, bio); |
1498 | if (el_ret == ELEVATOR_BACK_MERGE) { | |
73c10101 | 1499 | if (bio_attempt_back_merge(q, req, bio)) { |
07c2bd37 | 1500 | elv_bio_merged(q, req, bio); |
73c10101 JA |
1501 | if (!attempt_back_merge(q, req)) |
1502 | elv_merged_request(q, req, el_ret); | |
1503 | goto out_unlock; | |
1504 | } | |
1505 | } else if (el_ret == ELEVATOR_FRONT_MERGE) { | |
73c10101 | 1506 | if (bio_attempt_front_merge(q, req, bio)) { |
07c2bd37 | 1507 | elv_bio_merged(q, req, bio); |
73c10101 JA |
1508 | if (!attempt_front_merge(q, req)) |
1509 | elv_merged_request(q, req, el_ret); | |
1510 | goto out_unlock; | |
80a761fd | 1511 | } |
1da177e4 LT |
1512 | } |
1513 | ||
450991bc | 1514 | get_rq: |
7749a8d4 JA |
1515 | /* |
1516 | * This sync check and mask will be re-done in init_request_from_bio(), | |
1517 | * but we need to set it earlier to expose the sync flag to the | |
1518 | * rq allocator and io schedulers. | |
1519 | */ | |
1520 | rw_flags = bio_data_dir(bio); | |
1521 | if (sync) | |
7b6d91da | 1522 | rw_flags |= REQ_SYNC; |
7749a8d4 | 1523 | |
1da177e4 | 1524 | /* |
450991bc | 1525 | * Grab a free request. This is might sleep but can not fail. |
d6344532 | 1526 | * Returns with the queue unlocked. |
450991bc | 1527 | */ |
a06e05e6 | 1528 | req = get_request(q, rw_flags, bio, GFP_NOIO); |
da8303c6 TH |
1529 | if (unlikely(!req)) { |
1530 | bio_endio(bio, -ENODEV); /* @q is dead */ | |
1531 | goto out_unlock; | |
1532 | } | |
d6344532 | 1533 | |
450991bc NP |
1534 | /* |
1535 | * After dropping the lock and possibly sleeping here, our request | |
1536 | * may now be mergeable after it had proven unmergeable (above). | |
1537 | * We don't worry about that case for efficiency. It won't happen | |
1538 | * often, and the elevators are able to handle it. | |
1da177e4 | 1539 | */ |
52d9e675 | 1540 | init_request_from_bio(req, bio); |
1da177e4 | 1541 | |
9562ad9a | 1542 | if (test_bit(QUEUE_FLAG_SAME_COMP, &q->queue_flags)) |
11ccf116 | 1543 | req->cpu = raw_smp_processor_id(); |
73c10101 JA |
1544 | |
1545 | plug = current->plug; | |
721a9602 | 1546 | if (plug) { |
dc6d36c9 JA |
1547 | /* |
1548 | * If this is the first request added after a plug, fire | |
7aef2e78 | 1549 | * of a plug trace. |
dc6d36c9 | 1550 | */ |
7aef2e78 | 1551 | if (!request_count) |
dc6d36c9 | 1552 | trace_block_plug(q); |
3540d5e8 | 1553 | else { |
019ceb7d | 1554 | if (request_count >= BLK_MAX_REQUEST_COUNT) { |
3540d5e8 | 1555 | blk_flush_plug_list(plug, false); |
019ceb7d SL |
1556 | trace_block_plug(q); |
1557 | } | |
73c10101 | 1558 | } |
73c10101 JA |
1559 | list_add_tail(&req->queuelist, &plug->list); |
1560 | drive_stat_acct(req, 1); | |
1561 | } else { | |
1562 | spin_lock_irq(q->queue_lock); | |
1563 | add_acct_request(q, req, where); | |
24ecfbe2 | 1564 | __blk_run_queue(q); |
73c10101 JA |
1565 | out_unlock: |
1566 | spin_unlock_irq(q->queue_lock); | |
1567 | } | |
1da177e4 | 1568 | } |
c20e8de2 | 1569 | EXPORT_SYMBOL_GPL(blk_queue_bio); /* for device mapper only */ |
1da177e4 LT |
1570 | |
1571 | /* | |
1572 | * If bio->bi_dev is a partition, remap the location | |
1573 | */ | |
1574 | static inline void blk_partition_remap(struct bio *bio) | |
1575 | { | |
1576 | struct block_device *bdev = bio->bi_bdev; | |
1577 | ||
bf2de6f5 | 1578 | if (bio_sectors(bio) && bdev != bdev->bd_contains) { |
1da177e4 LT |
1579 | struct hd_struct *p = bdev->bd_part; |
1580 | ||
1da177e4 LT |
1581 | bio->bi_sector += p->start_sect; |
1582 | bio->bi_bdev = bdev->bd_contains; | |
c7149d6b | 1583 | |
d07335e5 MS |
1584 | trace_block_bio_remap(bdev_get_queue(bio->bi_bdev), bio, |
1585 | bdev->bd_dev, | |
1586 | bio->bi_sector - p->start_sect); | |
1da177e4 LT |
1587 | } |
1588 | } | |
1589 | ||
1da177e4 LT |
1590 | static void handle_bad_sector(struct bio *bio) |
1591 | { | |
1592 | char b[BDEVNAME_SIZE]; | |
1593 | ||
1594 | printk(KERN_INFO "attempt to access beyond end of device\n"); | |
1595 | printk(KERN_INFO "%s: rw=%ld, want=%Lu, limit=%Lu\n", | |
1596 | bdevname(bio->bi_bdev, b), | |
1597 | bio->bi_rw, | |
f73a1c7d | 1598 | (unsigned long long)bio_end_sector(bio), |
77304d2a | 1599 | (long long)(i_size_read(bio->bi_bdev->bd_inode) >> 9)); |
1da177e4 LT |
1600 | |
1601 | set_bit(BIO_EOF, &bio->bi_flags); | |
1602 | } | |
1603 | ||
c17bb495 AM |
1604 | #ifdef CONFIG_FAIL_MAKE_REQUEST |
1605 | ||
1606 | static DECLARE_FAULT_ATTR(fail_make_request); | |
1607 | ||
1608 | static int __init setup_fail_make_request(char *str) | |
1609 | { | |
1610 | return setup_fault_attr(&fail_make_request, str); | |
1611 | } | |
1612 | __setup("fail_make_request=", setup_fail_make_request); | |
1613 | ||
b2c9cd37 | 1614 | static bool should_fail_request(struct hd_struct *part, unsigned int bytes) |
c17bb495 | 1615 | { |
b2c9cd37 | 1616 | return part->make_it_fail && should_fail(&fail_make_request, bytes); |
c17bb495 AM |
1617 | } |
1618 | ||
1619 | static int __init fail_make_request_debugfs(void) | |
1620 | { | |
dd48c085 AM |
1621 | struct dentry *dir = fault_create_debugfs_attr("fail_make_request", |
1622 | NULL, &fail_make_request); | |
1623 | ||
1624 | return IS_ERR(dir) ? PTR_ERR(dir) : 0; | |
c17bb495 AM |
1625 | } |
1626 | ||
1627 | late_initcall(fail_make_request_debugfs); | |
1628 | ||
1629 | #else /* CONFIG_FAIL_MAKE_REQUEST */ | |
1630 | ||
b2c9cd37 AM |
1631 | static inline bool should_fail_request(struct hd_struct *part, |
1632 | unsigned int bytes) | |
c17bb495 | 1633 | { |
b2c9cd37 | 1634 | return false; |
c17bb495 AM |
1635 | } |
1636 | ||
1637 | #endif /* CONFIG_FAIL_MAKE_REQUEST */ | |
1638 | ||
c07e2b41 JA |
1639 | /* |
1640 | * Check whether this bio extends beyond the end of the device. | |
1641 | */ | |
1642 | static inline int bio_check_eod(struct bio *bio, unsigned int nr_sectors) | |
1643 | { | |
1644 | sector_t maxsector; | |
1645 | ||
1646 | if (!nr_sectors) | |
1647 | return 0; | |
1648 | ||
1649 | /* Test device or partition size, when known. */ | |
77304d2a | 1650 | maxsector = i_size_read(bio->bi_bdev->bd_inode) >> 9; |
c07e2b41 JA |
1651 | if (maxsector) { |
1652 | sector_t sector = bio->bi_sector; | |
1653 | ||
1654 | if (maxsector < nr_sectors || maxsector - nr_sectors < sector) { | |
1655 | /* | |
1656 | * This may well happen - the kernel calls bread() | |
1657 | * without checking the size of the device, e.g., when | |
1658 | * mounting a device. | |
1659 | */ | |
1660 | handle_bad_sector(bio); | |
1661 | return 1; | |
1662 | } | |
1663 | } | |
1664 | ||
1665 | return 0; | |
1666 | } | |
1667 | ||
27a84d54 CH |
1668 | static noinline_for_stack bool |
1669 | generic_make_request_checks(struct bio *bio) | |
1da177e4 | 1670 | { |
165125e1 | 1671 | struct request_queue *q; |
5a7bbad2 | 1672 | int nr_sectors = bio_sectors(bio); |
51fd77bd | 1673 | int err = -EIO; |
5a7bbad2 CH |
1674 | char b[BDEVNAME_SIZE]; |
1675 | struct hd_struct *part; | |
1da177e4 LT |
1676 | |
1677 | might_sleep(); | |
1da177e4 | 1678 | |
c07e2b41 JA |
1679 | if (bio_check_eod(bio, nr_sectors)) |
1680 | goto end_io; | |
1da177e4 | 1681 | |
5a7bbad2 CH |
1682 | q = bdev_get_queue(bio->bi_bdev); |
1683 | if (unlikely(!q)) { | |
1684 | printk(KERN_ERR | |
1685 | "generic_make_request: Trying to access " | |
1686 | "nonexistent block-device %s (%Lu)\n", | |
1687 | bdevname(bio->bi_bdev, b), | |
1688 | (long long) bio->bi_sector); | |
1689 | goto end_io; | |
1690 | } | |
c17bb495 | 1691 | |
e2a60da7 MP |
1692 | if (likely(bio_is_rw(bio) && |
1693 | nr_sectors > queue_max_hw_sectors(q))) { | |
5a7bbad2 CH |
1694 | printk(KERN_ERR "bio too big device %s (%u > %u)\n", |
1695 | bdevname(bio->bi_bdev, b), | |
1696 | bio_sectors(bio), | |
1697 | queue_max_hw_sectors(q)); | |
1698 | goto end_io; | |
1699 | } | |
1da177e4 | 1700 | |
5a7bbad2 CH |
1701 | part = bio->bi_bdev->bd_part; |
1702 | if (should_fail_request(part, bio->bi_size) || | |
1703 | should_fail_request(&part_to_disk(part)->part0, | |
1704 | bio->bi_size)) | |
1705 | goto end_io; | |
2056a782 | 1706 | |
5a7bbad2 CH |
1707 | /* |
1708 | * If this device has partitions, remap block n | |
1709 | * of partition p to block n+start(p) of the disk. | |
1710 | */ | |
1711 | blk_partition_remap(bio); | |
2056a782 | 1712 | |
5a7bbad2 CH |
1713 | if (bio_check_eod(bio, nr_sectors)) |
1714 | goto end_io; | |
1e87901e | 1715 | |
5a7bbad2 CH |
1716 | /* |
1717 | * Filter flush bio's early so that make_request based | |
1718 | * drivers without flush support don't have to worry | |
1719 | * about them. | |
1720 | */ | |
1721 | if ((bio->bi_rw & (REQ_FLUSH | REQ_FUA)) && !q->flush_flags) { | |
1722 | bio->bi_rw &= ~(REQ_FLUSH | REQ_FUA); | |
1723 | if (!nr_sectors) { | |
1724 | err = 0; | |
51fd77bd JA |
1725 | goto end_io; |
1726 | } | |
5a7bbad2 | 1727 | } |
5ddfe969 | 1728 | |
5a7bbad2 CH |
1729 | if ((bio->bi_rw & REQ_DISCARD) && |
1730 | (!blk_queue_discard(q) || | |
e2a60da7 | 1731 | ((bio->bi_rw & REQ_SECURE) && !blk_queue_secdiscard(q)))) { |
5a7bbad2 CH |
1732 | err = -EOPNOTSUPP; |
1733 | goto end_io; | |
1734 | } | |
01edede4 | 1735 | |
4363ac7c | 1736 | if (bio->bi_rw & REQ_WRITE_SAME && !bdev_write_same(bio->bi_bdev)) { |
5a7bbad2 CH |
1737 | err = -EOPNOTSUPP; |
1738 | goto end_io; | |
1739 | } | |
01edede4 | 1740 | |
7f4b35d1 TH |
1741 | /* |
1742 | * Various block parts want %current->io_context and lazy ioc | |
1743 | * allocation ends up trading a lot of pain for a small amount of | |
1744 | * memory. Just allocate it upfront. This may fail and block | |
1745 | * layer knows how to live with it. | |
1746 | */ | |
1747 | create_io_context(GFP_ATOMIC, q->node); | |
1748 | ||
bc16a4f9 TH |
1749 | if (blk_throtl_bio(q, bio)) |
1750 | return false; /* throttled, will be resubmitted later */ | |
27a84d54 | 1751 | |
5a7bbad2 | 1752 | trace_block_bio_queue(q, bio); |
27a84d54 | 1753 | return true; |
a7384677 TH |
1754 | |
1755 | end_io: | |
1756 | bio_endio(bio, err); | |
27a84d54 | 1757 | return false; |
1da177e4 LT |
1758 | } |
1759 | ||
27a84d54 CH |
1760 | /** |
1761 | * generic_make_request - hand a buffer to its device driver for I/O | |
1762 | * @bio: The bio describing the location in memory and on the device. | |
1763 | * | |
1764 | * generic_make_request() is used to make I/O requests of block | |
1765 | * devices. It is passed a &struct bio, which describes the I/O that needs | |
1766 | * to be done. | |
1767 | * | |
1768 | * generic_make_request() does not return any status. The | |
1769 | * success/failure status of the request, along with notification of | |
1770 | * completion, is delivered asynchronously through the bio->bi_end_io | |
1771 | * function described (one day) else where. | |
1772 | * | |
1773 | * The caller of generic_make_request must make sure that bi_io_vec | |
1774 | * are set to describe the memory buffer, and that bi_dev and bi_sector are | |
1775 | * set to describe the device address, and the | |
1776 | * bi_end_io and optionally bi_private are set to describe how | |
1777 | * completion notification should be signaled. | |
1778 | * | |
1779 | * generic_make_request and the drivers it calls may use bi_next if this | |
1780 | * bio happens to be merged with someone else, and may resubmit the bio to | |
1781 | * a lower device by calling into generic_make_request recursively, which | |
1782 | * means the bio should NOT be touched after the call to ->make_request_fn. | |
d89d8796 NB |
1783 | */ |
1784 | void generic_make_request(struct bio *bio) | |
1785 | { | |
bddd87c7 AM |
1786 | struct bio_list bio_list_on_stack; |
1787 | ||
27a84d54 CH |
1788 | if (!generic_make_request_checks(bio)) |
1789 | return; | |
1790 | ||
1791 | /* | |
1792 | * We only want one ->make_request_fn to be active at a time, else | |
1793 | * stack usage with stacked devices could be a problem. So use | |
1794 | * current->bio_list to keep a list of requests submited by a | |
1795 | * make_request_fn function. current->bio_list is also used as a | |
1796 | * flag to say if generic_make_request is currently active in this | |
1797 | * task or not. If it is NULL, then no make_request is active. If | |
1798 | * it is non-NULL, then a make_request is active, and new requests | |
1799 | * should be added at the tail | |
1800 | */ | |
bddd87c7 | 1801 | if (current->bio_list) { |
bddd87c7 | 1802 | bio_list_add(current->bio_list, bio); |
d89d8796 NB |
1803 | return; |
1804 | } | |
27a84d54 | 1805 | |
d89d8796 NB |
1806 | /* following loop may be a bit non-obvious, and so deserves some |
1807 | * explanation. | |
1808 | * Before entering the loop, bio->bi_next is NULL (as all callers | |
1809 | * ensure that) so we have a list with a single bio. | |
1810 | * We pretend that we have just taken it off a longer list, so | |
bddd87c7 AM |
1811 | * we assign bio_list to a pointer to the bio_list_on_stack, |
1812 | * thus initialising the bio_list of new bios to be | |
27a84d54 | 1813 | * added. ->make_request() may indeed add some more bios |
d89d8796 NB |
1814 | * through a recursive call to generic_make_request. If it |
1815 | * did, we find a non-NULL value in bio_list and re-enter the loop | |
1816 | * from the top. In this case we really did just take the bio | |
bddd87c7 | 1817 | * of the top of the list (no pretending) and so remove it from |
27a84d54 | 1818 | * bio_list, and call into ->make_request() again. |
d89d8796 NB |
1819 | */ |
1820 | BUG_ON(bio->bi_next); | |
bddd87c7 AM |
1821 | bio_list_init(&bio_list_on_stack); |
1822 | current->bio_list = &bio_list_on_stack; | |
d89d8796 | 1823 | do { |
27a84d54 CH |
1824 | struct request_queue *q = bdev_get_queue(bio->bi_bdev); |
1825 | ||
1826 | q->make_request_fn(q, bio); | |
1827 | ||
bddd87c7 | 1828 | bio = bio_list_pop(current->bio_list); |
d89d8796 | 1829 | } while (bio); |
bddd87c7 | 1830 | current->bio_list = NULL; /* deactivate */ |
d89d8796 | 1831 | } |
1da177e4 LT |
1832 | EXPORT_SYMBOL(generic_make_request); |
1833 | ||
1834 | /** | |
710027a4 | 1835 | * submit_bio - submit a bio to the block device layer for I/O |
1da177e4 LT |
1836 | * @rw: whether to %READ or %WRITE, or maybe to %READA (read ahead) |
1837 | * @bio: The &struct bio which describes the I/O | |
1838 | * | |
1839 | * submit_bio() is very similar in purpose to generic_make_request(), and | |
1840 | * uses that function to do most of the work. Both are fairly rough | |
710027a4 | 1841 | * interfaces; @bio must be presetup and ready for I/O. |
1da177e4 LT |
1842 | * |
1843 | */ | |
1844 | void submit_bio(int rw, struct bio *bio) | |
1845 | { | |
22e2c507 | 1846 | bio->bi_rw |= rw; |
1da177e4 | 1847 | |
bf2de6f5 JA |
1848 | /* |
1849 | * If it's a regular read/write or a barrier with data attached, | |
1850 | * go through the normal accounting stuff before submission. | |
1851 | */ | |
e2a60da7 | 1852 | if (bio_has_data(bio)) { |
4363ac7c MP |
1853 | unsigned int count; |
1854 | ||
1855 | if (unlikely(rw & REQ_WRITE_SAME)) | |
1856 | count = bdev_logical_block_size(bio->bi_bdev) >> 9; | |
1857 | else | |
1858 | count = bio_sectors(bio); | |
1859 | ||
bf2de6f5 JA |
1860 | if (rw & WRITE) { |
1861 | count_vm_events(PGPGOUT, count); | |
1862 | } else { | |
1863 | task_io_account_read(bio->bi_size); | |
1864 | count_vm_events(PGPGIN, count); | |
1865 | } | |
1866 | ||
1867 | if (unlikely(block_dump)) { | |
1868 | char b[BDEVNAME_SIZE]; | |
8dcbdc74 | 1869 | printk(KERN_DEBUG "%s(%d): %s block %Lu on %s (%u sectors)\n", |
ba25f9dc | 1870 | current->comm, task_pid_nr(current), |
bf2de6f5 JA |
1871 | (rw & WRITE) ? "WRITE" : "READ", |
1872 | (unsigned long long)bio->bi_sector, | |
8dcbdc74 SM |
1873 | bdevname(bio->bi_bdev, b), |
1874 | count); | |
bf2de6f5 | 1875 | } |
1da177e4 LT |
1876 | } |
1877 | ||
1878 | generic_make_request(bio); | |
1879 | } | |
1da177e4 LT |
1880 | EXPORT_SYMBOL(submit_bio); |
1881 | ||
82124d60 KU |
1882 | /** |
1883 | * blk_rq_check_limits - Helper function to check a request for the queue limit | |
1884 | * @q: the queue | |
1885 | * @rq: the request being checked | |
1886 | * | |
1887 | * Description: | |
1888 | * @rq may have been made based on weaker limitations of upper-level queues | |
1889 | * in request stacking drivers, and it may violate the limitation of @q. | |
1890 | * Since the block layer and the underlying device driver trust @rq | |
1891 | * after it is inserted to @q, it should be checked against @q before | |
1892 | * the insertion using this generic function. | |
1893 | * | |
1894 | * This function should also be useful for request stacking drivers | |
eef35c2d | 1895 | * in some cases below, so export this function. |
82124d60 KU |
1896 | * Request stacking drivers like request-based dm may change the queue |
1897 | * limits while requests are in the queue (e.g. dm's table swapping). | |
1898 | * Such request stacking drivers should check those requests agaist | |
1899 | * the new queue limits again when they dispatch those requests, | |
1900 | * although such checkings are also done against the old queue limits | |
1901 | * when submitting requests. | |
1902 | */ | |
1903 | int blk_rq_check_limits(struct request_queue *q, struct request *rq) | |
1904 | { | |
e2a60da7 | 1905 | if (!rq_mergeable(rq)) |
3383977f S |
1906 | return 0; |
1907 | ||
f31dc1cd | 1908 | if (blk_rq_sectors(rq) > blk_queue_get_max_sectors(q, rq->cmd_flags)) { |
82124d60 KU |
1909 | printk(KERN_ERR "%s: over max size limit.\n", __func__); |
1910 | return -EIO; | |
1911 | } | |
1912 | ||
1913 | /* | |
1914 | * queue's settings related to segment counting like q->bounce_pfn | |
1915 | * may differ from that of other stacking queues. | |
1916 | * Recalculate it to check the request correctly on this queue's | |
1917 | * limitation. | |
1918 | */ | |
1919 | blk_recalc_rq_segments(rq); | |
8a78362c | 1920 | if (rq->nr_phys_segments > queue_max_segments(q)) { |
82124d60 KU |
1921 | printk(KERN_ERR "%s: over max segments limit.\n", __func__); |
1922 | return -EIO; | |
1923 | } | |
1924 | ||
1925 | return 0; | |
1926 | } | |
1927 | EXPORT_SYMBOL_GPL(blk_rq_check_limits); | |
1928 | ||
1929 | /** | |
1930 | * blk_insert_cloned_request - Helper for stacking drivers to submit a request | |
1931 | * @q: the queue to submit the request | |
1932 | * @rq: the request being queued | |
1933 | */ | |
1934 | int blk_insert_cloned_request(struct request_queue *q, struct request *rq) | |
1935 | { | |
1936 | unsigned long flags; | |
4853abaa | 1937 | int where = ELEVATOR_INSERT_BACK; |
82124d60 KU |
1938 | |
1939 | if (blk_rq_check_limits(q, rq)) | |
1940 | return -EIO; | |
1941 | ||
b2c9cd37 AM |
1942 | if (rq->rq_disk && |
1943 | should_fail_request(&rq->rq_disk->part0, blk_rq_bytes(rq))) | |
82124d60 | 1944 | return -EIO; |
82124d60 KU |
1945 | |
1946 | spin_lock_irqsave(q->queue_lock, flags); | |
3f3299d5 | 1947 | if (unlikely(blk_queue_dying(q))) { |
8ba61435 TH |
1948 | spin_unlock_irqrestore(q->queue_lock, flags); |
1949 | return -ENODEV; | |
1950 | } | |
82124d60 KU |
1951 | |
1952 | /* | |
1953 | * Submitting request must be dequeued before calling this function | |
1954 | * because it will be linked to another request_queue | |
1955 | */ | |
1956 | BUG_ON(blk_queued_rq(rq)); | |
1957 | ||
4853abaa JM |
1958 | if (rq->cmd_flags & (REQ_FLUSH|REQ_FUA)) |
1959 | where = ELEVATOR_INSERT_FLUSH; | |
1960 | ||
1961 | add_acct_request(q, rq, where); | |
e67b77c7 JM |
1962 | if (where == ELEVATOR_INSERT_FLUSH) |
1963 | __blk_run_queue(q); | |
82124d60 KU |
1964 | spin_unlock_irqrestore(q->queue_lock, flags); |
1965 | ||
1966 | return 0; | |
1967 | } | |
1968 | EXPORT_SYMBOL_GPL(blk_insert_cloned_request); | |
1969 | ||
80a761fd TH |
1970 | /** |
1971 | * blk_rq_err_bytes - determine number of bytes till the next failure boundary | |
1972 | * @rq: request to examine | |
1973 | * | |
1974 | * Description: | |
1975 | * A request could be merge of IOs which require different failure | |
1976 | * handling. This function determines the number of bytes which | |
1977 | * can be failed from the beginning of the request without | |
1978 | * crossing into area which need to be retried further. | |
1979 | * | |
1980 | * Return: | |
1981 | * The number of bytes to fail. | |
1982 | * | |
1983 | * Context: | |
1984 | * queue_lock must be held. | |
1985 | */ | |
1986 | unsigned int blk_rq_err_bytes(const struct request *rq) | |
1987 | { | |
1988 | unsigned int ff = rq->cmd_flags & REQ_FAILFAST_MASK; | |
1989 | unsigned int bytes = 0; | |
1990 | struct bio *bio; | |
1991 | ||
1992 | if (!(rq->cmd_flags & REQ_MIXED_MERGE)) | |
1993 | return blk_rq_bytes(rq); | |
1994 | ||
1995 | /* | |
1996 | * Currently the only 'mixing' which can happen is between | |
1997 | * different fastfail types. We can safely fail portions | |
1998 | * which have all the failfast bits that the first one has - | |
1999 | * the ones which are at least as eager to fail as the first | |
2000 | * one. | |
2001 | */ | |
2002 | for (bio = rq->bio; bio; bio = bio->bi_next) { | |
2003 | if ((bio->bi_rw & ff) != ff) | |
2004 | break; | |
2005 | bytes += bio->bi_size; | |
2006 | } | |
2007 | ||
2008 | /* this could lead to infinite loop */ | |
2009 | BUG_ON(blk_rq_bytes(rq) && !bytes); | |
2010 | return bytes; | |
2011 | } | |
2012 | EXPORT_SYMBOL_GPL(blk_rq_err_bytes); | |
2013 | ||
bc58ba94 JA |
2014 | static void blk_account_io_completion(struct request *req, unsigned int bytes) |
2015 | { | |
c2553b58 | 2016 | if (blk_do_io_stat(req)) { |
bc58ba94 JA |
2017 | const int rw = rq_data_dir(req); |
2018 | struct hd_struct *part; | |
2019 | int cpu; | |
2020 | ||
2021 | cpu = part_stat_lock(); | |
09e099d4 | 2022 | part = req->part; |
bc58ba94 JA |
2023 | part_stat_add(cpu, part, sectors[rw], bytes >> 9); |
2024 | part_stat_unlock(); | |
2025 | } | |
2026 | } | |
2027 | ||
2028 | static void blk_account_io_done(struct request *req) | |
2029 | { | |
bc58ba94 | 2030 | /* |
dd4c133f TH |
2031 | * Account IO completion. flush_rq isn't accounted as a |
2032 | * normal IO on queueing nor completion. Accounting the | |
2033 | * containing request is enough. | |
bc58ba94 | 2034 | */ |
414b4ff5 | 2035 | if (blk_do_io_stat(req) && !(req->cmd_flags & REQ_FLUSH_SEQ)) { |
bc58ba94 JA |
2036 | unsigned long duration = jiffies - req->start_time; |
2037 | const int rw = rq_data_dir(req); | |
2038 | struct hd_struct *part; | |
2039 | int cpu; | |
2040 | ||
2041 | cpu = part_stat_lock(); | |
09e099d4 | 2042 | part = req->part; |
bc58ba94 JA |
2043 | |
2044 | part_stat_inc(cpu, part, ios[rw]); | |
2045 | part_stat_add(cpu, part, ticks[rw], duration); | |
2046 | part_round_stats(cpu, part); | |
316d315b | 2047 | part_dec_in_flight(part, rw); |
bc58ba94 | 2048 | |
6c23a968 | 2049 | hd_struct_put(part); |
bc58ba94 JA |
2050 | part_stat_unlock(); |
2051 | } | |
2052 | } | |
2053 | ||
c8158819 LM |
2054 | #ifdef CONFIG_PM_RUNTIME |
2055 | /* | |
2056 | * Don't process normal requests when queue is suspended | |
2057 | * or in the process of suspending/resuming | |
2058 | */ | |
2059 | static struct request *blk_pm_peek_request(struct request_queue *q, | |
2060 | struct request *rq) | |
2061 | { | |
2062 | if (q->dev && (q->rpm_status == RPM_SUSPENDED || | |
2063 | (q->rpm_status != RPM_ACTIVE && !(rq->cmd_flags & REQ_PM)))) | |
2064 | return NULL; | |
2065 | else | |
2066 | return rq; | |
2067 | } | |
2068 | #else | |
2069 | static inline struct request *blk_pm_peek_request(struct request_queue *q, | |
2070 | struct request *rq) | |
2071 | { | |
2072 | return rq; | |
2073 | } | |
2074 | #endif | |
2075 | ||
3bcddeac | 2076 | /** |
9934c8c0 TH |
2077 | * blk_peek_request - peek at the top of a request queue |
2078 | * @q: request queue to peek at | |
2079 | * | |
2080 | * Description: | |
2081 | * Return the request at the top of @q. The returned request | |
2082 | * should be started using blk_start_request() before LLD starts | |
2083 | * processing it. | |
2084 | * | |
2085 | * Return: | |
2086 | * Pointer to the request at the top of @q if available. Null | |
2087 | * otherwise. | |
2088 | * | |
2089 | * Context: | |
2090 | * queue_lock must be held. | |
2091 | */ | |
2092 | struct request *blk_peek_request(struct request_queue *q) | |
158dbda0 TH |
2093 | { |
2094 | struct request *rq; | |
2095 | int ret; | |
2096 | ||
2097 | while ((rq = __elv_next_request(q)) != NULL) { | |
c8158819 LM |
2098 | |
2099 | rq = blk_pm_peek_request(q, rq); | |
2100 | if (!rq) | |
2101 | break; | |
2102 | ||
158dbda0 TH |
2103 | if (!(rq->cmd_flags & REQ_STARTED)) { |
2104 | /* | |
2105 | * This is the first time the device driver | |
2106 | * sees this request (possibly after | |
2107 | * requeueing). Notify IO scheduler. | |
2108 | */ | |
33659ebb | 2109 | if (rq->cmd_flags & REQ_SORTED) |
158dbda0 TH |
2110 | elv_activate_rq(q, rq); |
2111 | ||
2112 | /* | |
2113 | * just mark as started even if we don't start | |
2114 | * it, a request that has been delayed should | |
2115 | * not be passed by new incoming requests | |
2116 | */ | |
2117 | rq->cmd_flags |= REQ_STARTED; | |
2118 | trace_block_rq_issue(q, rq); | |
2119 | } | |
2120 | ||
2121 | if (!q->boundary_rq || q->boundary_rq == rq) { | |
2122 | q->end_sector = rq_end_sector(rq); | |
2123 | q->boundary_rq = NULL; | |
2124 | } | |
2125 | ||
2126 | if (rq->cmd_flags & REQ_DONTPREP) | |
2127 | break; | |
2128 | ||
2e46e8b2 | 2129 | if (q->dma_drain_size && blk_rq_bytes(rq)) { |
158dbda0 TH |
2130 | /* |
2131 | * make sure space for the drain appears we | |
2132 | * know we can do this because max_hw_segments | |
2133 | * has been adjusted to be one fewer than the | |
2134 | * device can handle | |
2135 | */ | |
2136 | rq->nr_phys_segments++; | |
2137 | } | |
2138 | ||
2139 | if (!q->prep_rq_fn) | |
2140 | break; | |
2141 | ||
2142 | ret = q->prep_rq_fn(q, rq); | |
2143 | if (ret == BLKPREP_OK) { | |
2144 | break; | |
2145 | } else if (ret == BLKPREP_DEFER) { | |
2146 | /* | |
2147 | * the request may have been (partially) prepped. | |
2148 | * we need to keep this request in the front to | |
2149 | * avoid resource deadlock. REQ_STARTED will | |
2150 | * prevent other fs requests from passing this one. | |
2151 | */ | |
2e46e8b2 | 2152 | if (q->dma_drain_size && blk_rq_bytes(rq) && |
158dbda0 TH |
2153 | !(rq->cmd_flags & REQ_DONTPREP)) { |
2154 | /* | |
2155 | * remove the space for the drain we added | |
2156 | * so that we don't add it again | |
2157 | */ | |
2158 | --rq->nr_phys_segments; | |
2159 | } | |
2160 | ||
2161 | rq = NULL; | |
2162 | break; | |
2163 | } else if (ret == BLKPREP_KILL) { | |
2164 | rq->cmd_flags |= REQ_QUIET; | |
c143dc90 JB |
2165 | /* |
2166 | * Mark this request as started so we don't trigger | |
2167 | * any debug logic in the end I/O path. | |
2168 | */ | |
2169 | blk_start_request(rq); | |
40cbbb78 | 2170 | __blk_end_request_all(rq, -EIO); |
158dbda0 TH |
2171 | } else { |
2172 | printk(KERN_ERR "%s: bad return=%d\n", __func__, ret); | |
2173 | break; | |
2174 | } | |
2175 | } | |
2176 | ||
2177 | return rq; | |
2178 | } | |
9934c8c0 | 2179 | EXPORT_SYMBOL(blk_peek_request); |
158dbda0 | 2180 | |
9934c8c0 | 2181 | void blk_dequeue_request(struct request *rq) |
158dbda0 | 2182 | { |
9934c8c0 TH |
2183 | struct request_queue *q = rq->q; |
2184 | ||
158dbda0 TH |
2185 | BUG_ON(list_empty(&rq->queuelist)); |
2186 | BUG_ON(ELV_ON_HASH(rq)); | |
2187 | ||
2188 | list_del_init(&rq->queuelist); | |
2189 | ||
2190 | /* | |
2191 | * the time frame between a request being removed from the lists | |
2192 | * and to it is freed is accounted as io that is in progress at | |
2193 | * the driver side. | |
2194 | */ | |
9195291e | 2195 | if (blk_account_rq(rq)) { |
0a7ae2ff | 2196 | q->in_flight[rq_is_sync(rq)]++; |
9195291e DS |
2197 | set_io_start_time_ns(rq); |
2198 | } | |
158dbda0 TH |
2199 | } |
2200 | ||
9934c8c0 TH |
2201 | /** |
2202 | * blk_start_request - start request processing on the driver | |
2203 | * @req: request to dequeue | |
2204 | * | |
2205 | * Description: | |
2206 | * Dequeue @req and start timeout timer on it. This hands off the | |
2207 | * request to the driver. | |
2208 | * | |
2209 | * Block internal functions which don't want to start timer should | |
2210 | * call blk_dequeue_request(). | |
2211 | * | |
2212 | * Context: | |
2213 | * queue_lock must be held. | |
2214 | */ | |
2215 | void blk_start_request(struct request *req) | |
2216 | { | |
2217 | blk_dequeue_request(req); | |
2218 | ||
2219 | /* | |
5f49f631 TH |
2220 | * We are now handing the request to the hardware, initialize |
2221 | * resid_len to full count and add the timeout handler. | |
9934c8c0 | 2222 | */ |
5f49f631 | 2223 | req->resid_len = blk_rq_bytes(req); |
dbb66c4b FT |
2224 | if (unlikely(blk_bidi_rq(req))) |
2225 | req->next_rq->resid_len = blk_rq_bytes(req->next_rq); | |
2226 | ||
9934c8c0 TH |
2227 | blk_add_timer(req); |
2228 | } | |
2229 | EXPORT_SYMBOL(blk_start_request); | |
2230 | ||
2231 | /** | |
2232 | * blk_fetch_request - fetch a request from a request queue | |
2233 | * @q: request queue to fetch a request from | |
2234 | * | |
2235 | * Description: | |
2236 | * Return the request at the top of @q. The request is started on | |
2237 | * return and LLD can start processing it immediately. | |
2238 | * | |
2239 | * Return: | |
2240 | * Pointer to the request at the top of @q if available. Null | |
2241 | * otherwise. | |
2242 | * | |
2243 | * Context: | |
2244 | * queue_lock must be held. | |
2245 | */ | |
2246 | struct request *blk_fetch_request(struct request_queue *q) | |
2247 | { | |
2248 | struct request *rq; | |
2249 | ||
2250 | rq = blk_peek_request(q); | |
2251 | if (rq) | |
2252 | blk_start_request(rq); | |
2253 | return rq; | |
2254 | } | |
2255 | EXPORT_SYMBOL(blk_fetch_request); | |
2256 | ||
3bcddeac | 2257 | /** |
2e60e022 | 2258 | * blk_update_request - Special helper function for request stacking drivers |
8ebf9756 | 2259 | * @req: the request being processed |
710027a4 | 2260 | * @error: %0 for success, < %0 for error |
8ebf9756 | 2261 | * @nr_bytes: number of bytes to complete @req |
3bcddeac KU |
2262 | * |
2263 | * Description: | |
8ebf9756 RD |
2264 | * Ends I/O on a number of bytes attached to @req, but doesn't complete |
2265 | * the request structure even if @req doesn't have leftover. | |
2266 | * If @req has leftover, sets it up for the next range of segments. | |
2e60e022 TH |
2267 | * |
2268 | * This special helper function is only for request stacking drivers | |
2269 | * (e.g. request-based dm) so that they can handle partial completion. | |
2270 | * Actual device drivers should use blk_end_request instead. | |
2271 | * | |
2272 | * Passing the result of blk_rq_bytes() as @nr_bytes guarantees | |
2273 | * %false return from this function. | |
3bcddeac KU |
2274 | * |
2275 | * Return: | |
2e60e022 TH |
2276 | * %false - this request doesn't have any more data |
2277 | * %true - this request has more data | |
3bcddeac | 2278 | **/ |
2e60e022 | 2279 | bool blk_update_request(struct request *req, int error, unsigned int nr_bytes) |
1da177e4 | 2280 | { |
f79ea416 | 2281 | int total_bytes; |
1da177e4 | 2282 | |
2e60e022 TH |
2283 | if (!req->bio) |
2284 | return false; | |
2285 | ||
5f3ea37c | 2286 | trace_block_rq_complete(req->q, req); |
2056a782 | 2287 | |
1da177e4 | 2288 | /* |
6f41469c TH |
2289 | * For fs requests, rq is just carrier of independent bio's |
2290 | * and each partial completion should be handled separately. | |
2291 | * Reset per-request error on each partial completion. | |
2292 | * | |
2293 | * TODO: tj: This is too subtle. It would be better to let | |
2294 | * low level drivers do what they see fit. | |
1da177e4 | 2295 | */ |
33659ebb | 2296 | if (req->cmd_type == REQ_TYPE_FS) |
1da177e4 LT |
2297 | req->errors = 0; |
2298 | ||
33659ebb CH |
2299 | if (error && req->cmd_type == REQ_TYPE_FS && |
2300 | !(req->cmd_flags & REQ_QUIET)) { | |
79775567 HR |
2301 | char *error_type; |
2302 | ||
2303 | switch (error) { | |
2304 | case -ENOLINK: | |
2305 | error_type = "recoverable transport"; | |
2306 | break; | |
2307 | case -EREMOTEIO: | |
2308 | error_type = "critical target"; | |
2309 | break; | |
2310 | case -EBADE: | |
2311 | error_type = "critical nexus"; | |
2312 | break; | |
d1ffc1f8 HR |
2313 | case -ETIMEDOUT: |
2314 | error_type = "timeout"; | |
2315 | break; | |
a9d6ceb8 HR |
2316 | case -ENOSPC: |
2317 | error_type = "critical space allocation"; | |
2318 | break; | |
7e782af5 HR |
2319 | case -ENODATA: |
2320 | error_type = "critical medium"; | |
2321 | break; | |
79775567 HR |
2322 | case -EIO: |
2323 | default: | |
2324 | error_type = "I/O"; | |
2325 | break; | |
2326 | } | |
37d7b34f YZ |
2327 | printk_ratelimited(KERN_ERR "end_request: %s error, dev %s, sector %llu\n", |
2328 | error_type, req->rq_disk ? | |
2329 | req->rq_disk->disk_name : "?", | |
2330 | (unsigned long long)blk_rq_pos(req)); | |
2331 | ||
1da177e4 LT |
2332 | } |
2333 | ||
bc58ba94 | 2334 | blk_account_io_completion(req, nr_bytes); |
d72d904a | 2335 | |
f79ea416 KO |
2336 | total_bytes = 0; |
2337 | while (req->bio) { | |
2338 | struct bio *bio = req->bio; | |
2339 | unsigned bio_bytes = min(bio->bi_size, nr_bytes); | |
1da177e4 | 2340 | |
f79ea416 | 2341 | if (bio_bytes == bio->bi_size) |
1da177e4 | 2342 | req->bio = bio->bi_next; |
1da177e4 | 2343 | |
f79ea416 | 2344 | req_bio_endio(req, bio, bio_bytes, error); |
1da177e4 | 2345 | |
f79ea416 KO |
2346 | total_bytes += bio_bytes; |
2347 | nr_bytes -= bio_bytes; | |
1da177e4 | 2348 | |
f79ea416 KO |
2349 | if (!nr_bytes) |
2350 | break; | |
1da177e4 LT |
2351 | } |
2352 | ||
2353 | /* | |
2354 | * completely done | |
2355 | */ | |
2e60e022 TH |
2356 | if (!req->bio) { |
2357 | /* | |
2358 | * Reset counters so that the request stacking driver | |
2359 | * can find how many bytes remain in the request | |
2360 | * later. | |
2361 | */ | |
a2dec7b3 | 2362 | req->__data_len = 0; |
2e60e022 TH |
2363 | return false; |
2364 | } | |
1da177e4 | 2365 | |
a2dec7b3 | 2366 | req->__data_len -= total_bytes; |
2e46e8b2 TH |
2367 | req->buffer = bio_data(req->bio); |
2368 | ||
2369 | /* update sector only for requests with clear definition of sector */ | |
e2a60da7 | 2370 | if (req->cmd_type == REQ_TYPE_FS) |
a2dec7b3 | 2371 | req->__sector += total_bytes >> 9; |
2e46e8b2 | 2372 | |
80a761fd TH |
2373 | /* mixed attributes always follow the first bio */ |
2374 | if (req->cmd_flags & REQ_MIXED_MERGE) { | |
2375 | req->cmd_flags &= ~REQ_FAILFAST_MASK; | |
2376 | req->cmd_flags |= req->bio->bi_rw & REQ_FAILFAST_MASK; | |
2377 | } | |
2378 | ||
2e46e8b2 TH |
2379 | /* |
2380 | * If total number of sectors is less than the first segment | |
2381 | * size, something has gone terribly wrong. | |
2382 | */ | |
2383 | if (blk_rq_bytes(req) < blk_rq_cur_bytes(req)) { | |
8182924b | 2384 | blk_dump_rq_flags(req, "request botched"); |
a2dec7b3 | 2385 | req->__data_len = blk_rq_cur_bytes(req); |
2e46e8b2 TH |
2386 | } |
2387 | ||
2388 | /* recalculate the number of segments */ | |
1da177e4 | 2389 | blk_recalc_rq_segments(req); |
2e46e8b2 | 2390 | |
2e60e022 | 2391 | return true; |
1da177e4 | 2392 | } |
2e60e022 | 2393 | EXPORT_SYMBOL_GPL(blk_update_request); |
1da177e4 | 2394 | |
2e60e022 TH |
2395 | static bool blk_update_bidi_request(struct request *rq, int error, |
2396 | unsigned int nr_bytes, | |
2397 | unsigned int bidi_bytes) | |
5efccd17 | 2398 | { |
2e60e022 TH |
2399 | if (blk_update_request(rq, error, nr_bytes)) |
2400 | return true; | |
5efccd17 | 2401 | |
2e60e022 TH |
2402 | /* Bidi request must be completed as a whole */ |
2403 | if (unlikely(blk_bidi_rq(rq)) && | |
2404 | blk_update_request(rq->next_rq, error, bidi_bytes)) | |
2405 | return true; | |
5efccd17 | 2406 | |
e2e1a148 JA |
2407 | if (blk_queue_add_random(rq->q)) |
2408 | add_disk_randomness(rq->rq_disk); | |
2e60e022 TH |
2409 | |
2410 | return false; | |
1da177e4 LT |
2411 | } |
2412 | ||
28018c24 JB |
2413 | /** |
2414 | * blk_unprep_request - unprepare a request | |
2415 | * @req: the request | |
2416 | * | |
2417 | * This function makes a request ready for complete resubmission (or | |
2418 | * completion). It happens only after all error handling is complete, | |
2419 | * so represents the appropriate moment to deallocate any resources | |
2420 | * that were allocated to the request in the prep_rq_fn. The queue | |
2421 | * lock is held when calling this. | |
2422 | */ | |
2423 | void blk_unprep_request(struct request *req) | |
2424 | { | |
2425 | struct request_queue *q = req->q; | |
2426 | ||
2427 | req->cmd_flags &= ~REQ_DONTPREP; | |
2428 | if (q->unprep_rq_fn) | |
2429 | q->unprep_rq_fn(q, req); | |
2430 | } | |
2431 | EXPORT_SYMBOL_GPL(blk_unprep_request); | |
2432 | ||
1da177e4 LT |
2433 | /* |
2434 | * queue lock must be held | |
2435 | */ | |
2e60e022 | 2436 | static void blk_finish_request(struct request *req, int error) |
1da177e4 | 2437 | { |
b8286239 KU |
2438 | if (blk_rq_tagged(req)) |
2439 | blk_queue_end_tag(req->q, req); | |
2440 | ||
ba396a6c | 2441 | BUG_ON(blk_queued_rq(req)); |
1da177e4 | 2442 | |
33659ebb | 2443 | if (unlikely(laptop_mode) && req->cmd_type == REQ_TYPE_FS) |
31373d09 | 2444 | laptop_io_completion(&req->q->backing_dev_info); |
1da177e4 | 2445 | |
e78042e5 MA |
2446 | blk_delete_timer(req); |
2447 | ||
28018c24 JB |
2448 | if (req->cmd_flags & REQ_DONTPREP) |
2449 | blk_unprep_request(req); | |
2450 | ||
2451 | ||
bc58ba94 | 2452 | blk_account_io_done(req); |
b8286239 | 2453 | |
1da177e4 | 2454 | if (req->end_io) |
8ffdc655 | 2455 | req->end_io(req, error); |
b8286239 KU |
2456 | else { |
2457 | if (blk_bidi_rq(req)) | |
2458 | __blk_put_request(req->next_rq->q, req->next_rq); | |
2459 | ||
1da177e4 | 2460 | __blk_put_request(req->q, req); |
b8286239 | 2461 | } |
1da177e4 LT |
2462 | } |
2463 | ||
3b11313a | 2464 | /** |
2e60e022 TH |
2465 | * blk_end_bidi_request - Complete a bidi request |
2466 | * @rq: the request to complete | |
2467 | * @error: %0 for success, < %0 for error | |
2468 | * @nr_bytes: number of bytes to complete @rq | |
2469 | * @bidi_bytes: number of bytes to complete @rq->next_rq | |
a0cd1285 JA |
2470 | * |
2471 | * Description: | |
e3a04fe3 | 2472 | * Ends I/O on a number of bytes attached to @rq and @rq->next_rq. |
2e60e022 TH |
2473 | * Drivers that supports bidi can safely call this member for any |
2474 | * type of request, bidi or uni. In the later case @bidi_bytes is | |
2475 | * just ignored. | |
336cdb40 KU |
2476 | * |
2477 | * Return: | |
2e60e022 TH |
2478 | * %false - we are done with this request |
2479 | * %true - still buffers pending for this request | |
a0cd1285 | 2480 | **/ |
b1f74493 | 2481 | static bool blk_end_bidi_request(struct request *rq, int error, |
32fab448 KU |
2482 | unsigned int nr_bytes, unsigned int bidi_bytes) |
2483 | { | |
336cdb40 | 2484 | struct request_queue *q = rq->q; |
2e60e022 | 2485 | unsigned long flags; |
32fab448 | 2486 | |
2e60e022 TH |
2487 | if (blk_update_bidi_request(rq, error, nr_bytes, bidi_bytes)) |
2488 | return true; | |
32fab448 | 2489 | |
336cdb40 | 2490 | spin_lock_irqsave(q->queue_lock, flags); |
2e60e022 | 2491 | blk_finish_request(rq, error); |
336cdb40 KU |
2492 | spin_unlock_irqrestore(q->queue_lock, flags); |
2493 | ||
2e60e022 | 2494 | return false; |
32fab448 KU |
2495 | } |
2496 | ||
336cdb40 | 2497 | /** |
2e60e022 TH |
2498 | * __blk_end_bidi_request - Complete a bidi request with queue lock held |
2499 | * @rq: the request to complete | |
710027a4 | 2500 | * @error: %0 for success, < %0 for error |
e3a04fe3 KU |
2501 | * @nr_bytes: number of bytes to complete @rq |
2502 | * @bidi_bytes: number of bytes to complete @rq->next_rq | |
336cdb40 KU |
2503 | * |
2504 | * Description: | |
2e60e022 TH |
2505 | * Identical to blk_end_bidi_request() except that queue lock is |
2506 | * assumed to be locked on entry and remains so on return. | |
336cdb40 KU |
2507 | * |
2508 | * Return: | |
2e60e022 TH |
2509 | * %false - we are done with this request |
2510 | * %true - still buffers pending for this request | |
336cdb40 | 2511 | **/ |
4853abaa | 2512 | bool __blk_end_bidi_request(struct request *rq, int error, |
b1f74493 | 2513 | unsigned int nr_bytes, unsigned int bidi_bytes) |
336cdb40 | 2514 | { |
2e60e022 TH |
2515 | if (blk_update_bidi_request(rq, error, nr_bytes, bidi_bytes)) |
2516 | return true; | |
336cdb40 | 2517 | |
2e60e022 | 2518 | blk_finish_request(rq, error); |
336cdb40 | 2519 | |
2e60e022 | 2520 | return false; |
336cdb40 | 2521 | } |
e19a3ab0 KU |
2522 | |
2523 | /** | |
2524 | * blk_end_request - Helper function for drivers to complete the request. | |
2525 | * @rq: the request being processed | |
710027a4 | 2526 | * @error: %0 for success, < %0 for error |
e19a3ab0 KU |
2527 | * @nr_bytes: number of bytes to complete |
2528 | * | |
2529 | * Description: | |
2530 | * Ends I/O on a number of bytes attached to @rq. | |
2531 | * If @rq has leftover, sets it up for the next range of segments. | |
2532 | * | |
2533 | * Return: | |
b1f74493 FT |
2534 | * %false - we are done with this request |
2535 | * %true - still buffers pending for this request | |
e19a3ab0 | 2536 | **/ |
b1f74493 | 2537 | bool blk_end_request(struct request *rq, int error, unsigned int nr_bytes) |
e19a3ab0 | 2538 | { |
b1f74493 | 2539 | return blk_end_bidi_request(rq, error, nr_bytes, 0); |
e19a3ab0 | 2540 | } |
56ad1740 | 2541 | EXPORT_SYMBOL(blk_end_request); |
336cdb40 KU |
2542 | |
2543 | /** | |
b1f74493 FT |
2544 | * blk_end_request_all - Helper function for drives to finish the request. |
2545 | * @rq: the request to finish | |
8ebf9756 | 2546 | * @error: %0 for success, < %0 for error |
336cdb40 KU |
2547 | * |
2548 | * Description: | |
b1f74493 FT |
2549 | * Completely finish @rq. |
2550 | */ | |
2551 | void blk_end_request_all(struct request *rq, int error) | |
336cdb40 | 2552 | { |
b1f74493 FT |
2553 | bool pending; |
2554 | unsigned int bidi_bytes = 0; | |
336cdb40 | 2555 | |
b1f74493 FT |
2556 | if (unlikely(blk_bidi_rq(rq))) |
2557 | bidi_bytes = blk_rq_bytes(rq->next_rq); | |
336cdb40 | 2558 | |
b1f74493 FT |
2559 | pending = blk_end_bidi_request(rq, error, blk_rq_bytes(rq), bidi_bytes); |
2560 | BUG_ON(pending); | |
2561 | } | |
56ad1740 | 2562 | EXPORT_SYMBOL(blk_end_request_all); |
336cdb40 | 2563 | |
b1f74493 FT |
2564 | /** |
2565 | * blk_end_request_cur - Helper function to finish the current request chunk. | |
2566 | * @rq: the request to finish the current chunk for | |
8ebf9756 | 2567 | * @error: %0 for success, < %0 for error |
b1f74493 FT |
2568 | * |
2569 | * Description: | |
2570 | * Complete the current consecutively mapped chunk from @rq. | |
2571 | * | |
2572 | * Return: | |
2573 | * %false - we are done with this request | |
2574 | * %true - still buffers pending for this request | |
2575 | */ | |
2576 | bool blk_end_request_cur(struct request *rq, int error) | |
2577 | { | |
2578 | return blk_end_request(rq, error, blk_rq_cur_bytes(rq)); | |
336cdb40 | 2579 | } |
56ad1740 | 2580 | EXPORT_SYMBOL(blk_end_request_cur); |
336cdb40 | 2581 | |
80a761fd TH |
2582 | /** |
2583 | * blk_end_request_err - Finish a request till the next failure boundary. | |
2584 | * @rq: the request to finish till the next failure boundary for | |
2585 | * @error: must be negative errno | |
2586 | * | |
2587 | * Description: | |
2588 | * Complete @rq till the next failure boundary. | |
2589 | * | |
2590 | * Return: | |
2591 | * %false - we are done with this request | |
2592 | * %true - still buffers pending for this request | |
2593 | */ | |
2594 | bool blk_end_request_err(struct request *rq, int error) | |
2595 | { | |
2596 | WARN_ON(error >= 0); | |
2597 | return blk_end_request(rq, error, blk_rq_err_bytes(rq)); | |
2598 | } | |
2599 | EXPORT_SYMBOL_GPL(blk_end_request_err); | |
2600 | ||
e3a04fe3 | 2601 | /** |
b1f74493 FT |
2602 | * __blk_end_request - Helper function for drivers to complete the request. |
2603 | * @rq: the request being processed | |
2604 | * @error: %0 for success, < %0 for error | |
2605 | * @nr_bytes: number of bytes to complete | |
e3a04fe3 KU |
2606 | * |
2607 | * Description: | |
b1f74493 | 2608 | * Must be called with queue lock held unlike blk_end_request(). |
e3a04fe3 KU |
2609 | * |
2610 | * Return: | |
b1f74493 FT |
2611 | * %false - we are done with this request |
2612 | * %true - still buffers pending for this request | |
e3a04fe3 | 2613 | **/ |
b1f74493 | 2614 | bool __blk_end_request(struct request *rq, int error, unsigned int nr_bytes) |
e3a04fe3 | 2615 | { |
b1f74493 | 2616 | return __blk_end_bidi_request(rq, error, nr_bytes, 0); |
e3a04fe3 | 2617 | } |
56ad1740 | 2618 | EXPORT_SYMBOL(__blk_end_request); |
e3a04fe3 | 2619 | |
32fab448 | 2620 | /** |
b1f74493 FT |
2621 | * __blk_end_request_all - Helper function for drives to finish the request. |
2622 | * @rq: the request to finish | |
8ebf9756 | 2623 | * @error: %0 for success, < %0 for error |
32fab448 KU |
2624 | * |
2625 | * Description: | |
b1f74493 | 2626 | * Completely finish @rq. Must be called with queue lock held. |
32fab448 | 2627 | */ |
b1f74493 | 2628 | void __blk_end_request_all(struct request *rq, int error) |
32fab448 | 2629 | { |
b1f74493 FT |
2630 | bool pending; |
2631 | unsigned int bidi_bytes = 0; | |
2632 | ||
2633 | if (unlikely(blk_bidi_rq(rq))) | |
2634 | bidi_bytes = blk_rq_bytes(rq->next_rq); | |
2635 | ||
2636 | pending = __blk_end_bidi_request(rq, error, blk_rq_bytes(rq), bidi_bytes); | |
2637 | BUG_ON(pending); | |
32fab448 | 2638 | } |
56ad1740 | 2639 | EXPORT_SYMBOL(__blk_end_request_all); |
32fab448 | 2640 | |
e19a3ab0 | 2641 | /** |
b1f74493 FT |
2642 | * __blk_end_request_cur - Helper function to finish the current request chunk. |
2643 | * @rq: the request to finish the current chunk for | |
8ebf9756 | 2644 | * @error: %0 for success, < %0 for error |
e19a3ab0 KU |
2645 | * |
2646 | * Description: | |
b1f74493 FT |
2647 | * Complete the current consecutively mapped chunk from @rq. Must |
2648 | * be called with queue lock held. | |
e19a3ab0 KU |
2649 | * |
2650 | * Return: | |
b1f74493 FT |
2651 | * %false - we are done with this request |
2652 | * %true - still buffers pending for this request | |
2653 | */ | |
2654 | bool __blk_end_request_cur(struct request *rq, int error) | |
e19a3ab0 | 2655 | { |
b1f74493 | 2656 | return __blk_end_request(rq, error, blk_rq_cur_bytes(rq)); |
e19a3ab0 | 2657 | } |
56ad1740 | 2658 | EXPORT_SYMBOL(__blk_end_request_cur); |
e19a3ab0 | 2659 | |
80a761fd TH |
2660 | /** |
2661 | * __blk_end_request_err - Finish a request till the next failure boundary. | |
2662 | * @rq: the request to finish till the next failure boundary for | |
2663 | * @error: must be negative errno | |
2664 | * | |
2665 | * Description: | |
2666 | * Complete @rq till the next failure boundary. Must be called | |
2667 | * with queue lock held. | |
2668 | * | |
2669 | * Return: | |
2670 | * %false - we are done with this request | |
2671 | * %true - still buffers pending for this request | |
2672 | */ | |
2673 | bool __blk_end_request_err(struct request *rq, int error) | |
2674 | { | |
2675 | WARN_ON(error >= 0); | |
2676 | return __blk_end_request(rq, error, blk_rq_err_bytes(rq)); | |
2677 | } | |
2678 | EXPORT_SYMBOL_GPL(__blk_end_request_err); | |
2679 | ||
86db1e29 JA |
2680 | void blk_rq_bio_prep(struct request_queue *q, struct request *rq, |
2681 | struct bio *bio) | |
1da177e4 | 2682 | { |
a82afdfc | 2683 | /* Bit 0 (R/W) is identical in rq->cmd_flags and bio->bi_rw */ |
7b6d91da | 2684 | rq->cmd_flags |= bio->bi_rw & REQ_WRITE; |
1da177e4 | 2685 | |
fb2dce86 DW |
2686 | if (bio_has_data(bio)) { |
2687 | rq->nr_phys_segments = bio_phys_segments(q, bio); | |
fb2dce86 DW |
2688 | rq->buffer = bio_data(bio); |
2689 | } | |
a2dec7b3 | 2690 | rq->__data_len = bio->bi_size; |
1da177e4 | 2691 | rq->bio = rq->biotail = bio; |
1da177e4 | 2692 | |
66846572 N |
2693 | if (bio->bi_bdev) |
2694 | rq->rq_disk = bio->bi_bdev->bd_disk; | |
2695 | } | |
1da177e4 | 2696 | |
2d4dc890 IL |
2697 | #if ARCH_IMPLEMENTS_FLUSH_DCACHE_PAGE |
2698 | /** | |
2699 | * rq_flush_dcache_pages - Helper function to flush all pages in a request | |
2700 | * @rq: the request to be flushed | |
2701 | * | |
2702 | * Description: | |
2703 | * Flush all pages in @rq. | |
2704 | */ | |
2705 | void rq_flush_dcache_pages(struct request *rq) | |
2706 | { | |
2707 | struct req_iterator iter; | |
2708 | struct bio_vec *bvec; | |
2709 | ||
2710 | rq_for_each_segment(bvec, rq, iter) | |
2711 | flush_dcache_page(bvec->bv_page); | |
2712 | } | |
2713 | EXPORT_SYMBOL_GPL(rq_flush_dcache_pages); | |
2714 | #endif | |
2715 | ||
ef9e3fac KU |
2716 | /** |
2717 | * blk_lld_busy - Check if underlying low-level drivers of a device are busy | |
2718 | * @q : the queue of the device being checked | |
2719 | * | |
2720 | * Description: | |
2721 | * Check if underlying low-level drivers of a device are busy. | |
2722 | * If the drivers want to export their busy state, they must set own | |
2723 | * exporting function using blk_queue_lld_busy() first. | |
2724 | * | |
2725 | * Basically, this function is used only by request stacking drivers | |
2726 | * to stop dispatching requests to underlying devices when underlying | |
2727 | * devices are busy. This behavior helps more I/O merging on the queue | |
2728 | * of the request stacking driver and prevents I/O throughput regression | |
2729 | * on burst I/O load. | |
2730 | * | |
2731 | * Return: | |
2732 | * 0 - Not busy (The request stacking driver should dispatch request) | |
2733 | * 1 - Busy (The request stacking driver should stop dispatching request) | |
2734 | */ | |
2735 | int blk_lld_busy(struct request_queue *q) | |
2736 | { | |
2737 | if (q->lld_busy_fn) | |
2738 | return q->lld_busy_fn(q); | |
2739 | ||
2740 | return 0; | |
2741 | } | |
2742 | EXPORT_SYMBOL_GPL(blk_lld_busy); | |
2743 | ||
b0fd271d KU |
2744 | /** |
2745 | * blk_rq_unprep_clone - Helper function to free all bios in a cloned request | |
2746 | * @rq: the clone request to be cleaned up | |
2747 | * | |
2748 | * Description: | |
2749 | * Free all bios in @rq for a cloned request. | |
2750 | */ | |
2751 | void blk_rq_unprep_clone(struct request *rq) | |
2752 | { | |
2753 | struct bio *bio; | |
2754 | ||
2755 | while ((bio = rq->bio) != NULL) { | |
2756 | rq->bio = bio->bi_next; | |
2757 | ||
2758 | bio_put(bio); | |
2759 | } | |
2760 | } | |
2761 | EXPORT_SYMBOL_GPL(blk_rq_unprep_clone); | |
2762 | ||
2763 | /* | |
2764 | * Copy attributes of the original request to the clone request. | |
2765 | * The actual data parts (e.g. ->cmd, ->buffer, ->sense) are not copied. | |
2766 | */ | |
2767 | static void __blk_rq_prep_clone(struct request *dst, struct request *src) | |
2768 | { | |
2769 | dst->cpu = src->cpu; | |
3a2edd0d | 2770 | dst->cmd_flags = (src->cmd_flags & REQ_CLONE_MASK) | REQ_NOMERGE; |
b0fd271d KU |
2771 | dst->cmd_type = src->cmd_type; |
2772 | dst->__sector = blk_rq_pos(src); | |
2773 | dst->__data_len = blk_rq_bytes(src); | |
2774 | dst->nr_phys_segments = src->nr_phys_segments; | |
2775 | dst->ioprio = src->ioprio; | |
2776 | dst->extra_len = src->extra_len; | |
2777 | } | |
2778 | ||
2779 | /** | |
2780 | * blk_rq_prep_clone - Helper function to setup clone request | |
2781 | * @rq: the request to be setup | |
2782 | * @rq_src: original request to be cloned | |
2783 | * @bs: bio_set that bios for clone are allocated from | |
2784 | * @gfp_mask: memory allocation mask for bio | |
2785 | * @bio_ctr: setup function to be called for each clone bio. | |
2786 | * Returns %0 for success, non %0 for failure. | |
2787 | * @data: private data to be passed to @bio_ctr | |
2788 | * | |
2789 | * Description: | |
2790 | * Clones bios in @rq_src to @rq, and copies attributes of @rq_src to @rq. | |
2791 | * The actual data parts of @rq_src (e.g. ->cmd, ->buffer, ->sense) | |
2792 | * are not copied, and copying such parts is the caller's responsibility. | |
2793 | * Also, pages which the original bios are pointing to are not copied | |
2794 | * and the cloned bios just point same pages. | |
2795 | * So cloned bios must be completed before original bios, which means | |
2796 | * the caller must complete @rq before @rq_src. | |
2797 | */ | |
2798 | int blk_rq_prep_clone(struct request *rq, struct request *rq_src, | |
2799 | struct bio_set *bs, gfp_t gfp_mask, | |
2800 | int (*bio_ctr)(struct bio *, struct bio *, void *), | |
2801 | void *data) | |
2802 | { | |
2803 | struct bio *bio, *bio_src; | |
2804 | ||
2805 | if (!bs) | |
2806 | bs = fs_bio_set; | |
2807 | ||
2808 | blk_rq_init(NULL, rq); | |
2809 | ||
2810 | __rq_for_each_bio(bio_src, rq_src) { | |
bf800ef1 | 2811 | bio = bio_clone_bioset(bio_src, gfp_mask, bs); |
b0fd271d KU |
2812 | if (!bio) |
2813 | goto free_and_out; | |
2814 | ||
b0fd271d KU |
2815 | if (bio_ctr && bio_ctr(bio, bio_src, data)) |
2816 | goto free_and_out; | |
2817 | ||
2818 | if (rq->bio) { | |
2819 | rq->biotail->bi_next = bio; | |
2820 | rq->biotail = bio; | |
2821 | } else | |
2822 | rq->bio = rq->biotail = bio; | |
2823 | } | |
2824 | ||
2825 | __blk_rq_prep_clone(rq, rq_src); | |
2826 | ||
2827 | return 0; | |
2828 | ||
2829 | free_and_out: | |
2830 | if (bio) | |
4254bba1 | 2831 | bio_put(bio); |
b0fd271d KU |
2832 | blk_rq_unprep_clone(rq); |
2833 | ||
2834 | return -ENOMEM; | |
2835 | } | |
2836 | EXPORT_SYMBOL_GPL(blk_rq_prep_clone); | |
2837 | ||
18887ad9 | 2838 | int kblockd_schedule_work(struct request_queue *q, struct work_struct *work) |
1da177e4 LT |
2839 | { |
2840 | return queue_work(kblockd_workqueue, work); | |
2841 | } | |
1da177e4 LT |
2842 | EXPORT_SYMBOL(kblockd_schedule_work); |
2843 | ||
e43473b7 VG |
2844 | int kblockd_schedule_delayed_work(struct request_queue *q, |
2845 | struct delayed_work *dwork, unsigned long delay) | |
2846 | { | |
2847 | return queue_delayed_work(kblockd_workqueue, dwork, delay); | |
2848 | } | |
2849 | EXPORT_SYMBOL(kblockd_schedule_delayed_work); | |
2850 | ||
73c10101 JA |
2851 | #define PLUG_MAGIC 0x91827364 |
2852 | ||
75df7136 SJ |
2853 | /** |
2854 | * blk_start_plug - initialize blk_plug and track it inside the task_struct | |
2855 | * @plug: The &struct blk_plug that needs to be initialized | |
2856 | * | |
2857 | * Description: | |
2858 | * Tracking blk_plug inside the task_struct will help with auto-flushing the | |
2859 | * pending I/O should the task end up blocking between blk_start_plug() and | |
2860 | * blk_finish_plug(). This is important from a performance perspective, but | |
2861 | * also ensures that we don't deadlock. For instance, if the task is blocking | |
2862 | * for a memory allocation, memory reclaim could end up wanting to free a | |
2863 | * page belonging to that request that is currently residing in our private | |
2864 | * plug. By flushing the pending I/O when the process goes to sleep, we avoid | |
2865 | * this kind of deadlock. | |
2866 | */ | |
73c10101 JA |
2867 | void blk_start_plug(struct blk_plug *plug) |
2868 | { | |
2869 | struct task_struct *tsk = current; | |
2870 | ||
2871 | plug->magic = PLUG_MAGIC; | |
2872 | INIT_LIST_HEAD(&plug->list); | |
048c9374 | 2873 | INIT_LIST_HEAD(&plug->cb_list); |
73c10101 JA |
2874 | |
2875 | /* | |
2876 | * If this is a nested plug, don't actually assign it. It will be | |
2877 | * flushed on its own. | |
2878 | */ | |
2879 | if (!tsk->plug) { | |
2880 | /* | |
2881 | * Store ordering should not be needed here, since a potential | |
2882 | * preempt will imply a full memory barrier | |
2883 | */ | |
2884 | tsk->plug = plug; | |
2885 | } | |
2886 | } | |
2887 | EXPORT_SYMBOL(blk_start_plug); | |
2888 | ||
2889 | static int plug_rq_cmp(void *priv, struct list_head *a, struct list_head *b) | |
2890 | { | |
2891 | struct request *rqa = container_of(a, struct request, queuelist); | |
2892 | struct request *rqb = container_of(b, struct request, queuelist); | |
2893 | ||
975927b9 JM |
2894 | return !(rqa->q < rqb->q || |
2895 | (rqa->q == rqb->q && blk_rq_pos(rqa) < blk_rq_pos(rqb))); | |
73c10101 JA |
2896 | } |
2897 | ||
49cac01e JA |
2898 | /* |
2899 | * If 'from_schedule' is true, then postpone the dispatch of requests | |
2900 | * until a safe kblockd context. We due this to avoid accidental big | |
2901 | * additional stack usage in driver dispatch, in places where the originally | |
2902 | * plugger did not intend it. | |
2903 | */ | |
f6603783 | 2904 | static void queue_unplugged(struct request_queue *q, unsigned int depth, |
49cac01e | 2905 | bool from_schedule) |
99e22598 | 2906 | __releases(q->queue_lock) |
94b5eb28 | 2907 | { |
49cac01e | 2908 | trace_block_unplug(q, depth, !from_schedule); |
99e22598 | 2909 | |
70460571 | 2910 | if (from_schedule) |
24ecfbe2 | 2911 | blk_run_queue_async(q); |
70460571 | 2912 | else |
24ecfbe2 | 2913 | __blk_run_queue(q); |
70460571 | 2914 | spin_unlock(q->queue_lock); |
94b5eb28 JA |
2915 | } |
2916 | ||
74018dc3 | 2917 | static void flush_plug_callbacks(struct blk_plug *plug, bool from_schedule) |
048c9374 N |
2918 | { |
2919 | LIST_HEAD(callbacks); | |
2920 | ||
2a7d5559 SL |
2921 | while (!list_empty(&plug->cb_list)) { |
2922 | list_splice_init(&plug->cb_list, &callbacks); | |
048c9374 | 2923 | |
2a7d5559 SL |
2924 | while (!list_empty(&callbacks)) { |
2925 | struct blk_plug_cb *cb = list_first_entry(&callbacks, | |
048c9374 N |
2926 | struct blk_plug_cb, |
2927 | list); | |
2a7d5559 | 2928 | list_del(&cb->list); |
74018dc3 | 2929 | cb->callback(cb, from_schedule); |
2a7d5559 | 2930 | } |
048c9374 N |
2931 | } |
2932 | } | |
2933 | ||
9cbb1750 N |
2934 | struct blk_plug_cb *blk_check_plugged(blk_plug_cb_fn unplug, void *data, |
2935 | int size) | |
2936 | { | |
2937 | struct blk_plug *plug = current->plug; | |
2938 | struct blk_plug_cb *cb; | |
2939 | ||
2940 | if (!plug) | |
2941 | return NULL; | |
2942 | ||
2943 | list_for_each_entry(cb, &plug->cb_list, list) | |
2944 | if (cb->callback == unplug && cb->data == data) | |
2945 | return cb; | |
2946 | ||
2947 | /* Not currently on the callback list */ | |
2948 | BUG_ON(size < sizeof(*cb)); | |
2949 | cb = kzalloc(size, GFP_ATOMIC); | |
2950 | if (cb) { | |
2951 | cb->data = data; | |
2952 | cb->callback = unplug; | |
2953 | list_add(&cb->list, &plug->cb_list); | |
2954 | } | |
2955 | return cb; | |
2956 | } | |
2957 | EXPORT_SYMBOL(blk_check_plugged); | |
2958 | ||
49cac01e | 2959 | void blk_flush_plug_list(struct blk_plug *plug, bool from_schedule) |
73c10101 JA |
2960 | { |
2961 | struct request_queue *q; | |
2962 | unsigned long flags; | |
2963 | struct request *rq; | |
109b8129 | 2964 | LIST_HEAD(list); |
94b5eb28 | 2965 | unsigned int depth; |
73c10101 JA |
2966 | |
2967 | BUG_ON(plug->magic != PLUG_MAGIC); | |
2968 | ||
74018dc3 | 2969 | flush_plug_callbacks(plug, from_schedule); |
73c10101 JA |
2970 | if (list_empty(&plug->list)) |
2971 | return; | |
2972 | ||
109b8129 N |
2973 | list_splice_init(&plug->list, &list); |
2974 | ||
422765c2 | 2975 | list_sort(NULL, &list, plug_rq_cmp); |
73c10101 JA |
2976 | |
2977 | q = NULL; | |
94b5eb28 | 2978 | depth = 0; |
18811272 JA |
2979 | |
2980 | /* | |
2981 | * Save and disable interrupts here, to avoid doing it for every | |
2982 | * queue lock we have to take. | |
2983 | */ | |
73c10101 | 2984 | local_irq_save(flags); |
109b8129 N |
2985 | while (!list_empty(&list)) { |
2986 | rq = list_entry_rq(list.next); | |
73c10101 | 2987 | list_del_init(&rq->queuelist); |
73c10101 JA |
2988 | BUG_ON(!rq->q); |
2989 | if (rq->q != q) { | |
99e22598 JA |
2990 | /* |
2991 | * This drops the queue lock | |
2992 | */ | |
2993 | if (q) | |
49cac01e | 2994 | queue_unplugged(q, depth, from_schedule); |
73c10101 | 2995 | q = rq->q; |
94b5eb28 | 2996 | depth = 0; |
73c10101 JA |
2997 | spin_lock(q->queue_lock); |
2998 | } | |
8ba61435 TH |
2999 | |
3000 | /* | |
3001 | * Short-circuit if @q is dead | |
3002 | */ | |
3f3299d5 | 3003 | if (unlikely(blk_queue_dying(q))) { |
8ba61435 TH |
3004 | __blk_end_request_all(rq, -ENODEV); |
3005 | continue; | |
3006 | } | |
3007 | ||
73c10101 JA |
3008 | /* |
3009 | * rq is already accounted, so use raw insert | |
3010 | */ | |
401a18e9 JA |
3011 | if (rq->cmd_flags & (REQ_FLUSH | REQ_FUA)) |
3012 | __elv_add_request(q, rq, ELEVATOR_INSERT_FLUSH); | |
3013 | else | |
3014 | __elv_add_request(q, rq, ELEVATOR_INSERT_SORT_MERGE); | |
94b5eb28 JA |
3015 | |
3016 | depth++; | |
73c10101 JA |
3017 | } |
3018 | ||
99e22598 JA |
3019 | /* |
3020 | * This drops the queue lock | |
3021 | */ | |
3022 | if (q) | |
49cac01e | 3023 | queue_unplugged(q, depth, from_schedule); |
73c10101 | 3024 | |
73c10101 JA |
3025 | local_irq_restore(flags); |
3026 | } | |
73c10101 JA |
3027 | |
3028 | void blk_finish_plug(struct blk_plug *plug) | |
3029 | { | |
f6603783 | 3030 | blk_flush_plug_list(plug, false); |
73c10101 | 3031 | |
88b996cd CH |
3032 | if (plug == current->plug) |
3033 | current->plug = NULL; | |
73c10101 | 3034 | } |
88b996cd | 3035 | EXPORT_SYMBOL(blk_finish_plug); |
73c10101 | 3036 | |
6c954667 LM |
3037 | #ifdef CONFIG_PM_RUNTIME |
3038 | /** | |
3039 | * blk_pm_runtime_init - Block layer runtime PM initialization routine | |
3040 | * @q: the queue of the device | |
3041 | * @dev: the device the queue belongs to | |
3042 | * | |
3043 | * Description: | |
3044 | * Initialize runtime-PM-related fields for @q and start auto suspend for | |
3045 | * @dev. Drivers that want to take advantage of request-based runtime PM | |
3046 | * should call this function after @dev has been initialized, and its | |
3047 | * request queue @q has been allocated, and runtime PM for it can not happen | |
3048 | * yet(either due to disabled/forbidden or its usage_count > 0). In most | |
3049 | * cases, driver should call this function before any I/O has taken place. | |
3050 | * | |
3051 | * This function takes care of setting up using auto suspend for the device, | |
3052 | * the autosuspend delay is set to -1 to make runtime suspend impossible | |
3053 | * until an updated value is either set by user or by driver. Drivers do | |
3054 | * not need to touch other autosuspend settings. | |
3055 | * | |
3056 | * The block layer runtime PM is request based, so only works for drivers | |
3057 | * that use request as their IO unit instead of those directly use bio's. | |
3058 | */ | |
3059 | void blk_pm_runtime_init(struct request_queue *q, struct device *dev) | |
3060 | { | |
3061 | q->dev = dev; | |
3062 | q->rpm_status = RPM_ACTIVE; | |
3063 | pm_runtime_set_autosuspend_delay(q->dev, -1); | |
3064 | pm_runtime_use_autosuspend(q->dev); | |
3065 | } | |
3066 | EXPORT_SYMBOL(blk_pm_runtime_init); | |
3067 | ||
3068 | /** | |
3069 | * blk_pre_runtime_suspend - Pre runtime suspend check | |
3070 | * @q: the queue of the device | |
3071 | * | |
3072 | * Description: | |
3073 | * This function will check if runtime suspend is allowed for the device | |
3074 | * by examining if there are any requests pending in the queue. If there | |
3075 | * are requests pending, the device can not be runtime suspended; otherwise, | |
3076 | * the queue's status will be updated to SUSPENDING and the driver can | |
3077 | * proceed to suspend the device. | |
3078 | * | |
3079 | * For the not allowed case, we mark last busy for the device so that | |
3080 | * runtime PM core will try to autosuspend it some time later. | |
3081 | * | |
3082 | * This function should be called near the start of the device's | |
3083 | * runtime_suspend callback. | |
3084 | * | |
3085 | * Return: | |
3086 | * 0 - OK to runtime suspend the device | |
3087 | * -EBUSY - Device should not be runtime suspended | |
3088 | */ | |
3089 | int blk_pre_runtime_suspend(struct request_queue *q) | |
3090 | { | |
3091 | int ret = 0; | |
3092 | ||
3093 | spin_lock_irq(q->queue_lock); | |
3094 | if (q->nr_pending) { | |
3095 | ret = -EBUSY; | |
3096 | pm_runtime_mark_last_busy(q->dev); | |
3097 | } else { | |
3098 | q->rpm_status = RPM_SUSPENDING; | |
3099 | } | |
3100 | spin_unlock_irq(q->queue_lock); | |
3101 | return ret; | |
3102 | } | |
3103 | EXPORT_SYMBOL(blk_pre_runtime_suspend); | |
3104 | ||
3105 | /** | |
3106 | * blk_post_runtime_suspend - Post runtime suspend processing | |
3107 | * @q: the queue of the device | |
3108 | * @err: return value of the device's runtime_suspend function | |
3109 | * | |
3110 | * Description: | |
3111 | * Update the queue's runtime status according to the return value of the | |
3112 | * device's runtime suspend function and mark last busy for the device so | |
3113 | * that PM core will try to auto suspend the device at a later time. | |
3114 | * | |
3115 | * This function should be called near the end of the device's | |
3116 | * runtime_suspend callback. | |
3117 | */ | |
3118 | void blk_post_runtime_suspend(struct request_queue *q, int err) | |
3119 | { | |
3120 | spin_lock_irq(q->queue_lock); | |
3121 | if (!err) { | |
3122 | q->rpm_status = RPM_SUSPENDED; | |
3123 | } else { | |
3124 | q->rpm_status = RPM_ACTIVE; | |
3125 | pm_runtime_mark_last_busy(q->dev); | |
3126 | } | |
3127 | spin_unlock_irq(q->queue_lock); | |
3128 | } | |
3129 | EXPORT_SYMBOL(blk_post_runtime_suspend); | |
3130 | ||
3131 | /** | |
3132 | * blk_pre_runtime_resume - Pre runtime resume processing | |
3133 | * @q: the queue of the device | |
3134 | * | |
3135 | * Description: | |
3136 | * Update the queue's runtime status to RESUMING in preparation for the | |
3137 | * runtime resume of the device. | |
3138 | * | |
3139 | * This function should be called near the start of the device's | |
3140 | * runtime_resume callback. | |
3141 | */ | |
3142 | void blk_pre_runtime_resume(struct request_queue *q) | |
3143 | { | |
3144 | spin_lock_irq(q->queue_lock); | |
3145 | q->rpm_status = RPM_RESUMING; | |
3146 | spin_unlock_irq(q->queue_lock); | |
3147 | } | |
3148 | EXPORT_SYMBOL(blk_pre_runtime_resume); | |
3149 | ||
3150 | /** | |
3151 | * blk_post_runtime_resume - Post runtime resume processing | |
3152 | * @q: the queue of the device | |
3153 | * @err: return value of the device's runtime_resume function | |
3154 | * | |
3155 | * Description: | |
3156 | * Update the queue's runtime status according to the return value of the | |
3157 | * device's runtime_resume function. If it is successfully resumed, process | |
3158 | * the requests that are queued into the device's queue when it is resuming | |
3159 | * and then mark last busy and initiate autosuspend for it. | |
3160 | * | |
3161 | * This function should be called near the end of the device's | |
3162 | * runtime_resume callback. | |
3163 | */ | |
3164 | void blk_post_runtime_resume(struct request_queue *q, int err) | |
3165 | { | |
3166 | spin_lock_irq(q->queue_lock); | |
3167 | if (!err) { | |
3168 | q->rpm_status = RPM_ACTIVE; | |
3169 | __blk_run_queue(q); | |
3170 | pm_runtime_mark_last_busy(q->dev); | |
c60855cd | 3171 | pm_request_autosuspend(q->dev); |
6c954667 LM |
3172 | } else { |
3173 | q->rpm_status = RPM_SUSPENDED; | |
3174 | } | |
3175 | spin_unlock_irq(q->queue_lock); | |
3176 | } | |
3177 | EXPORT_SYMBOL(blk_post_runtime_resume); | |
3178 | #endif | |
3179 | ||
1da177e4 LT |
3180 | int __init blk_dev_init(void) |
3181 | { | |
9eb55b03 NK |
3182 | BUILD_BUG_ON(__REQ_NR_BITS > 8 * |
3183 | sizeof(((struct request *)0)->cmd_flags)); | |
3184 | ||
89b90be2 TH |
3185 | /* used for unplugging and affects IO latency/throughput - HIGHPRI */ |
3186 | kblockd_workqueue = alloc_workqueue("kblockd", | |
695588f9 VK |
3187 | WQ_MEM_RECLAIM | WQ_HIGHPRI | |
3188 | WQ_POWER_EFFICIENT, 0); | |
1da177e4 LT |
3189 | if (!kblockd_workqueue) |
3190 | panic("Failed to create kblockd\n"); | |
3191 | ||
3192 | request_cachep = kmem_cache_create("blkdev_requests", | |
20c2df83 | 3193 | sizeof(struct request), 0, SLAB_PANIC, NULL); |
1da177e4 | 3194 | |
8324aa91 | 3195 | blk_requestq_cachep = kmem_cache_create("blkdev_queue", |
165125e1 | 3196 | sizeof(struct request_queue), 0, SLAB_PANIC, NULL); |
1da177e4 | 3197 | |
d38ecf93 | 3198 | return 0; |
1da177e4 | 3199 | } |