Commit | Line | Data |
---|---|---|
1da177e4 | 1 | /* |
1da177e4 LT |
2 | * Copyright (C) 1991, 1992 Linus Torvalds |
3 | * Copyright (C) 1994, Karl Keyte: Added support for disk statistics | |
4 | * Elevator latency, (C) 2000 Andrea Arcangeli <andrea@suse.de> SuSE | |
5 | * Queue request tables / lock, selectable elevator, Jens Axboe <axboe@suse.de> | |
6728cb0e JA |
6 | * kernel-doc documentation started by NeilBrown <neilb@cse.unsw.edu.au> |
7 | * - July2000 | |
1da177e4 LT |
8 | * bio rewrite, highmem i/o, etc, Jens Axboe <axboe@suse.de> - may 2001 |
9 | */ | |
10 | ||
11 | /* | |
12 | * This handles all read/write requests to block devices | |
13 | */ | |
1da177e4 LT |
14 | #include <linux/kernel.h> |
15 | #include <linux/module.h> | |
16 | #include <linux/backing-dev.h> | |
17 | #include <linux/bio.h> | |
18 | #include <linux/blkdev.h> | |
320ae51f | 19 | #include <linux/blk-mq.h> |
1da177e4 LT |
20 | #include <linux/highmem.h> |
21 | #include <linux/mm.h> | |
22 | #include <linux/kernel_stat.h> | |
23 | #include <linux/string.h> | |
24 | #include <linux/init.h> | |
1da177e4 LT |
25 | #include <linux/completion.h> |
26 | #include <linux/slab.h> | |
27 | #include <linux/swap.h> | |
28 | #include <linux/writeback.h> | |
faccbd4b | 29 | #include <linux/task_io_accounting_ops.h> |
c17bb495 | 30 | #include <linux/fault-inject.h> |
73c10101 | 31 | #include <linux/list_sort.h> |
e3c78ca5 | 32 | #include <linux/delay.h> |
aaf7c680 | 33 | #include <linux/ratelimit.h> |
6c954667 | 34 | #include <linux/pm_runtime.h> |
eea8f41c | 35 | #include <linux/blk-cgroup.h> |
55782138 LZ |
36 | |
37 | #define CREATE_TRACE_POINTS | |
38 | #include <trace/events/block.h> | |
1da177e4 | 39 | |
8324aa91 | 40 | #include "blk.h" |
43a5e4e2 | 41 | #include "blk-mq.h" |
8324aa91 | 42 | |
d07335e5 | 43 | EXPORT_TRACEPOINT_SYMBOL_GPL(block_bio_remap); |
b0da3f0d | 44 | EXPORT_TRACEPOINT_SYMBOL_GPL(block_rq_remap); |
0a82a8d1 | 45 | EXPORT_TRACEPOINT_SYMBOL_GPL(block_bio_complete); |
3291fa57 | 46 | EXPORT_TRACEPOINT_SYMBOL_GPL(block_split); |
cbae8d45 | 47 | EXPORT_TRACEPOINT_SYMBOL_GPL(block_unplug); |
0bfc2455 | 48 | |
a73f730d TH |
49 | DEFINE_IDA(blk_queue_ida); |
50 | ||
1da177e4 LT |
51 | /* |
52 | * For the allocated request tables | |
53 | */ | |
d674d414 | 54 | struct kmem_cache *request_cachep; |
1da177e4 LT |
55 | |
56 | /* | |
57 | * For queue allocation | |
58 | */ | |
6728cb0e | 59 | struct kmem_cache *blk_requestq_cachep; |
1da177e4 | 60 | |
1da177e4 LT |
61 | /* |
62 | * Controlling structure to kblockd | |
63 | */ | |
ff856bad | 64 | static struct workqueue_struct *kblockd_workqueue; |
1da177e4 | 65 | |
d40f75a0 TH |
66 | static void blk_clear_congested(struct request_list *rl, int sync) |
67 | { | |
d40f75a0 TH |
68 | #ifdef CONFIG_CGROUP_WRITEBACK |
69 | clear_wb_congested(rl->blkg->wb_congested, sync); | |
70 | #else | |
482cf79c TH |
71 | /* |
72 | * If !CGROUP_WRITEBACK, all blkg's map to bdi->wb and we shouldn't | |
73 | * flip its congestion state for events on other blkcgs. | |
74 | */ | |
75 | if (rl == &rl->q->root_rl) | |
76 | clear_wb_congested(rl->q->backing_dev_info.wb.congested, sync); | |
d40f75a0 TH |
77 | #endif |
78 | } | |
79 | ||
80 | static void blk_set_congested(struct request_list *rl, int sync) | |
81 | { | |
d40f75a0 TH |
82 | #ifdef CONFIG_CGROUP_WRITEBACK |
83 | set_wb_congested(rl->blkg->wb_congested, sync); | |
84 | #else | |
482cf79c TH |
85 | /* see blk_clear_congested() */ |
86 | if (rl == &rl->q->root_rl) | |
87 | set_wb_congested(rl->q->backing_dev_info.wb.congested, sync); | |
d40f75a0 TH |
88 | #endif |
89 | } | |
90 | ||
8324aa91 | 91 | void blk_queue_congestion_threshold(struct request_queue *q) |
1da177e4 LT |
92 | { |
93 | int nr; | |
94 | ||
95 | nr = q->nr_requests - (q->nr_requests / 8) + 1; | |
96 | if (nr > q->nr_requests) | |
97 | nr = q->nr_requests; | |
98 | q->nr_congestion_on = nr; | |
99 | ||
100 | nr = q->nr_requests - (q->nr_requests / 8) - (q->nr_requests / 16) - 1; | |
101 | if (nr < 1) | |
102 | nr = 1; | |
103 | q->nr_congestion_off = nr; | |
104 | } | |
105 | ||
1da177e4 LT |
106 | /** |
107 | * blk_get_backing_dev_info - get the address of a queue's backing_dev_info | |
108 | * @bdev: device | |
109 | * | |
110 | * Locates the passed device's request queue and returns the address of its | |
ff9ea323 TH |
111 | * backing_dev_info. This function can only be called if @bdev is opened |
112 | * and the return value is never NULL. | |
1da177e4 LT |
113 | */ |
114 | struct backing_dev_info *blk_get_backing_dev_info(struct block_device *bdev) | |
115 | { | |
165125e1 | 116 | struct request_queue *q = bdev_get_queue(bdev); |
1da177e4 | 117 | |
ff9ea323 | 118 | return &q->backing_dev_info; |
1da177e4 | 119 | } |
1da177e4 LT |
120 | EXPORT_SYMBOL(blk_get_backing_dev_info); |
121 | ||
2a4aa30c | 122 | void blk_rq_init(struct request_queue *q, struct request *rq) |
1da177e4 | 123 | { |
1afb20f3 FT |
124 | memset(rq, 0, sizeof(*rq)); |
125 | ||
1da177e4 | 126 | INIT_LIST_HEAD(&rq->queuelist); |
242f9dcb | 127 | INIT_LIST_HEAD(&rq->timeout_list); |
c7c22e4d | 128 | rq->cpu = -1; |
63a71386 | 129 | rq->q = q; |
a2dec7b3 | 130 | rq->__sector = (sector_t) -1; |
2e662b65 JA |
131 | INIT_HLIST_NODE(&rq->hash); |
132 | RB_CLEAR_NODE(&rq->rb_node); | |
d7e3c324 | 133 | rq->cmd = rq->__cmd; |
e2494e1b | 134 | rq->cmd_len = BLK_MAX_CDB; |
63a71386 | 135 | rq->tag = -1; |
b243ddcb | 136 | rq->start_time = jiffies; |
9195291e | 137 | set_start_time_ns(rq); |
09e099d4 | 138 | rq->part = NULL; |
1da177e4 | 139 | } |
2a4aa30c | 140 | EXPORT_SYMBOL(blk_rq_init); |
1da177e4 | 141 | |
5bb23a68 N |
142 | static void req_bio_endio(struct request *rq, struct bio *bio, |
143 | unsigned int nbytes, int error) | |
1da177e4 | 144 | { |
78d8e58a | 145 | if (error) |
4246a0b6 | 146 | bio->bi_error = error; |
797e7dbb | 147 | |
143a87f4 | 148 | if (unlikely(rq->cmd_flags & REQ_QUIET)) |
b7c44ed9 | 149 | bio_set_flag(bio, BIO_QUIET); |
08bafc03 | 150 | |
f79ea416 | 151 | bio_advance(bio, nbytes); |
7ba1ba12 | 152 | |
143a87f4 | 153 | /* don't actually finish bio if it's part of flush sequence */ |
78d8e58a | 154 | if (bio->bi_iter.bi_size == 0 && !(rq->cmd_flags & REQ_FLUSH_SEQ)) |
4246a0b6 | 155 | bio_endio(bio); |
1da177e4 | 156 | } |
1da177e4 | 157 | |
1da177e4 LT |
158 | void blk_dump_rq_flags(struct request *rq, char *msg) |
159 | { | |
160 | int bit; | |
161 | ||
5953316d | 162 | printk(KERN_INFO "%s: dev %s: type=%x, flags=%llx\n", msg, |
4aff5e23 | 163 | rq->rq_disk ? rq->rq_disk->disk_name : "?", rq->cmd_type, |
5953316d | 164 | (unsigned long long) rq->cmd_flags); |
1da177e4 | 165 | |
83096ebf TH |
166 | printk(KERN_INFO " sector %llu, nr/cnr %u/%u\n", |
167 | (unsigned long long)blk_rq_pos(rq), | |
168 | blk_rq_sectors(rq), blk_rq_cur_sectors(rq)); | |
b4f42e28 JA |
169 | printk(KERN_INFO " bio %p, biotail %p, len %u\n", |
170 | rq->bio, rq->biotail, blk_rq_bytes(rq)); | |
1da177e4 | 171 | |
33659ebb | 172 | if (rq->cmd_type == REQ_TYPE_BLOCK_PC) { |
6728cb0e | 173 | printk(KERN_INFO " cdb: "); |
d34c87e4 | 174 | for (bit = 0; bit < BLK_MAX_CDB; bit++) |
1da177e4 LT |
175 | printk("%02x ", rq->cmd[bit]); |
176 | printk("\n"); | |
177 | } | |
178 | } | |
1da177e4 LT |
179 | EXPORT_SYMBOL(blk_dump_rq_flags); |
180 | ||
3cca6dc1 | 181 | static void blk_delay_work(struct work_struct *work) |
1da177e4 | 182 | { |
3cca6dc1 | 183 | struct request_queue *q; |
1da177e4 | 184 | |
3cca6dc1 JA |
185 | q = container_of(work, struct request_queue, delay_work.work); |
186 | spin_lock_irq(q->queue_lock); | |
24ecfbe2 | 187 | __blk_run_queue(q); |
3cca6dc1 | 188 | spin_unlock_irq(q->queue_lock); |
1da177e4 | 189 | } |
1da177e4 LT |
190 | |
191 | /** | |
3cca6dc1 JA |
192 | * blk_delay_queue - restart queueing after defined interval |
193 | * @q: The &struct request_queue in question | |
194 | * @msecs: Delay in msecs | |
1da177e4 LT |
195 | * |
196 | * Description: | |
3cca6dc1 JA |
197 | * Sometimes queueing needs to be postponed for a little while, to allow |
198 | * resources to come back. This function will make sure that queueing is | |
70460571 | 199 | * restarted around the specified time. Queue lock must be held. |
3cca6dc1 JA |
200 | */ |
201 | void blk_delay_queue(struct request_queue *q, unsigned long msecs) | |
2ad8b1ef | 202 | { |
70460571 BVA |
203 | if (likely(!blk_queue_dead(q))) |
204 | queue_delayed_work(kblockd_workqueue, &q->delay_work, | |
205 | msecs_to_jiffies(msecs)); | |
2ad8b1ef | 206 | } |
3cca6dc1 | 207 | EXPORT_SYMBOL(blk_delay_queue); |
2ad8b1ef | 208 | |
21491412 JA |
209 | /** |
210 | * blk_start_queue_async - asynchronously restart a previously stopped queue | |
211 | * @q: The &struct request_queue in question | |
212 | * | |
213 | * Description: | |
214 | * blk_start_queue_async() will clear the stop flag on the queue, and | |
215 | * ensure that the request_fn for the queue is run from an async | |
216 | * context. | |
217 | **/ | |
218 | void blk_start_queue_async(struct request_queue *q) | |
219 | { | |
220 | queue_flag_clear(QUEUE_FLAG_STOPPED, q); | |
221 | blk_run_queue_async(q); | |
222 | } | |
223 | EXPORT_SYMBOL(blk_start_queue_async); | |
224 | ||
1da177e4 LT |
225 | /** |
226 | * blk_start_queue - restart a previously stopped queue | |
165125e1 | 227 | * @q: The &struct request_queue in question |
1da177e4 LT |
228 | * |
229 | * Description: | |
230 | * blk_start_queue() will clear the stop flag on the queue, and call | |
231 | * the request_fn for the queue if it was in a stopped state when | |
232 | * entered. Also see blk_stop_queue(). Queue lock must be held. | |
233 | **/ | |
165125e1 | 234 | void blk_start_queue(struct request_queue *q) |
1da177e4 | 235 | { |
a038e253 PBG |
236 | WARN_ON(!irqs_disabled()); |
237 | ||
75ad23bc | 238 | queue_flag_clear(QUEUE_FLAG_STOPPED, q); |
24ecfbe2 | 239 | __blk_run_queue(q); |
1da177e4 | 240 | } |
1da177e4 LT |
241 | EXPORT_SYMBOL(blk_start_queue); |
242 | ||
243 | /** | |
244 | * blk_stop_queue - stop a queue | |
165125e1 | 245 | * @q: The &struct request_queue in question |
1da177e4 LT |
246 | * |
247 | * Description: | |
248 | * The Linux block layer assumes that a block driver will consume all | |
249 | * entries on the request queue when the request_fn strategy is called. | |
250 | * Often this will not happen, because of hardware limitations (queue | |
251 | * depth settings). If a device driver gets a 'queue full' response, | |
252 | * or if it simply chooses not to queue more I/O at one point, it can | |
253 | * call this function to prevent the request_fn from being called until | |
254 | * the driver has signalled it's ready to go again. This happens by calling | |
255 | * blk_start_queue() to restart queue operations. Queue lock must be held. | |
256 | **/ | |
165125e1 | 257 | void blk_stop_queue(struct request_queue *q) |
1da177e4 | 258 | { |
136b5721 | 259 | cancel_delayed_work(&q->delay_work); |
75ad23bc | 260 | queue_flag_set(QUEUE_FLAG_STOPPED, q); |
1da177e4 LT |
261 | } |
262 | EXPORT_SYMBOL(blk_stop_queue); | |
263 | ||
264 | /** | |
265 | * blk_sync_queue - cancel any pending callbacks on a queue | |
266 | * @q: the queue | |
267 | * | |
268 | * Description: | |
269 | * The block layer may perform asynchronous callback activity | |
270 | * on a queue, such as calling the unplug function after a timeout. | |
271 | * A block device may call blk_sync_queue to ensure that any | |
272 | * such activity is cancelled, thus allowing it to release resources | |
59c51591 | 273 | * that the callbacks might use. The caller must already have made sure |
1da177e4 LT |
274 | * that its ->make_request_fn will not re-add plugging prior to calling |
275 | * this function. | |
276 | * | |
da527770 | 277 | * This function does not cancel any asynchronous activity arising |
da3dae54 | 278 | * out of elevator or throttling code. That would require elevator_exit() |
5efd6113 | 279 | * and blkcg_exit_queue() to be called with queue lock initialized. |
da527770 | 280 | * |
1da177e4 LT |
281 | */ |
282 | void blk_sync_queue(struct request_queue *q) | |
283 | { | |
70ed28b9 | 284 | del_timer_sync(&q->timeout); |
f04c1fe7 ML |
285 | |
286 | if (q->mq_ops) { | |
287 | struct blk_mq_hw_ctx *hctx; | |
288 | int i; | |
289 | ||
70f4db63 CH |
290 | queue_for_each_hw_ctx(q, hctx, i) { |
291 | cancel_delayed_work_sync(&hctx->run_work); | |
292 | cancel_delayed_work_sync(&hctx->delay_work); | |
293 | } | |
f04c1fe7 ML |
294 | } else { |
295 | cancel_delayed_work_sync(&q->delay_work); | |
296 | } | |
1da177e4 LT |
297 | } |
298 | EXPORT_SYMBOL(blk_sync_queue); | |
299 | ||
c246e80d BVA |
300 | /** |
301 | * __blk_run_queue_uncond - run a queue whether or not it has been stopped | |
302 | * @q: The queue to run | |
303 | * | |
304 | * Description: | |
305 | * Invoke request handling on a queue if there are any pending requests. | |
306 | * May be used to restart request handling after a request has completed. | |
307 | * This variant runs the queue whether or not the queue has been | |
308 | * stopped. Must be called with the queue lock held and interrupts | |
309 | * disabled. See also @blk_run_queue. | |
310 | */ | |
311 | inline void __blk_run_queue_uncond(struct request_queue *q) | |
312 | { | |
313 | if (unlikely(blk_queue_dead(q))) | |
314 | return; | |
315 | ||
24faf6f6 BVA |
316 | /* |
317 | * Some request_fn implementations, e.g. scsi_request_fn(), unlock | |
318 | * the queue lock internally. As a result multiple threads may be | |
319 | * running such a request function concurrently. Keep track of the | |
320 | * number of active request_fn invocations such that blk_drain_queue() | |
321 | * can wait until all these request_fn calls have finished. | |
322 | */ | |
323 | q->request_fn_active++; | |
c246e80d | 324 | q->request_fn(q); |
24faf6f6 | 325 | q->request_fn_active--; |
c246e80d | 326 | } |
a7928c15 | 327 | EXPORT_SYMBOL_GPL(__blk_run_queue_uncond); |
c246e80d | 328 | |
1da177e4 | 329 | /** |
80a4b58e | 330 | * __blk_run_queue - run a single device queue |
1da177e4 | 331 | * @q: The queue to run |
80a4b58e JA |
332 | * |
333 | * Description: | |
334 | * See @blk_run_queue. This variant must be called with the queue lock | |
24ecfbe2 | 335 | * held and interrupts disabled. |
1da177e4 | 336 | */ |
24ecfbe2 | 337 | void __blk_run_queue(struct request_queue *q) |
1da177e4 | 338 | { |
a538cd03 TH |
339 | if (unlikely(blk_queue_stopped(q))) |
340 | return; | |
341 | ||
c246e80d | 342 | __blk_run_queue_uncond(q); |
75ad23bc NP |
343 | } |
344 | EXPORT_SYMBOL(__blk_run_queue); | |
dac07ec1 | 345 | |
24ecfbe2 CH |
346 | /** |
347 | * blk_run_queue_async - run a single device queue in workqueue context | |
348 | * @q: The queue to run | |
349 | * | |
350 | * Description: | |
351 | * Tells kblockd to perform the equivalent of @blk_run_queue on behalf | |
70460571 | 352 | * of us. The caller must hold the queue lock. |
24ecfbe2 CH |
353 | */ |
354 | void blk_run_queue_async(struct request_queue *q) | |
355 | { | |
70460571 | 356 | if (likely(!blk_queue_stopped(q) && !blk_queue_dead(q))) |
e7c2f967 | 357 | mod_delayed_work(kblockd_workqueue, &q->delay_work, 0); |
24ecfbe2 | 358 | } |
c21e6beb | 359 | EXPORT_SYMBOL(blk_run_queue_async); |
24ecfbe2 | 360 | |
75ad23bc NP |
361 | /** |
362 | * blk_run_queue - run a single device queue | |
363 | * @q: The queue to run | |
80a4b58e JA |
364 | * |
365 | * Description: | |
366 | * Invoke request handling on this queue, if it has pending work to do. | |
a7f55792 | 367 | * May be used to restart queueing when a request has completed. |
75ad23bc NP |
368 | */ |
369 | void blk_run_queue(struct request_queue *q) | |
370 | { | |
371 | unsigned long flags; | |
372 | ||
373 | spin_lock_irqsave(q->queue_lock, flags); | |
24ecfbe2 | 374 | __blk_run_queue(q); |
1da177e4 LT |
375 | spin_unlock_irqrestore(q->queue_lock, flags); |
376 | } | |
377 | EXPORT_SYMBOL(blk_run_queue); | |
378 | ||
165125e1 | 379 | void blk_put_queue(struct request_queue *q) |
483f4afc AV |
380 | { |
381 | kobject_put(&q->kobj); | |
382 | } | |
d86e0e83 | 383 | EXPORT_SYMBOL(blk_put_queue); |
483f4afc | 384 | |
e3c78ca5 | 385 | /** |
807592a4 | 386 | * __blk_drain_queue - drain requests from request_queue |
e3c78ca5 | 387 | * @q: queue to drain |
c9a929dd | 388 | * @drain_all: whether to drain all requests or only the ones w/ ELVPRIV |
e3c78ca5 | 389 | * |
c9a929dd TH |
390 | * Drain requests from @q. If @drain_all is set, all requests are drained. |
391 | * If not, only ELVPRIV requests are drained. The caller is responsible | |
392 | * for ensuring that no new requests which need to be drained are queued. | |
e3c78ca5 | 393 | */ |
807592a4 BVA |
394 | static void __blk_drain_queue(struct request_queue *q, bool drain_all) |
395 | __releases(q->queue_lock) | |
396 | __acquires(q->queue_lock) | |
e3c78ca5 | 397 | { |
458f27a9 AH |
398 | int i; |
399 | ||
807592a4 BVA |
400 | lockdep_assert_held(q->queue_lock); |
401 | ||
e3c78ca5 | 402 | while (true) { |
481a7d64 | 403 | bool drain = false; |
e3c78ca5 | 404 | |
b855b04a TH |
405 | /* |
406 | * The caller might be trying to drain @q before its | |
407 | * elevator is initialized. | |
408 | */ | |
409 | if (q->elevator) | |
410 | elv_drain_elevator(q); | |
411 | ||
5efd6113 | 412 | blkcg_drain_queue(q); |
e3c78ca5 | 413 | |
4eabc941 TH |
414 | /* |
415 | * This function might be called on a queue which failed | |
b855b04a TH |
416 | * driver init after queue creation or is not yet fully |
417 | * active yet. Some drivers (e.g. fd and loop) get unhappy | |
418 | * in such cases. Kick queue iff dispatch queue has | |
419 | * something on it and @q has request_fn set. | |
4eabc941 | 420 | */ |
b855b04a | 421 | if (!list_empty(&q->queue_head) && q->request_fn) |
4eabc941 | 422 | __blk_run_queue(q); |
c9a929dd | 423 | |
8a5ecdd4 | 424 | drain |= q->nr_rqs_elvpriv; |
24faf6f6 | 425 | drain |= q->request_fn_active; |
481a7d64 TH |
426 | |
427 | /* | |
428 | * Unfortunately, requests are queued at and tracked from | |
429 | * multiple places and there's no single counter which can | |
430 | * be drained. Check all the queues and counters. | |
431 | */ | |
432 | if (drain_all) { | |
e97c293c | 433 | struct blk_flush_queue *fq = blk_get_flush_queue(q, NULL); |
481a7d64 TH |
434 | drain |= !list_empty(&q->queue_head); |
435 | for (i = 0; i < 2; i++) { | |
8a5ecdd4 | 436 | drain |= q->nr_rqs[i]; |
481a7d64 | 437 | drain |= q->in_flight[i]; |
7c94e1c1 ML |
438 | if (fq) |
439 | drain |= !list_empty(&fq->flush_queue[i]); | |
481a7d64 TH |
440 | } |
441 | } | |
e3c78ca5 | 442 | |
481a7d64 | 443 | if (!drain) |
e3c78ca5 | 444 | break; |
807592a4 BVA |
445 | |
446 | spin_unlock_irq(q->queue_lock); | |
447 | ||
e3c78ca5 | 448 | msleep(10); |
807592a4 BVA |
449 | |
450 | spin_lock_irq(q->queue_lock); | |
e3c78ca5 | 451 | } |
458f27a9 AH |
452 | |
453 | /* | |
454 | * With queue marked dead, any woken up waiter will fail the | |
455 | * allocation path, so the wakeup chaining is lost and we're | |
456 | * left with hung waiters. We need to wake up those waiters. | |
457 | */ | |
458 | if (q->request_fn) { | |
a051661c TH |
459 | struct request_list *rl; |
460 | ||
a051661c TH |
461 | blk_queue_for_each_rl(rl, q) |
462 | for (i = 0; i < ARRAY_SIZE(rl->wait); i++) | |
463 | wake_up_all(&rl->wait[i]); | |
458f27a9 | 464 | } |
e3c78ca5 TH |
465 | } |
466 | ||
d732580b TH |
467 | /** |
468 | * blk_queue_bypass_start - enter queue bypass mode | |
469 | * @q: queue of interest | |
470 | * | |
471 | * In bypass mode, only the dispatch FIFO queue of @q is used. This | |
472 | * function makes @q enter bypass mode and drains all requests which were | |
6ecf23af | 473 | * throttled or issued before. On return, it's guaranteed that no request |
80fd9979 TH |
474 | * is being throttled or has ELVPRIV set and blk_queue_bypass() %true |
475 | * inside queue or RCU read lock. | |
d732580b TH |
476 | */ |
477 | void blk_queue_bypass_start(struct request_queue *q) | |
478 | { | |
479 | spin_lock_irq(q->queue_lock); | |
776687bc | 480 | q->bypass_depth++; |
d732580b TH |
481 | queue_flag_set(QUEUE_FLAG_BYPASS, q); |
482 | spin_unlock_irq(q->queue_lock); | |
483 | ||
776687bc TH |
484 | /* |
485 | * Queues start drained. Skip actual draining till init is | |
486 | * complete. This avoids lenghty delays during queue init which | |
487 | * can happen many times during boot. | |
488 | */ | |
489 | if (blk_queue_init_done(q)) { | |
807592a4 BVA |
490 | spin_lock_irq(q->queue_lock); |
491 | __blk_drain_queue(q, false); | |
492 | spin_unlock_irq(q->queue_lock); | |
493 | ||
b82d4b19 TH |
494 | /* ensure blk_queue_bypass() is %true inside RCU read lock */ |
495 | synchronize_rcu(); | |
496 | } | |
d732580b TH |
497 | } |
498 | EXPORT_SYMBOL_GPL(blk_queue_bypass_start); | |
499 | ||
500 | /** | |
501 | * blk_queue_bypass_end - leave queue bypass mode | |
502 | * @q: queue of interest | |
503 | * | |
504 | * Leave bypass mode and restore the normal queueing behavior. | |
505 | */ | |
506 | void blk_queue_bypass_end(struct request_queue *q) | |
507 | { | |
508 | spin_lock_irq(q->queue_lock); | |
509 | if (!--q->bypass_depth) | |
510 | queue_flag_clear(QUEUE_FLAG_BYPASS, q); | |
511 | WARN_ON_ONCE(q->bypass_depth < 0); | |
512 | spin_unlock_irq(q->queue_lock); | |
513 | } | |
514 | EXPORT_SYMBOL_GPL(blk_queue_bypass_end); | |
515 | ||
aed3ea94 JA |
516 | void blk_set_queue_dying(struct request_queue *q) |
517 | { | |
518 | queue_flag_set_unlocked(QUEUE_FLAG_DYING, q); | |
519 | ||
520 | if (q->mq_ops) | |
521 | blk_mq_wake_waiters(q); | |
522 | else { | |
523 | struct request_list *rl; | |
524 | ||
525 | blk_queue_for_each_rl(rl, q) { | |
526 | if (rl->rq_pool) { | |
527 | wake_up(&rl->wait[BLK_RW_SYNC]); | |
528 | wake_up(&rl->wait[BLK_RW_ASYNC]); | |
529 | } | |
530 | } | |
531 | } | |
532 | } | |
533 | EXPORT_SYMBOL_GPL(blk_set_queue_dying); | |
534 | ||
c9a929dd TH |
535 | /** |
536 | * blk_cleanup_queue - shutdown a request queue | |
537 | * @q: request queue to shutdown | |
538 | * | |
c246e80d BVA |
539 | * Mark @q DYING, drain all pending requests, mark @q DEAD, destroy and |
540 | * put it. All future requests will be failed immediately with -ENODEV. | |
c94a96ac | 541 | */ |
6728cb0e | 542 | void blk_cleanup_queue(struct request_queue *q) |
483f4afc | 543 | { |
c9a929dd | 544 | spinlock_t *lock = q->queue_lock; |
e3335de9 | 545 | |
3f3299d5 | 546 | /* mark @q DYING, no new request or merges will be allowed afterwards */ |
483f4afc | 547 | mutex_lock(&q->sysfs_lock); |
aed3ea94 | 548 | blk_set_queue_dying(q); |
c9a929dd | 549 | spin_lock_irq(lock); |
6ecf23af | 550 | |
80fd9979 | 551 | /* |
3f3299d5 | 552 | * A dying queue is permanently in bypass mode till released. Note |
80fd9979 TH |
553 | * that, unlike blk_queue_bypass_start(), we aren't performing |
554 | * synchronize_rcu() after entering bypass mode to avoid the delay | |
555 | * as some drivers create and destroy a lot of queues while | |
556 | * probing. This is still safe because blk_release_queue() will be | |
557 | * called only after the queue refcnt drops to zero and nothing, | |
558 | * RCU or not, would be traversing the queue by then. | |
559 | */ | |
6ecf23af TH |
560 | q->bypass_depth++; |
561 | queue_flag_set(QUEUE_FLAG_BYPASS, q); | |
562 | ||
c9a929dd TH |
563 | queue_flag_set(QUEUE_FLAG_NOMERGES, q); |
564 | queue_flag_set(QUEUE_FLAG_NOXMERGES, q); | |
3f3299d5 | 565 | queue_flag_set(QUEUE_FLAG_DYING, q); |
c9a929dd TH |
566 | spin_unlock_irq(lock); |
567 | mutex_unlock(&q->sysfs_lock); | |
568 | ||
c246e80d BVA |
569 | /* |
570 | * Drain all requests queued before DYING marking. Set DEAD flag to | |
571 | * prevent that q->request_fn() gets invoked after draining finished. | |
572 | */ | |
3ef28e83 DW |
573 | blk_freeze_queue(q); |
574 | spin_lock_irq(lock); | |
575 | if (!q->mq_ops) | |
43a5e4e2 | 576 | __blk_drain_queue(q, true); |
c246e80d | 577 | queue_flag_set(QUEUE_FLAG_DEAD, q); |
807592a4 | 578 | spin_unlock_irq(lock); |
c9a929dd | 579 | |
5a48fc14 DW |
580 | /* for synchronous bio-based driver finish in-flight integrity i/o */ |
581 | blk_flush_integrity(); | |
582 | ||
c9a929dd TH |
583 | /* @q won't process any more request, flush async actions */ |
584 | del_timer_sync(&q->backing_dev_info.laptop_mode_wb_timer); | |
585 | blk_sync_queue(q); | |
586 | ||
45a9c9d9 BVA |
587 | if (q->mq_ops) |
588 | blk_mq_free_queue(q); | |
3ef28e83 | 589 | percpu_ref_exit(&q->q_usage_counter); |
45a9c9d9 | 590 | |
5e5cfac0 AH |
591 | spin_lock_irq(lock); |
592 | if (q->queue_lock != &q->__queue_lock) | |
593 | q->queue_lock = &q->__queue_lock; | |
594 | spin_unlock_irq(lock); | |
595 | ||
b02176f3 | 596 | bdi_unregister(&q->backing_dev_info); |
6cd18e71 | 597 | |
c9a929dd | 598 | /* @q is and will stay empty, shutdown and put */ |
483f4afc AV |
599 | blk_put_queue(q); |
600 | } | |
1da177e4 LT |
601 | EXPORT_SYMBOL(blk_cleanup_queue); |
602 | ||
271508db DR |
603 | /* Allocate memory local to the request queue */ |
604 | static void *alloc_request_struct(gfp_t gfp_mask, void *data) | |
605 | { | |
606 | int nid = (int)(long)data; | |
607 | return kmem_cache_alloc_node(request_cachep, gfp_mask, nid); | |
608 | } | |
609 | ||
610 | static void free_request_struct(void *element, void *unused) | |
611 | { | |
612 | kmem_cache_free(request_cachep, element); | |
613 | } | |
614 | ||
5b788ce3 TH |
615 | int blk_init_rl(struct request_list *rl, struct request_queue *q, |
616 | gfp_t gfp_mask) | |
1da177e4 | 617 | { |
1abec4fd MS |
618 | if (unlikely(rl->rq_pool)) |
619 | return 0; | |
620 | ||
5b788ce3 | 621 | rl->q = q; |
1faa16d2 JA |
622 | rl->count[BLK_RW_SYNC] = rl->count[BLK_RW_ASYNC] = 0; |
623 | rl->starved[BLK_RW_SYNC] = rl->starved[BLK_RW_ASYNC] = 0; | |
1faa16d2 JA |
624 | init_waitqueue_head(&rl->wait[BLK_RW_SYNC]); |
625 | init_waitqueue_head(&rl->wait[BLK_RW_ASYNC]); | |
1da177e4 | 626 | |
271508db DR |
627 | rl->rq_pool = mempool_create_node(BLKDEV_MIN_RQ, alloc_request_struct, |
628 | free_request_struct, | |
629 | (void *)(long)q->node, gfp_mask, | |
630 | q->node); | |
1da177e4 LT |
631 | if (!rl->rq_pool) |
632 | return -ENOMEM; | |
633 | ||
634 | return 0; | |
635 | } | |
636 | ||
5b788ce3 TH |
637 | void blk_exit_rl(struct request_list *rl) |
638 | { | |
639 | if (rl->rq_pool) | |
640 | mempool_destroy(rl->rq_pool); | |
641 | } | |
642 | ||
165125e1 | 643 | struct request_queue *blk_alloc_queue(gfp_t gfp_mask) |
1da177e4 | 644 | { |
c304a51b | 645 | return blk_alloc_queue_node(gfp_mask, NUMA_NO_NODE); |
1946089a CL |
646 | } |
647 | EXPORT_SYMBOL(blk_alloc_queue); | |
1da177e4 | 648 | |
6f3b0e8b | 649 | int blk_queue_enter(struct request_queue *q, bool nowait) |
3ef28e83 DW |
650 | { |
651 | while (true) { | |
652 | int ret; | |
653 | ||
654 | if (percpu_ref_tryget_live(&q->q_usage_counter)) | |
655 | return 0; | |
656 | ||
6f3b0e8b | 657 | if (nowait) |
3ef28e83 DW |
658 | return -EBUSY; |
659 | ||
660 | ret = wait_event_interruptible(q->mq_freeze_wq, | |
661 | !atomic_read(&q->mq_freeze_depth) || | |
662 | blk_queue_dying(q)); | |
663 | if (blk_queue_dying(q)) | |
664 | return -ENODEV; | |
665 | if (ret) | |
666 | return ret; | |
667 | } | |
668 | } | |
669 | ||
670 | void blk_queue_exit(struct request_queue *q) | |
671 | { | |
672 | percpu_ref_put(&q->q_usage_counter); | |
673 | } | |
674 | ||
675 | static void blk_queue_usage_counter_release(struct percpu_ref *ref) | |
676 | { | |
677 | struct request_queue *q = | |
678 | container_of(ref, struct request_queue, q_usage_counter); | |
679 | ||
680 | wake_up_all(&q->mq_freeze_wq); | |
681 | } | |
682 | ||
287922eb CH |
683 | static void blk_rq_timed_out_timer(unsigned long data) |
684 | { | |
685 | struct request_queue *q = (struct request_queue *)data; | |
686 | ||
687 | kblockd_schedule_work(&q->timeout_work); | |
688 | } | |
689 | ||
165125e1 | 690 | struct request_queue *blk_alloc_queue_node(gfp_t gfp_mask, int node_id) |
1946089a | 691 | { |
165125e1 | 692 | struct request_queue *q; |
e0bf68dd | 693 | int err; |
1946089a | 694 | |
8324aa91 | 695 | q = kmem_cache_alloc_node(blk_requestq_cachep, |
94f6030c | 696 | gfp_mask | __GFP_ZERO, node_id); |
1da177e4 LT |
697 | if (!q) |
698 | return NULL; | |
699 | ||
00380a40 | 700 | q->id = ida_simple_get(&blk_queue_ida, 0, 0, gfp_mask); |
a73f730d | 701 | if (q->id < 0) |
3d2936f4 | 702 | goto fail_q; |
a73f730d | 703 | |
54efd50b KO |
704 | q->bio_split = bioset_create(BIO_POOL_SIZE, 0); |
705 | if (!q->bio_split) | |
706 | goto fail_id; | |
707 | ||
0989a025 JA |
708 | q->backing_dev_info.ra_pages = |
709 | (VM_MAX_READAHEAD * 1024) / PAGE_CACHE_SIZE; | |
89e9b9e0 | 710 | q->backing_dev_info.capabilities = BDI_CAP_CGROUP_WRITEBACK; |
d993831f | 711 | q->backing_dev_info.name = "block"; |
5151412d | 712 | q->node = node_id; |
0989a025 | 713 | |
e0bf68dd | 714 | err = bdi_init(&q->backing_dev_info); |
a73f730d | 715 | if (err) |
54efd50b | 716 | goto fail_split; |
e0bf68dd | 717 | |
31373d09 MG |
718 | setup_timer(&q->backing_dev_info.laptop_mode_wb_timer, |
719 | laptop_mode_timer_fn, (unsigned long) q); | |
242f9dcb | 720 | setup_timer(&q->timeout, blk_rq_timed_out_timer, (unsigned long) q); |
b855b04a | 721 | INIT_LIST_HEAD(&q->queue_head); |
242f9dcb | 722 | INIT_LIST_HEAD(&q->timeout_list); |
a612fddf | 723 | INIT_LIST_HEAD(&q->icq_list); |
4eef3049 | 724 | #ifdef CONFIG_BLK_CGROUP |
e8989fae | 725 | INIT_LIST_HEAD(&q->blkg_list); |
4eef3049 | 726 | #endif |
3cca6dc1 | 727 | INIT_DELAYED_WORK(&q->delay_work, blk_delay_work); |
483f4afc | 728 | |
8324aa91 | 729 | kobject_init(&q->kobj, &blk_queue_ktype); |
1da177e4 | 730 | |
483f4afc | 731 | mutex_init(&q->sysfs_lock); |
e7e72bf6 | 732 | spin_lock_init(&q->__queue_lock); |
483f4afc | 733 | |
c94a96ac VG |
734 | /* |
735 | * By default initialize queue_lock to internal lock and driver can | |
736 | * override it later if need be. | |
737 | */ | |
738 | q->queue_lock = &q->__queue_lock; | |
739 | ||
b82d4b19 TH |
740 | /* |
741 | * A queue starts its life with bypass turned on to avoid | |
742 | * unnecessary bypass on/off overhead and nasty surprises during | |
749fefe6 TH |
743 | * init. The initial bypass will be finished when the queue is |
744 | * registered by blk_register_queue(). | |
b82d4b19 TH |
745 | */ |
746 | q->bypass_depth = 1; | |
747 | __set_bit(QUEUE_FLAG_BYPASS, &q->queue_flags); | |
748 | ||
320ae51f JA |
749 | init_waitqueue_head(&q->mq_freeze_wq); |
750 | ||
3ef28e83 DW |
751 | /* |
752 | * Init percpu_ref in atomic mode so that it's faster to shutdown. | |
753 | * See blk_register_queue() for details. | |
754 | */ | |
755 | if (percpu_ref_init(&q->q_usage_counter, | |
756 | blk_queue_usage_counter_release, | |
757 | PERCPU_REF_INIT_ATOMIC, GFP_KERNEL)) | |
fff4996b | 758 | goto fail_bdi; |
f51b802c | 759 | |
3ef28e83 DW |
760 | if (blkcg_init_queue(q)) |
761 | goto fail_ref; | |
762 | ||
1da177e4 | 763 | return q; |
a73f730d | 764 | |
3ef28e83 DW |
765 | fail_ref: |
766 | percpu_ref_exit(&q->q_usage_counter); | |
fff4996b MP |
767 | fail_bdi: |
768 | bdi_destroy(&q->backing_dev_info); | |
54efd50b KO |
769 | fail_split: |
770 | bioset_free(q->bio_split); | |
a73f730d TH |
771 | fail_id: |
772 | ida_simple_remove(&blk_queue_ida, q->id); | |
773 | fail_q: | |
774 | kmem_cache_free(blk_requestq_cachep, q); | |
775 | return NULL; | |
1da177e4 | 776 | } |
1946089a | 777 | EXPORT_SYMBOL(blk_alloc_queue_node); |
1da177e4 LT |
778 | |
779 | /** | |
780 | * blk_init_queue - prepare a request queue for use with a block device | |
781 | * @rfn: The function to be called to process requests that have been | |
782 | * placed on the queue. | |
783 | * @lock: Request queue spin lock | |
784 | * | |
785 | * Description: | |
786 | * If a block device wishes to use the standard request handling procedures, | |
787 | * which sorts requests and coalesces adjacent requests, then it must | |
788 | * call blk_init_queue(). The function @rfn will be called when there | |
789 | * are requests on the queue that need to be processed. If the device | |
790 | * supports plugging, then @rfn may not be called immediately when requests | |
791 | * are available on the queue, but may be called at some time later instead. | |
792 | * Plugged queues are generally unplugged when a buffer belonging to one | |
793 | * of the requests on the queue is needed, or due to memory pressure. | |
794 | * | |
795 | * @rfn is not required, or even expected, to remove all requests off the | |
796 | * queue, but only as many as it can handle at a time. If it does leave | |
797 | * requests on the queue, it is responsible for arranging that the requests | |
798 | * get dealt with eventually. | |
799 | * | |
800 | * The queue spin lock must be held while manipulating the requests on the | |
a038e253 PBG |
801 | * request queue; this lock will be taken also from interrupt context, so irq |
802 | * disabling is needed for it. | |
1da177e4 | 803 | * |
710027a4 | 804 | * Function returns a pointer to the initialized request queue, or %NULL if |
1da177e4 LT |
805 | * it didn't succeed. |
806 | * | |
807 | * Note: | |
808 | * blk_init_queue() must be paired with a blk_cleanup_queue() call | |
809 | * when the block device is deactivated (such as at module unload). | |
810 | **/ | |
1946089a | 811 | |
165125e1 | 812 | struct request_queue *blk_init_queue(request_fn_proc *rfn, spinlock_t *lock) |
1da177e4 | 813 | { |
c304a51b | 814 | return blk_init_queue_node(rfn, lock, NUMA_NO_NODE); |
1946089a CL |
815 | } |
816 | EXPORT_SYMBOL(blk_init_queue); | |
817 | ||
165125e1 | 818 | struct request_queue * |
1946089a CL |
819 | blk_init_queue_node(request_fn_proc *rfn, spinlock_t *lock, int node_id) |
820 | { | |
c86d1b8a | 821 | struct request_queue *uninit_q, *q; |
1da177e4 | 822 | |
c86d1b8a MS |
823 | uninit_q = blk_alloc_queue_node(GFP_KERNEL, node_id); |
824 | if (!uninit_q) | |
825 | return NULL; | |
826 | ||
5151412d | 827 | q = blk_init_allocated_queue(uninit_q, rfn, lock); |
c86d1b8a | 828 | if (!q) |
7982e90c | 829 | blk_cleanup_queue(uninit_q); |
18741986 | 830 | |
7982e90c | 831 | return q; |
01effb0d MS |
832 | } |
833 | EXPORT_SYMBOL(blk_init_queue_node); | |
834 | ||
dece1635 | 835 | static blk_qc_t blk_queue_bio(struct request_queue *q, struct bio *bio); |
336b7e1f | 836 | |
01effb0d MS |
837 | struct request_queue * |
838 | blk_init_allocated_queue(struct request_queue *q, request_fn_proc *rfn, | |
839 | spinlock_t *lock) | |
01effb0d | 840 | { |
1da177e4 LT |
841 | if (!q) |
842 | return NULL; | |
843 | ||
f70ced09 | 844 | q->fq = blk_alloc_flush_queue(q, NUMA_NO_NODE, 0); |
ba483388 | 845 | if (!q->fq) |
7982e90c MS |
846 | return NULL; |
847 | ||
a051661c | 848 | if (blk_init_rl(&q->root_rl, q, GFP_KERNEL)) |
708f04d2 | 849 | goto fail; |
1da177e4 | 850 | |
287922eb | 851 | INIT_WORK(&q->timeout_work, blk_timeout_work); |
1da177e4 | 852 | q->request_fn = rfn; |
1da177e4 | 853 | q->prep_rq_fn = NULL; |
28018c24 | 854 | q->unprep_rq_fn = NULL; |
60ea8226 | 855 | q->queue_flags |= QUEUE_FLAG_DEFAULT; |
c94a96ac VG |
856 | |
857 | /* Override internal queue lock with supplied lock pointer */ | |
858 | if (lock) | |
859 | q->queue_lock = lock; | |
1da177e4 | 860 | |
f3b144aa JA |
861 | /* |
862 | * This also sets hw/phys segments, boundary and size | |
863 | */ | |
c20e8de2 | 864 | blk_queue_make_request(q, blk_queue_bio); |
1da177e4 | 865 | |
44ec9542 AS |
866 | q->sg_reserved_size = INT_MAX; |
867 | ||
eb1c160b TS |
868 | /* Protect q->elevator from elevator_change */ |
869 | mutex_lock(&q->sysfs_lock); | |
870 | ||
b82d4b19 | 871 | /* init elevator */ |
eb1c160b TS |
872 | if (elevator_init(q, NULL)) { |
873 | mutex_unlock(&q->sysfs_lock); | |
708f04d2 | 874 | goto fail; |
eb1c160b TS |
875 | } |
876 | ||
877 | mutex_unlock(&q->sysfs_lock); | |
878 | ||
b82d4b19 | 879 | return q; |
708f04d2 DJ |
880 | |
881 | fail: | |
ba483388 | 882 | blk_free_flush_queue(q->fq); |
708f04d2 | 883 | return NULL; |
1da177e4 | 884 | } |
5151412d | 885 | EXPORT_SYMBOL(blk_init_allocated_queue); |
1da177e4 | 886 | |
09ac46c4 | 887 | bool blk_get_queue(struct request_queue *q) |
1da177e4 | 888 | { |
3f3299d5 | 889 | if (likely(!blk_queue_dying(q))) { |
09ac46c4 TH |
890 | __blk_get_queue(q); |
891 | return true; | |
1da177e4 LT |
892 | } |
893 | ||
09ac46c4 | 894 | return false; |
1da177e4 | 895 | } |
d86e0e83 | 896 | EXPORT_SYMBOL(blk_get_queue); |
1da177e4 | 897 | |
5b788ce3 | 898 | static inline void blk_free_request(struct request_list *rl, struct request *rq) |
1da177e4 | 899 | { |
f1f8cc94 | 900 | if (rq->cmd_flags & REQ_ELVPRIV) { |
5b788ce3 | 901 | elv_put_request(rl->q, rq); |
f1f8cc94 | 902 | if (rq->elv.icq) |
11a3122f | 903 | put_io_context(rq->elv.icq->ioc); |
f1f8cc94 TH |
904 | } |
905 | ||
5b788ce3 | 906 | mempool_free(rq, rl->rq_pool); |
1da177e4 LT |
907 | } |
908 | ||
1da177e4 LT |
909 | /* |
910 | * ioc_batching returns true if the ioc is a valid batching request and | |
911 | * should be given priority access to a request. | |
912 | */ | |
165125e1 | 913 | static inline int ioc_batching(struct request_queue *q, struct io_context *ioc) |
1da177e4 LT |
914 | { |
915 | if (!ioc) | |
916 | return 0; | |
917 | ||
918 | /* | |
919 | * Make sure the process is able to allocate at least 1 request | |
920 | * even if the batch times out, otherwise we could theoretically | |
921 | * lose wakeups. | |
922 | */ | |
923 | return ioc->nr_batch_requests == q->nr_batching || | |
924 | (ioc->nr_batch_requests > 0 | |
925 | && time_before(jiffies, ioc->last_waited + BLK_BATCH_TIME)); | |
926 | } | |
927 | ||
928 | /* | |
929 | * ioc_set_batching sets ioc to be a new "batcher" if it is not one. This | |
930 | * will cause the process to be a "batcher" on all queues in the system. This | |
931 | * is the behaviour we want though - once it gets a wakeup it should be given | |
932 | * a nice run. | |
933 | */ | |
165125e1 | 934 | static void ioc_set_batching(struct request_queue *q, struct io_context *ioc) |
1da177e4 LT |
935 | { |
936 | if (!ioc || ioc_batching(q, ioc)) | |
937 | return; | |
938 | ||
939 | ioc->nr_batch_requests = q->nr_batching; | |
940 | ioc->last_waited = jiffies; | |
941 | } | |
942 | ||
5b788ce3 | 943 | static void __freed_request(struct request_list *rl, int sync) |
1da177e4 | 944 | { |
5b788ce3 | 945 | struct request_queue *q = rl->q; |
1da177e4 | 946 | |
d40f75a0 TH |
947 | if (rl->count[sync] < queue_congestion_off_threshold(q)) |
948 | blk_clear_congested(rl, sync); | |
1da177e4 | 949 | |
1faa16d2 JA |
950 | if (rl->count[sync] + 1 <= q->nr_requests) { |
951 | if (waitqueue_active(&rl->wait[sync])) | |
952 | wake_up(&rl->wait[sync]); | |
1da177e4 | 953 | |
5b788ce3 | 954 | blk_clear_rl_full(rl, sync); |
1da177e4 LT |
955 | } |
956 | } | |
957 | ||
958 | /* | |
959 | * A request has just been released. Account for it, update the full and | |
960 | * congestion status, wake up any waiters. Called under q->queue_lock. | |
961 | */ | |
5b788ce3 | 962 | static void freed_request(struct request_list *rl, unsigned int flags) |
1da177e4 | 963 | { |
5b788ce3 | 964 | struct request_queue *q = rl->q; |
75eb6c37 | 965 | int sync = rw_is_sync(flags); |
1da177e4 | 966 | |
8a5ecdd4 | 967 | q->nr_rqs[sync]--; |
1faa16d2 | 968 | rl->count[sync]--; |
75eb6c37 | 969 | if (flags & REQ_ELVPRIV) |
8a5ecdd4 | 970 | q->nr_rqs_elvpriv--; |
1da177e4 | 971 | |
5b788ce3 | 972 | __freed_request(rl, sync); |
1da177e4 | 973 | |
1faa16d2 | 974 | if (unlikely(rl->starved[sync ^ 1])) |
5b788ce3 | 975 | __freed_request(rl, sync ^ 1); |
1da177e4 LT |
976 | } |
977 | ||
e3a2b3f9 JA |
978 | int blk_update_nr_requests(struct request_queue *q, unsigned int nr) |
979 | { | |
980 | struct request_list *rl; | |
d40f75a0 | 981 | int on_thresh, off_thresh; |
e3a2b3f9 JA |
982 | |
983 | spin_lock_irq(q->queue_lock); | |
984 | q->nr_requests = nr; | |
985 | blk_queue_congestion_threshold(q); | |
d40f75a0 TH |
986 | on_thresh = queue_congestion_on_threshold(q); |
987 | off_thresh = queue_congestion_off_threshold(q); | |
e3a2b3f9 | 988 | |
d40f75a0 TH |
989 | blk_queue_for_each_rl(rl, q) { |
990 | if (rl->count[BLK_RW_SYNC] >= on_thresh) | |
991 | blk_set_congested(rl, BLK_RW_SYNC); | |
992 | else if (rl->count[BLK_RW_SYNC] < off_thresh) | |
993 | blk_clear_congested(rl, BLK_RW_SYNC); | |
e3a2b3f9 | 994 | |
d40f75a0 TH |
995 | if (rl->count[BLK_RW_ASYNC] >= on_thresh) |
996 | blk_set_congested(rl, BLK_RW_ASYNC); | |
997 | else if (rl->count[BLK_RW_ASYNC] < off_thresh) | |
998 | blk_clear_congested(rl, BLK_RW_ASYNC); | |
e3a2b3f9 | 999 | |
e3a2b3f9 JA |
1000 | if (rl->count[BLK_RW_SYNC] >= q->nr_requests) { |
1001 | blk_set_rl_full(rl, BLK_RW_SYNC); | |
1002 | } else { | |
1003 | blk_clear_rl_full(rl, BLK_RW_SYNC); | |
1004 | wake_up(&rl->wait[BLK_RW_SYNC]); | |
1005 | } | |
1006 | ||
1007 | if (rl->count[BLK_RW_ASYNC] >= q->nr_requests) { | |
1008 | blk_set_rl_full(rl, BLK_RW_ASYNC); | |
1009 | } else { | |
1010 | blk_clear_rl_full(rl, BLK_RW_ASYNC); | |
1011 | wake_up(&rl->wait[BLK_RW_ASYNC]); | |
1012 | } | |
1013 | } | |
1014 | ||
1015 | spin_unlock_irq(q->queue_lock); | |
1016 | return 0; | |
1017 | } | |
1018 | ||
9d5a4e94 MS |
1019 | /* |
1020 | * Determine if elevator data should be initialized when allocating the | |
1021 | * request associated with @bio. | |
1022 | */ | |
1023 | static bool blk_rq_should_init_elevator(struct bio *bio) | |
1024 | { | |
1025 | if (!bio) | |
1026 | return true; | |
1027 | ||
1028 | /* | |
1029 | * Flush requests do not use the elevator so skip initialization. | |
1030 | * This allows a request to share the flush and elevator data. | |
1031 | */ | |
1032 | if (bio->bi_rw & (REQ_FLUSH | REQ_FUA)) | |
1033 | return false; | |
1034 | ||
1035 | return true; | |
1036 | } | |
1037 | ||
852c788f TH |
1038 | /** |
1039 | * rq_ioc - determine io_context for request allocation | |
1040 | * @bio: request being allocated is for this bio (can be %NULL) | |
1041 | * | |
1042 | * Determine io_context to use for request allocation for @bio. May return | |
1043 | * %NULL if %current->io_context doesn't exist. | |
1044 | */ | |
1045 | static struct io_context *rq_ioc(struct bio *bio) | |
1046 | { | |
1047 | #ifdef CONFIG_BLK_CGROUP | |
1048 | if (bio && bio->bi_ioc) | |
1049 | return bio->bi_ioc; | |
1050 | #endif | |
1051 | return current->io_context; | |
1052 | } | |
1053 | ||
da8303c6 | 1054 | /** |
a06e05e6 | 1055 | * __get_request - get a free request |
5b788ce3 | 1056 | * @rl: request list to allocate from |
da8303c6 TH |
1057 | * @rw_flags: RW and SYNC flags |
1058 | * @bio: bio to allocate request for (can be %NULL) | |
1059 | * @gfp_mask: allocation mask | |
1060 | * | |
1061 | * Get a free request from @q. This function may fail under memory | |
1062 | * pressure or if @q is dead. | |
1063 | * | |
da3dae54 | 1064 | * Must be called with @q->queue_lock held and, |
a492f075 JL |
1065 | * Returns ERR_PTR on failure, with @q->queue_lock held. |
1066 | * Returns request pointer on success, with @q->queue_lock *not held*. | |
1da177e4 | 1067 | */ |
5b788ce3 | 1068 | static struct request *__get_request(struct request_list *rl, int rw_flags, |
a06e05e6 | 1069 | struct bio *bio, gfp_t gfp_mask) |
1da177e4 | 1070 | { |
5b788ce3 | 1071 | struct request_queue *q = rl->q; |
b679281a | 1072 | struct request *rq; |
7f4b35d1 TH |
1073 | struct elevator_type *et = q->elevator->type; |
1074 | struct io_context *ioc = rq_ioc(bio); | |
f1f8cc94 | 1075 | struct io_cq *icq = NULL; |
1faa16d2 | 1076 | const bool is_sync = rw_is_sync(rw_flags) != 0; |
75eb6c37 | 1077 | int may_queue; |
88ee5ef1 | 1078 | |
3f3299d5 | 1079 | if (unlikely(blk_queue_dying(q))) |
a492f075 | 1080 | return ERR_PTR(-ENODEV); |
da8303c6 | 1081 | |
7749a8d4 | 1082 | may_queue = elv_may_queue(q, rw_flags); |
88ee5ef1 JA |
1083 | if (may_queue == ELV_MQUEUE_NO) |
1084 | goto rq_starved; | |
1085 | ||
1faa16d2 JA |
1086 | if (rl->count[is_sync]+1 >= queue_congestion_on_threshold(q)) { |
1087 | if (rl->count[is_sync]+1 >= q->nr_requests) { | |
88ee5ef1 JA |
1088 | /* |
1089 | * The queue will fill after this allocation, so set | |
1090 | * it as full, and mark this process as "batching". | |
1091 | * This process will be allowed to complete a batch of | |
1092 | * requests, others will be blocked. | |
1093 | */ | |
5b788ce3 | 1094 | if (!blk_rl_full(rl, is_sync)) { |
88ee5ef1 | 1095 | ioc_set_batching(q, ioc); |
5b788ce3 | 1096 | blk_set_rl_full(rl, is_sync); |
88ee5ef1 JA |
1097 | } else { |
1098 | if (may_queue != ELV_MQUEUE_MUST | |
1099 | && !ioc_batching(q, ioc)) { | |
1100 | /* | |
1101 | * The queue is full and the allocating | |
1102 | * process is not a "batcher", and not | |
1103 | * exempted by the IO scheduler | |
1104 | */ | |
a492f075 | 1105 | return ERR_PTR(-ENOMEM); |
88ee5ef1 JA |
1106 | } |
1107 | } | |
1da177e4 | 1108 | } |
d40f75a0 | 1109 | blk_set_congested(rl, is_sync); |
1da177e4 LT |
1110 | } |
1111 | ||
082cf69e JA |
1112 | /* |
1113 | * Only allow batching queuers to allocate up to 50% over the defined | |
1114 | * limit of requests, otherwise we could have thousands of requests | |
1115 | * allocated with any setting of ->nr_requests | |
1116 | */ | |
1faa16d2 | 1117 | if (rl->count[is_sync] >= (3 * q->nr_requests / 2)) |
a492f075 | 1118 | return ERR_PTR(-ENOMEM); |
fd782a4a | 1119 | |
8a5ecdd4 | 1120 | q->nr_rqs[is_sync]++; |
1faa16d2 JA |
1121 | rl->count[is_sync]++; |
1122 | rl->starved[is_sync] = 0; | |
cb98fc8b | 1123 | |
f1f8cc94 TH |
1124 | /* |
1125 | * Decide whether the new request will be managed by elevator. If | |
1126 | * so, mark @rw_flags and increment elvpriv. Non-zero elvpriv will | |
1127 | * prevent the current elevator from being destroyed until the new | |
1128 | * request is freed. This guarantees icq's won't be destroyed and | |
1129 | * makes creating new ones safe. | |
1130 | * | |
1131 | * Also, lookup icq while holding queue_lock. If it doesn't exist, | |
1132 | * it will be created after releasing queue_lock. | |
1133 | */ | |
d732580b | 1134 | if (blk_rq_should_init_elevator(bio) && !blk_queue_bypass(q)) { |
75eb6c37 | 1135 | rw_flags |= REQ_ELVPRIV; |
8a5ecdd4 | 1136 | q->nr_rqs_elvpriv++; |
f1f8cc94 TH |
1137 | if (et->icq_cache && ioc) |
1138 | icq = ioc_lookup_icq(ioc, q); | |
9d5a4e94 | 1139 | } |
cb98fc8b | 1140 | |
f253b86b JA |
1141 | if (blk_queue_io_stat(q)) |
1142 | rw_flags |= REQ_IO_STAT; | |
1da177e4 LT |
1143 | spin_unlock_irq(q->queue_lock); |
1144 | ||
29e2b09a | 1145 | /* allocate and init request */ |
5b788ce3 | 1146 | rq = mempool_alloc(rl->rq_pool, gfp_mask); |
29e2b09a | 1147 | if (!rq) |
b679281a | 1148 | goto fail_alloc; |
1da177e4 | 1149 | |
29e2b09a | 1150 | blk_rq_init(q, rq); |
a051661c | 1151 | blk_rq_set_rl(rq, rl); |
29e2b09a TH |
1152 | rq->cmd_flags = rw_flags | REQ_ALLOCED; |
1153 | ||
aaf7c680 | 1154 | /* init elvpriv */ |
29e2b09a | 1155 | if (rw_flags & REQ_ELVPRIV) { |
aaf7c680 | 1156 | if (unlikely(et->icq_cache && !icq)) { |
7f4b35d1 TH |
1157 | if (ioc) |
1158 | icq = ioc_create_icq(ioc, q, gfp_mask); | |
aaf7c680 TH |
1159 | if (!icq) |
1160 | goto fail_elvpriv; | |
29e2b09a | 1161 | } |
aaf7c680 TH |
1162 | |
1163 | rq->elv.icq = icq; | |
1164 | if (unlikely(elv_set_request(q, rq, bio, gfp_mask))) | |
1165 | goto fail_elvpriv; | |
1166 | ||
1167 | /* @rq->elv.icq holds io_context until @rq is freed */ | |
29e2b09a TH |
1168 | if (icq) |
1169 | get_io_context(icq->ioc); | |
1170 | } | |
aaf7c680 | 1171 | out: |
88ee5ef1 JA |
1172 | /* |
1173 | * ioc may be NULL here, and ioc_batching will be false. That's | |
1174 | * OK, if the queue is under the request limit then requests need | |
1175 | * not count toward the nr_batch_requests limit. There will always | |
1176 | * be some limit enforced by BLK_BATCH_TIME. | |
1177 | */ | |
1da177e4 LT |
1178 | if (ioc_batching(q, ioc)) |
1179 | ioc->nr_batch_requests--; | |
6728cb0e | 1180 | |
1faa16d2 | 1181 | trace_block_getrq(q, bio, rw_flags & 1); |
1da177e4 | 1182 | return rq; |
b679281a | 1183 | |
aaf7c680 TH |
1184 | fail_elvpriv: |
1185 | /* | |
1186 | * elvpriv init failed. ioc, icq and elvpriv aren't mempool backed | |
1187 | * and may fail indefinitely under memory pressure and thus | |
1188 | * shouldn't stall IO. Treat this request as !elvpriv. This will | |
1189 | * disturb iosched and blkcg but weird is bettern than dead. | |
1190 | */ | |
7b2b10e0 RE |
1191 | printk_ratelimited(KERN_WARNING "%s: dev %s: request aux data allocation failed, iosched may be disturbed\n", |
1192 | __func__, dev_name(q->backing_dev_info.dev)); | |
aaf7c680 TH |
1193 | |
1194 | rq->cmd_flags &= ~REQ_ELVPRIV; | |
1195 | rq->elv.icq = NULL; | |
1196 | ||
1197 | spin_lock_irq(q->queue_lock); | |
8a5ecdd4 | 1198 | q->nr_rqs_elvpriv--; |
aaf7c680 TH |
1199 | spin_unlock_irq(q->queue_lock); |
1200 | goto out; | |
1201 | ||
b679281a TH |
1202 | fail_alloc: |
1203 | /* | |
1204 | * Allocation failed presumably due to memory. Undo anything we | |
1205 | * might have messed up. | |
1206 | * | |
1207 | * Allocating task should really be put onto the front of the wait | |
1208 | * queue, but this is pretty rare. | |
1209 | */ | |
1210 | spin_lock_irq(q->queue_lock); | |
5b788ce3 | 1211 | freed_request(rl, rw_flags); |
b679281a TH |
1212 | |
1213 | /* | |
1214 | * in the very unlikely event that allocation failed and no | |
1215 | * requests for this direction was pending, mark us starved so that | |
1216 | * freeing of a request in the other direction will notice | |
1217 | * us. another possible fix would be to split the rq mempool into | |
1218 | * READ and WRITE | |
1219 | */ | |
1220 | rq_starved: | |
1221 | if (unlikely(rl->count[is_sync] == 0)) | |
1222 | rl->starved[is_sync] = 1; | |
a492f075 | 1223 | return ERR_PTR(-ENOMEM); |
1da177e4 LT |
1224 | } |
1225 | ||
da8303c6 | 1226 | /** |
a06e05e6 | 1227 | * get_request - get a free request |
da8303c6 TH |
1228 | * @q: request_queue to allocate request from |
1229 | * @rw_flags: RW and SYNC flags | |
1230 | * @bio: bio to allocate request for (can be %NULL) | |
a06e05e6 | 1231 | * @gfp_mask: allocation mask |
da8303c6 | 1232 | * |
d0164adc MG |
1233 | * Get a free request from @q. If %__GFP_DIRECT_RECLAIM is set in @gfp_mask, |
1234 | * this function keeps retrying under memory pressure and fails iff @q is dead. | |
d6344532 | 1235 | * |
da3dae54 | 1236 | * Must be called with @q->queue_lock held and, |
a492f075 JL |
1237 | * Returns ERR_PTR on failure, with @q->queue_lock held. |
1238 | * Returns request pointer on success, with @q->queue_lock *not held*. | |
1da177e4 | 1239 | */ |
a06e05e6 TH |
1240 | static struct request *get_request(struct request_queue *q, int rw_flags, |
1241 | struct bio *bio, gfp_t gfp_mask) | |
1da177e4 | 1242 | { |
1faa16d2 | 1243 | const bool is_sync = rw_is_sync(rw_flags) != 0; |
a06e05e6 | 1244 | DEFINE_WAIT(wait); |
a051661c | 1245 | struct request_list *rl; |
1da177e4 | 1246 | struct request *rq; |
a051661c TH |
1247 | |
1248 | rl = blk_get_rl(q, bio); /* transferred to @rq on success */ | |
a06e05e6 | 1249 | retry: |
a051661c | 1250 | rq = __get_request(rl, rw_flags, bio, gfp_mask); |
a492f075 | 1251 | if (!IS_ERR(rq)) |
a06e05e6 | 1252 | return rq; |
1da177e4 | 1253 | |
d0164adc | 1254 | if (!gfpflags_allow_blocking(gfp_mask) || unlikely(blk_queue_dying(q))) { |
a051661c | 1255 | blk_put_rl(rl); |
a492f075 | 1256 | return rq; |
a051661c | 1257 | } |
1da177e4 | 1258 | |
a06e05e6 TH |
1259 | /* wait on @rl and retry */ |
1260 | prepare_to_wait_exclusive(&rl->wait[is_sync], &wait, | |
1261 | TASK_UNINTERRUPTIBLE); | |
1da177e4 | 1262 | |
a06e05e6 | 1263 | trace_block_sleeprq(q, bio, rw_flags & 1); |
1da177e4 | 1264 | |
a06e05e6 TH |
1265 | spin_unlock_irq(q->queue_lock); |
1266 | io_schedule(); | |
d6344532 | 1267 | |
a06e05e6 TH |
1268 | /* |
1269 | * After sleeping, we become a "batching" process and will be able | |
1270 | * to allocate at least one request, and up to a big batch of them | |
1271 | * for a small period time. See ioc_batching, ioc_set_batching | |
1272 | */ | |
a06e05e6 | 1273 | ioc_set_batching(q, current->io_context); |
05caf8db | 1274 | |
a06e05e6 TH |
1275 | spin_lock_irq(q->queue_lock); |
1276 | finish_wait(&rl->wait[is_sync], &wait); | |
1da177e4 | 1277 | |
a06e05e6 | 1278 | goto retry; |
1da177e4 LT |
1279 | } |
1280 | ||
320ae51f JA |
1281 | static struct request *blk_old_get_request(struct request_queue *q, int rw, |
1282 | gfp_t gfp_mask) | |
1da177e4 LT |
1283 | { |
1284 | struct request *rq; | |
1285 | ||
1286 | BUG_ON(rw != READ && rw != WRITE); | |
1287 | ||
7f4b35d1 TH |
1288 | /* create ioc upfront */ |
1289 | create_io_context(gfp_mask, q->node); | |
1290 | ||
d6344532 | 1291 | spin_lock_irq(q->queue_lock); |
a06e05e6 | 1292 | rq = get_request(q, rw, NULL, gfp_mask); |
a492f075 | 1293 | if (IS_ERR(rq)) |
da8303c6 | 1294 | spin_unlock_irq(q->queue_lock); |
d6344532 | 1295 | /* q->queue_lock is unlocked at this point */ |
1da177e4 LT |
1296 | |
1297 | return rq; | |
1298 | } | |
320ae51f JA |
1299 | |
1300 | struct request *blk_get_request(struct request_queue *q, int rw, gfp_t gfp_mask) | |
1301 | { | |
1302 | if (q->mq_ops) | |
6f3b0e8b CH |
1303 | return blk_mq_alloc_request(q, rw, |
1304 | (gfp_mask & __GFP_DIRECT_RECLAIM) ? | |
1305 | 0 : BLK_MQ_REQ_NOWAIT); | |
320ae51f JA |
1306 | else |
1307 | return blk_old_get_request(q, rw, gfp_mask); | |
1308 | } | |
1da177e4 LT |
1309 | EXPORT_SYMBOL(blk_get_request); |
1310 | ||
dc72ef4a | 1311 | /** |
79eb63e9 | 1312 | * blk_make_request - given a bio, allocate a corresponding struct request. |
8ebf9756 | 1313 | * @q: target request queue |
79eb63e9 BH |
1314 | * @bio: The bio describing the memory mappings that will be submitted for IO. |
1315 | * It may be a chained-bio properly constructed by block/bio layer. | |
8ebf9756 | 1316 | * @gfp_mask: gfp flags to be used for memory allocation |
dc72ef4a | 1317 | * |
79eb63e9 BH |
1318 | * blk_make_request is the parallel of generic_make_request for BLOCK_PC |
1319 | * type commands. Where the struct request needs to be farther initialized by | |
1320 | * the caller. It is passed a &struct bio, which describes the memory info of | |
1321 | * the I/O transfer. | |
dc72ef4a | 1322 | * |
79eb63e9 BH |
1323 | * The caller of blk_make_request must make sure that bi_io_vec |
1324 | * are set to describe the memory buffers. That bio_data_dir() will return | |
1325 | * the needed direction of the request. (And all bio's in the passed bio-chain | |
1326 | * are properly set accordingly) | |
1327 | * | |
1328 | * If called under none-sleepable conditions, mapped bio buffers must not | |
1329 | * need bouncing, by calling the appropriate masked or flagged allocator, | |
1330 | * suitable for the target device. Otherwise the call to blk_queue_bounce will | |
1331 | * BUG. | |
53674ac5 JA |
1332 | * |
1333 | * WARNING: When allocating/cloning a bio-chain, careful consideration should be | |
d0164adc MG |
1334 | * given to how you allocate bios. In particular, you cannot use |
1335 | * __GFP_DIRECT_RECLAIM for anything but the first bio in the chain. Otherwise | |
1336 | * you risk waiting for IO completion of a bio that hasn't been submitted yet, | |
1337 | * thus resulting in a deadlock. Alternatively bios should be allocated using | |
1338 | * bio_kmalloc() instead of bio_alloc(), as that avoids the mempool deadlock. | |
53674ac5 JA |
1339 | * If possible a big IO should be split into smaller parts when allocation |
1340 | * fails. Partial allocation should not be an error, or you risk a live-lock. | |
dc72ef4a | 1341 | */ |
79eb63e9 BH |
1342 | struct request *blk_make_request(struct request_queue *q, struct bio *bio, |
1343 | gfp_t gfp_mask) | |
dc72ef4a | 1344 | { |
79eb63e9 BH |
1345 | struct request *rq = blk_get_request(q, bio_data_dir(bio), gfp_mask); |
1346 | ||
a492f075 JL |
1347 | if (IS_ERR(rq)) |
1348 | return rq; | |
79eb63e9 | 1349 | |
f27b087b JA |
1350 | blk_rq_set_block_pc(rq); |
1351 | ||
79eb63e9 BH |
1352 | for_each_bio(bio) { |
1353 | struct bio *bounce_bio = bio; | |
1354 | int ret; | |
1355 | ||
1356 | blk_queue_bounce(q, &bounce_bio); | |
1357 | ret = blk_rq_append_bio(q, rq, bounce_bio); | |
1358 | if (unlikely(ret)) { | |
1359 | blk_put_request(rq); | |
1360 | return ERR_PTR(ret); | |
1361 | } | |
1362 | } | |
1363 | ||
1364 | return rq; | |
dc72ef4a | 1365 | } |
79eb63e9 | 1366 | EXPORT_SYMBOL(blk_make_request); |
dc72ef4a | 1367 | |
f27b087b | 1368 | /** |
da3dae54 | 1369 | * blk_rq_set_block_pc - initialize a request to type BLOCK_PC |
f27b087b JA |
1370 | * @rq: request to be initialized |
1371 | * | |
1372 | */ | |
1373 | void blk_rq_set_block_pc(struct request *rq) | |
1374 | { | |
1375 | rq->cmd_type = REQ_TYPE_BLOCK_PC; | |
1376 | rq->__data_len = 0; | |
1377 | rq->__sector = (sector_t) -1; | |
1378 | rq->bio = rq->biotail = NULL; | |
1379 | memset(rq->__cmd, 0, sizeof(rq->__cmd)); | |
f27b087b JA |
1380 | } |
1381 | EXPORT_SYMBOL(blk_rq_set_block_pc); | |
1382 | ||
1da177e4 LT |
1383 | /** |
1384 | * blk_requeue_request - put a request back on queue | |
1385 | * @q: request queue where request should be inserted | |
1386 | * @rq: request to be inserted | |
1387 | * | |
1388 | * Description: | |
1389 | * Drivers often keep queueing requests until the hardware cannot accept | |
1390 | * more, when that condition happens we need to put the request back | |
1391 | * on the queue. Must be called with queue lock held. | |
1392 | */ | |
165125e1 | 1393 | void blk_requeue_request(struct request_queue *q, struct request *rq) |
1da177e4 | 1394 | { |
242f9dcb JA |
1395 | blk_delete_timer(rq); |
1396 | blk_clear_rq_complete(rq); | |
5f3ea37c | 1397 | trace_block_rq_requeue(q, rq); |
2056a782 | 1398 | |
125c99bc | 1399 | if (rq->cmd_flags & REQ_QUEUED) |
1da177e4 LT |
1400 | blk_queue_end_tag(q, rq); |
1401 | ||
ba396a6c JB |
1402 | BUG_ON(blk_queued_rq(rq)); |
1403 | ||
1da177e4 LT |
1404 | elv_requeue_request(q, rq); |
1405 | } | |
1da177e4 LT |
1406 | EXPORT_SYMBOL(blk_requeue_request); |
1407 | ||
73c10101 JA |
1408 | static void add_acct_request(struct request_queue *q, struct request *rq, |
1409 | int where) | |
1410 | { | |
320ae51f | 1411 | blk_account_io_start(rq, true); |
7eaceacc | 1412 | __elv_add_request(q, rq, where); |
73c10101 JA |
1413 | } |
1414 | ||
074a7aca TH |
1415 | static void part_round_stats_single(int cpu, struct hd_struct *part, |
1416 | unsigned long now) | |
1417 | { | |
7276d02e JA |
1418 | int inflight; |
1419 | ||
074a7aca TH |
1420 | if (now == part->stamp) |
1421 | return; | |
1422 | ||
7276d02e JA |
1423 | inflight = part_in_flight(part); |
1424 | if (inflight) { | |
074a7aca | 1425 | __part_stat_add(cpu, part, time_in_queue, |
7276d02e | 1426 | inflight * (now - part->stamp)); |
074a7aca TH |
1427 | __part_stat_add(cpu, part, io_ticks, (now - part->stamp)); |
1428 | } | |
1429 | part->stamp = now; | |
1430 | } | |
1431 | ||
1432 | /** | |
496aa8a9 RD |
1433 | * part_round_stats() - Round off the performance stats on a struct disk_stats. |
1434 | * @cpu: cpu number for stats access | |
1435 | * @part: target partition | |
1da177e4 LT |
1436 | * |
1437 | * The average IO queue length and utilisation statistics are maintained | |
1438 | * by observing the current state of the queue length and the amount of | |
1439 | * time it has been in this state for. | |
1440 | * | |
1441 | * Normally, that accounting is done on IO completion, but that can result | |
1442 | * in more than a second's worth of IO being accounted for within any one | |
1443 | * second, leading to >100% utilisation. To deal with that, we call this | |
1444 | * function to do a round-off before returning the results when reading | |
1445 | * /proc/diskstats. This accounts immediately for all queue usage up to | |
1446 | * the current jiffies and restarts the counters again. | |
1447 | */ | |
c9959059 | 1448 | void part_round_stats(int cpu, struct hd_struct *part) |
6f2576af JM |
1449 | { |
1450 | unsigned long now = jiffies; | |
1451 | ||
074a7aca TH |
1452 | if (part->partno) |
1453 | part_round_stats_single(cpu, &part_to_disk(part)->part0, now); | |
1454 | part_round_stats_single(cpu, part, now); | |
6f2576af | 1455 | } |
074a7aca | 1456 | EXPORT_SYMBOL_GPL(part_round_stats); |
6f2576af | 1457 | |
47fafbc7 | 1458 | #ifdef CONFIG_PM |
c8158819 LM |
1459 | static void blk_pm_put_request(struct request *rq) |
1460 | { | |
1461 | if (rq->q->dev && !(rq->cmd_flags & REQ_PM) && !--rq->q->nr_pending) | |
1462 | pm_runtime_mark_last_busy(rq->q->dev); | |
1463 | } | |
1464 | #else | |
1465 | static inline void blk_pm_put_request(struct request *rq) {} | |
1466 | #endif | |
1467 | ||
1da177e4 LT |
1468 | /* |
1469 | * queue lock must be held | |
1470 | */ | |
165125e1 | 1471 | void __blk_put_request(struct request_queue *q, struct request *req) |
1da177e4 | 1472 | { |
1da177e4 LT |
1473 | if (unlikely(!q)) |
1474 | return; | |
1da177e4 | 1475 | |
6f5ba581 CH |
1476 | if (q->mq_ops) { |
1477 | blk_mq_free_request(req); | |
1478 | return; | |
1479 | } | |
1480 | ||
c8158819 LM |
1481 | blk_pm_put_request(req); |
1482 | ||
8922e16c TH |
1483 | elv_completed_request(q, req); |
1484 | ||
1cd96c24 BH |
1485 | /* this is a bio leak */ |
1486 | WARN_ON(req->bio != NULL); | |
1487 | ||
1da177e4 LT |
1488 | /* |
1489 | * Request may not have originated from ll_rw_blk. if not, | |
1490 | * it didn't come out of our reserved rq pools | |
1491 | */ | |
49171e5c | 1492 | if (req->cmd_flags & REQ_ALLOCED) { |
75eb6c37 | 1493 | unsigned int flags = req->cmd_flags; |
a051661c | 1494 | struct request_list *rl = blk_rq_rl(req); |
1da177e4 | 1495 | |
1da177e4 | 1496 | BUG_ON(!list_empty(&req->queuelist)); |
360f92c2 | 1497 | BUG_ON(ELV_ON_HASH(req)); |
1da177e4 | 1498 | |
a051661c TH |
1499 | blk_free_request(rl, req); |
1500 | freed_request(rl, flags); | |
1501 | blk_put_rl(rl); | |
1da177e4 LT |
1502 | } |
1503 | } | |
6e39b69e MC |
1504 | EXPORT_SYMBOL_GPL(__blk_put_request); |
1505 | ||
1da177e4 LT |
1506 | void blk_put_request(struct request *req) |
1507 | { | |
165125e1 | 1508 | struct request_queue *q = req->q; |
8922e16c | 1509 | |
320ae51f JA |
1510 | if (q->mq_ops) |
1511 | blk_mq_free_request(req); | |
1512 | else { | |
1513 | unsigned long flags; | |
1514 | ||
1515 | spin_lock_irqsave(q->queue_lock, flags); | |
1516 | __blk_put_request(q, req); | |
1517 | spin_unlock_irqrestore(q->queue_lock, flags); | |
1518 | } | |
1da177e4 | 1519 | } |
1da177e4 LT |
1520 | EXPORT_SYMBOL(blk_put_request); |
1521 | ||
66ac0280 CH |
1522 | /** |
1523 | * blk_add_request_payload - add a payload to a request | |
1524 | * @rq: request to update | |
1525 | * @page: page backing the payload | |
1526 | * @len: length of the payload. | |
1527 | * | |
1528 | * This allows to later add a payload to an already submitted request by | |
1529 | * a block driver. The driver needs to take care of freeing the payload | |
1530 | * itself. | |
1531 | * | |
1532 | * Note that this is a quite horrible hack and nothing but handling of | |
1533 | * discard requests should ever use it. | |
1534 | */ | |
1535 | void blk_add_request_payload(struct request *rq, struct page *page, | |
1536 | unsigned int len) | |
1537 | { | |
1538 | struct bio *bio = rq->bio; | |
1539 | ||
1540 | bio->bi_io_vec->bv_page = page; | |
1541 | bio->bi_io_vec->bv_offset = 0; | |
1542 | bio->bi_io_vec->bv_len = len; | |
1543 | ||
4f024f37 | 1544 | bio->bi_iter.bi_size = len; |
66ac0280 CH |
1545 | bio->bi_vcnt = 1; |
1546 | bio->bi_phys_segments = 1; | |
1547 | ||
1548 | rq->__data_len = rq->resid_len = len; | |
1549 | rq->nr_phys_segments = 1; | |
66ac0280 CH |
1550 | } |
1551 | EXPORT_SYMBOL_GPL(blk_add_request_payload); | |
1552 | ||
320ae51f JA |
1553 | bool bio_attempt_back_merge(struct request_queue *q, struct request *req, |
1554 | struct bio *bio) | |
73c10101 JA |
1555 | { |
1556 | const int ff = bio->bi_rw & REQ_FAILFAST_MASK; | |
1557 | ||
73c10101 JA |
1558 | if (!ll_back_merge_fn(q, req, bio)) |
1559 | return false; | |
1560 | ||
8c1cf6bb | 1561 | trace_block_bio_backmerge(q, req, bio); |
73c10101 JA |
1562 | |
1563 | if ((req->cmd_flags & REQ_FAILFAST_MASK) != ff) | |
1564 | blk_rq_set_mixed_merge(req); | |
1565 | ||
1566 | req->biotail->bi_next = bio; | |
1567 | req->biotail = bio; | |
4f024f37 | 1568 | req->__data_len += bio->bi_iter.bi_size; |
73c10101 JA |
1569 | req->ioprio = ioprio_best(req->ioprio, bio_prio(bio)); |
1570 | ||
320ae51f | 1571 | blk_account_io_start(req, false); |
73c10101 JA |
1572 | return true; |
1573 | } | |
1574 | ||
320ae51f JA |
1575 | bool bio_attempt_front_merge(struct request_queue *q, struct request *req, |
1576 | struct bio *bio) | |
73c10101 JA |
1577 | { |
1578 | const int ff = bio->bi_rw & REQ_FAILFAST_MASK; | |
73c10101 | 1579 | |
73c10101 JA |
1580 | if (!ll_front_merge_fn(q, req, bio)) |
1581 | return false; | |
1582 | ||
8c1cf6bb | 1583 | trace_block_bio_frontmerge(q, req, bio); |
73c10101 JA |
1584 | |
1585 | if ((req->cmd_flags & REQ_FAILFAST_MASK) != ff) | |
1586 | blk_rq_set_mixed_merge(req); | |
1587 | ||
73c10101 JA |
1588 | bio->bi_next = req->bio; |
1589 | req->bio = bio; | |
1590 | ||
4f024f37 KO |
1591 | req->__sector = bio->bi_iter.bi_sector; |
1592 | req->__data_len += bio->bi_iter.bi_size; | |
73c10101 JA |
1593 | req->ioprio = ioprio_best(req->ioprio, bio_prio(bio)); |
1594 | ||
320ae51f | 1595 | blk_account_io_start(req, false); |
73c10101 JA |
1596 | return true; |
1597 | } | |
1598 | ||
bd87b589 | 1599 | /** |
320ae51f | 1600 | * blk_attempt_plug_merge - try to merge with %current's plugged list |
bd87b589 TH |
1601 | * @q: request_queue new bio is being queued at |
1602 | * @bio: new bio being queued | |
1603 | * @request_count: out parameter for number of traversed plugged requests | |
ccc2600b RD |
1604 | * @same_queue_rq: pointer to &struct request that gets filled in when |
1605 | * another request associated with @q is found on the plug list | |
1606 | * (optional, may be %NULL) | |
bd87b589 TH |
1607 | * |
1608 | * Determine whether @bio being queued on @q can be merged with a request | |
1609 | * on %current's plugged list. Returns %true if merge was successful, | |
1610 | * otherwise %false. | |
1611 | * | |
07c2bd37 TH |
1612 | * Plugging coalesces IOs from the same issuer for the same purpose without |
1613 | * going through @q->queue_lock. As such it's more of an issuing mechanism | |
1614 | * than scheduling, and the request, while may have elvpriv data, is not | |
1615 | * added on the elevator at this point. In addition, we don't have | |
1616 | * reliable access to the elevator outside queue lock. Only check basic | |
1617 | * merging parameters without querying the elevator. | |
da41a589 RE |
1618 | * |
1619 | * Caller must ensure !blk_queue_nomerges(q) beforehand. | |
73c10101 | 1620 | */ |
320ae51f | 1621 | bool blk_attempt_plug_merge(struct request_queue *q, struct bio *bio, |
5b3f341f SL |
1622 | unsigned int *request_count, |
1623 | struct request **same_queue_rq) | |
73c10101 JA |
1624 | { |
1625 | struct blk_plug *plug; | |
1626 | struct request *rq; | |
1627 | bool ret = false; | |
92f399c7 | 1628 | struct list_head *plug_list; |
73c10101 | 1629 | |
bd87b589 | 1630 | plug = current->plug; |
73c10101 JA |
1631 | if (!plug) |
1632 | goto out; | |
56ebdaf2 | 1633 | *request_count = 0; |
73c10101 | 1634 | |
92f399c7 SL |
1635 | if (q->mq_ops) |
1636 | plug_list = &plug->mq_list; | |
1637 | else | |
1638 | plug_list = &plug->list; | |
1639 | ||
1640 | list_for_each_entry_reverse(rq, plug_list, queuelist) { | |
73c10101 JA |
1641 | int el_ret; |
1642 | ||
5b3f341f | 1643 | if (rq->q == q) { |
1b2e19f1 | 1644 | (*request_count)++; |
5b3f341f SL |
1645 | /* |
1646 | * Only blk-mq multiple hardware queues case checks the | |
1647 | * rq in the same queue, there should be only one such | |
1648 | * rq in a queue | |
1649 | **/ | |
1650 | if (same_queue_rq) | |
1651 | *same_queue_rq = rq; | |
1652 | } | |
56ebdaf2 | 1653 | |
07c2bd37 | 1654 | if (rq->q != q || !blk_rq_merge_ok(rq, bio)) |
73c10101 JA |
1655 | continue; |
1656 | ||
050c8ea8 | 1657 | el_ret = blk_try_merge(rq, bio); |
73c10101 JA |
1658 | if (el_ret == ELEVATOR_BACK_MERGE) { |
1659 | ret = bio_attempt_back_merge(q, rq, bio); | |
1660 | if (ret) | |
1661 | break; | |
1662 | } else if (el_ret == ELEVATOR_FRONT_MERGE) { | |
1663 | ret = bio_attempt_front_merge(q, rq, bio); | |
1664 | if (ret) | |
1665 | break; | |
1666 | } | |
1667 | } | |
1668 | out: | |
1669 | return ret; | |
1670 | } | |
1671 | ||
0809e3ac JM |
1672 | unsigned int blk_plug_queued_count(struct request_queue *q) |
1673 | { | |
1674 | struct blk_plug *plug; | |
1675 | struct request *rq; | |
1676 | struct list_head *plug_list; | |
1677 | unsigned int ret = 0; | |
1678 | ||
1679 | plug = current->plug; | |
1680 | if (!plug) | |
1681 | goto out; | |
1682 | ||
1683 | if (q->mq_ops) | |
1684 | plug_list = &plug->mq_list; | |
1685 | else | |
1686 | plug_list = &plug->list; | |
1687 | ||
1688 | list_for_each_entry(rq, plug_list, queuelist) { | |
1689 | if (rq->q == q) | |
1690 | ret++; | |
1691 | } | |
1692 | out: | |
1693 | return ret; | |
1694 | } | |
1695 | ||
86db1e29 | 1696 | void init_request_from_bio(struct request *req, struct bio *bio) |
52d9e675 | 1697 | { |
4aff5e23 | 1698 | req->cmd_type = REQ_TYPE_FS; |
52d9e675 | 1699 | |
7b6d91da CH |
1700 | req->cmd_flags |= bio->bi_rw & REQ_COMMON_MASK; |
1701 | if (bio->bi_rw & REQ_RAHEAD) | |
a82afdfc | 1702 | req->cmd_flags |= REQ_FAILFAST_MASK; |
b31dc66a | 1703 | |
52d9e675 | 1704 | req->errors = 0; |
4f024f37 | 1705 | req->__sector = bio->bi_iter.bi_sector; |
52d9e675 | 1706 | req->ioprio = bio_prio(bio); |
bc1c56fd | 1707 | blk_rq_bio_prep(req->q, req, bio); |
52d9e675 TH |
1708 | } |
1709 | ||
dece1635 | 1710 | static blk_qc_t blk_queue_bio(struct request_queue *q, struct bio *bio) |
1da177e4 | 1711 | { |
5e00d1b5 | 1712 | const bool sync = !!(bio->bi_rw & REQ_SYNC); |
73c10101 JA |
1713 | struct blk_plug *plug; |
1714 | int el_ret, rw_flags, where = ELEVATOR_INSERT_SORT; | |
1715 | struct request *req; | |
56ebdaf2 | 1716 | unsigned int request_count = 0; |
1da177e4 | 1717 | |
1da177e4 LT |
1718 | /* |
1719 | * low level driver can indicate that it wants pages above a | |
1720 | * certain limit bounced to low memory (ie for highmem, or even | |
1721 | * ISA dma in theory) | |
1722 | */ | |
1723 | blk_queue_bounce(q, &bio); | |
1724 | ||
23688bf4 JN |
1725 | blk_queue_split(q, &bio, q->bio_split); |
1726 | ||
ffecfd1a | 1727 | if (bio_integrity_enabled(bio) && bio_integrity_prep(bio)) { |
4246a0b6 CH |
1728 | bio->bi_error = -EIO; |
1729 | bio_endio(bio); | |
dece1635 | 1730 | return BLK_QC_T_NONE; |
ffecfd1a DW |
1731 | } |
1732 | ||
4fed947c | 1733 | if (bio->bi_rw & (REQ_FLUSH | REQ_FUA)) { |
73c10101 | 1734 | spin_lock_irq(q->queue_lock); |
ae1b1539 | 1735 | where = ELEVATOR_INSERT_FLUSH; |
28e7d184 TH |
1736 | goto get_rq; |
1737 | } | |
1738 | ||
73c10101 JA |
1739 | /* |
1740 | * Check if we can merge with the plugged list before grabbing | |
1741 | * any locks. | |
1742 | */ | |
0809e3ac JM |
1743 | if (!blk_queue_nomerges(q)) { |
1744 | if (blk_attempt_plug_merge(q, bio, &request_count, NULL)) | |
dece1635 | 1745 | return BLK_QC_T_NONE; |
0809e3ac JM |
1746 | } else |
1747 | request_count = blk_plug_queued_count(q); | |
1da177e4 | 1748 | |
73c10101 | 1749 | spin_lock_irq(q->queue_lock); |
2056a782 | 1750 | |
73c10101 JA |
1751 | el_ret = elv_merge(q, &req, bio); |
1752 | if (el_ret == ELEVATOR_BACK_MERGE) { | |
73c10101 | 1753 | if (bio_attempt_back_merge(q, req, bio)) { |
07c2bd37 | 1754 | elv_bio_merged(q, req, bio); |
73c10101 JA |
1755 | if (!attempt_back_merge(q, req)) |
1756 | elv_merged_request(q, req, el_ret); | |
1757 | goto out_unlock; | |
1758 | } | |
1759 | } else if (el_ret == ELEVATOR_FRONT_MERGE) { | |
73c10101 | 1760 | if (bio_attempt_front_merge(q, req, bio)) { |
07c2bd37 | 1761 | elv_bio_merged(q, req, bio); |
73c10101 JA |
1762 | if (!attempt_front_merge(q, req)) |
1763 | elv_merged_request(q, req, el_ret); | |
1764 | goto out_unlock; | |
80a761fd | 1765 | } |
1da177e4 LT |
1766 | } |
1767 | ||
450991bc | 1768 | get_rq: |
7749a8d4 JA |
1769 | /* |
1770 | * This sync check and mask will be re-done in init_request_from_bio(), | |
1771 | * but we need to set it earlier to expose the sync flag to the | |
1772 | * rq allocator and io schedulers. | |
1773 | */ | |
1774 | rw_flags = bio_data_dir(bio); | |
1775 | if (sync) | |
7b6d91da | 1776 | rw_flags |= REQ_SYNC; |
7749a8d4 | 1777 | |
1da177e4 | 1778 | /* |
450991bc | 1779 | * Grab a free request. This is might sleep but can not fail. |
d6344532 | 1780 | * Returns with the queue unlocked. |
450991bc | 1781 | */ |
a06e05e6 | 1782 | req = get_request(q, rw_flags, bio, GFP_NOIO); |
a492f075 | 1783 | if (IS_ERR(req)) { |
4246a0b6 CH |
1784 | bio->bi_error = PTR_ERR(req); |
1785 | bio_endio(bio); | |
da8303c6 TH |
1786 | goto out_unlock; |
1787 | } | |
d6344532 | 1788 | |
450991bc NP |
1789 | /* |
1790 | * After dropping the lock and possibly sleeping here, our request | |
1791 | * may now be mergeable after it had proven unmergeable (above). | |
1792 | * We don't worry about that case for efficiency. It won't happen | |
1793 | * often, and the elevators are able to handle it. | |
1da177e4 | 1794 | */ |
52d9e675 | 1795 | init_request_from_bio(req, bio); |
1da177e4 | 1796 | |
9562ad9a | 1797 | if (test_bit(QUEUE_FLAG_SAME_COMP, &q->queue_flags)) |
11ccf116 | 1798 | req->cpu = raw_smp_processor_id(); |
73c10101 JA |
1799 | |
1800 | plug = current->plug; | |
721a9602 | 1801 | if (plug) { |
dc6d36c9 JA |
1802 | /* |
1803 | * If this is the first request added after a plug, fire | |
7aef2e78 | 1804 | * of a plug trace. |
dc6d36c9 | 1805 | */ |
7aef2e78 | 1806 | if (!request_count) |
dc6d36c9 | 1807 | trace_block_plug(q); |
3540d5e8 | 1808 | else { |
019ceb7d | 1809 | if (request_count >= BLK_MAX_REQUEST_COUNT) { |
3540d5e8 | 1810 | blk_flush_plug_list(plug, false); |
019ceb7d SL |
1811 | trace_block_plug(q); |
1812 | } | |
73c10101 | 1813 | } |
73c10101 | 1814 | list_add_tail(&req->queuelist, &plug->list); |
320ae51f | 1815 | blk_account_io_start(req, true); |
73c10101 JA |
1816 | } else { |
1817 | spin_lock_irq(q->queue_lock); | |
1818 | add_acct_request(q, req, where); | |
24ecfbe2 | 1819 | __blk_run_queue(q); |
73c10101 JA |
1820 | out_unlock: |
1821 | spin_unlock_irq(q->queue_lock); | |
1822 | } | |
dece1635 JA |
1823 | |
1824 | return BLK_QC_T_NONE; | |
1da177e4 LT |
1825 | } |
1826 | ||
1827 | /* | |
1828 | * If bio->bi_dev is a partition, remap the location | |
1829 | */ | |
1830 | static inline void blk_partition_remap(struct bio *bio) | |
1831 | { | |
1832 | struct block_device *bdev = bio->bi_bdev; | |
1833 | ||
bf2de6f5 | 1834 | if (bio_sectors(bio) && bdev != bdev->bd_contains) { |
1da177e4 LT |
1835 | struct hd_struct *p = bdev->bd_part; |
1836 | ||
4f024f37 | 1837 | bio->bi_iter.bi_sector += p->start_sect; |
1da177e4 | 1838 | bio->bi_bdev = bdev->bd_contains; |
c7149d6b | 1839 | |
d07335e5 MS |
1840 | trace_block_bio_remap(bdev_get_queue(bio->bi_bdev), bio, |
1841 | bdev->bd_dev, | |
4f024f37 | 1842 | bio->bi_iter.bi_sector - p->start_sect); |
1da177e4 LT |
1843 | } |
1844 | } | |
1845 | ||
1da177e4 LT |
1846 | static void handle_bad_sector(struct bio *bio) |
1847 | { | |
1848 | char b[BDEVNAME_SIZE]; | |
1849 | ||
1850 | printk(KERN_INFO "attempt to access beyond end of device\n"); | |
1851 | printk(KERN_INFO "%s: rw=%ld, want=%Lu, limit=%Lu\n", | |
1852 | bdevname(bio->bi_bdev, b), | |
1853 | bio->bi_rw, | |
f73a1c7d | 1854 | (unsigned long long)bio_end_sector(bio), |
77304d2a | 1855 | (long long)(i_size_read(bio->bi_bdev->bd_inode) >> 9)); |
1da177e4 LT |
1856 | } |
1857 | ||
c17bb495 AM |
1858 | #ifdef CONFIG_FAIL_MAKE_REQUEST |
1859 | ||
1860 | static DECLARE_FAULT_ATTR(fail_make_request); | |
1861 | ||
1862 | static int __init setup_fail_make_request(char *str) | |
1863 | { | |
1864 | return setup_fault_attr(&fail_make_request, str); | |
1865 | } | |
1866 | __setup("fail_make_request=", setup_fail_make_request); | |
1867 | ||
b2c9cd37 | 1868 | static bool should_fail_request(struct hd_struct *part, unsigned int bytes) |
c17bb495 | 1869 | { |
b2c9cd37 | 1870 | return part->make_it_fail && should_fail(&fail_make_request, bytes); |
c17bb495 AM |
1871 | } |
1872 | ||
1873 | static int __init fail_make_request_debugfs(void) | |
1874 | { | |
dd48c085 AM |
1875 | struct dentry *dir = fault_create_debugfs_attr("fail_make_request", |
1876 | NULL, &fail_make_request); | |
1877 | ||
21f9fcd8 | 1878 | return PTR_ERR_OR_ZERO(dir); |
c17bb495 AM |
1879 | } |
1880 | ||
1881 | late_initcall(fail_make_request_debugfs); | |
1882 | ||
1883 | #else /* CONFIG_FAIL_MAKE_REQUEST */ | |
1884 | ||
b2c9cd37 AM |
1885 | static inline bool should_fail_request(struct hd_struct *part, |
1886 | unsigned int bytes) | |
c17bb495 | 1887 | { |
b2c9cd37 | 1888 | return false; |
c17bb495 AM |
1889 | } |
1890 | ||
1891 | #endif /* CONFIG_FAIL_MAKE_REQUEST */ | |
1892 | ||
c07e2b41 JA |
1893 | /* |
1894 | * Check whether this bio extends beyond the end of the device. | |
1895 | */ | |
1896 | static inline int bio_check_eod(struct bio *bio, unsigned int nr_sectors) | |
1897 | { | |
1898 | sector_t maxsector; | |
1899 | ||
1900 | if (!nr_sectors) | |
1901 | return 0; | |
1902 | ||
1903 | /* Test device or partition size, when known. */ | |
77304d2a | 1904 | maxsector = i_size_read(bio->bi_bdev->bd_inode) >> 9; |
c07e2b41 | 1905 | if (maxsector) { |
4f024f37 | 1906 | sector_t sector = bio->bi_iter.bi_sector; |
c07e2b41 JA |
1907 | |
1908 | if (maxsector < nr_sectors || maxsector - nr_sectors < sector) { | |
1909 | /* | |
1910 | * This may well happen - the kernel calls bread() | |
1911 | * without checking the size of the device, e.g., when | |
1912 | * mounting a device. | |
1913 | */ | |
1914 | handle_bad_sector(bio); | |
1915 | return 1; | |
1916 | } | |
1917 | } | |
1918 | ||
1919 | return 0; | |
1920 | } | |
1921 | ||
27a84d54 CH |
1922 | static noinline_for_stack bool |
1923 | generic_make_request_checks(struct bio *bio) | |
1da177e4 | 1924 | { |
165125e1 | 1925 | struct request_queue *q; |
5a7bbad2 | 1926 | int nr_sectors = bio_sectors(bio); |
51fd77bd | 1927 | int err = -EIO; |
5a7bbad2 CH |
1928 | char b[BDEVNAME_SIZE]; |
1929 | struct hd_struct *part; | |
1da177e4 LT |
1930 | |
1931 | might_sleep(); | |
1da177e4 | 1932 | |
c07e2b41 JA |
1933 | if (bio_check_eod(bio, nr_sectors)) |
1934 | goto end_io; | |
1da177e4 | 1935 | |
5a7bbad2 CH |
1936 | q = bdev_get_queue(bio->bi_bdev); |
1937 | if (unlikely(!q)) { | |
1938 | printk(KERN_ERR | |
1939 | "generic_make_request: Trying to access " | |
1940 | "nonexistent block-device %s (%Lu)\n", | |
1941 | bdevname(bio->bi_bdev, b), | |
4f024f37 | 1942 | (long long) bio->bi_iter.bi_sector); |
5a7bbad2 CH |
1943 | goto end_io; |
1944 | } | |
c17bb495 | 1945 | |
5a7bbad2 | 1946 | part = bio->bi_bdev->bd_part; |
4f024f37 | 1947 | if (should_fail_request(part, bio->bi_iter.bi_size) || |
5a7bbad2 | 1948 | should_fail_request(&part_to_disk(part)->part0, |
4f024f37 | 1949 | bio->bi_iter.bi_size)) |
5a7bbad2 | 1950 | goto end_io; |
2056a782 | 1951 | |
5a7bbad2 CH |
1952 | /* |
1953 | * If this device has partitions, remap block n | |
1954 | * of partition p to block n+start(p) of the disk. | |
1955 | */ | |
1956 | blk_partition_remap(bio); | |
2056a782 | 1957 | |
5a7bbad2 CH |
1958 | if (bio_check_eod(bio, nr_sectors)) |
1959 | goto end_io; | |
1e87901e | 1960 | |
5a7bbad2 CH |
1961 | /* |
1962 | * Filter flush bio's early so that make_request based | |
1963 | * drivers without flush support don't have to worry | |
1964 | * about them. | |
1965 | */ | |
1966 | if ((bio->bi_rw & (REQ_FLUSH | REQ_FUA)) && !q->flush_flags) { | |
1967 | bio->bi_rw &= ~(REQ_FLUSH | REQ_FUA); | |
1968 | if (!nr_sectors) { | |
1969 | err = 0; | |
51fd77bd JA |
1970 | goto end_io; |
1971 | } | |
5a7bbad2 | 1972 | } |
5ddfe969 | 1973 | |
5a7bbad2 CH |
1974 | if ((bio->bi_rw & REQ_DISCARD) && |
1975 | (!blk_queue_discard(q) || | |
e2a60da7 | 1976 | ((bio->bi_rw & REQ_SECURE) && !blk_queue_secdiscard(q)))) { |
5a7bbad2 CH |
1977 | err = -EOPNOTSUPP; |
1978 | goto end_io; | |
1979 | } | |
01edede4 | 1980 | |
4363ac7c | 1981 | if (bio->bi_rw & REQ_WRITE_SAME && !bdev_write_same(bio->bi_bdev)) { |
5a7bbad2 CH |
1982 | err = -EOPNOTSUPP; |
1983 | goto end_io; | |
1984 | } | |
01edede4 | 1985 | |
7f4b35d1 TH |
1986 | /* |
1987 | * Various block parts want %current->io_context and lazy ioc | |
1988 | * allocation ends up trading a lot of pain for a small amount of | |
1989 | * memory. Just allocate it upfront. This may fail and block | |
1990 | * layer knows how to live with it. | |
1991 | */ | |
1992 | create_io_context(GFP_ATOMIC, q->node); | |
1993 | ||
ae118896 TH |
1994 | if (!blkcg_bio_issue_check(q, bio)) |
1995 | return false; | |
27a84d54 | 1996 | |
5a7bbad2 | 1997 | trace_block_bio_queue(q, bio); |
27a84d54 | 1998 | return true; |
a7384677 TH |
1999 | |
2000 | end_io: | |
4246a0b6 CH |
2001 | bio->bi_error = err; |
2002 | bio_endio(bio); | |
27a84d54 | 2003 | return false; |
1da177e4 LT |
2004 | } |
2005 | ||
27a84d54 CH |
2006 | /** |
2007 | * generic_make_request - hand a buffer to its device driver for I/O | |
2008 | * @bio: The bio describing the location in memory and on the device. | |
2009 | * | |
2010 | * generic_make_request() is used to make I/O requests of block | |
2011 | * devices. It is passed a &struct bio, which describes the I/O that needs | |
2012 | * to be done. | |
2013 | * | |
2014 | * generic_make_request() does not return any status. The | |
2015 | * success/failure status of the request, along with notification of | |
2016 | * completion, is delivered asynchronously through the bio->bi_end_io | |
2017 | * function described (one day) else where. | |
2018 | * | |
2019 | * The caller of generic_make_request must make sure that bi_io_vec | |
2020 | * are set to describe the memory buffer, and that bi_dev and bi_sector are | |
2021 | * set to describe the device address, and the | |
2022 | * bi_end_io and optionally bi_private are set to describe how | |
2023 | * completion notification should be signaled. | |
2024 | * | |
2025 | * generic_make_request and the drivers it calls may use bi_next if this | |
2026 | * bio happens to be merged with someone else, and may resubmit the bio to | |
2027 | * a lower device by calling into generic_make_request recursively, which | |
2028 | * means the bio should NOT be touched after the call to ->make_request_fn. | |
d89d8796 | 2029 | */ |
dece1635 | 2030 | blk_qc_t generic_make_request(struct bio *bio) |
d89d8796 | 2031 | { |
bddd87c7 | 2032 | struct bio_list bio_list_on_stack; |
dece1635 | 2033 | blk_qc_t ret = BLK_QC_T_NONE; |
bddd87c7 | 2034 | |
27a84d54 | 2035 | if (!generic_make_request_checks(bio)) |
dece1635 | 2036 | goto out; |
27a84d54 CH |
2037 | |
2038 | /* | |
2039 | * We only want one ->make_request_fn to be active at a time, else | |
2040 | * stack usage with stacked devices could be a problem. So use | |
2041 | * current->bio_list to keep a list of requests submited by a | |
2042 | * make_request_fn function. current->bio_list is also used as a | |
2043 | * flag to say if generic_make_request is currently active in this | |
2044 | * task or not. If it is NULL, then no make_request is active. If | |
2045 | * it is non-NULL, then a make_request is active, and new requests | |
2046 | * should be added at the tail | |
2047 | */ | |
bddd87c7 | 2048 | if (current->bio_list) { |
bddd87c7 | 2049 | bio_list_add(current->bio_list, bio); |
dece1635 | 2050 | goto out; |
d89d8796 | 2051 | } |
27a84d54 | 2052 | |
d89d8796 NB |
2053 | /* following loop may be a bit non-obvious, and so deserves some |
2054 | * explanation. | |
2055 | * Before entering the loop, bio->bi_next is NULL (as all callers | |
2056 | * ensure that) so we have a list with a single bio. | |
2057 | * We pretend that we have just taken it off a longer list, so | |
bddd87c7 AM |
2058 | * we assign bio_list to a pointer to the bio_list_on_stack, |
2059 | * thus initialising the bio_list of new bios to be | |
27a84d54 | 2060 | * added. ->make_request() may indeed add some more bios |
d89d8796 NB |
2061 | * through a recursive call to generic_make_request. If it |
2062 | * did, we find a non-NULL value in bio_list and re-enter the loop | |
2063 | * from the top. In this case we really did just take the bio | |
bddd87c7 | 2064 | * of the top of the list (no pretending) and so remove it from |
27a84d54 | 2065 | * bio_list, and call into ->make_request() again. |
d89d8796 NB |
2066 | */ |
2067 | BUG_ON(bio->bi_next); | |
bddd87c7 AM |
2068 | bio_list_init(&bio_list_on_stack); |
2069 | current->bio_list = &bio_list_on_stack; | |
d89d8796 | 2070 | do { |
27a84d54 CH |
2071 | struct request_queue *q = bdev_get_queue(bio->bi_bdev); |
2072 | ||
6f3b0e8b | 2073 | if (likely(blk_queue_enter(q, false) == 0)) { |
dece1635 | 2074 | ret = q->make_request_fn(q, bio); |
3ef28e83 DW |
2075 | |
2076 | blk_queue_exit(q); | |
27a84d54 | 2077 | |
3ef28e83 DW |
2078 | bio = bio_list_pop(current->bio_list); |
2079 | } else { | |
2080 | struct bio *bio_next = bio_list_pop(current->bio_list); | |
2081 | ||
2082 | bio_io_error(bio); | |
2083 | bio = bio_next; | |
2084 | } | |
d89d8796 | 2085 | } while (bio); |
bddd87c7 | 2086 | current->bio_list = NULL; /* deactivate */ |
dece1635 JA |
2087 | |
2088 | out: | |
2089 | return ret; | |
d89d8796 | 2090 | } |
1da177e4 LT |
2091 | EXPORT_SYMBOL(generic_make_request); |
2092 | ||
2093 | /** | |
710027a4 | 2094 | * submit_bio - submit a bio to the block device layer for I/O |
1da177e4 LT |
2095 | * @rw: whether to %READ or %WRITE, or maybe to %READA (read ahead) |
2096 | * @bio: The &struct bio which describes the I/O | |
2097 | * | |
2098 | * submit_bio() is very similar in purpose to generic_make_request(), and | |
2099 | * uses that function to do most of the work. Both are fairly rough | |
710027a4 | 2100 | * interfaces; @bio must be presetup and ready for I/O. |
1da177e4 LT |
2101 | * |
2102 | */ | |
dece1635 | 2103 | blk_qc_t submit_bio(int rw, struct bio *bio) |
1da177e4 | 2104 | { |
22e2c507 | 2105 | bio->bi_rw |= rw; |
1da177e4 | 2106 | |
bf2de6f5 JA |
2107 | /* |
2108 | * If it's a regular read/write or a barrier with data attached, | |
2109 | * go through the normal accounting stuff before submission. | |
2110 | */ | |
e2a60da7 | 2111 | if (bio_has_data(bio)) { |
4363ac7c MP |
2112 | unsigned int count; |
2113 | ||
2114 | if (unlikely(rw & REQ_WRITE_SAME)) | |
2115 | count = bdev_logical_block_size(bio->bi_bdev) >> 9; | |
2116 | else | |
2117 | count = bio_sectors(bio); | |
2118 | ||
bf2de6f5 JA |
2119 | if (rw & WRITE) { |
2120 | count_vm_events(PGPGOUT, count); | |
2121 | } else { | |
4f024f37 | 2122 | task_io_account_read(bio->bi_iter.bi_size); |
bf2de6f5 JA |
2123 | count_vm_events(PGPGIN, count); |
2124 | } | |
2125 | ||
2126 | if (unlikely(block_dump)) { | |
2127 | char b[BDEVNAME_SIZE]; | |
8dcbdc74 | 2128 | printk(KERN_DEBUG "%s(%d): %s block %Lu on %s (%u sectors)\n", |
ba25f9dc | 2129 | current->comm, task_pid_nr(current), |
bf2de6f5 | 2130 | (rw & WRITE) ? "WRITE" : "READ", |
4f024f37 | 2131 | (unsigned long long)bio->bi_iter.bi_sector, |
8dcbdc74 SM |
2132 | bdevname(bio->bi_bdev, b), |
2133 | count); | |
bf2de6f5 | 2134 | } |
1da177e4 LT |
2135 | } |
2136 | ||
dece1635 | 2137 | return generic_make_request(bio); |
1da177e4 | 2138 | } |
1da177e4 LT |
2139 | EXPORT_SYMBOL(submit_bio); |
2140 | ||
82124d60 | 2141 | /** |
bf4e6b4e HR |
2142 | * blk_cloned_rq_check_limits - Helper function to check a cloned request |
2143 | * for new the queue limits | |
82124d60 KU |
2144 | * @q: the queue |
2145 | * @rq: the request being checked | |
2146 | * | |
2147 | * Description: | |
2148 | * @rq may have been made based on weaker limitations of upper-level queues | |
2149 | * in request stacking drivers, and it may violate the limitation of @q. | |
2150 | * Since the block layer and the underlying device driver trust @rq | |
2151 | * after it is inserted to @q, it should be checked against @q before | |
2152 | * the insertion using this generic function. | |
2153 | * | |
82124d60 | 2154 | * Request stacking drivers like request-based dm may change the queue |
bf4e6b4e HR |
2155 | * limits when retrying requests on other queues. Those requests need |
2156 | * to be checked against the new queue limits again during dispatch. | |
82124d60 | 2157 | */ |
bf4e6b4e HR |
2158 | static int blk_cloned_rq_check_limits(struct request_queue *q, |
2159 | struct request *rq) | |
82124d60 | 2160 | { |
f31dc1cd | 2161 | if (blk_rq_sectors(rq) > blk_queue_get_max_sectors(q, rq->cmd_flags)) { |
82124d60 KU |
2162 | printk(KERN_ERR "%s: over max size limit.\n", __func__); |
2163 | return -EIO; | |
2164 | } | |
2165 | ||
2166 | /* | |
2167 | * queue's settings related to segment counting like q->bounce_pfn | |
2168 | * may differ from that of other stacking queues. | |
2169 | * Recalculate it to check the request correctly on this queue's | |
2170 | * limitation. | |
2171 | */ | |
2172 | blk_recalc_rq_segments(rq); | |
8a78362c | 2173 | if (rq->nr_phys_segments > queue_max_segments(q)) { |
82124d60 KU |
2174 | printk(KERN_ERR "%s: over max segments limit.\n", __func__); |
2175 | return -EIO; | |
2176 | } | |
2177 | ||
2178 | return 0; | |
2179 | } | |
82124d60 KU |
2180 | |
2181 | /** | |
2182 | * blk_insert_cloned_request - Helper for stacking drivers to submit a request | |
2183 | * @q: the queue to submit the request | |
2184 | * @rq: the request being queued | |
2185 | */ | |
2186 | int blk_insert_cloned_request(struct request_queue *q, struct request *rq) | |
2187 | { | |
2188 | unsigned long flags; | |
4853abaa | 2189 | int where = ELEVATOR_INSERT_BACK; |
82124d60 | 2190 | |
bf4e6b4e | 2191 | if (blk_cloned_rq_check_limits(q, rq)) |
82124d60 KU |
2192 | return -EIO; |
2193 | ||
b2c9cd37 AM |
2194 | if (rq->rq_disk && |
2195 | should_fail_request(&rq->rq_disk->part0, blk_rq_bytes(rq))) | |
82124d60 | 2196 | return -EIO; |
82124d60 | 2197 | |
7fb4898e KB |
2198 | if (q->mq_ops) { |
2199 | if (blk_queue_io_stat(q)) | |
2200 | blk_account_io_start(rq, true); | |
2201 | blk_mq_insert_request(rq, false, true, true); | |
2202 | return 0; | |
2203 | } | |
2204 | ||
82124d60 | 2205 | spin_lock_irqsave(q->queue_lock, flags); |
3f3299d5 | 2206 | if (unlikely(blk_queue_dying(q))) { |
8ba61435 TH |
2207 | spin_unlock_irqrestore(q->queue_lock, flags); |
2208 | return -ENODEV; | |
2209 | } | |
82124d60 KU |
2210 | |
2211 | /* | |
2212 | * Submitting request must be dequeued before calling this function | |
2213 | * because it will be linked to another request_queue | |
2214 | */ | |
2215 | BUG_ON(blk_queued_rq(rq)); | |
2216 | ||
4853abaa JM |
2217 | if (rq->cmd_flags & (REQ_FLUSH|REQ_FUA)) |
2218 | where = ELEVATOR_INSERT_FLUSH; | |
2219 | ||
2220 | add_acct_request(q, rq, where); | |
e67b77c7 JM |
2221 | if (where == ELEVATOR_INSERT_FLUSH) |
2222 | __blk_run_queue(q); | |
82124d60 KU |
2223 | spin_unlock_irqrestore(q->queue_lock, flags); |
2224 | ||
2225 | return 0; | |
2226 | } | |
2227 | EXPORT_SYMBOL_GPL(blk_insert_cloned_request); | |
2228 | ||
80a761fd TH |
2229 | /** |
2230 | * blk_rq_err_bytes - determine number of bytes till the next failure boundary | |
2231 | * @rq: request to examine | |
2232 | * | |
2233 | * Description: | |
2234 | * A request could be merge of IOs which require different failure | |
2235 | * handling. This function determines the number of bytes which | |
2236 | * can be failed from the beginning of the request without | |
2237 | * crossing into area which need to be retried further. | |
2238 | * | |
2239 | * Return: | |
2240 | * The number of bytes to fail. | |
2241 | * | |
2242 | * Context: | |
2243 | * queue_lock must be held. | |
2244 | */ | |
2245 | unsigned int blk_rq_err_bytes(const struct request *rq) | |
2246 | { | |
2247 | unsigned int ff = rq->cmd_flags & REQ_FAILFAST_MASK; | |
2248 | unsigned int bytes = 0; | |
2249 | struct bio *bio; | |
2250 | ||
2251 | if (!(rq->cmd_flags & REQ_MIXED_MERGE)) | |
2252 | return blk_rq_bytes(rq); | |
2253 | ||
2254 | /* | |
2255 | * Currently the only 'mixing' which can happen is between | |
2256 | * different fastfail types. We can safely fail portions | |
2257 | * which have all the failfast bits that the first one has - | |
2258 | * the ones which are at least as eager to fail as the first | |
2259 | * one. | |
2260 | */ | |
2261 | for (bio = rq->bio; bio; bio = bio->bi_next) { | |
2262 | if ((bio->bi_rw & ff) != ff) | |
2263 | break; | |
4f024f37 | 2264 | bytes += bio->bi_iter.bi_size; |
80a761fd TH |
2265 | } |
2266 | ||
2267 | /* this could lead to infinite loop */ | |
2268 | BUG_ON(blk_rq_bytes(rq) && !bytes); | |
2269 | return bytes; | |
2270 | } | |
2271 | EXPORT_SYMBOL_GPL(blk_rq_err_bytes); | |
2272 | ||
320ae51f | 2273 | void blk_account_io_completion(struct request *req, unsigned int bytes) |
bc58ba94 | 2274 | { |
c2553b58 | 2275 | if (blk_do_io_stat(req)) { |
bc58ba94 JA |
2276 | const int rw = rq_data_dir(req); |
2277 | struct hd_struct *part; | |
2278 | int cpu; | |
2279 | ||
2280 | cpu = part_stat_lock(); | |
09e099d4 | 2281 | part = req->part; |
bc58ba94 JA |
2282 | part_stat_add(cpu, part, sectors[rw], bytes >> 9); |
2283 | part_stat_unlock(); | |
2284 | } | |
2285 | } | |
2286 | ||
320ae51f | 2287 | void blk_account_io_done(struct request *req) |
bc58ba94 | 2288 | { |
bc58ba94 | 2289 | /* |
dd4c133f TH |
2290 | * Account IO completion. flush_rq isn't accounted as a |
2291 | * normal IO on queueing nor completion. Accounting the | |
2292 | * containing request is enough. | |
bc58ba94 | 2293 | */ |
414b4ff5 | 2294 | if (blk_do_io_stat(req) && !(req->cmd_flags & REQ_FLUSH_SEQ)) { |
bc58ba94 JA |
2295 | unsigned long duration = jiffies - req->start_time; |
2296 | const int rw = rq_data_dir(req); | |
2297 | struct hd_struct *part; | |
2298 | int cpu; | |
2299 | ||
2300 | cpu = part_stat_lock(); | |
09e099d4 | 2301 | part = req->part; |
bc58ba94 JA |
2302 | |
2303 | part_stat_inc(cpu, part, ios[rw]); | |
2304 | part_stat_add(cpu, part, ticks[rw], duration); | |
2305 | part_round_stats(cpu, part); | |
316d315b | 2306 | part_dec_in_flight(part, rw); |
bc58ba94 | 2307 | |
6c23a968 | 2308 | hd_struct_put(part); |
bc58ba94 JA |
2309 | part_stat_unlock(); |
2310 | } | |
2311 | } | |
2312 | ||
47fafbc7 | 2313 | #ifdef CONFIG_PM |
c8158819 LM |
2314 | /* |
2315 | * Don't process normal requests when queue is suspended | |
2316 | * or in the process of suspending/resuming | |
2317 | */ | |
2318 | static struct request *blk_pm_peek_request(struct request_queue *q, | |
2319 | struct request *rq) | |
2320 | { | |
2321 | if (q->dev && (q->rpm_status == RPM_SUSPENDED || | |
2322 | (q->rpm_status != RPM_ACTIVE && !(rq->cmd_flags & REQ_PM)))) | |
2323 | return NULL; | |
2324 | else | |
2325 | return rq; | |
2326 | } | |
2327 | #else | |
2328 | static inline struct request *blk_pm_peek_request(struct request_queue *q, | |
2329 | struct request *rq) | |
2330 | { | |
2331 | return rq; | |
2332 | } | |
2333 | #endif | |
2334 | ||
320ae51f JA |
2335 | void blk_account_io_start(struct request *rq, bool new_io) |
2336 | { | |
2337 | struct hd_struct *part; | |
2338 | int rw = rq_data_dir(rq); | |
2339 | int cpu; | |
2340 | ||
2341 | if (!blk_do_io_stat(rq)) | |
2342 | return; | |
2343 | ||
2344 | cpu = part_stat_lock(); | |
2345 | ||
2346 | if (!new_io) { | |
2347 | part = rq->part; | |
2348 | part_stat_inc(cpu, part, merges[rw]); | |
2349 | } else { | |
2350 | part = disk_map_sector_rcu(rq->rq_disk, blk_rq_pos(rq)); | |
2351 | if (!hd_struct_try_get(part)) { | |
2352 | /* | |
2353 | * The partition is already being removed, | |
2354 | * the request will be accounted on the disk only | |
2355 | * | |
2356 | * We take a reference on disk->part0 although that | |
2357 | * partition will never be deleted, so we can treat | |
2358 | * it as any other partition. | |
2359 | */ | |
2360 | part = &rq->rq_disk->part0; | |
2361 | hd_struct_get(part); | |
2362 | } | |
2363 | part_round_stats(cpu, part); | |
2364 | part_inc_in_flight(part, rw); | |
2365 | rq->part = part; | |
2366 | } | |
2367 | ||
2368 | part_stat_unlock(); | |
2369 | } | |
2370 | ||
3bcddeac | 2371 | /** |
9934c8c0 TH |
2372 | * blk_peek_request - peek at the top of a request queue |
2373 | * @q: request queue to peek at | |
2374 | * | |
2375 | * Description: | |
2376 | * Return the request at the top of @q. The returned request | |
2377 | * should be started using blk_start_request() before LLD starts | |
2378 | * processing it. | |
2379 | * | |
2380 | * Return: | |
2381 | * Pointer to the request at the top of @q if available. Null | |
2382 | * otherwise. | |
2383 | * | |
2384 | * Context: | |
2385 | * queue_lock must be held. | |
2386 | */ | |
2387 | struct request *blk_peek_request(struct request_queue *q) | |
158dbda0 TH |
2388 | { |
2389 | struct request *rq; | |
2390 | int ret; | |
2391 | ||
2392 | while ((rq = __elv_next_request(q)) != NULL) { | |
c8158819 LM |
2393 | |
2394 | rq = blk_pm_peek_request(q, rq); | |
2395 | if (!rq) | |
2396 | break; | |
2397 | ||
158dbda0 TH |
2398 | if (!(rq->cmd_flags & REQ_STARTED)) { |
2399 | /* | |
2400 | * This is the first time the device driver | |
2401 | * sees this request (possibly after | |
2402 | * requeueing). Notify IO scheduler. | |
2403 | */ | |
33659ebb | 2404 | if (rq->cmd_flags & REQ_SORTED) |
158dbda0 TH |
2405 | elv_activate_rq(q, rq); |
2406 | ||
2407 | /* | |
2408 | * just mark as started even if we don't start | |
2409 | * it, a request that has been delayed should | |
2410 | * not be passed by new incoming requests | |
2411 | */ | |
2412 | rq->cmd_flags |= REQ_STARTED; | |
2413 | trace_block_rq_issue(q, rq); | |
2414 | } | |
2415 | ||
2416 | if (!q->boundary_rq || q->boundary_rq == rq) { | |
2417 | q->end_sector = rq_end_sector(rq); | |
2418 | q->boundary_rq = NULL; | |
2419 | } | |
2420 | ||
2421 | if (rq->cmd_flags & REQ_DONTPREP) | |
2422 | break; | |
2423 | ||
2e46e8b2 | 2424 | if (q->dma_drain_size && blk_rq_bytes(rq)) { |
158dbda0 TH |
2425 | /* |
2426 | * make sure space for the drain appears we | |
2427 | * know we can do this because max_hw_segments | |
2428 | * has been adjusted to be one fewer than the | |
2429 | * device can handle | |
2430 | */ | |
2431 | rq->nr_phys_segments++; | |
2432 | } | |
2433 | ||
2434 | if (!q->prep_rq_fn) | |
2435 | break; | |
2436 | ||
2437 | ret = q->prep_rq_fn(q, rq); | |
2438 | if (ret == BLKPREP_OK) { | |
2439 | break; | |
2440 | } else if (ret == BLKPREP_DEFER) { | |
2441 | /* | |
2442 | * the request may have been (partially) prepped. | |
2443 | * we need to keep this request in the front to | |
2444 | * avoid resource deadlock. REQ_STARTED will | |
2445 | * prevent other fs requests from passing this one. | |
2446 | */ | |
2e46e8b2 | 2447 | if (q->dma_drain_size && blk_rq_bytes(rq) && |
158dbda0 TH |
2448 | !(rq->cmd_flags & REQ_DONTPREP)) { |
2449 | /* | |
2450 | * remove the space for the drain we added | |
2451 | * so that we don't add it again | |
2452 | */ | |
2453 | --rq->nr_phys_segments; | |
2454 | } | |
2455 | ||
2456 | rq = NULL; | |
2457 | break; | |
0fb5b1fb MP |
2458 | } else if (ret == BLKPREP_KILL || ret == BLKPREP_INVALID) { |
2459 | int err = (ret == BLKPREP_INVALID) ? -EREMOTEIO : -EIO; | |
2460 | ||
158dbda0 | 2461 | rq->cmd_flags |= REQ_QUIET; |
c143dc90 JB |
2462 | /* |
2463 | * Mark this request as started so we don't trigger | |
2464 | * any debug logic in the end I/O path. | |
2465 | */ | |
2466 | blk_start_request(rq); | |
0fb5b1fb | 2467 | __blk_end_request_all(rq, err); |
158dbda0 TH |
2468 | } else { |
2469 | printk(KERN_ERR "%s: bad return=%d\n", __func__, ret); | |
2470 | break; | |
2471 | } | |
2472 | } | |
2473 | ||
2474 | return rq; | |
2475 | } | |
9934c8c0 | 2476 | EXPORT_SYMBOL(blk_peek_request); |
158dbda0 | 2477 | |
9934c8c0 | 2478 | void blk_dequeue_request(struct request *rq) |
158dbda0 | 2479 | { |
9934c8c0 TH |
2480 | struct request_queue *q = rq->q; |
2481 | ||
158dbda0 TH |
2482 | BUG_ON(list_empty(&rq->queuelist)); |
2483 | BUG_ON(ELV_ON_HASH(rq)); | |
2484 | ||
2485 | list_del_init(&rq->queuelist); | |
2486 | ||
2487 | /* | |
2488 | * the time frame between a request being removed from the lists | |
2489 | * and to it is freed is accounted as io that is in progress at | |
2490 | * the driver side. | |
2491 | */ | |
9195291e | 2492 | if (blk_account_rq(rq)) { |
0a7ae2ff | 2493 | q->in_flight[rq_is_sync(rq)]++; |
9195291e DS |
2494 | set_io_start_time_ns(rq); |
2495 | } | |
158dbda0 TH |
2496 | } |
2497 | ||
9934c8c0 TH |
2498 | /** |
2499 | * blk_start_request - start request processing on the driver | |
2500 | * @req: request to dequeue | |
2501 | * | |
2502 | * Description: | |
2503 | * Dequeue @req and start timeout timer on it. This hands off the | |
2504 | * request to the driver. | |
2505 | * | |
2506 | * Block internal functions which don't want to start timer should | |
2507 | * call blk_dequeue_request(). | |
2508 | * | |
2509 | * Context: | |
2510 | * queue_lock must be held. | |
2511 | */ | |
2512 | void blk_start_request(struct request *req) | |
2513 | { | |
2514 | blk_dequeue_request(req); | |
2515 | ||
2516 | /* | |
5f49f631 TH |
2517 | * We are now handing the request to the hardware, initialize |
2518 | * resid_len to full count and add the timeout handler. | |
9934c8c0 | 2519 | */ |
5f49f631 | 2520 | req->resid_len = blk_rq_bytes(req); |
dbb66c4b FT |
2521 | if (unlikely(blk_bidi_rq(req))) |
2522 | req->next_rq->resid_len = blk_rq_bytes(req->next_rq); | |
2523 | ||
4912aa6c | 2524 | BUG_ON(test_bit(REQ_ATOM_COMPLETE, &req->atomic_flags)); |
9934c8c0 TH |
2525 | blk_add_timer(req); |
2526 | } | |
2527 | EXPORT_SYMBOL(blk_start_request); | |
2528 | ||
2529 | /** | |
2530 | * blk_fetch_request - fetch a request from a request queue | |
2531 | * @q: request queue to fetch a request from | |
2532 | * | |
2533 | * Description: | |
2534 | * Return the request at the top of @q. The request is started on | |
2535 | * return and LLD can start processing it immediately. | |
2536 | * | |
2537 | * Return: | |
2538 | * Pointer to the request at the top of @q if available. Null | |
2539 | * otherwise. | |
2540 | * | |
2541 | * Context: | |
2542 | * queue_lock must be held. | |
2543 | */ | |
2544 | struct request *blk_fetch_request(struct request_queue *q) | |
2545 | { | |
2546 | struct request *rq; | |
2547 | ||
2548 | rq = blk_peek_request(q); | |
2549 | if (rq) | |
2550 | blk_start_request(rq); | |
2551 | return rq; | |
2552 | } | |
2553 | EXPORT_SYMBOL(blk_fetch_request); | |
2554 | ||
3bcddeac | 2555 | /** |
2e60e022 | 2556 | * blk_update_request - Special helper function for request stacking drivers |
8ebf9756 | 2557 | * @req: the request being processed |
710027a4 | 2558 | * @error: %0 for success, < %0 for error |
8ebf9756 | 2559 | * @nr_bytes: number of bytes to complete @req |
3bcddeac KU |
2560 | * |
2561 | * Description: | |
8ebf9756 RD |
2562 | * Ends I/O on a number of bytes attached to @req, but doesn't complete |
2563 | * the request structure even if @req doesn't have leftover. | |
2564 | * If @req has leftover, sets it up for the next range of segments. | |
2e60e022 TH |
2565 | * |
2566 | * This special helper function is only for request stacking drivers | |
2567 | * (e.g. request-based dm) so that they can handle partial completion. | |
2568 | * Actual device drivers should use blk_end_request instead. | |
2569 | * | |
2570 | * Passing the result of blk_rq_bytes() as @nr_bytes guarantees | |
2571 | * %false return from this function. | |
3bcddeac KU |
2572 | * |
2573 | * Return: | |
2e60e022 TH |
2574 | * %false - this request doesn't have any more data |
2575 | * %true - this request has more data | |
3bcddeac | 2576 | **/ |
2e60e022 | 2577 | bool blk_update_request(struct request *req, int error, unsigned int nr_bytes) |
1da177e4 | 2578 | { |
f79ea416 | 2579 | int total_bytes; |
1da177e4 | 2580 | |
4a0efdc9 HR |
2581 | trace_block_rq_complete(req->q, req, nr_bytes); |
2582 | ||
2e60e022 TH |
2583 | if (!req->bio) |
2584 | return false; | |
2585 | ||
1da177e4 | 2586 | /* |
6f41469c TH |
2587 | * For fs requests, rq is just carrier of independent bio's |
2588 | * and each partial completion should be handled separately. | |
2589 | * Reset per-request error on each partial completion. | |
2590 | * | |
2591 | * TODO: tj: This is too subtle. It would be better to let | |
2592 | * low level drivers do what they see fit. | |
1da177e4 | 2593 | */ |
33659ebb | 2594 | if (req->cmd_type == REQ_TYPE_FS) |
1da177e4 LT |
2595 | req->errors = 0; |
2596 | ||
33659ebb CH |
2597 | if (error && req->cmd_type == REQ_TYPE_FS && |
2598 | !(req->cmd_flags & REQ_QUIET)) { | |
79775567 HR |
2599 | char *error_type; |
2600 | ||
2601 | switch (error) { | |
2602 | case -ENOLINK: | |
2603 | error_type = "recoverable transport"; | |
2604 | break; | |
2605 | case -EREMOTEIO: | |
2606 | error_type = "critical target"; | |
2607 | break; | |
2608 | case -EBADE: | |
2609 | error_type = "critical nexus"; | |
2610 | break; | |
d1ffc1f8 HR |
2611 | case -ETIMEDOUT: |
2612 | error_type = "timeout"; | |
2613 | break; | |
a9d6ceb8 HR |
2614 | case -ENOSPC: |
2615 | error_type = "critical space allocation"; | |
2616 | break; | |
7e782af5 HR |
2617 | case -ENODATA: |
2618 | error_type = "critical medium"; | |
2619 | break; | |
79775567 HR |
2620 | case -EIO: |
2621 | default: | |
2622 | error_type = "I/O"; | |
2623 | break; | |
2624 | } | |
ef3ecb66 RE |
2625 | printk_ratelimited(KERN_ERR "%s: %s error, dev %s, sector %llu\n", |
2626 | __func__, error_type, req->rq_disk ? | |
37d7b34f YZ |
2627 | req->rq_disk->disk_name : "?", |
2628 | (unsigned long long)blk_rq_pos(req)); | |
2629 | ||
1da177e4 LT |
2630 | } |
2631 | ||
bc58ba94 | 2632 | blk_account_io_completion(req, nr_bytes); |
d72d904a | 2633 | |
f79ea416 KO |
2634 | total_bytes = 0; |
2635 | while (req->bio) { | |
2636 | struct bio *bio = req->bio; | |
4f024f37 | 2637 | unsigned bio_bytes = min(bio->bi_iter.bi_size, nr_bytes); |
1da177e4 | 2638 | |
4f024f37 | 2639 | if (bio_bytes == bio->bi_iter.bi_size) |
1da177e4 | 2640 | req->bio = bio->bi_next; |
1da177e4 | 2641 | |
f79ea416 | 2642 | req_bio_endio(req, bio, bio_bytes, error); |
1da177e4 | 2643 | |
f79ea416 KO |
2644 | total_bytes += bio_bytes; |
2645 | nr_bytes -= bio_bytes; | |
1da177e4 | 2646 | |
f79ea416 KO |
2647 | if (!nr_bytes) |
2648 | break; | |
1da177e4 LT |
2649 | } |
2650 | ||
2651 | /* | |
2652 | * completely done | |
2653 | */ | |
2e60e022 TH |
2654 | if (!req->bio) { |
2655 | /* | |
2656 | * Reset counters so that the request stacking driver | |
2657 | * can find how many bytes remain in the request | |
2658 | * later. | |
2659 | */ | |
a2dec7b3 | 2660 | req->__data_len = 0; |
2e60e022 TH |
2661 | return false; |
2662 | } | |
1da177e4 | 2663 | |
a2dec7b3 | 2664 | req->__data_len -= total_bytes; |
2e46e8b2 TH |
2665 | |
2666 | /* update sector only for requests with clear definition of sector */ | |
e2a60da7 | 2667 | if (req->cmd_type == REQ_TYPE_FS) |
a2dec7b3 | 2668 | req->__sector += total_bytes >> 9; |
2e46e8b2 | 2669 | |
80a761fd TH |
2670 | /* mixed attributes always follow the first bio */ |
2671 | if (req->cmd_flags & REQ_MIXED_MERGE) { | |
2672 | req->cmd_flags &= ~REQ_FAILFAST_MASK; | |
2673 | req->cmd_flags |= req->bio->bi_rw & REQ_FAILFAST_MASK; | |
2674 | } | |
2675 | ||
2e46e8b2 TH |
2676 | /* |
2677 | * If total number of sectors is less than the first segment | |
2678 | * size, something has gone terribly wrong. | |
2679 | */ | |
2680 | if (blk_rq_bytes(req) < blk_rq_cur_bytes(req)) { | |
8182924b | 2681 | blk_dump_rq_flags(req, "request botched"); |
a2dec7b3 | 2682 | req->__data_len = blk_rq_cur_bytes(req); |
2e46e8b2 TH |
2683 | } |
2684 | ||
2685 | /* recalculate the number of segments */ | |
1da177e4 | 2686 | blk_recalc_rq_segments(req); |
2e46e8b2 | 2687 | |
2e60e022 | 2688 | return true; |
1da177e4 | 2689 | } |
2e60e022 | 2690 | EXPORT_SYMBOL_GPL(blk_update_request); |
1da177e4 | 2691 | |
2e60e022 TH |
2692 | static bool blk_update_bidi_request(struct request *rq, int error, |
2693 | unsigned int nr_bytes, | |
2694 | unsigned int bidi_bytes) | |
5efccd17 | 2695 | { |
2e60e022 TH |
2696 | if (blk_update_request(rq, error, nr_bytes)) |
2697 | return true; | |
5efccd17 | 2698 | |
2e60e022 TH |
2699 | /* Bidi request must be completed as a whole */ |
2700 | if (unlikely(blk_bidi_rq(rq)) && | |
2701 | blk_update_request(rq->next_rq, error, bidi_bytes)) | |
2702 | return true; | |
5efccd17 | 2703 | |
e2e1a148 JA |
2704 | if (blk_queue_add_random(rq->q)) |
2705 | add_disk_randomness(rq->rq_disk); | |
2e60e022 TH |
2706 | |
2707 | return false; | |
1da177e4 LT |
2708 | } |
2709 | ||
28018c24 JB |
2710 | /** |
2711 | * blk_unprep_request - unprepare a request | |
2712 | * @req: the request | |
2713 | * | |
2714 | * This function makes a request ready for complete resubmission (or | |
2715 | * completion). It happens only after all error handling is complete, | |
2716 | * so represents the appropriate moment to deallocate any resources | |
2717 | * that were allocated to the request in the prep_rq_fn. The queue | |
2718 | * lock is held when calling this. | |
2719 | */ | |
2720 | void blk_unprep_request(struct request *req) | |
2721 | { | |
2722 | struct request_queue *q = req->q; | |
2723 | ||
2724 | req->cmd_flags &= ~REQ_DONTPREP; | |
2725 | if (q->unprep_rq_fn) | |
2726 | q->unprep_rq_fn(q, req); | |
2727 | } | |
2728 | EXPORT_SYMBOL_GPL(blk_unprep_request); | |
2729 | ||
1da177e4 LT |
2730 | /* |
2731 | * queue lock must be held | |
2732 | */ | |
12120077 | 2733 | void blk_finish_request(struct request *req, int error) |
1da177e4 | 2734 | { |
125c99bc | 2735 | if (req->cmd_flags & REQ_QUEUED) |
b8286239 KU |
2736 | blk_queue_end_tag(req->q, req); |
2737 | ||
ba396a6c | 2738 | BUG_ON(blk_queued_rq(req)); |
1da177e4 | 2739 | |
33659ebb | 2740 | if (unlikely(laptop_mode) && req->cmd_type == REQ_TYPE_FS) |
31373d09 | 2741 | laptop_io_completion(&req->q->backing_dev_info); |
1da177e4 | 2742 | |
e78042e5 MA |
2743 | blk_delete_timer(req); |
2744 | ||
28018c24 JB |
2745 | if (req->cmd_flags & REQ_DONTPREP) |
2746 | blk_unprep_request(req); | |
2747 | ||
bc58ba94 | 2748 | blk_account_io_done(req); |
b8286239 | 2749 | |
1da177e4 | 2750 | if (req->end_io) |
8ffdc655 | 2751 | req->end_io(req, error); |
b8286239 KU |
2752 | else { |
2753 | if (blk_bidi_rq(req)) | |
2754 | __blk_put_request(req->next_rq->q, req->next_rq); | |
2755 | ||
1da177e4 | 2756 | __blk_put_request(req->q, req); |
b8286239 | 2757 | } |
1da177e4 | 2758 | } |
12120077 | 2759 | EXPORT_SYMBOL(blk_finish_request); |
1da177e4 | 2760 | |
3b11313a | 2761 | /** |
2e60e022 TH |
2762 | * blk_end_bidi_request - Complete a bidi request |
2763 | * @rq: the request to complete | |
2764 | * @error: %0 for success, < %0 for error | |
2765 | * @nr_bytes: number of bytes to complete @rq | |
2766 | * @bidi_bytes: number of bytes to complete @rq->next_rq | |
a0cd1285 JA |
2767 | * |
2768 | * Description: | |
e3a04fe3 | 2769 | * Ends I/O on a number of bytes attached to @rq and @rq->next_rq. |
2e60e022 TH |
2770 | * Drivers that supports bidi can safely call this member for any |
2771 | * type of request, bidi or uni. In the later case @bidi_bytes is | |
2772 | * just ignored. | |
336cdb40 KU |
2773 | * |
2774 | * Return: | |
2e60e022 TH |
2775 | * %false - we are done with this request |
2776 | * %true - still buffers pending for this request | |
a0cd1285 | 2777 | **/ |
b1f74493 | 2778 | static bool blk_end_bidi_request(struct request *rq, int error, |
32fab448 KU |
2779 | unsigned int nr_bytes, unsigned int bidi_bytes) |
2780 | { | |
336cdb40 | 2781 | struct request_queue *q = rq->q; |
2e60e022 | 2782 | unsigned long flags; |
32fab448 | 2783 | |
2e60e022 TH |
2784 | if (blk_update_bidi_request(rq, error, nr_bytes, bidi_bytes)) |
2785 | return true; | |
32fab448 | 2786 | |
336cdb40 | 2787 | spin_lock_irqsave(q->queue_lock, flags); |
2e60e022 | 2788 | blk_finish_request(rq, error); |
336cdb40 KU |
2789 | spin_unlock_irqrestore(q->queue_lock, flags); |
2790 | ||
2e60e022 | 2791 | return false; |
32fab448 KU |
2792 | } |
2793 | ||
336cdb40 | 2794 | /** |
2e60e022 TH |
2795 | * __blk_end_bidi_request - Complete a bidi request with queue lock held |
2796 | * @rq: the request to complete | |
710027a4 | 2797 | * @error: %0 for success, < %0 for error |
e3a04fe3 KU |
2798 | * @nr_bytes: number of bytes to complete @rq |
2799 | * @bidi_bytes: number of bytes to complete @rq->next_rq | |
336cdb40 KU |
2800 | * |
2801 | * Description: | |
2e60e022 TH |
2802 | * Identical to blk_end_bidi_request() except that queue lock is |
2803 | * assumed to be locked on entry and remains so on return. | |
336cdb40 KU |
2804 | * |
2805 | * Return: | |
2e60e022 TH |
2806 | * %false - we are done with this request |
2807 | * %true - still buffers pending for this request | |
336cdb40 | 2808 | **/ |
4853abaa | 2809 | bool __blk_end_bidi_request(struct request *rq, int error, |
b1f74493 | 2810 | unsigned int nr_bytes, unsigned int bidi_bytes) |
336cdb40 | 2811 | { |
2e60e022 TH |
2812 | if (blk_update_bidi_request(rq, error, nr_bytes, bidi_bytes)) |
2813 | return true; | |
336cdb40 | 2814 | |
2e60e022 | 2815 | blk_finish_request(rq, error); |
336cdb40 | 2816 | |
2e60e022 | 2817 | return false; |
336cdb40 | 2818 | } |
e19a3ab0 KU |
2819 | |
2820 | /** | |
2821 | * blk_end_request - Helper function for drivers to complete the request. | |
2822 | * @rq: the request being processed | |
710027a4 | 2823 | * @error: %0 for success, < %0 for error |
e19a3ab0 KU |
2824 | * @nr_bytes: number of bytes to complete |
2825 | * | |
2826 | * Description: | |
2827 | * Ends I/O on a number of bytes attached to @rq. | |
2828 | * If @rq has leftover, sets it up for the next range of segments. | |
2829 | * | |
2830 | * Return: | |
b1f74493 FT |
2831 | * %false - we are done with this request |
2832 | * %true - still buffers pending for this request | |
e19a3ab0 | 2833 | **/ |
b1f74493 | 2834 | bool blk_end_request(struct request *rq, int error, unsigned int nr_bytes) |
e19a3ab0 | 2835 | { |
b1f74493 | 2836 | return blk_end_bidi_request(rq, error, nr_bytes, 0); |
e19a3ab0 | 2837 | } |
56ad1740 | 2838 | EXPORT_SYMBOL(blk_end_request); |
336cdb40 KU |
2839 | |
2840 | /** | |
b1f74493 FT |
2841 | * blk_end_request_all - Helper function for drives to finish the request. |
2842 | * @rq: the request to finish | |
8ebf9756 | 2843 | * @error: %0 for success, < %0 for error |
336cdb40 KU |
2844 | * |
2845 | * Description: | |
b1f74493 FT |
2846 | * Completely finish @rq. |
2847 | */ | |
2848 | void blk_end_request_all(struct request *rq, int error) | |
336cdb40 | 2849 | { |
b1f74493 FT |
2850 | bool pending; |
2851 | unsigned int bidi_bytes = 0; | |
336cdb40 | 2852 | |
b1f74493 FT |
2853 | if (unlikely(blk_bidi_rq(rq))) |
2854 | bidi_bytes = blk_rq_bytes(rq->next_rq); | |
336cdb40 | 2855 | |
b1f74493 FT |
2856 | pending = blk_end_bidi_request(rq, error, blk_rq_bytes(rq), bidi_bytes); |
2857 | BUG_ON(pending); | |
2858 | } | |
56ad1740 | 2859 | EXPORT_SYMBOL(blk_end_request_all); |
336cdb40 | 2860 | |
b1f74493 FT |
2861 | /** |
2862 | * blk_end_request_cur - Helper function to finish the current request chunk. | |
2863 | * @rq: the request to finish the current chunk for | |
8ebf9756 | 2864 | * @error: %0 for success, < %0 for error |
b1f74493 FT |
2865 | * |
2866 | * Description: | |
2867 | * Complete the current consecutively mapped chunk from @rq. | |
2868 | * | |
2869 | * Return: | |
2870 | * %false - we are done with this request | |
2871 | * %true - still buffers pending for this request | |
2872 | */ | |
2873 | bool blk_end_request_cur(struct request *rq, int error) | |
2874 | { | |
2875 | return blk_end_request(rq, error, blk_rq_cur_bytes(rq)); | |
336cdb40 | 2876 | } |
56ad1740 | 2877 | EXPORT_SYMBOL(blk_end_request_cur); |
336cdb40 | 2878 | |
80a761fd TH |
2879 | /** |
2880 | * blk_end_request_err - Finish a request till the next failure boundary. | |
2881 | * @rq: the request to finish till the next failure boundary for | |
2882 | * @error: must be negative errno | |
2883 | * | |
2884 | * Description: | |
2885 | * Complete @rq till the next failure boundary. | |
2886 | * | |
2887 | * Return: | |
2888 | * %false - we are done with this request | |
2889 | * %true - still buffers pending for this request | |
2890 | */ | |
2891 | bool blk_end_request_err(struct request *rq, int error) | |
2892 | { | |
2893 | WARN_ON(error >= 0); | |
2894 | return blk_end_request(rq, error, blk_rq_err_bytes(rq)); | |
2895 | } | |
2896 | EXPORT_SYMBOL_GPL(blk_end_request_err); | |
2897 | ||
e3a04fe3 | 2898 | /** |
b1f74493 FT |
2899 | * __blk_end_request - Helper function for drivers to complete the request. |
2900 | * @rq: the request being processed | |
2901 | * @error: %0 for success, < %0 for error | |
2902 | * @nr_bytes: number of bytes to complete | |
e3a04fe3 KU |
2903 | * |
2904 | * Description: | |
b1f74493 | 2905 | * Must be called with queue lock held unlike blk_end_request(). |
e3a04fe3 KU |
2906 | * |
2907 | * Return: | |
b1f74493 FT |
2908 | * %false - we are done with this request |
2909 | * %true - still buffers pending for this request | |
e3a04fe3 | 2910 | **/ |
b1f74493 | 2911 | bool __blk_end_request(struct request *rq, int error, unsigned int nr_bytes) |
e3a04fe3 | 2912 | { |
b1f74493 | 2913 | return __blk_end_bidi_request(rq, error, nr_bytes, 0); |
e3a04fe3 | 2914 | } |
56ad1740 | 2915 | EXPORT_SYMBOL(__blk_end_request); |
e3a04fe3 | 2916 | |
32fab448 | 2917 | /** |
b1f74493 FT |
2918 | * __blk_end_request_all - Helper function for drives to finish the request. |
2919 | * @rq: the request to finish | |
8ebf9756 | 2920 | * @error: %0 for success, < %0 for error |
32fab448 KU |
2921 | * |
2922 | * Description: | |
b1f74493 | 2923 | * Completely finish @rq. Must be called with queue lock held. |
32fab448 | 2924 | */ |
b1f74493 | 2925 | void __blk_end_request_all(struct request *rq, int error) |
32fab448 | 2926 | { |
b1f74493 FT |
2927 | bool pending; |
2928 | unsigned int bidi_bytes = 0; | |
2929 | ||
2930 | if (unlikely(blk_bidi_rq(rq))) | |
2931 | bidi_bytes = blk_rq_bytes(rq->next_rq); | |
2932 | ||
2933 | pending = __blk_end_bidi_request(rq, error, blk_rq_bytes(rq), bidi_bytes); | |
2934 | BUG_ON(pending); | |
32fab448 | 2935 | } |
56ad1740 | 2936 | EXPORT_SYMBOL(__blk_end_request_all); |
32fab448 | 2937 | |
e19a3ab0 | 2938 | /** |
b1f74493 FT |
2939 | * __blk_end_request_cur - Helper function to finish the current request chunk. |
2940 | * @rq: the request to finish the current chunk for | |
8ebf9756 | 2941 | * @error: %0 for success, < %0 for error |
e19a3ab0 KU |
2942 | * |
2943 | * Description: | |
b1f74493 FT |
2944 | * Complete the current consecutively mapped chunk from @rq. Must |
2945 | * be called with queue lock held. | |
e19a3ab0 KU |
2946 | * |
2947 | * Return: | |
b1f74493 FT |
2948 | * %false - we are done with this request |
2949 | * %true - still buffers pending for this request | |
2950 | */ | |
2951 | bool __blk_end_request_cur(struct request *rq, int error) | |
e19a3ab0 | 2952 | { |
b1f74493 | 2953 | return __blk_end_request(rq, error, blk_rq_cur_bytes(rq)); |
e19a3ab0 | 2954 | } |
56ad1740 | 2955 | EXPORT_SYMBOL(__blk_end_request_cur); |
e19a3ab0 | 2956 | |
80a761fd TH |
2957 | /** |
2958 | * __blk_end_request_err - Finish a request till the next failure boundary. | |
2959 | * @rq: the request to finish till the next failure boundary for | |
2960 | * @error: must be negative errno | |
2961 | * | |
2962 | * Description: | |
2963 | * Complete @rq till the next failure boundary. Must be called | |
2964 | * with queue lock held. | |
2965 | * | |
2966 | * Return: | |
2967 | * %false - we are done with this request | |
2968 | * %true - still buffers pending for this request | |
2969 | */ | |
2970 | bool __blk_end_request_err(struct request *rq, int error) | |
2971 | { | |
2972 | WARN_ON(error >= 0); | |
2973 | return __blk_end_request(rq, error, blk_rq_err_bytes(rq)); | |
2974 | } | |
2975 | EXPORT_SYMBOL_GPL(__blk_end_request_err); | |
2976 | ||
86db1e29 JA |
2977 | void blk_rq_bio_prep(struct request_queue *q, struct request *rq, |
2978 | struct bio *bio) | |
1da177e4 | 2979 | { |
a82afdfc | 2980 | /* Bit 0 (R/W) is identical in rq->cmd_flags and bio->bi_rw */ |
7b6d91da | 2981 | rq->cmd_flags |= bio->bi_rw & REQ_WRITE; |
1da177e4 | 2982 | |
b4f42e28 | 2983 | if (bio_has_data(bio)) |
fb2dce86 | 2984 | rq->nr_phys_segments = bio_phys_segments(q, bio); |
b4f42e28 | 2985 | |
4f024f37 | 2986 | rq->__data_len = bio->bi_iter.bi_size; |
1da177e4 | 2987 | rq->bio = rq->biotail = bio; |
1da177e4 | 2988 | |
66846572 N |
2989 | if (bio->bi_bdev) |
2990 | rq->rq_disk = bio->bi_bdev->bd_disk; | |
2991 | } | |
1da177e4 | 2992 | |
2d4dc890 IL |
2993 | #if ARCH_IMPLEMENTS_FLUSH_DCACHE_PAGE |
2994 | /** | |
2995 | * rq_flush_dcache_pages - Helper function to flush all pages in a request | |
2996 | * @rq: the request to be flushed | |
2997 | * | |
2998 | * Description: | |
2999 | * Flush all pages in @rq. | |
3000 | */ | |
3001 | void rq_flush_dcache_pages(struct request *rq) | |
3002 | { | |
3003 | struct req_iterator iter; | |
7988613b | 3004 | struct bio_vec bvec; |
2d4dc890 IL |
3005 | |
3006 | rq_for_each_segment(bvec, rq, iter) | |
7988613b | 3007 | flush_dcache_page(bvec.bv_page); |
2d4dc890 IL |
3008 | } |
3009 | EXPORT_SYMBOL_GPL(rq_flush_dcache_pages); | |
3010 | #endif | |
3011 | ||
ef9e3fac KU |
3012 | /** |
3013 | * blk_lld_busy - Check if underlying low-level drivers of a device are busy | |
3014 | * @q : the queue of the device being checked | |
3015 | * | |
3016 | * Description: | |
3017 | * Check if underlying low-level drivers of a device are busy. | |
3018 | * If the drivers want to export their busy state, they must set own | |
3019 | * exporting function using blk_queue_lld_busy() first. | |
3020 | * | |
3021 | * Basically, this function is used only by request stacking drivers | |
3022 | * to stop dispatching requests to underlying devices when underlying | |
3023 | * devices are busy. This behavior helps more I/O merging on the queue | |
3024 | * of the request stacking driver and prevents I/O throughput regression | |
3025 | * on burst I/O load. | |
3026 | * | |
3027 | * Return: | |
3028 | * 0 - Not busy (The request stacking driver should dispatch request) | |
3029 | * 1 - Busy (The request stacking driver should stop dispatching request) | |
3030 | */ | |
3031 | int blk_lld_busy(struct request_queue *q) | |
3032 | { | |
3033 | if (q->lld_busy_fn) | |
3034 | return q->lld_busy_fn(q); | |
3035 | ||
3036 | return 0; | |
3037 | } | |
3038 | EXPORT_SYMBOL_GPL(blk_lld_busy); | |
3039 | ||
78d8e58a MS |
3040 | /** |
3041 | * blk_rq_unprep_clone - Helper function to free all bios in a cloned request | |
3042 | * @rq: the clone request to be cleaned up | |
3043 | * | |
3044 | * Description: | |
3045 | * Free all bios in @rq for a cloned request. | |
3046 | */ | |
3047 | void blk_rq_unprep_clone(struct request *rq) | |
3048 | { | |
3049 | struct bio *bio; | |
3050 | ||
3051 | while ((bio = rq->bio) != NULL) { | |
3052 | rq->bio = bio->bi_next; | |
3053 | ||
3054 | bio_put(bio); | |
3055 | } | |
3056 | } | |
3057 | EXPORT_SYMBOL_GPL(blk_rq_unprep_clone); | |
3058 | ||
3059 | /* | |
3060 | * Copy attributes of the original request to the clone request. | |
3061 | * The actual data parts (e.g. ->cmd, ->sense) are not copied. | |
3062 | */ | |
3063 | static void __blk_rq_prep_clone(struct request *dst, struct request *src) | |
b0fd271d KU |
3064 | { |
3065 | dst->cpu = src->cpu; | |
78d8e58a | 3066 | dst->cmd_flags |= (src->cmd_flags & REQ_CLONE_MASK) | REQ_NOMERGE; |
b0fd271d KU |
3067 | dst->cmd_type = src->cmd_type; |
3068 | dst->__sector = blk_rq_pos(src); | |
3069 | dst->__data_len = blk_rq_bytes(src); | |
3070 | dst->nr_phys_segments = src->nr_phys_segments; | |
3071 | dst->ioprio = src->ioprio; | |
3072 | dst->extra_len = src->extra_len; | |
78d8e58a MS |
3073 | } |
3074 | ||
3075 | /** | |
3076 | * blk_rq_prep_clone - Helper function to setup clone request | |
3077 | * @rq: the request to be setup | |
3078 | * @rq_src: original request to be cloned | |
3079 | * @bs: bio_set that bios for clone are allocated from | |
3080 | * @gfp_mask: memory allocation mask for bio | |
3081 | * @bio_ctr: setup function to be called for each clone bio. | |
3082 | * Returns %0 for success, non %0 for failure. | |
3083 | * @data: private data to be passed to @bio_ctr | |
3084 | * | |
3085 | * Description: | |
3086 | * Clones bios in @rq_src to @rq, and copies attributes of @rq_src to @rq. | |
3087 | * The actual data parts of @rq_src (e.g. ->cmd, ->sense) | |
3088 | * are not copied, and copying such parts is the caller's responsibility. | |
3089 | * Also, pages which the original bios are pointing to are not copied | |
3090 | * and the cloned bios just point same pages. | |
3091 | * So cloned bios must be completed before original bios, which means | |
3092 | * the caller must complete @rq before @rq_src. | |
3093 | */ | |
3094 | int blk_rq_prep_clone(struct request *rq, struct request *rq_src, | |
3095 | struct bio_set *bs, gfp_t gfp_mask, | |
3096 | int (*bio_ctr)(struct bio *, struct bio *, void *), | |
3097 | void *data) | |
3098 | { | |
3099 | struct bio *bio, *bio_src; | |
3100 | ||
3101 | if (!bs) | |
3102 | bs = fs_bio_set; | |
3103 | ||
3104 | __rq_for_each_bio(bio_src, rq_src) { | |
3105 | bio = bio_clone_fast(bio_src, gfp_mask, bs); | |
3106 | if (!bio) | |
3107 | goto free_and_out; | |
3108 | ||
3109 | if (bio_ctr && bio_ctr(bio, bio_src, data)) | |
3110 | goto free_and_out; | |
3111 | ||
3112 | if (rq->bio) { | |
3113 | rq->biotail->bi_next = bio; | |
3114 | rq->biotail = bio; | |
3115 | } else | |
3116 | rq->bio = rq->biotail = bio; | |
3117 | } | |
3118 | ||
3119 | __blk_rq_prep_clone(rq, rq_src); | |
3120 | ||
3121 | return 0; | |
3122 | ||
3123 | free_and_out: | |
3124 | if (bio) | |
3125 | bio_put(bio); | |
3126 | blk_rq_unprep_clone(rq); | |
3127 | ||
3128 | return -ENOMEM; | |
b0fd271d KU |
3129 | } |
3130 | EXPORT_SYMBOL_GPL(blk_rq_prep_clone); | |
3131 | ||
59c3d45e | 3132 | int kblockd_schedule_work(struct work_struct *work) |
1da177e4 LT |
3133 | { |
3134 | return queue_work(kblockd_workqueue, work); | |
3135 | } | |
1da177e4 LT |
3136 | EXPORT_SYMBOL(kblockd_schedule_work); |
3137 | ||
59c3d45e JA |
3138 | int kblockd_schedule_delayed_work(struct delayed_work *dwork, |
3139 | unsigned long delay) | |
e43473b7 VG |
3140 | { |
3141 | return queue_delayed_work(kblockd_workqueue, dwork, delay); | |
3142 | } | |
3143 | EXPORT_SYMBOL(kblockd_schedule_delayed_work); | |
3144 | ||
8ab14595 JA |
3145 | int kblockd_schedule_delayed_work_on(int cpu, struct delayed_work *dwork, |
3146 | unsigned long delay) | |
3147 | { | |
3148 | return queue_delayed_work_on(cpu, kblockd_workqueue, dwork, delay); | |
3149 | } | |
3150 | EXPORT_SYMBOL(kblockd_schedule_delayed_work_on); | |
3151 | ||
75df7136 SJ |
3152 | /** |
3153 | * blk_start_plug - initialize blk_plug and track it inside the task_struct | |
3154 | * @plug: The &struct blk_plug that needs to be initialized | |
3155 | * | |
3156 | * Description: | |
3157 | * Tracking blk_plug inside the task_struct will help with auto-flushing the | |
3158 | * pending I/O should the task end up blocking between blk_start_plug() and | |
3159 | * blk_finish_plug(). This is important from a performance perspective, but | |
3160 | * also ensures that we don't deadlock. For instance, if the task is blocking | |
3161 | * for a memory allocation, memory reclaim could end up wanting to free a | |
3162 | * page belonging to that request that is currently residing in our private | |
3163 | * plug. By flushing the pending I/O when the process goes to sleep, we avoid | |
3164 | * this kind of deadlock. | |
3165 | */ | |
73c10101 JA |
3166 | void blk_start_plug(struct blk_plug *plug) |
3167 | { | |
3168 | struct task_struct *tsk = current; | |
3169 | ||
dd6cf3e1 SL |
3170 | /* |
3171 | * If this is a nested plug, don't actually assign it. | |
3172 | */ | |
3173 | if (tsk->plug) | |
3174 | return; | |
3175 | ||
73c10101 | 3176 | INIT_LIST_HEAD(&plug->list); |
320ae51f | 3177 | INIT_LIST_HEAD(&plug->mq_list); |
048c9374 | 3178 | INIT_LIST_HEAD(&plug->cb_list); |
73c10101 | 3179 | /* |
dd6cf3e1 SL |
3180 | * Store ordering should not be needed here, since a potential |
3181 | * preempt will imply a full memory barrier | |
73c10101 | 3182 | */ |
dd6cf3e1 | 3183 | tsk->plug = plug; |
73c10101 JA |
3184 | } |
3185 | EXPORT_SYMBOL(blk_start_plug); | |
3186 | ||
3187 | static int plug_rq_cmp(void *priv, struct list_head *a, struct list_head *b) | |
3188 | { | |
3189 | struct request *rqa = container_of(a, struct request, queuelist); | |
3190 | struct request *rqb = container_of(b, struct request, queuelist); | |
3191 | ||
975927b9 JM |
3192 | return !(rqa->q < rqb->q || |
3193 | (rqa->q == rqb->q && blk_rq_pos(rqa) < blk_rq_pos(rqb))); | |
73c10101 JA |
3194 | } |
3195 | ||
49cac01e JA |
3196 | /* |
3197 | * If 'from_schedule' is true, then postpone the dispatch of requests | |
3198 | * until a safe kblockd context. We due this to avoid accidental big | |
3199 | * additional stack usage in driver dispatch, in places where the originally | |
3200 | * plugger did not intend it. | |
3201 | */ | |
f6603783 | 3202 | static void queue_unplugged(struct request_queue *q, unsigned int depth, |
49cac01e | 3203 | bool from_schedule) |
99e22598 | 3204 | __releases(q->queue_lock) |
94b5eb28 | 3205 | { |
49cac01e | 3206 | trace_block_unplug(q, depth, !from_schedule); |
99e22598 | 3207 | |
70460571 | 3208 | if (from_schedule) |
24ecfbe2 | 3209 | blk_run_queue_async(q); |
70460571 | 3210 | else |
24ecfbe2 | 3211 | __blk_run_queue(q); |
70460571 | 3212 | spin_unlock(q->queue_lock); |
94b5eb28 JA |
3213 | } |
3214 | ||
74018dc3 | 3215 | static void flush_plug_callbacks(struct blk_plug *plug, bool from_schedule) |
048c9374 N |
3216 | { |
3217 | LIST_HEAD(callbacks); | |
3218 | ||
2a7d5559 SL |
3219 | while (!list_empty(&plug->cb_list)) { |
3220 | list_splice_init(&plug->cb_list, &callbacks); | |
048c9374 | 3221 | |
2a7d5559 SL |
3222 | while (!list_empty(&callbacks)) { |
3223 | struct blk_plug_cb *cb = list_first_entry(&callbacks, | |
048c9374 N |
3224 | struct blk_plug_cb, |
3225 | list); | |
2a7d5559 | 3226 | list_del(&cb->list); |
74018dc3 | 3227 | cb->callback(cb, from_schedule); |
2a7d5559 | 3228 | } |
048c9374 N |
3229 | } |
3230 | } | |
3231 | ||
9cbb1750 N |
3232 | struct blk_plug_cb *blk_check_plugged(blk_plug_cb_fn unplug, void *data, |
3233 | int size) | |
3234 | { | |
3235 | struct blk_plug *plug = current->plug; | |
3236 | struct blk_plug_cb *cb; | |
3237 | ||
3238 | if (!plug) | |
3239 | return NULL; | |
3240 | ||
3241 | list_for_each_entry(cb, &plug->cb_list, list) | |
3242 | if (cb->callback == unplug && cb->data == data) | |
3243 | return cb; | |
3244 | ||
3245 | /* Not currently on the callback list */ | |
3246 | BUG_ON(size < sizeof(*cb)); | |
3247 | cb = kzalloc(size, GFP_ATOMIC); | |
3248 | if (cb) { | |
3249 | cb->data = data; | |
3250 | cb->callback = unplug; | |
3251 | list_add(&cb->list, &plug->cb_list); | |
3252 | } | |
3253 | return cb; | |
3254 | } | |
3255 | EXPORT_SYMBOL(blk_check_plugged); | |
3256 | ||
49cac01e | 3257 | void blk_flush_plug_list(struct blk_plug *plug, bool from_schedule) |
73c10101 JA |
3258 | { |
3259 | struct request_queue *q; | |
3260 | unsigned long flags; | |
3261 | struct request *rq; | |
109b8129 | 3262 | LIST_HEAD(list); |
94b5eb28 | 3263 | unsigned int depth; |
73c10101 | 3264 | |
74018dc3 | 3265 | flush_plug_callbacks(plug, from_schedule); |
320ae51f JA |
3266 | |
3267 | if (!list_empty(&plug->mq_list)) | |
3268 | blk_mq_flush_plug_list(plug, from_schedule); | |
3269 | ||
73c10101 JA |
3270 | if (list_empty(&plug->list)) |
3271 | return; | |
3272 | ||
109b8129 N |
3273 | list_splice_init(&plug->list, &list); |
3274 | ||
422765c2 | 3275 | list_sort(NULL, &list, plug_rq_cmp); |
73c10101 JA |
3276 | |
3277 | q = NULL; | |
94b5eb28 | 3278 | depth = 0; |
18811272 JA |
3279 | |
3280 | /* | |
3281 | * Save and disable interrupts here, to avoid doing it for every | |
3282 | * queue lock we have to take. | |
3283 | */ | |
73c10101 | 3284 | local_irq_save(flags); |
109b8129 N |
3285 | while (!list_empty(&list)) { |
3286 | rq = list_entry_rq(list.next); | |
73c10101 | 3287 | list_del_init(&rq->queuelist); |
73c10101 JA |
3288 | BUG_ON(!rq->q); |
3289 | if (rq->q != q) { | |
99e22598 JA |
3290 | /* |
3291 | * This drops the queue lock | |
3292 | */ | |
3293 | if (q) | |
49cac01e | 3294 | queue_unplugged(q, depth, from_schedule); |
73c10101 | 3295 | q = rq->q; |
94b5eb28 | 3296 | depth = 0; |
73c10101 JA |
3297 | spin_lock(q->queue_lock); |
3298 | } | |
8ba61435 TH |
3299 | |
3300 | /* | |
3301 | * Short-circuit if @q is dead | |
3302 | */ | |
3f3299d5 | 3303 | if (unlikely(blk_queue_dying(q))) { |
8ba61435 TH |
3304 | __blk_end_request_all(rq, -ENODEV); |
3305 | continue; | |
3306 | } | |
3307 | ||
73c10101 JA |
3308 | /* |
3309 | * rq is already accounted, so use raw insert | |
3310 | */ | |
401a18e9 JA |
3311 | if (rq->cmd_flags & (REQ_FLUSH | REQ_FUA)) |
3312 | __elv_add_request(q, rq, ELEVATOR_INSERT_FLUSH); | |
3313 | else | |
3314 | __elv_add_request(q, rq, ELEVATOR_INSERT_SORT_MERGE); | |
94b5eb28 JA |
3315 | |
3316 | depth++; | |
73c10101 JA |
3317 | } |
3318 | ||
99e22598 JA |
3319 | /* |
3320 | * This drops the queue lock | |
3321 | */ | |
3322 | if (q) | |
49cac01e | 3323 | queue_unplugged(q, depth, from_schedule); |
73c10101 | 3324 | |
73c10101 JA |
3325 | local_irq_restore(flags); |
3326 | } | |
73c10101 JA |
3327 | |
3328 | void blk_finish_plug(struct blk_plug *plug) | |
3329 | { | |
dd6cf3e1 SL |
3330 | if (plug != current->plug) |
3331 | return; | |
f6603783 | 3332 | blk_flush_plug_list(plug, false); |
73c10101 | 3333 | |
dd6cf3e1 | 3334 | current->plug = NULL; |
73c10101 | 3335 | } |
88b996cd | 3336 | EXPORT_SYMBOL(blk_finish_plug); |
73c10101 | 3337 | |
05229bee JA |
3338 | bool blk_poll(struct request_queue *q, blk_qc_t cookie) |
3339 | { | |
3340 | struct blk_plug *plug; | |
3341 | long state; | |
3342 | ||
3343 | if (!q->mq_ops || !q->mq_ops->poll || !blk_qc_t_valid(cookie) || | |
3344 | !test_bit(QUEUE_FLAG_POLL, &q->queue_flags)) | |
3345 | return false; | |
3346 | ||
3347 | plug = current->plug; | |
3348 | if (plug) | |
3349 | blk_flush_plug_list(plug, false); | |
3350 | ||
3351 | state = current->state; | |
3352 | while (!need_resched()) { | |
3353 | unsigned int queue_num = blk_qc_t_to_queue_num(cookie); | |
3354 | struct blk_mq_hw_ctx *hctx = q->queue_hw_ctx[queue_num]; | |
3355 | int ret; | |
3356 | ||
3357 | hctx->poll_invoked++; | |
3358 | ||
3359 | ret = q->mq_ops->poll(hctx, blk_qc_t_to_tag(cookie)); | |
3360 | if (ret > 0) { | |
3361 | hctx->poll_success++; | |
3362 | set_current_state(TASK_RUNNING); | |
3363 | return true; | |
3364 | } | |
3365 | ||
3366 | if (signal_pending_state(state, current)) | |
3367 | set_current_state(TASK_RUNNING); | |
3368 | ||
3369 | if (current->state == TASK_RUNNING) | |
3370 | return true; | |
3371 | if (ret < 0) | |
3372 | break; | |
3373 | cpu_relax(); | |
3374 | } | |
3375 | ||
3376 | return false; | |
3377 | } | |
3378 | ||
47fafbc7 | 3379 | #ifdef CONFIG_PM |
6c954667 LM |
3380 | /** |
3381 | * blk_pm_runtime_init - Block layer runtime PM initialization routine | |
3382 | * @q: the queue of the device | |
3383 | * @dev: the device the queue belongs to | |
3384 | * | |
3385 | * Description: | |
3386 | * Initialize runtime-PM-related fields for @q and start auto suspend for | |
3387 | * @dev. Drivers that want to take advantage of request-based runtime PM | |
3388 | * should call this function after @dev has been initialized, and its | |
3389 | * request queue @q has been allocated, and runtime PM for it can not happen | |
3390 | * yet(either due to disabled/forbidden or its usage_count > 0). In most | |
3391 | * cases, driver should call this function before any I/O has taken place. | |
3392 | * | |
3393 | * This function takes care of setting up using auto suspend for the device, | |
3394 | * the autosuspend delay is set to -1 to make runtime suspend impossible | |
3395 | * until an updated value is either set by user or by driver. Drivers do | |
3396 | * not need to touch other autosuspend settings. | |
3397 | * | |
3398 | * The block layer runtime PM is request based, so only works for drivers | |
3399 | * that use request as their IO unit instead of those directly use bio's. | |
3400 | */ | |
3401 | void blk_pm_runtime_init(struct request_queue *q, struct device *dev) | |
3402 | { | |
3403 | q->dev = dev; | |
3404 | q->rpm_status = RPM_ACTIVE; | |
3405 | pm_runtime_set_autosuspend_delay(q->dev, -1); | |
3406 | pm_runtime_use_autosuspend(q->dev); | |
3407 | } | |
3408 | EXPORT_SYMBOL(blk_pm_runtime_init); | |
3409 | ||
3410 | /** | |
3411 | * blk_pre_runtime_suspend - Pre runtime suspend check | |
3412 | * @q: the queue of the device | |
3413 | * | |
3414 | * Description: | |
3415 | * This function will check if runtime suspend is allowed for the device | |
3416 | * by examining if there are any requests pending in the queue. If there | |
3417 | * are requests pending, the device can not be runtime suspended; otherwise, | |
3418 | * the queue's status will be updated to SUSPENDING and the driver can | |
3419 | * proceed to suspend the device. | |
3420 | * | |
3421 | * For the not allowed case, we mark last busy for the device so that | |
3422 | * runtime PM core will try to autosuspend it some time later. | |
3423 | * | |
3424 | * This function should be called near the start of the device's | |
3425 | * runtime_suspend callback. | |
3426 | * | |
3427 | * Return: | |
3428 | * 0 - OK to runtime suspend the device | |
3429 | * -EBUSY - Device should not be runtime suspended | |
3430 | */ | |
3431 | int blk_pre_runtime_suspend(struct request_queue *q) | |
3432 | { | |
3433 | int ret = 0; | |
3434 | ||
4fd41a85 KX |
3435 | if (!q->dev) |
3436 | return ret; | |
3437 | ||
6c954667 LM |
3438 | spin_lock_irq(q->queue_lock); |
3439 | if (q->nr_pending) { | |
3440 | ret = -EBUSY; | |
3441 | pm_runtime_mark_last_busy(q->dev); | |
3442 | } else { | |
3443 | q->rpm_status = RPM_SUSPENDING; | |
3444 | } | |
3445 | spin_unlock_irq(q->queue_lock); | |
3446 | return ret; | |
3447 | } | |
3448 | EXPORT_SYMBOL(blk_pre_runtime_suspend); | |
3449 | ||
3450 | /** | |
3451 | * blk_post_runtime_suspend - Post runtime suspend processing | |
3452 | * @q: the queue of the device | |
3453 | * @err: return value of the device's runtime_suspend function | |
3454 | * | |
3455 | * Description: | |
3456 | * Update the queue's runtime status according to the return value of the | |
3457 | * device's runtime suspend function and mark last busy for the device so | |
3458 | * that PM core will try to auto suspend the device at a later time. | |
3459 | * | |
3460 | * This function should be called near the end of the device's | |
3461 | * runtime_suspend callback. | |
3462 | */ | |
3463 | void blk_post_runtime_suspend(struct request_queue *q, int err) | |
3464 | { | |
4fd41a85 KX |
3465 | if (!q->dev) |
3466 | return; | |
3467 | ||
6c954667 LM |
3468 | spin_lock_irq(q->queue_lock); |
3469 | if (!err) { | |
3470 | q->rpm_status = RPM_SUSPENDED; | |
3471 | } else { | |
3472 | q->rpm_status = RPM_ACTIVE; | |
3473 | pm_runtime_mark_last_busy(q->dev); | |
3474 | } | |
3475 | spin_unlock_irq(q->queue_lock); | |
3476 | } | |
3477 | EXPORT_SYMBOL(blk_post_runtime_suspend); | |
3478 | ||
3479 | /** | |
3480 | * blk_pre_runtime_resume - Pre runtime resume processing | |
3481 | * @q: the queue of the device | |
3482 | * | |
3483 | * Description: | |
3484 | * Update the queue's runtime status to RESUMING in preparation for the | |
3485 | * runtime resume of the device. | |
3486 | * | |
3487 | * This function should be called near the start of the device's | |
3488 | * runtime_resume callback. | |
3489 | */ | |
3490 | void blk_pre_runtime_resume(struct request_queue *q) | |
3491 | { | |
4fd41a85 KX |
3492 | if (!q->dev) |
3493 | return; | |
3494 | ||
6c954667 LM |
3495 | spin_lock_irq(q->queue_lock); |
3496 | q->rpm_status = RPM_RESUMING; | |
3497 | spin_unlock_irq(q->queue_lock); | |
3498 | } | |
3499 | EXPORT_SYMBOL(blk_pre_runtime_resume); | |
3500 | ||
3501 | /** | |
3502 | * blk_post_runtime_resume - Post runtime resume processing | |
3503 | * @q: the queue of the device | |
3504 | * @err: return value of the device's runtime_resume function | |
3505 | * | |
3506 | * Description: | |
3507 | * Update the queue's runtime status according to the return value of the | |
3508 | * device's runtime_resume function. If it is successfully resumed, process | |
3509 | * the requests that are queued into the device's queue when it is resuming | |
3510 | * and then mark last busy and initiate autosuspend for it. | |
3511 | * | |
3512 | * This function should be called near the end of the device's | |
3513 | * runtime_resume callback. | |
3514 | */ | |
3515 | void blk_post_runtime_resume(struct request_queue *q, int err) | |
3516 | { | |
4fd41a85 KX |
3517 | if (!q->dev) |
3518 | return; | |
3519 | ||
6c954667 LM |
3520 | spin_lock_irq(q->queue_lock); |
3521 | if (!err) { | |
3522 | q->rpm_status = RPM_ACTIVE; | |
3523 | __blk_run_queue(q); | |
3524 | pm_runtime_mark_last_busy(q->dev); | |
c60855cd | 3525 | pm_request_autosuspend(q->dev); |
6c954667 LM |
3526 | } else { |
3527 | q->rpm_status = RPM_SUSPENDED; | |
3528 | } | |
3529 | spin_unlock_irq(q->queue_lock); | |
3530 | } | |
3531 | EXPORT_SYMBOL(blk_post_runtime_resume); | |
3532 | #endif | |
3533 | ||
1da177e4 LT |
3534 | int __init blk_dev_init(void) |
3535 | { | |
9eb55b03 | 3536 | BUILD_BUG_ON(__REQ_NR_BITS > 8 * |
0762b23d | 3537 | FIELD_SIZEOF(struct request, cmd_flags)); |
9eb55b03 | 3538 | |
89b90be2 TH |
3539 | /* used for unplugging and affects IO latency/throughput - HIGHPRI */ |
3540 | kblockd_workqueue = alloc_workqueue("kblockd", | |
28747fcd | 3541 | WQ_MEM_RECLAIM | WQ_HIGHPRI, 0); |
1da177e4 LT |
3542 | if (!kblockd_workqueue) |
3543 | panic("Failed to create kblockd\n"); | |
3544 | ||
3545 | request_cachep = kmem_cache_create("blkdev_requests", | |
20c2df83 | 3546 | sizeof(struct request), 0, SLAB_PANIC, NULL); |
1da177e4 | 3547 | |
c2789bd4 | 3548 | blk_requestq_cachep = kmem_cache_create("request_queue", |
165125e1 | 3549 | sizeof(struct request_queue), 0, SLAB_PANIC, NULL); |
1da177e4 | 3550 | |
d38ecf93 | 3551 | return 0; |
1da177e4 | 3552 | } |