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1 | /* | |
2 | * Functions to sequence FLUSH and FUA writes. | |
3 | * | |
4 | * Copyright (C) 2011 Max Planck Institute for Gravitational Physics | |
5 | * Copyright (C) 2011 Tejun Heo <tj@kernel.org> | |
6 | * | |
7 | * This file is released under the GPLv2. | |
8 | * | |
9 | * REQ_{FLUSH|FUA} requests are decomposed to sequences consisted of three | |
10 | * optional steps - PREFLUSH, DATA and POSTFLUSH - according to the request | |
11 | * properties and hardware capability. | |
12 | * | |
13 | * If a request doesn't have data, only REQ_FLUSH makes sense, which | |
14 | * indicates a simple flush request. If there is data, REQ_FLUSH indicates | |
15 | * that the device cache should be flushed before the data is executed, and | |
16 | * REQ_FUA means that the data must be on non-volatile media on request | |
17 | * completion. | |
18 | * | |
19 | * If the device doesn't have writeback cache, FLUSH and FUA don't make any | |
20 | * difference. The requests are either completed immediately if there's no | |
21 | * data or executed as normal requests otherwise. | |
22 | * | |
23 | * If the device has writeback cache and supports FUA, REQ_FLUSH is | |
24 | * translated to PREFLUSH but REQ_FUA is passed down directly with DATA. | |
25 | * | |
26 | * If the device has writeback cache and doesn't support FUA, REQ_FLUSH is | |
27 | * translated to PREFLUSH and REQ_FUA to POSTFLUSH. | |
28 | * | |
29 | * The actual execution of flush is double buffered. Whenever a request | |
30 | * needs to execute PRE or POSTFLUSH, it queues at | |
31 | * q->flush_queue[q->flush_pending_idx]. Once certain criteria are met, a | |
32 | * flush is issued and the pending_idx is toggled. When the flush | |
33 | * completes, all the requests which were pending are proceeded to the next | |
34 | * step. This allows arbitrary merging of different types of FLUSH/FUA | |
35 | * requests. | |
36 | * | |
37 | * Currently, the following conditions are used to determine when to issue | |
38 | * flush. | |
39 | * | |
40 | * C1. At any given time, only one flush shall be in progress. This makes | |
41 | * double buffering sufficient. | |
42 | * | |
43 | * C2. Flush is deferred if any request is executing DATA of its sequence. | |
44 | * This avoids issuing separate POSTFLUSHes for requests which shared | |
45 | * PREFLUSH. | |
46 | * | |
47 | * C3. The second condition is ignored if there is a request which has | |
48 | * waited longer than FLUSH_PENDING_TIMEOUT. This is to avoid | |
49 | * starvation in the unlikely case where there are continuous stream of | |
50 | * FUA (without FLUSH) requests. | |
51 | * | |
52 | * For devices which support FUA, it isn't clear whether C2 (and thus C3) | |
53 | * is beneficial. | |
54 | * | |
55 | * Note that a sequenced FLUSH/FUA request with DATA is completed twice. | |
56 | * Once while executing DATA and again after the whole sequence is | |
57 | * complete. The first completion updates the contained bio but doesn't | |
58 | * finish it so that the bio submitter is notified only after the whole | |
59 | * sequence is complete. This is implemented by testing REQ_FLUSH_SEQ in | |
60 | * req_bio_endio(). | |
61 | * | |
62 | * The above peculiarity requires that each FLUSH/FUA request has only one | |
63 | * bio attached to it, which is guaranteed as they aren't allowed to be | |
64 | * merged in the usual way. | |
65 | */ | |
66 | ||
67 | #include <linux/kernel.h> | |
68 | #include <linux/module.h> | |
69 | #include <linux/bio.h> | |
70 | #include <linux/blkdev.h> | |
71 | #include <linux/gfp.h> | |
72 | #include <linux/blk-mq.h> | |
73 | ||
74 | #include "blk.h" | |
75 | #include "blk-mq.h" | |
76 | ||
77 | /* FLUSH/FUA sequences */ | |
78 | enum { | |
79 | REQ_FSEQ_PREFLUSH = (1 << 0), /* pre-flushing in progress */ | |
80 | REQ_FSEQ_DATA = (1 << 1), /* data write in progress */ | |
81 | REQ_FSEQ_POSTFLUSH = (1 << 2), /* post-flushing in progress */ | |
82 | REQ_FSEQ_DONE = (1 << 3), | |
83 | ||
84 | REQ_FSEQ_ACTIONS = REQ_FSEQ_PREFLUSH | REQ_FSEQ_DATA | | |
85 | REQ_FSEQ_POSTFLUSH, | |
86 | ||
87 | /* | |
88 | * If flush has been pending longer than the following timeout, | |
89 | * it's issued even if flush_data requests are still in flight. | |
90 | */ | |
91 | FLUSH_PENDING_TIMEOUT = 5 * HZ, | |
92 | }; | |
93 | ||
94 | static bool blk_kick_flush(struct request_queue *q); | |
95 | ||
96 | static unsigned int blk_flush_policy(unsigned int fflags, struct request *rq) | |
97 | { | |
98 | unsigned int policy = 0; | |
99 | ||
100 | if (blk_rq_sectors(rq)) | |
101 | policy |= REQ_FSEQ_DATA; | |
102 | ||
103 | if (fflags & REQ_FLUSH) { | |
104 | if (rq->cmd_flags & REQ_FLUSH) | |
105 | policy |= REQ_FSEQ_PREFLUSH; | |
106 | if (!(fflags & REQ_FUA) && (rq->cmd_flags & REQ_FUA)) | |
107 | policy |= REQ_FSEQ_POSTFLUSH; | |
108 | } | |
109 | return policy; | |
110 | } | |
111 | ||
112 | static unsigned int blk_flush_cur_seq(struct request *rq) | |
113 | { | |
114 | return 1 << ffz(rq->flush.seq); | |
115 | } | |
116 | ||
117 | static void blk_flush_restore_request(struct request *rq) | |
118 | { | |
119 | /* | |
120 | * After flush data completion, @rq->bio is %NULL but we need to | |
121 | * complete the bio again. @rq->biotail is guaranteed to equal the | |
122 | * original @rq->bio. Restore it. | |
123 | */ | |
124 | rq->bio = rq->biotail; | |
125 | ||
126 | /* make @rq a normal request */ | |
127 | rq->cmd_flags &= ~REQ_FLUSH_SEQ; | |
128 | rq->end_io = rq->flush.saved_end_io; | |
129 | ||
130 | blk_clear_rq_complete(rq); | |
131 | } | |
132 | ||
133 | static void mq_flush_data_run(struct work_struct *work) | |
134 | { | |
135 | struct request *rq; | |
136 | ||
137 | rq = container_of(work, struct request, mq_flush_data); | |
138 | ||
139 | memset(&rq->csd, 0, sizeof(rq->csd)); | |
140 | blk_mq_run_request(rq, true, false); | |
141 | } | |
142 | ||
143 | static void blk_mq_flush_data_insert(struct request *rq) | |
144 | { | |
145 | INIT_WORK(&rq->mq_flush_data, mq_flush_data_run); | |
146 | kblockd_schedule_work(rq->q, &rq->mq_flush_data); | |
147 | } | |
148 | ||
149 | /** | |
150 | * blk_flush_complete_seq - complete flush sequence | |
151 | * @rq: FLUSH/FUA request being sequenced | |
152 | * @seq: sequences to complete (mask of %REQ_FSEQ_*, can be zero) | |
153 | * @error: whether an error occurred | |
154 | * | |
155 | * @rq just completed @seq part of its flush sequence, record the | |
156 | * completion and trigger the next step. | |
157 | * | |
158 | * CONTEXT: | |
159 | * spin_lock_irq(q->queue_lock or q->mq_flush_lock) | |
160 | * | |
161 | * RETURNS: | |
162 | * %true if requests were added to the dispatch queue, %false otherwise. | |
163 | */ | |
164 | static bool blk_flush_complete_seq(struct request *rq, unsigned int seq, | |
165 | int error) | |
166 | { | |
167 | struct request_queue *q = rq->q; | |
168 | struct list_head *pending = &q->flush_queue[q->flush_pending_idx]; | |
169 | bool queued = false, kicked; | |
170 | ||
171 | BUG_ON(rq->flush.seq & seq); | |
172 | rq->flush.seq |= seq; | |
173 | ||
174 | if (likely(!error)) | |
175 | seq = blk_flush_cur_seq(rq); | |
176 | else | |
177 | seq = REQ_FSEQ_DONE; | |
178 | ||
179 | switch (seq) { | |
180 | case REQ_FSEQ_PREFLUSH: | |
181 | case REQ_FSEQ_POSTFLUSH: | |
182 | /* queue for flush */ | |
183 | if (list_empty(pending)) | |
184 | q->flush_pending_since = jiffies; | |
185 | list_move_tail(&rq->flush.list, pending); | |
186 | break; | |
187 | ||
188 | case REQ_FSEQ_DATA: | |
189 | list_move_tail(&rq->flush.list, &q->flush_data_in_flight); | |
190 | if (q->mq_ops) | |
191 | blk_mq_flush_data_insert(rq); | |
192 | else { | |
193 | list_add(&rq->queuelist, &q->queue_head); | |
194 | queued = true; | |
195 | } | |
196 | break; | |
197 | ||
198 | case REQ_FSEQ_DONE: | |
199 | /* | |
200 | * @rq was previously adjusted by blk_flush_issue() for | |
201 | * flush sequencing and may already have gone through the | |
202 | * flush data request completion path. Restore @rq for | |
203 | * normal completion and end it. | |
204 | */ | |
205 | BUG_ON(!list_empty(&rq->queuelist)); | |
206 | list_del_init(&rq->flush.list); | |
207 | blk_flush_restore_request(rq); | |
208 | if (q->mq_ops) | |
209 | blk_mq_end_io(rq, error); | |
210 | else | |
211 | __blk_end_request_all(rq, error); | |
212 | break; | |
213 | ||
214 | default: | |
215 | BUG(); | |
216 | } | |
217 | ||
218 | kicked = blk_kick_flush(q); | |
219 | /* blk_mq_run_flush will run queue */ | |
220 | if (q->mq_ops) | |
221 | return queued; | |
222 | return kicked | queued; | |
223 | } | |
224 | ||
225 | static void flush_end_io(struct request *flush_rq, int error) | |
226 | { | |
227 | struct request_queue *q = flush_rq->q; | |
228 | struct list_head *running; | |
229 | bool queued = false; | |
230 | struct request *rq, *n; | |
231 | unsigned long flags = 0; | |
232 | ||
233 | if (q->mq_ops) { | |
234 | blk_mq_free_request(flush_rq); | |
235 | spin_lock_irqsave(&q->mq_flush_lock, flags); | |
236 | } | |
237 | running = &q->flush_queue[q->flush_running_idx]; | |
238 | BUG_ON(q->flush_pending_idx == q->flush_running_idx); | |
239 | ||
240 | /* account completion of the flush request */ | |
241 | q->flush_running_idx ^= 1; | |
242 | ||
243 | if (!q->mq_ops) | |
244 | elv_completed_request(q, flush_rq); | |
245 | ||
246 | /* and push the waiting requests to the next stage */ | |
247 | list_for_each_entry_safe(rq, n, running, flush.list) { | |
248 | unsigned int seq = blk_flush_cur_seq(rq); | |
249 | ||
250 | BUG_ON(seq != REQ_FSEQ_PREFLUSH && seq != REQ_FSEQ_POSTFLUSH); | |
251 | queued |= blk_flush_complete_seq(rq, seq, error); | |
252 | } | |
253 | ||
254 | /* | |
255 | * Kick the queue to avoid stall for two cases: | |
256 | * 1. Moving a request silently to empty queue_head may stall the | |
257 | * queue. | |
258 | * 2. When flush request is running in non-queueable queue, the | |
259 | * queue is hold. Restart the queue after flush request is finished | |
260 | * to avoid stall. | |
261 | * This function is called from request completion path and calling | |
262 | * directly into request_fn may confuse the driver. Always use | |
263 | * kblockd. | |
264 | */ | |
265 | if (queued || q->flush_queue_delayed) { | |
266 | if (!q->mq_ops) | |
267 | blk_run_queue_async(q); | |
268 | else | |
269 | /* | |
270 | * This can be optimized to only run queues with requests | |
271 | * queued if necessary. | |
272 | */ | |
273 | blk_mq_run_queues(q, true); | |
274 | } | |
275 | q->flush_queue_delayed = 0; | |
276 | if (q->mq_ops) | |
277 | spin_unlock_irqrestore(&q->mq_flush_lock, flags); | |
278 | } | |
279 | ||
280 | static void mq_flush_work(struct work_struct *work) | |
281 | { | |
282 | struct request_queue *q; | |
283 | struct request *rq; | |
284 | ||
285 | q = container_of(work, struct request_queue, mq_flush_work); | |
286 | ||
287 | /* We don't need set REQ_FLUSH_SEQ, it's for consistency */ | |
288 | rq = blk_mq_alloc_request(q, WRITE_FLUSH|REQ_FLUSH_SEQ, | |
289 | __GFP_WAIT|GFP_ATOMIC, true); | |
290 | rq->cmd_type = REQ_TYPE_FS; | |
291 | rq->end_io = flush_end_io; | |
292 | ||
293 | blk_mq_run_request(rq, true, false); | |
294 | } | |
295 | ||
296 | /* | |
297 | * We can't directly use q->flush_rq, because it doesn't have tag and is not in | |
298 | * hctx->rqs[]. so we must allocate a new request, since we can't sleep here, | |
299 | * so offload the work to workqueue. | |
300 | * | |
301 | * Note: we assume a flush request finished in any hardware queue will flush | |
302 | * the whole disk cache. | |
303 | */ | |
304 | static void mq_run_flush(struct request_queue *q) | |
305 | { | |
306 | kblockd_schedule_work(q, &q->mq_flush_work); | |
307 | } | |
308 | ||
309 | /** | |
310 | * blk_kick_flush - consider issuing flush request | |
311 | * @q: request_queue being kicked | |
312 | * | |
313 | * Flush related states of @q have changed, consider issuing flush request. | |
314 | * Please read the comment at the top of this file for more info. | |
315 | * | |
316 | * CONTEXT: | |
317 | * spin_lock_irq(q->queue_lock or q->mq_flush_lock) | |
318 | * | |
319 | * RETURNS: | |
320 | * %true if flush was issued, %false otherwise. | |
321 | */ | |
322 | static bool blk_kick_flush(struct request_queue *q) | |
323 | { | |
324 | struct list_head *pending = &q->flush_queue[q->flush_pending_idx]; | |
325 | struct request *first_rq = | |
326 | list_first_entry(pending, struct request, flush.list); | |
327 | ||
328 | /* C1 described at the top of this file */ | |
329 | if (q->flush_pending_idx != q->flush_running_idx || list_empty(pending)) | |
330 | return false; | |
331 | ||
332 | /* C2 and C3 */ | |
333 | if (!list_empty(&q->flush_data_in_flight) && | |
334 | time_before(jiffies, | |
335 | q->flush_pending_since + FLUSH_PENDING_TIMEOUT)) | |
336 | return false; | |
337 | ||
338 | /* | |
339 | * Issue flush and toggle pending_idx. This makes pending_idx | |
340 | * different from running_idx, which means flush is in flight. | |
341 | */ | |
342 | q->flush_pending_idx ^= 1; | |
343 | if (q->mq_ops) { | |
344 | mq_run_flush(q); | |
345 | return true; | |
346 | } | |
347 | ||
348 | blk_rq_init(q, &q->flush_rq); | |
349 | q->flush_rq.cmd_type = REQ_TYPE_FS; | |
350 | q->flush_rq.cmd_flags = WRITE_FLUSH | REQ_FLUSH_SEQ; | |
351 | q->flush_rq.rq_disk = first_rq->rq_disk; | |
352 | q->flush_rq.end_io = flush_end_io; | |
353 | ||
354 | list_add_tail(&q->flush_rq.queuelist, &q->queue_head); | |
355 | return true; | |
356 | } | |
357 | ||
358 | static void flush_data_end_io(struct request *rq, int error) | |
359 | { | |
360 | struct request_queue *q = rq->q; | |
361 | ||
362 | /* | |
363 | * After populating an empty queue, kick it to avoid stall. Read | |
364 | * the comment in flush_end_io(). | |
365 | */ | |
366 | if (blk_flush_complete_seq(rq, REQ_FSEQ_DATA, error)) | |
367 | blk_run_queue_async(q); | |
368 | } | |
369 | ||
370 | static void mq_flush_data_end_io(struct request *rq, int error) | |
371 | { | |
372 | struct request_queue *q = rq->q; | |
373 | struct blk_mq_hw_ctx *hctx; | |
374 | struct blk_mq_ctx *ctx; | |
375 | unsigned long flags; | |
376 | ||
377 | ctx = rq->mq_ctx; | |
378 | hctx = q->mq_ops->map_queue(q, ctx->cpu); | |
379 | ||
380 | /* | |
381 | * After populating an empty queue, kick it to avoid stall. Read | |
382 | * the comment in flush_end_io(). | |
383 | */ | |
384 | spin_lock_irqsave(&q->mq_flush_lock, flags); | |
385 | if (blk_flush_complete_seq(rq, REQ_FSEQ_DATA, error)) | |
386 | blk_mq_run_hw_queue(hctx, true); | |
387 | spin_unlock_irqrestore(&q->mq_flush_lock, flags); | |
388 | } | |
389 | ||
390 | /** | |
391 | * blk_insert_flush - insert a new FLUSH/FUA request | |
392 | * @rq: request to insert | |
393 | * | |
394 | * To be called from __elv_add_request() for %ELEVATOR_INSERT_FLUSH insertions. | |
395 | * or __blk_mq_run_hw_queue() to dispatch request. | |
396 | * @rq is being submitted. Analyze what needs to be done and put it on the | |
397 | * right queue. | |
398 | * | |
399 | * CONTEXT: | |
400 | * spin_lock_irq(q->queue_lock) in !mq case | |
401 | */ | |
402 | void blk_insert_flush(struct request *rq) | |
403 | { | |
404 | struct request_queue *q = rq->q; | |
405 | unsigned int fflags = q->flush_flags; /* may change, cache */ | |
406 | unsigned int policy = blk_flush_policy(fflags, rq); | |
407 | ||
408 | /* | |
409 | * @policy now records what operations need to be done. Adjust | |
410 | * REQ_FLUSH and FUA for the driver. | |
411 | */ | |
412 | rq->cmd_flags &= ~REQ_FLUSH; | |
413 | if (!(fflags & REQ_FUA)) | |
414 | rq->cmd_flags &= ~REQ_FUA; | |
415 | ||
416 | /* | |
417 | * An empty flush handed down from a stacking driver may | |
418 | * translate into nothing if the underlying device does not | |
419 | * advertise a write-back cache. In this case, simply | |
420 | * complete the request. | |
421 | */ | |
422 | if (!policy) { | |
423 | if (q->mq_ops) | |
424 | blk_mq_end_io(rq, 0); | |
425 | else | |
426 | __blk_end_bidi_request(rq, 0, 0, 0); | |
427 | return; | |
428 | } | |
429 | ||
430 | BUG_ON(rq->bio != rq->biotail); /*assumes zero or single bio rq */ | |
431 | ||
432 | /* | |
433 | * If there's data but flush is not necessary, the request can be | |
434 | * processed directly without going through flush machinery. Queue | |
435 | * for normal execution. | |
436 | */ | |
437 | if ((policy & REQ_FSEQ_DATA) && | |
438 | !(policy & (REQ_FSEQ_PREFLUSH | REQ_FSEQ_POSTFLUSH))) { | |
439 | if (q->mq_ops) { | |
440 | blk_mq_run_request(rq, false, true); | |
441 | } else | |
442 | list_add_tail(&rq->queuelist, &q->queue_head); | |
443 | return; | |
444 | } | |
445 | ||
446 | /* | |
447 | * @rq should go through flush machinery. Mark it part of flush | |
448 | * sequence and submit for further processing. | |
449 | */ | |
450 | memset(&rq->flush, 0, sizeof(rq->flush)); | |
451 | INIT_LIST_HEAD(&rq->flush.list); | |
452 | rq->cmd_flags |= REQ_FLUSH_SEQ; | |
453 | rq->flush.saved_end_io = rq->end_io; /* Usually NULL */ | |
454 | if (q->mq_ops) { | |
455 | rq->end_io = mq_flush_data_end_io; | |
456 | ||
457 | spin_lock_irq(&q->mq_flush_lock); | |
458 | blk_flush_complete_seq(rq, REQ_FSEQ_ACTIONS & ~policy, 0); | |
459 | spin_unlock_irq(&q->mq_flush_lock); | |
460 | return; | |
461 | } | |
462 | rq->end_io = flush_data_end_io; | |
463 | ||
464 | blk_flush_complete_seq(rq, REQ_FSEQ_ACTIONS & ~policy, 0); | |
465 | } | |
466 | ||
467 | /** | |
468 | * blk_abort_flushes - @q is being aborted, abort flush requests | |
469 | * @q: request_queue being aborted | |
470 | * | |
471 | * To be called from elv_abort_queue(). @q is being aborted. Prepare all | |
472 | * FLUSH/FUA requests for abortion. | |
473 | * | |
474 | * CONTEXT: | |
475 | * spin_lock_irq(q->queue_lock) | |
476 | */ | |
477 | void blk_abort_flushes(struct request_queue *q) | |
478 | { | |
479 | struct request *rq, *n; | |
480 | int i; | |
481 | ||
482 | /* | |
483 | * Requests in flight for data are already owned by the dispatch | |
484 | * queue or the device driver. Just restore for normal completion. | |
485 | */ | |
486 | list_for_each_entry_safe(rq, n, &q->flush_data_in_flight, flush.list) { | |
487 | list_del_init(&rq->flush.list); | |
488 | blk_flush_restore_request(rq); | |
489 | } | |
490 | ||
491 | /* | |
492 | * We need to give away requests on flush queues. Restore for | |
493 | * normal completion and put them on the dispatch queue. | |
494 | */ | |
495 | for (i = 0; i < ARRAY_SIZE(q->flush_queue); i++) { | |
496 | list_for_each_entry_safe(rq, n, &q->flush_queue[i], | |
497 | flush.list) { | |
498 | list_del_init(&rq->flush.list); | |
499 | blk_flush_restore_request(rq); | |
500 | list_add_tail(&rq->queuelist, &q->queue_head); | |
501 | } | |
502 | } | |
503 | } | |
504 | ||
505 | static void bio_end_flush(struct bio *bio, int err) | |
506 | { | |
507 | if (err) | |
508 | clear_bit(BIO_UPTODATE, &bio->bi_flags); | |
509 | if (bio->bi_private) | |
510 | complete(bio->bi_private); | |
511 | bio_put(bio); | |
512 | } | |
513 | ||
514 | /** | |
515 | * blkdev_issue_flush - queue a flush | |
516 | * @bdev: blockdev to issue flush for | |
517 | * @gfp_mask: memory allocation flags (for bio_alloc) | |
518 | * @error_sector: error sector | |
519 | * | |
520 | * Description: | |
521 | * Issue a flush for the block device in question. Caller can supply | |
522 | * room for storing the error offset in case of a flush error, if they | |
523 | * wish to. If WAIT flag is not passed then caller may check only what | |
524 | * request was pushed in some internal queue for later handling. | |
525 | */ | |
526 | int blkdev_issue_flush(struct block_device *bdev, gfp_t gfp_mask, | |
527 | sector_t *error_sector) | |
528 | { | |
529 | DECLARE_COMPLETION_ONSTACK(wait); | |
530 | struct request_queue *q; | |
531 | struct bio *bio; | |
532 | int ret = 0; | |
533 | ||
534 | if (bdev->bd_disk == NULL) | |
535 | return -ENXIO; | |
536 | ||
537 | q = bdev_get_queue(bdev); | |
538 | if (!q) | |
539 | return -ENXIO; | |
540 | ||
541 | /* | |
542 | * some block devices may not have their queue correctly set up here | |
543 | * (e.g. loop device without a backing file) and so issuing a flush | |
544 | * here will panic. Ensure there is a request function before issuing | |
545 | * the flush. | |
546 | */ | |
547 | if (!q->make_request_fn) | |
548 | return -ENXIO; | |
549 | ||
550 | bio = bio_alloc(gfp_mask, 0); | |
551 | bio->bi_end_io = bio_end_flush; | |
552 | bio->bi_bdev = bdev; | |
553 | bio->bi_private = &wait; | |
554 | ||
555 | bio_get(bio); | |
556 | submit_bio(WRITE_FLUSH, bio); | |
557 | wait_for_completion_io(&wait); | |
558 | ||
559 | /* | |
560 | * The driver must store the error location in ->bi_sector, if | |
561 | * it supports it. For non-stacked drivers, this should be | |
562 | * copied from blk_rq_pos(rq). | |
563 | */ | |
564 | if (error_sector) | |
565 | *error_sector = bio->bi_sector; | |
566 | ||
567 | if (!bio_flagged(bio, BIO_UPTODATE)) | |
568 | ret = -EIO; | |
569 | ||
570 | bio_put(bio); | |
571 | return ret; | |
572 | } | |
573 | EXPORT_SYMBOL(blkdev_issue_flush); | |
574 | ||
575 | void blk_mq_init_flush(struct request_queue *q) | |
576 | { | |
577 | spin_lock_init(&q->mq_flush_lock); | |
578 | INIT_WORK(&q->mq_flush_work, mq_flush_work); | |
579 | } |