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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_PREFLUSH makes sense, which | |
14 | * indicates a simple flush request. If there is data, REQ_PREFLUSH 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_PREFLUSH 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_PREFLUSH | |
27 | * is 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 | * fq->flush_queue[fq->flush_pending_idx]. Once certain criteria are met, a | |
32 | * REQ_OP_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 RQF_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 | #include "blk-mq-tag.h" | |
77 | ||
78 | /* FLUSH/FUA sequences */ | |
79 | enum { | |
80 | REQ_FSEQ_PREFLUSH = (1 << 0), /* pre-flushing in progress */ | |
81 | REQ_FSEQ_DATA = (1 << 1), /* data write in progress */ | |
82 | REQ_FSEQ_POSTFLUSH = (1 << 2), /* post-flushing in progress */ | |
83 | REQ_FSEQ_DONE = (1 << 3), | |
84 | ||
85 | REQ_FSEQ_ACTIONS = REQ_FSEQ_PREFLUSH | REQ_FSEQ_DATA | | |
86 | REQ_FSEQ_POSTFLUSH, | |
87 | ||
88 | /* | |
89 | * If flush has been pending longer than the following timeout, | |
90 | * it's issued even if flush_data requests are still in flight. | |
91 | */ | |
92 | FLUSH_PENDING_TIMEOUT = 5 * HZ, | |
93 | }; | |
94 | ||
95 | static bool blk_kick_flush(struct request_queue *q, | |
96 | struct blk_flush_queue *fq); | |
97 | ||
98 | static unsigned int blk_flush_policy(unsigned long fflags, struct request *rq) | |
99 | { | |
100 | unsigned int policy = 0; | |
101 | ||
102 | if (blk_rq_sectors(rq)) | |
103 | policy |= REQ_FSEQ_DATA; | |
104 | ||
105 | if (fflags & (1UL << QUEUE_FLAG_WC)) { | |
106 | if (rq->cmd_flags & REQ_PREFLUSH) | |
107 | policy |= REQ_FSEQ_PREFLUSH; | |
108 | if (!(fflags & (1UL << QUEUE_FLAG_FUA)) && | |
109 | (rq->cmd_flags & REQ_FUA)) | |
110 | policy |= REQ_FSEQ_POSTFLUSH; | |
111 | } | |
112 | return policy; | |
113 | } | |
114 | ||
115 | static unsigned int blk_flush_cur_seq(struct request *rq) | |
116 | { | |
117 | return 1 << ffz(rq->flush.seq); | |
118 | } | |
119 | ||
120 | static void blk_flush_restore_request(struct request *rq) | |
121 | { | |
122 | /* | |
123 | * After flush data completion, @rq->bio is %NULL but we need to | |
124 | * complete the bio again. @rq->biotail is guaranteed to equal the | |
125 | * original @rq->bio. Restore it. | |
126 | */ | |
127 | rq->bio = rq->biotail; | |
128 | ||
129 | /* make @rq a normal request */ | |
130 | rq->rq_flags &= ~RQF_FLUSH_SEQ; | |
131 | rq->end_io = rq->flush.saved_end_io; | |
132 | } | |
133 | ||
134 | static bool blk_flush_queue_rq(struct request *rq, bool add_front) | |
135 | { | |
136 | if (rq->q->mq_ops) { | |
137 | blk_mq_add_to_requeue_list(rq, add_front, true); | |
138 | return false; | |
139 | } else { | |
140 | if (add_front) | |
141 | list_add(&rq->queuelist, &rq->q->queue_head); | |
142 | else | |
143 | list_add_tail(&rq->queuelist, &rq->q->queue_head); | |
144 | return true; | |
145 | } | |
146 | } | |
147 | ||
148 | /** | |
149 | * blk_flush_complete_seq - complete flush sequence | |
150 | * @rq: FLUSH/FUA request being sequenced | |
151 | * @fq: flush queue | |
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 fq->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, | |
165 | struct blk_flush_queue *fq, | |
166 | unsigned int seq, int error) | |
167 | { | |
168 | struct request_queue *q = rq->q; | |
169 | struct list_head *pending = &fq->flush_queue[fq->flush_pending_idx]; | |
170 | bool queued = false, kicked; | |
171 | ||
172 | BUG_ON(rq->flush.seq & seq); | |
173 | rq->flush.seq |= seq; | |
174 | ||
175 | if (likely(!error)) | |
176 | seq = blk_flush_cur_seq(rq); | |
177 | else | |
178 | seq = REQ_FSEQ_DONE; | |
179 | ||
180 | switch (seq) { | |
181 | case REQ_FSEQ_PREFLUSH: | |
182 | case REQ_FSEQ_POSTFLUSH: | |
183 | /* queue for flush */ | |
184 | if (list_empty(pending)) | |
185 | fq->flush_pending_since = jiffies; | |
186 | list_move_tail(&rq->flush.list, pending); | |
187 | break; | |
188 | ||
189 | case REQ_FSEQ_DATA: | |
190 | list_move_tail(&rq->flush.list, &fq->flush_data_in_flight); | |
191 | queued = blk_flush_queue_rq(rq, true); | |
192 | break; | |
193 | ||
194 | case REQ_FSEQ_DONE: | |
195 | /* | |
196 | * @rq was previously adjusted by blk_flush_issue() for | |
197 | * flush sequencing and may already have gone through the | |
198 | * flush data request completion path. Restore @rq for | |
199 | * normal completion and end it. | |
200 | */ | |
201 | BUG_ON(!list_empty(&rq->queuelist)); | |
202 | list_del_init(&rq->flush.list); | |
203 | blk_flush_restore_request(rq); | |
204 | if (q->mq_ops) | |
205 | blk_mq_end_request(rq, error); | |
206 | else | |
207 | __blk_end_request_all(rq, error); | |
208 | break; | |
209 | ||
210 | default: | |
211 | BUG(); | |
212 | } | |
213 | ||
214 | kicked = blk_kick_flush(q, fq); | |
215 | return kicked | queued; | |
216 | } | |
217 | ||
218 | static void flush_end_io(struct request *flush_rq, int error) | |
219 | { | |
220 | struct request_queue *q = flush_rq->q; | |
221 | struct list_head *running; | |
222 | bool queued = false; | |
223 | struct request *rq, *n; | |
224 | unsigned long flags = 0; | |
225 | struct blk_flush_queue *fq = blk_get_flush_queue(q, flush_rq->mq_ctx); | |
226 | ||
227 | if (q->mq_ops) { | |
228 | struct blk_mq_hw_ctx *hctx; | |
229 | ||
230 | /* release the tag's ownership to the req cloned from */ | |
231 | spin_lock_irqsave(&fq->mq_flush_lock, flags); | |
232 | hctx = blk_mq_map_queue(q, flush_rq->mq_ctx->cpu); | |
233 | blk_mq_tag_set_rq(hctx, flush_rq->tag, fq->orig_rq); | |
234 | flush_rq->tag = -1; | |
235 | } | |
236 | ||
237 | running = &fq->flush_queue[fq->flush_running_idx]; | |
238 | BUG_ON(fq->flush_pending_idx == fq->flush_running_idx); | |
239 | ||
240 | /* account completion of the flush request */ | |
241 | fq->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, fq, 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 || fq->flush_queue_delayed) { | |
266 | WARN_ON(q->mq_ops); | |
267 | blk_run_queue_async(q); | |
268 | } | |
269 | fq->flush_queue_delayed = 0; | |
270 | if (q->mq_ops) | |
271 | spin_unlock_irqrestore(&fq->mq_flush_lock, flags); | |
272 | } | |
273 | ||
274 | /** | |
275 | * blk_kick_flush - consider issuing flush request | |
276 | * @q: request_queue being kicked | |
277 | * @fq: flush queue | |
278 | * | |
279 | * Flush related states of @q have changed, consider issuing flush request. | |
280 | * Please read the comment at the top of this file for more info. | |
281 | * | |
282 | * CONTEXT: | |
283 | * spin_lock_irq(q->queue_lock or fq->mq_flush_lock) | |
284 | * | |
285 | * RETURNS: | |
286 | * %true if flush was issued, %false otherwise. | |
287 | */ | |
288 | static bool blk_kick_flush(struct request_queue *q, struct blk_flush_queue *fq) | |
289 | { | |
290 | struct list_head *pending = &fq->flush_queue[fq->flush_pending_idx]; | |
291 | struct request *first_rq = | |
292 | list_first_entry(pending, struct request, flush.list); | |
293 | struct request *flush_rq = fq->flush_rq; | |
294 | ||
295 | /* C1 described at the top of this file */ | |
296 | if (fq->flush_pending_idx != fq->flush_running_idx || list_empty(pending)) | |
297 | return false; | |
298 | ||
299 | /* C2 and C3 */ | |
300 | if (!list_empty(&fq->flush_data_in_flight) && | |
301 | time_before(jiffies, | |
302 | fq->flush_pending_since + FLUSH_PENDING_TIMEOUT)) | |
303 | return false; | |
304 | ||
305 | /* | |
306 | * Issue flush and toggle pending_idx. This makes pending_idx | |
307 | * different from running_idx, which means flush is in flight. | |
308 | */ | |
309 | fq->flush_pending_idx ^= 1; | |
310 | ||
311 | blk_rq_init(q, flush_rq); | |
312 | ||
313 | /* | |
314 | * Borrow tag from the first request since they can't | |
315 | * be in flight at the same time. And acquire the tag's | |
316 | * ownership for flush req. | |
317 | */ | |
318 | if (q->mq_ops) { | |
319 | struct blk_mq_hw_ctx *hctx; | |
320 | ||
321 | flush_rq->mq_ctx = first_rq->mq_ctx; | |
322 | flush_rq->tag = first_rq->tag; | |
323 | fq->orig_rq = first_rq; | |
324 | ||
325 | hctx = blk_mq_map_queue(q, first_rq->mq_ctx->cpu); | |
326 | blk_mq_tag_set_rq(hctx, first_rq->tag, flush_rq); | |
327 | } | |
328 | ||
329 | flush_rq->cmd_type = REQ_TYPE_FS; | |
330 | flush_rq->cmd_flags = REQ_OP_FLUSH | REQ_PREFLUSH; | |
331 | flush_rq->rq_flags |= RQF_FLUSH_SEQ; | |
332 | flush_rq->rq_disk = first_rq->rq_disk; | |
333 | flush_rq->end_io = flush_end_io; | |
334 | ||
335 | return blk_flush_queue_rq(flush_rq, false); | |
336 | } | |
337 | ||
338 | static void flush_data_end_io(struct request *rq, int error) | |
339 | { | |
340 | struct request_queue *q = rq->q; | |
341 | struct blk_flush_queue *fq = blk_get_flush_queue(q, NULL); | |
342 | ||
343 | /* | |
344 | * Updating q->in_flight[] here for making this tag usable | |
345 | * early. Because in blk_queue_start_tag(), | |
346 | * q->in_flight[BLK_RW_ASYNC] is used to limit async I/O and | |
347 | * reserve tags for sync I/O. | |
348 | * | |
349 | * More importantly this way can avoid the following I/O | |
350 | * deadlock: | |
351 | * | |
352 | * - suppose there are 40 fua requests comming to flush queue | |
353 | * and queue depth is 31 | |
354 | * - 30 rqs are scheduled then blk_queue_start_tag() can't alloc | |
355 | * tag for async I/O any more | |
356 | * - all the 30 rqs are completed before FLUSH_PENDING_TIMEOUT | |
357 | * and flush_data_end_io() is called | |
358 | * - the other rqs still can't go ahead if not updating | |
359 | * q->in_flight[BLK_RW_ASYNC] here, meantime these rqs | |
360 | * are held in flush data queue and make no progress of | |
361 | * handling post flush rq | |
362 | * - only after the post flush rq is handled, all these rqs | |
363 | * can be completed | |
364 | */ | |
365 | ||
366 | elv_completed_request(q, rq); | |
367 | ||
368 | /* for avoiding double accounting */ | |
369 | rq->rq_flags &= ~RQF_STARTED; | |
370 | ||
371 | /* | |
372 | * After populating an empty queue, kick it to avoid stall. Read | |
373 | * the comment in flush_end_io(). | |
374 | */ | |
375 | if (blk_flush_complete_seq(rq, fq, REQ_FSEQ_DATA, error)) | |
376 | blk_run_queue_async(q); | |
377 | } | |
378 | ||
379 | static void mq_flush_data_end_io(struct request *rq, int error) | |
380 | { | |
381 | struct request_queue *q = rq->q; | |
382 | struct blk_mq_hw_ctx *hctx; | |
383 | struct blk_mq_ctx *ctx = rq->mq_ctx; | |
384 | unsigned long flags; | |
385 | struct blk_flush_queue *fq = blk_get_flush_queue(q, ctx); | |
386 | ||
387 | hctx = blk_mq_map_queue(q, ctx->cpu); | |
388 | ||
389 | /* | |
390 | * After populating an empty queue, kick it to avoid stall. Read | |
391 | * the comment in flush_end_io(). | |
392 | */ | |
393 | spin_lock_irqsave(&fq->mq_flush_lock, flags); | |
394 | if (blk_flush_complete_seq(rq, fq, REQ_FSEQ_DATA, error)) | |
395 | blk_mq_run_hw_queue(hctx, true); | |
396 | spin_unlock_irqrestore(&fq->mq_flush_lock, flags); | |
397 | } | |
398 | ||
399 | /** | |
400 | * blk_insert_flush - insert a new FLUSH/FUA request | |
401 | * @rq: request to insert | |
402 | * | |
403 | * To be called from __elv_add_request() for %ELEVATOR_INSERT_FLUSH insertions. | |
404 | * or __blk_mq_run_hw_queue() to dispatch request. | |
405 | * @rq is being submitted. Analyze what needs to be done and put it on the | |
406 | * right queue. | |
407 | * | |
408 | * CONTEXT: | |
409 | * spin_lock_irq(q->queue_lock) in !mq case | |
410 | */ | |
411 | void blk_insert_flush(struct request *rq) | |
412 | { | |
413 | struct request_queue *q = rq->q; | |
414 | unsigned long fflags = q->queue_flags; /* may change, cache */ | |
415 | unsigned int policy = blk_flush_policy(fflags, rq); | |
416 | struct blk_flush_queue *fq = blk_get_flush_queue(q, rq->mq_ctx); | |
417 | ||
418 | /* | |
419 | * @policy now records what operations need to be done. Adjust | |
420 | * REQ_PREFLUSH and FUA for the driver. | |
421 | */ | |
422 | rq->cmd_flags &= ~REQ_PREFLUSH; | |
423 | if (!(fflags & (1UL << QUEUE_FLAG_FUA))) | |
424 | rq->cmd_flags &= ~REQ_FUA; | |
425 | ||
426 | /* | |
427 | * REQ_PREFLUSH|REQ_FUA implies REQ_SYNC, so if we clear any | |
428 | * of those flags, we have to set REQ_SYNC to avoid skewing | |
429 | * the request accounting. | |
430 | */ | |
431 | rq->cmd_flags |= REQ_SYNC; | |
432 | ||
433 | /* | |
434 | * An empty flush handed down from a stacking driver may | |
435 | * translate into nothing if the underlying device does not | |
436 | * advertise a write-back cache. In this case, simply | |
437 | * complete the request. | |
438 | */ | |
439 | if (!policy) { | |
440 | if (q->mq_ops) | |
441 | blk_mq_end_request(rq, 0); | |
442 | else | |
443 | __blk_end_bidi_request(rq, 0, 0, 0); | |
444 | return; | |
445 | } | |
446 | ||
447 | BUG_ON(rq->bio != rq->biotail); /*assumes zero or single bio rq */ | |
448 | ||
449 | /* | |
450 | * If there's data but flush is not necessary, the request can be | |
451 | * processed directly without going through flush machinery. Queue | |
452 | * for normal execution. | |
453 | */ | |
454 | if ((policy & REQ_FSEQ_DATA) && | |
455 | !(policy & (REQ_FSEQ_PREFLUSH | REQ_FSEQ_POSTFLUSH))) { | |
456 | if (q->mq_ops) { | |
457 | blk_mq_insert_request(rq, false, true, false); | |
458 | } else | |
459 | list_add_tail(&rq->queuelist, &q->queue_head); | |
460 | return; | |
461 | } | |
462 | ||
463 | /* | |
464 | * @rq should go through flush machinery. Mark it part of flush | |
465 | * sequence and submit for further processing. | |
466 | */ | |
467 | memset(&rq->flush, 0, sizeof(rq->flush)); | |
468 | INIT_LIST_HEAD(&rq->flush.list); | |
469 | rq->rq_flags |= RQF_FLUSH_SEQ; | |
470 | rq->flush.saved_end_io = rq->end_io; /* Usually NULL */ | |
471 | if (q->mq_ops) { | |
472 | rq->end_io = mq_flush_data_end_io; | |
473 | ||
474 | spin_lock_irq(&fq->mq_flush_lock); | |
475 | blk_flush_complete_seq(rq, fq, REQ_FSEQ_ACTIONS & ~policy, 0); | |
476 | spin_unlock_irq(&fq->mq_flush_lock); | |
477 | return; | |
478 | } | |
479 | rq->end_io = flush_data_end_io; | |
480 | ||
481 | blk_flush_complete_seq(rq, fq, REQ_FSEQ_ACTIONS & ~policy, 0); | |
482 | } | |
483 | ||
484 | /** | |
485 | * blkdev_issue_flush - queue a flush | |
486 | * @bdev: blockdev to issue flush for | |
487 | * @gfp_mask: memory allocation flags (for bio_alloc) | |
488 | * @error_sector: error sector | |
489 | * | |
490 | * Description: | |
491 | * Issue a flush for the block device in question. Caller can supply | |
492 | * room for storing the error offset in case of a flush error, if they | |
493 | * wish to. If WAIT flag is not passed then caller may check only what | |
494 | * request was pushed in some internal queue for later handling. | |
495 | */ | |
496 | int blkdev_issue_flush(struct block_device *bdev, gfp_t gfp_mask, | |
497 | sector_t *error_sector) | |
498 | { | |
499 | struct request_queue *q; | |
500 | struct bio *bio; | |
501 | int ret = 0; | |
502 | ||
503 | if (bdev->bd_disk == NULL) | |
504 | return -ENXIO; | |
505 | ||
506 | q = bdev_get_queue(bdev); | |
507 | if (!q) | |
508 | return -ENXIO; | |
509 | ||
510 | /* | |
511 | * some block devices may not have their queue correctly set up here | |
512 | * (e.g. loop device without a backing file) and so issuing a flush | |
513 | * here will panic. Ensure there is a request function before issuing | |
514 | * the flush. | |
515 | */ | |
516 | if (!q->make_request_fn) | |
517 | return -ENXIO; | |
518 | ||
519 | bio = bio_alloc(gfp_mask, 0); | |
520 | bio->bi_bdev = bdev; | |
521 | bio->bi_opf = REQ_OP_WRITE | REQ_PREFLUSH; | |
522 | ||
523 | ret = submit_bio_wait(bio); | |
524 | ||
525 | /* | |
526 | * The driver must store the error location in ->bi_sector, if | |
527 | * it supports it. For non-stacked drivers, this should be | |
528 | * copied from blk_rq_pos(rq). | |
529 | */ | |
530 | if (error_sector) | |
531 | *error_sector = bio->bi_iter.bi_sector; | |
532 | ||
533 | bio_put(bio); | |
534 | return ret; | |
535 | } | |
536 | EXPORT_SYMBOL(blkdev_issue_flush); | |
537 | ||
538 | struct blk_flush_queue *blk_alloc_flush_queue(struct request_queue *q, | |
539 | int node, int cmd_size) | |
540 | { | |
541 | struct blk_flush_queue *fq; | |
542 | int rq_sz = sizeof(struct request); | |
543 | ||
544 | fq = kzalloc_node(sizeof(*fq), GFP_KERNEL, node); | |
545 | if (!fq) | |
546 | goto fail; | |
547 | ||
548 | if (q->mq_ops) { | |
549 | spin_lock_init(&fq->mq_flush_lock); | |
550 | rq_sz = round_up(rq_sz + cmd_size, cache_line_size()); | |
551 | } | |
552 | ||
553 | fq->flush_rq = kzalloc_node(rq_sz, GFP_KERNEL, node); | |
554 | if (!fq->flush_rq) | |
555 | goto fail_rq; | |
556 | ||
557 | INIT_LIST_HEAD(&fq->flush_queue[0]); | |
558 | INIT_LIST_HEAD(&fq->flush_queue[1]); | |
559 | INIT_LIST_HEAD(&fq->flush_data_in_flight); | |
560 | ||
561 | return fq; | |
562 | ||
563 | fail_rq: | |
564 | kfree(fq); | |
565 | fail: | |
566 | return NULL; | |
567 | } | |
568 | ||
569 | void blk_free_flush_queue(struct blk_flush_queue *fq) | |
570 | { | |
571 | /* bio based request queue hasn't flush queue */ | |
572 | if (!fq) | |
573 | return; | |
574 | ||
575 | kfree(fq->flush_rq); | |
576 | kfree(fq); | |
577 | } |