~ [ source navigation ] ~ [ diff markup ] ~ [ identifier search ] ~

TOMOYO Linux Cross Reference
Linux/block/blk-mq.c

Version: ~ [ linux-5.9 ] ~ [ linux-5.8.14 ] ~ [ linux-5.7.19 ] ~ [ linux-5.6.19 ] ~ [ linux-5.5.19 ] ~ [ linux-5.4.70 ] ~ [ linux-5.3.18 ] ~ [ linux-5.2.21 ] ~ [ linux-5.1.21 ] ~ [ linux-5.0.21 ] ~ [ linux-4.20.17 ] ~ [ linux-4.19.150 ] ~ [ linux-4.18.20 ] ~ [ linux-4.17.19 ] ~ [ linux-4.16.18 ] ~ [ linux-4.15.18 ] ~ [ linux-4.14.200 ] ~ [ linux-4.13.16 ] ~ [ linux-4.12.14 ] ~ [ linux-4.11.12 ] ~ [ linux-4.10.17 ] ~ [ linux-4.9.238 ] ~ [ linux-4.8.17 ] ~ [ linux-4.7.10 ] ~ [ linux-4.6.7 ] ~ [ linux-4.5.7 ] ~ [ linux-4.4.238 ] ~ [ linux-4.3.6 ] ~ [ linux-4.2.8 ] ~ [ linux-4.1.52 ] ~ [ linux-4.0.9 ] ~ [ linux-3.19.8 ] ~ [ linux-3.18.140 ] ~ [ linux-3.17.8 ] ~ [ linux-3.16.85 ] ~ [ linux-3.15.10 ] ~ [ linux-3.14.79 ] ~ [ linux-3.13.11 ] ~ [ linux-3.12.74 ] ~ [ linux-3.11.10 ] ~ [ linux-3.10.108 ] ~ [ linux-2.6.32.71 ] ~ [ linux-2.6.0 ] ~ [ linux-2.4.37.11 ] ~ [ unix-v6-master ] ~ [ ccs-tools-1.8.5 ] ~ [ policy-sample ] ~
Architecture: ~ [ i386 ] ~ [ alpha ] ~ [ m68k ] ~ [ mips ] ~ [ ppc ] ~ [ sparc ] ~ [ sparc64 ] ~

  1 #include <linux/kernel.h>
  2 #include <linux/module.h>
  3 #include <linux/backing-dev.h>
  4 #include <linux/bio.h>
  5 #include <linux/blkdev.h>
  6 #include <linux/mm.h>
  7 #include <linux/init.h>
  8 #include <linux/slab.h>
  9 #include <linux/workqueue.h>
 10 #include <linux/smp.h>
 11 #include <linux/llist.h>
 12 #include <linux/list_sort.h>
 13 #include <linux/cpu.h>
 14 #include <linux/cache.h>
 15 #include <linux/sched/sysctl.h>
 16 #include <linux/delay.h>
 17 
 18 #include <trace/events/block.h>
 19 
 20 #include <linux/blk-mq.h>
 21 #include "blk.h"
 22 #include "blk-mq.h"
 23 #include "blk-mq-tag.h"
 24 
 25 static DEFINE_MUTEX(all_q_mutex);
 26 static LIST_HEAD(all_q_list);
 27 
 28 static void __blk_mq_run_hw_queue(struct blk_mq_hw_ctx *hctx);
 29 
 30 static struct blk_mq_ctx *__blk_mq_get_ctx(struct request_queue *q,
 31                                            unsigned int cpu)
 32 {
 33         return per_cpu_ptr(q->queue_ctx, cpu);
 34 }
 35 
 36 /*
 37  * This assumes per-cpu software queueing queues. They could be per-node
 38  * as well, for instance. For now this is hardcoded as-is. Note that we don't
 39  * care about preemption, since we know the ctx's are persistent. This does
 40  * mean that we can't rely on ctx always matching the currently running CPU.
 41  */
 42 static struct blk_mq_ctx *blk_mq_get_ctx(struct request_queue *q)
 43 {
 44         return __blk_mq_get_ctx(q, get_cpu());
 45 }
 46 
 47 static void blk_mq_put_ctx(struct blk_mq_ctx *ctx)
 48 {
 49         put_cpu();
 50 }
 51 
 52 /*
 53  * Check if any of the ctx's have pending work in this hardware queue
 54  */
 55 static bool blk_mq_hctx_has_pending(struct blk_mq_hw_ctx *hctx)
 56 {
 57         unsigned int i;
 58 
 59         for (i = 0; i < hctx->nr_ctx_map; i++)
 60                 if (hctx->ctx_map[i])
 61                         return true;
 62 
 63         return false;
 64 }
 65 
 66 /*
 67  * Mark this ctx as having pending work in this hardware queue
 68  */
 69 static void blk_mq_hctx_mark_pending(struct blk_mq_hw_ctx *hctx,
 70                                      struct blk_mq_ctx *ctx)
 71 {
 72         if (!test_bit(ctx->index_hw, hctx->ctx_map))
 73                 set_bit(ctx->index_hw, hctx->ctx_map);
 74 }
 75 
 76 static struct request *__blk_mq_alloc_request(struct blk_mq_hw_ctx *hctx,
 77                                               gfp_t gfp, bool reserved)
 78 {
 79         struct request *rq;
 80         unsigned int tag;
 81 
 82         tag = blk_mq_get_tag(hctx->tags, gfp, reserved);
 83         if (tag != BLK_MQ_TAG_FAIL) {
 84                 rq = hctx->rqs[tag];
 85                 rq->tag = tag;
 86 
 87                 return rq;
 88         }
 89 
 90         return NULL;
 91 }
 92 
 93 static int blk_mq_queue_enter(struct request_queue *q)
 94 {
 95         int ret;
 96 
 97         __percpu_counter_add(&q->mq_usage_counter, 1, 1000000);
 98         smp_wmb();
 99         /* we have problems to freeze the queue if it's initializing */
100         if (!blk_queue_bypass(q) || !blk_queue_init_done(q))
101                 return 0;
102 
103         __percpu_counter_add(&q->mq_usage_counter, -1, 1000000);
104 
105         spin_lock_irq(q->queue_lock);
106         ret = wait_event_interruptible_lock_irq(q->mq_freeze_wq,
107                 !blk_queue_bypass(q) || blk_queue_dying(q),
108                 *q->queue_lock);
109         /* inc usage with lock hold to avoid freeze_queue runs here */
110         if (!ret && !blk_queue_dying(q))
111                 __percpu_counter_add(&q->mq_usage_counter, 1, 1000000);
112         else if (blk_queue_dying(q))
113                 ret = -ENODEV;
114         spin_unlock_irq(q->queue_lock);
115 
116         return ret;
117 }
118 
119 static void blk_mq_queue_exit(struct request_queue *q)
120 {
121         __percpu_counter_add(&q->mq_usage_counter, -1, 1000000);
122 }
123 
124 static void __blk_mq_drain_queue(struct request_queue *q)
125 {
126         while (true) {
127                 s64 count;
128 
129                 spin_lock_irq(q->queue_lock);
130                 count = percpu_counter_sum(&q->mq_usage_counter);
131                 spin_unlock_irq(q->queue_lock);
132 
133                 if (count == 0)
134                         break;
135                 blk_mq_run_queues(q, false);
136                 msleep(10);
137         }
138 }
139 
140 /*
141  * Guarantee no request is in use, so we can change any data structure of
142  * the queue afterward.
143  */
144 static void blk_mq_freeze_queue(struct request_queue *q)
145 {
146         bool drain;
147 
148         spin_lock_irq(q->queue_lock);
149         drain = !q->bypass_depth++;
150         queue_flag_set(QUEUE_FLAG_BYPASS, q);
151         spin_unlock_irq(q->queue_lock);
152 
153         if (drain)
154                 __blk_mq_drain_queue(q);
155 }
156 
157 void blk_mq_drain_queue(struct request_queue *q)
158 {
159         __blk_mq_drain_queue(q);
160 }
161 
162 static void blk_mq_unfreeze_queue(struct request_queue *q)
163 {
164         bool wake = false;
165 
166         spin_lock_irq(q->queue_lock);
167         if (!--q->bypass_depth) {
168                 queue_flag_clear(QUEUE_FLAG_BYPASS, q);
169                 wake = true;
170         }
171         WARN_ON_ONCE(q->bypass_depth < 0);
172         spin_unlock_irq(q->queue_lock);
173         if (wake)
174                 wake_up_all(&q->mq_freeze_wq);
175 }
176 
177 bool blk_mq_can_queue(struct blk_mq_hw_ctx *hctx)
178 {
179         return blk_mq_has_free_tags(hctx->tags);
180 }
181 EXPORT_SYMBOL(blk_mq_can_queue);
182 
183 static void blk_mq_rq_ctx_init(struct request_queue *q, struct blk_mq_ctx *ctx,
184                                struct request *rq, unsigned int rw_flags)
185 {
186         if (blk_queue_io_stat(q))
187                 rw_flags |= REQ_IO_STAT;
188 
189         rq->mq_ctx = ctx;
190         rq->cmd_flags = rw_flags;
191         rq->start_time = jiffies;
192         set_start_time_ns(rq);
193         ctx->rq_dispatched[rw_is_sync(rw_flags)]++;
194 }
195 
196 static struct request *blk_mq_alloc_request_pinned(struct request_queue *q,
197                                                    int rw, gfp_t gfp,
198                                                    bool reserved)
199 {
200         struct request *rq;
201 
202         do {
203                 struct blk_mq_ctx *ctx = blk_mq_get_ctx(q);
204                 struct blk_mq_hw_ctx *hctx = q->mq_ops->map_queue(q, ctx->cpu);
205 
206                 rq = __blk_mq_alloc_request(hctx, gfp & ~__GFP_WAIT, reserved);
207                 if (rq) {
208                         blk_mq_rq_ctx_init(q, ctx, rq, rw);
209                         break;
210                 }
211 
212                 blk_mq_put_ctx(ctx);
213                 if (!(gfp & __GFP_WAIT))
214                         break;
215 
216                 __blk_mq_run_hw_queue(hctx);
217                 blk_mq_wait_for_tags(hctx->tags);
218         } while (1);
219 
220         return rq;
221 }
222 
223 struct request *blk_mq_alloc_request(struct request_queue *q, int rw, gfp_t gfp)
224 {
225         struct request *rq;
226 
227         if (blk_mq_queue_enter(q))
228                 return NULL;
229 
230         rq = blk_mq_alloc_request_pinned(q, rw, gfp, false);
231         if (rq)
232                 blk_mq_put_ctx(rq->mq_ctx);
233         return rq;
234 }
235 
236 struct request *blk_mq_alloc_reserved_request(struct request_queue *q, int rw,
237                                               gfp_t gfp)
238 {
239         struct request *rq;
240 
241         if (blk_mq_queue_enter(q))
242                 return NULL;
243 
244         rq = blk_mq_alloc_request_pinned(q, rw, gfp, true);
245         if (rq)
246                 blk_mq_put_ctx(rq->mq_ctx);
247         return rq;
248 }
249 EXPORT_SYMBOL(blk_mq_alloc_reserved_request);
250 
251 /*
252  * Re-init and set pdu, if we have it
253  */
254 void blk_mq_rq_init(struct blk_mq_hw_ctx *hctx, struct request *rq)
255 {
256         blk_rq_init(hctx->queue, rq);
257 
258         if (hctx->cmd_size)
259                 rq->special = blk_mq_rq_to_pdu(rq);
260 }
261 
262 static void __blk_mq_free_request(struct blk_mq_hw_ctx *hctx,
263                                   struct blk_mq_ctx *ctx, struct request *rq)
264 {
265         const int tag = rq->tag;
266         struct request_queue *q = rq->q;
267 
268         blk_mq_rq_init(hctx, rq);
269         blk_mq_put_tag(hctx->tags, tag);
270 
271         blk_mq_queue_exit(q);
272 }
273 
274 void blk_mq_free_request(struct request *rq)
275 {
276         struct blk_mq_ctx *ctx = rq->mq_ctx;
277         struct blk_mq_hw_ctx *hctx;
278         struct request_queue *q = rq->q;
279 
280         ctx->rq_completed[rq_is_sync(rq)]++;
281 
282         hctx = q->mq_ops->map_queue(q, ctx->cpu);
283         __blk_mq_free_request(hctx, ctx, rq);
284 }
285 
286 bool blk_mq_end_io_partial(struct request *rq, int error, unsigned int nr_bytes)
287 {
288         if (blk_update_request(rq, error, blk_rq_bytes(rq)))
289                 return true;
290 
291         blk_account_io_done(rq);
292 
293         if (rq->end_io)
294                 rq->end_io(rq, error);
295         else
296                 blk_mq_free_request(rq);
297         return false;
298 }
299 EXPORT_SYMBOL(blk_mq_end_io_partial);
300 
301 static void __blk_mq_complete_request_remote(void *data)
302 {
303         struct request *rq = data;
304 
305         rq->q->softirq_done_fn(rq);
306 }
307 
308 void __blk_mq_complete_request(struct request *rq)
309 {
310         struct blk_mq_ctx *ctx = rq->mq_ctx;
311         int cpu;
312 
313         if (!ctx->ipi_redirect) {
314                 rq->q->softirq_done_fn(rq);
315                 return;
316         }
317 
318         cpu = get_cpu();
319         if (cpu != ctx->cpu && cpu_online(ctx->cpu)) {
320                 rq->csd.func = __blk_mq_complete_request_remote;
321                 rq->csd.info = rq;
322                 rq->csd.flags = 0;
323                 smp_call_function_single_async(ctx->cpu, &rq->csd);
324         } else {
325                 rq->q->softirq_done_fn(rq);
326         }
327         put_cpu();
328 }
329 
330 /**
331  * blk_mq_complete_request - end I/O on a request
332  * @rq:         the request being processed
333  *
334  * Description:
335  *      Ends all I/O on a request. It does not handle partial completions.
336  *      The actual completion happens out-of-order, through a IPI handler.
337  **/
338 void blk_mq_complete_request(struct request *rq)
339 {
340         if (unlikely(blk_should_fake_timeout(rq->q)))
341                 return;
342         if (!blk_mark_rq_complete(rq))
343                 __blk_mq_complete_request(rq);
344 }
345 EXPORT_SYMBOL(blk_mq_complete_request);
346 
347 static void blk_mq_start_request(struct request *rq, bool last)
348 {
349         struct request_queue *q = rq->q;
350 
351         trace_block_rq_issue(q, rq);
352 
353         /*
354          * Just mark start time and set the started bit. Due to memory
355          * ordering, we know we'll see the correct deadline as long as
356          * REQ_ATOMIC_STARTED is seen.
357          */
358         rq->deadline = jiffies + q->rq_timeout;
359         set_bit(REQ_ATOM_STARTED, &rq->atomic_flags);
360 
361         if (q->dma_drain_size && blk_rq_bytes(rq)) {
362                 /*
363                  * Make sure space for the drain appears.  We know we can do
364                  * this because max_hw_segments has been adjusted to be one
365                  * fewer than the device can handle.
366                  */
367                 rq->nr_phys_segments++;
368         }
369 
370         /*
371          * Flag the last request in the series so that drivers know when IO
372          * should be kicked off, if they don't do it on a per-request basis.
373          *
374          * Note: the flag isn't the only condition drivers should do kick off.
375          * If drive is busy, the last request might not have the bit set.
376          */
377         if (last)
378                 rq->cmd_flags |= REQ_END;
379 }
380 
381 static void blk_mq_requeue_request(struct request *rq)
382 {
383         struct request_queue *q = rq->q;
384 
385         trace_block_rq_requeue(q, rq);
386         clear_bit(REQ_ATOM_STARTED, &rq->atomic_flags);
387 
388         rq->cmd_flags &= ~REQ_END;
389 
390         if (q->dma_drain_size && blk_rq_bytes(rq))
391                 rq->nr_phys_segments--;
392 }
393 
394 struct blk_mq_timeout_data {
395         struct blk_mq_hw_ctx *hctx;
396         unsigned long *next;
397         unsigned int *next_set;
398 };
399 
400 static void blk_mq_timeout_check(void *__data, unsigned long *free_tags)
401 {
402         struct blk_mq_timeout_data *data = __data;
403         struct blk_mq_hw_ctx *hctx = data->hctx;
404         unsigned int tag;
405 
406          /* It may not be in flight yet (this is where
407          * the REQ_ATOMIC_STARTED flag comes in). The requests are
408          * statically allocated, so we know it's always safe to access the
409          * memory associated with a bit offset into ->rqs[].
410          */
411         tag = 0;
412         do {
413                 struct request *rq;
414 
415                 tag = find_next_zero_bit(free_tags, hctx->queue_depth, tag);
416                 if (tag >= hctx->queue_depth)
417                         break;
418 
419                 rq = hctx->rqs[tag++];
420 
421                 if (!test_bit(REQ_ATOM_STARTED, &rq->atomic_flags))
422                         continue;
423 
424                 blk_rq_check_expired(rq, data->next, data->next_set);
425         } while (1);
426 }
427 
428 static void blk_mq_hw_ctx_check_timeout(struct blk_mq_hw_ctx *hctx,
429                                         unsigned long *next,
430                                         unsigned int *next_set)
431 {
432         struct blk_mq_timeout_data data = {
433                 .hctx           = hctx,
434                 .next           = next,
435                 .next_set       = next_set,
436         };
437 
438         /*
439          * Ask the tagging code to iterate busy requests, so we can
440          * check them for timeout.
441          */
442         blk_mq_tag_busy_iter(hctx->tags, blk_mq_timeout_check, &data);
443 }
444 
445 static void blk_mq_rq_timer(unsigned long data)
446 {
447         struct request_queue *q = (struct request_queue *) data;
448         struct blk_mq_hw_ctx *hctx;
449         unsigned long next = 0;
450         int i, next_set = 0;
451 
452         queue_for_each_hw_ctx(q, hctx, i)
453                 blk_mq_hw_ctx_check_timeout(hctx, &next, &next_set);
454 
455         if (next_set)
456                 mod_timer(&q->timeout, round_jiffies_up(next));
457 }
458 
459 /*
460  * Reverse check our software queue for entries that we could potentially
461  * merge with. Currently includes a hand-wavy stop count of 8, to not spend
462  * too much time checking for merges.
463  */
464 static bool blk_mq_attempt_merge(struct request_queue *q,
465                                  struct blk_mq_ctx *ctx, struct bio *bio)
466 {
467         struct request *rq;
468         int checked = 8;
469 
470         list_for_each_entry_reverse(rq, &ctx->rq_list, queuelist) {
471                 int el_ret;
472 
473                 if (!checked--)
474                         break;
475 
476                 if (!blk_rq_merge_ok(rq, bio))
477                         continue;
478 
479                 el_ret = blk_try_merge(rq, bio);
480                 if (el_ret == ELEVATOR_BACK_MERGE) {
481                         if (bio_attempt_back_merge(q, rq, bio)) {
482                                 ctx->rq_merged++;
483                                 return true;
484                         }
485                         break;
486                 } else if (el_ret == ELEVATOR_FRONT_MERGE) {
487                         if (bio_attempt_front_merge(q, rq, bio)) {
488                                 ctx->rq_merged++;
489                                 return true;
490                         }
491                         break;
492                 }
493         }
494 
495         return false;
496 }
497 
498 void blk_mq_add_timer(struct request *rq)
499 {
500         __blk_add_timer(rq, NULL);
501 }
502 
503 /*
504  * Run this hardware queue, pulling any software queues mapped to it in.
505  * Note that this function currently has various problems around ordering
506  * of IO. In particular, we'd like FIFO behaviour on handling existing
507  * items on the hctx->dispatch list. Ignore that for now.
508  */
509 static void __blk_mq_run_hw_queue(struct blk_mq_hw_ctx *hctx)
510 {
511         struct request_queue *q = hctx->queue;
512         struct blk_mq_ctx *ctx;
513         struct request *rq;
514         LIST_HEAD(rq_list);
515         int bit, queued;
516 
517         if (unlikely(test_bit(BLK_MQ_S_STOPPED, &hctx->state)))
518                 return;
519 
520         hctx->run++;
521 
522         /*
523          * Touch any software queue that has pending entries.
524          */
525         for_each_set_bit(bit, hctx->ctx_map, hctx->nr_ctx) {
526                 clear_bit(bit, hctx->ctx_map);
527                 ctx = hctx->ctxs[bit];
528                 BUG_ON(bit != ctx->index_hw);
529 
530                 spin_lock(&ctx->lock);
531                 list_splice_tail_init(&ctx->rq_list, &rq_list);
532                 spin_unlock(&ctx->lock);
533         }
534 
535         /*
536          * If we have previous entries on our dispatch list, grab them
537          * and stuff them at the front for more fair dispatch.
538          */
539         if (!list_empty_careful(&hctx->dispatch)) {
540                 spin_lock(&hctx->lock);
541                 if (!list_empty(&hctx->dispatch))
542                         list_splice_init(&hctx->dispatch, &rq_list);
543                 spin_unlock(&hctx->lock);
544         }
545 
546         /*
547          * Delete and return all entries from our dispatch list
548          */
549         queued = 0;
550 
551         /*
552          * Now process all the entries, sending them to the driver.
553          */
554         while (!list_empty(&rq_list)) {
555                 int ret;
556 
557                 rq = list_first_entry(&rq_list, struct request, queuelist);
558                 list_del_init(&rq->queuelist);
559 
560                 blk_mq_start_request(rq, list_empty(&rq_list));
561 
562                 ret = q->mq_ops->queue_rq(hctx, rq);
563                 switch (ret) {
564                 case BLK_MQ_RQ_QUEUE_OK:
565                         queued++;
566                         continue;
567                 case BLK_MQ_RQ_QUEUE_BUSY:
568                         /*
569                          * FIXME: we should have a mechanism to stop the queue
570                          * like blk_stop_queue, otherwise we will waste cpu
571                          * time
572                          */
573                         list_add(&rq->queuelist, &rq_list);
574                         blk_mq_requeue_request(rq);
575                         break;
576                 default:
577                         pr_err("blk-mq: bad return on queue: %d\n", ret);
578                 case BLK_MQ_RQ_QUEUE_ERROR:
579                         rq->errors = -EIO;
580                         blk_mq_end_io(rq, rq->errors);
581                         break;
582                 }
583 
584                 if (ret == BLK_MQ_RQ_QUEUE_BUSY)
585                         break;
586         }
587 
588         if (!queued)
589                 hctx->dispatched[0]++;
590         else if (queued < (1 << (BLK_MQ_MAX_DISPATCH_ORDER - 1)))
591                 hctx->dispatched[ilog2(queued) + 1]++;
592 
593         /*
594          * Any items that need requeuing? Stuff them into hctx->dispatch,
595          * that is where we will continue on next queue run.
596          */
597         if (!list_empty(&rq_list)) {
598                 spin_lock(&hctx->lock);
599                 list_splice(&rq_list, &hctx->dispatch);
600                 spin_unlock(&hctx->lock);
601         }
602 }
603 
604 void blk_mq_run_hw_queue(struct blk_mq_hw_ctx *hctx, bool async)
605 {
606         if (unlikely(test_bit(BLK_MQ_S_STOPPED, &hctx->state)))
607                 return;
608 
609         if (!async)
610                 __blk_mq_run_hw_queue(hctx);
611         else {
612                 struct request_queue *q = hctx->queue;
613 
614                 kblockd_schedule_delayed_work(q, &hctx->delayed_work, 0);
615         }
616 }
617 
618 void blk_mq_run_queues(struct request_queue *q, bool async)
619 {
620         struct blk_mq_hw_ctx *hctx;
621         int i;
622 
623         queue_for_each_hw_ctx(q, hctx, i) {
624                 if ((!blk_mq_hctx_has_pending(hctx) &&
625                     list_empty_careful(&hctx->dispatch)) ||
626                     test_bit(BLK_MQ_S_STOPPED, &hctx->state))
627                         continue;
628 
629                 blk_mq_run_hw_queue(hctx, async);
630         }
631 }
632 EXPORT_SYMBOL(blk_mq_run_queues);
633 
634 void blk_mq_stop_hw_queue(struct blk_mq_hw_ctx *hctx)
635 {
636         cancel_delayed_work(&hctx->delayed_work);
637         set_bit(BLK_MQ_S_STOPPED, &hctx->state);
638 }
639 EXPORT_SYMBOL(blk_mq_stop_hw_queue);
640 
641 void blk_mq_stop_hw_queues(struct request_queue *q)
642 {
643         struct blk_mq_hw_ctx *hctx;
644         int i;
645 
646         queue_for_each_hw_ctx(q, hctx, i)
647                 blk_mq_stop_hw_queue(hctx);
648 }
649 EXPORT_SYMBOL(blk_mq_stop_hw_queues);
650 
651 void blk_mq_start_hw_queue(struct blk_mq_hw_ctx *hctx)
652 {
653         clear_bit(BLK_MQ_S_STOPPED, &hctx->state);
654         __blk_mq_run_hw_queue(hctx);
655 }
656 EXPORT_SYMBOL(blk_mq_start_hw_queue);
657 
658 void blk_mq_start_stopped_hw_queues(struct request_queue *q)
659 {
660         struct blk_mq_hw_ctx *hctx;
661         int i;
662 
663         queue_for_each_hw_ctx(q, hctx, i) {
664                 if (!test_bit(BLK_MQ_S_STOPPED, &hctx->state))
665                         continue;
666 
667                 clear_bit(BLK_MQ_S_STOPPED, &hctx->state);
668                 blk_mq_run_hw_queue(hctx, true);
669         }
670 }
671 EXPORT_SYMBOL(blk_mq_start_stopped_hw_queues);
672 
673 static void blk_mq_work_fn(struct work_struct *work)
674 {
675         struct blk_mq_hw_ctx *hctx;
676 
677         hctx = container_of(work, struct blk_mq_hw_ctx, delayed_work.work);
678         __blk_mq_run_hw_queue(hctx);
679 }
680 
681 static void __blk_mq_insert_request(struct blk_mq_hw_ctx *hctx,
682                                     struct request *rq, bool at_head)
683 {
684         struct blk_mq_ctx *ctx = rq->mq_ctx;
685 
686         trace_block_rq_insert(hctx->queue, rq);
687 
688         if (at_head)
689                 list_add(&rq->queuelist, &ctx->rq_list);
690         else
691                 list_add_tail(&rq->queuelist, &ctx->rq_list);
692         blk_mq_hctx_mark_pending(hctx, ctx);
693 
694         /*
695          * We do this early, to ensure we are on the right CPU.
696          */
697         blk_mq_add_timer(rq);
698 }
699 
700 void blk_mq_insert_request(struct request *rq, bool at_head, bool run_queue,
701                 bool async)
702 {
703         struct request_queue *q = rq->q;
704         struct blk_mq_hw_ctx *hctx;
705         struct blk_mq_ctx *ctx = rq->mq_ctx, *current_ctx;
706 
707         current_ctx = blk_mq_get_ctx(q);
708         if (!cpu_online(ctx->cpu))
709                 rq->mq_ctx = ctx = current_ctx;
710 
711         hctx = q->mq_ops->map_queue(q, ctx->cpu);
712 
713         if (rq->cmd_flags & (REQ_FLUSH | REQ_FUA) &&
714             !(rq->cmd_flags & (REQ_FLUSH_SEQ))) {
715                 blk_insert_flush(rq);
716         } else {
717                 spin_lock(&ctx->lock);
718                 __blk_mq_insert_request(hctx, rq, at_head);
719                 spin_unlock(&ctx->lock);
720         }
721 
722         blk_mq_put_ctx(current_ctx);
723 
724         if (run_queue)
725                 blk_mq_run_hw_queue(hctx, async);
726 }
727 
728 static void blk_mq_insert_requests(struct request_queue *q,
729                                      struct blk_mq_ctx *ctx,
730                                      struct list_head *list,
731                                      int depth,
732                                      bool from_schedule)
733 
734 {
735         struct blk_mq_hw_ctx *hctx;
736         struct blk_mq_ctx *current_ctx;
737 
738         trace_block_unplug(q, depth, !from_schedule);
739 
740         current_ctx = blk_mq_get_ctx(q);
741 
742         if (!cpu_online(ctx->cpu))
743                 ctx = current_ctx;
744         hctx = q->mq_ops->map_queue(q, ctx->cpu);
745 
746         /*
747          * preemption doesn't flush plug list, so it's possible ctx->cpu is
748          * offline now
749          */
750         spin_lock(&ctx->lock);
751         while (!list_empty(list)) {
752                 struct request *rq;
753 
754                 rq = list_first_entry(list, struct request, queuelist);
755                 list_del_init(&rq->queuelist);
756                 rq->mq_ctx = ctx;
757                 __blk_mq_insert_request(hctx, rq, false);
758         }
759         spin_unlock(&ctx->lock);
760 
761         blk_mq_put_ctx(current_ctx);
762 
763         blk_mq_run_hw_queue(hctx, from_schedule);
764 }
765 
766 static int plug_ctx_cmp(void *priv, struct list_head *a, struct list_head *b)
767 {
768         struct request *rqa = container_of(a, struct request, queuelist);
769         struct request *rqb = container_of(b, struct request, queuelist);
770 
771         return !(rqa->mq_ctx < rqb->mq_ctx ||
772                  (rqa->mq_ctx == rqb->mq_ctx &&
773                   blk_rq_pos(rqa) < blk_rq_pos(rqb)));
774 }
775 
776 void blk_mq_flush_plug_list(struct blk_plug *plug, bool from_schedule)
777 {
778         struct blk_mq_ctx *this_ctx;
779         struct request_queue *this_q;
780         struct request *rq;
781         LIST_HEAD(list);
782         LIST_HEAD(ctx_list);
783         unsigned int depth;
784 
785         list_splice_init(&plug->mq_list, &list);
786 
787         list_sort(NULL, &list, plug_ctx_cmp);
788 
789         this_q = NULL;
790         this_ctx = NULL;
791         depth = 0;
792 
793         while (!list_empty(&list)) {
794                 rq = list_entry_rq(list.next);
795                 list_del_init(&rq->queuelist);
796                 BUG_ON(!rq->q);
797                 if (rq->mq_ctx != this_ctx) {
798                         if (this_ctx) {
799                                 blk_mq_insert_requests(this_q, this_ctx,
800                                                         &ctx_list, depth,
801                                                         from_schedule);
802                         }
803 
804                         this_ctx = rq->mq_ctx;
805                         this_q = rq->q;
806                         depth = 0;
807                 }
808 
809                 depth++;
810                 list_add_tail(&rq->queuelist, &ctx_list);
811         }
812 
813         /*
814          * If 'this_ctx' is set, we know we have entries to complete
815          * on 'ctx_list'. Do those.
816          */
817         if (this_ctx) {
818                 blk_mq_insert_requests(this_q, this_ctx, &ctx_list, depth,
819                                        from_schedule);
820         }
821 }
822 
823 static void blk_mq_bio_to_request(struct request *rq, struct bio *bio)
824 {
825         init_request_from_bio(rq, bio);
826         blk_account_io_start(rq, 1);
827 }
828 
829 static void blk_mq_make_request(struct request_queue *q, struct bio *bio)
830 {
831         struct blk_mq_hw_ctx *hctx;
832         struct blk_mq_ctx *ctx;
833         const int is_sync = rw_is_sync(bio->bi_rw);
834         const int is_flush_fua = bio->bi_rw & (REQ_FLUSH | REQ_FUA);
835         int rw = bio_data_dir(bio);
836         struct request *rq;
837         unsigned int use_plug, request_count = 0;
838 
839         /*
840          * If we have multiple hardware queues, just go directly to
841          * one of those for sync IO.
842          */
843         use_plug = !is_flush_fua && ((q->nr_hw_queues == 1) || !is_sync);
844 
845         blk_queue_bounce(q, &bio);
846 
847         if (bio_integrity_enabled(bio) && bio_integrity_prep(bio)) {
848                 bio_endio(bio, -EIO);
849                 return;
850         }
851 
852         if (use_plug && blk_attempt_plug_merge(q, bio, &request_count))
853                 return;
854 
855         if (blk_mq_queue_enter(q)) {
856                 bio_endio(bio, -EIO);
857                 return;
858         }
859 
860         ctx = blk_mq_get_ctx(q);
861         hctx = q->mq_ops->map_queue(q, ctx->cpu);
862 
863         if (is_sync)
864                 rw |= REQ_SYNC;
865         trace_block_getrq(q, bio, rw);
866         rq = __blk_mq_alloc_request(hctx, GFP_ATOMIC, false);
867         if (likely(rq))
868                 blk_mq_rq_ctx_init(q, ctx, rq, rw);
869         else {
870                 blk_mq_put_ctx(ctx);
871                 trace_block_sleeprq(q, bio, rw);
872                 rq = blk_mq_alloc_request_pinned(q, rw, __GFP_WAIT|GFP_ATOMIC,
873                                                         false);
874                 ctx = rq->mq_ctx;
875                 hctx = q->mq_ops->map_queue(q, ctx->cpu);
876         }
877 
878         hctx->queued++;
879 
880         if (unlikely(is_flush_fua)) {
881                 blk_mq_bio_to_request(rq, bio);
882                 blk_mq_put_ctx(ctx);
883                 blk_insert_flush(rq);
884                 goto run_queue;
885         }
886 
887         /*
888          * A task plug currently exists. Since this is completely lockless,
889          * utilize that to temporarily store requests until the task is
890          * either done or scheduled away.
891          */
892         if (use_plug) {
893                 struct blk_plug *plug = current->plug;
894 
895                 if (plug) {
896                         blk_mq_bio_to_request(rq, bio);
897                         if (list_empty(&plug->mq_list))
898                                 trace_block_plug(q);
899                         else if (request_count >= BLK_MAX_REQUEST_COUNT) {
900                                 blk_flush_plug_list(plug, false);
901                                 trace_block_plug(q);
902                         }
903                         list_add_tail(&rq->queuelist, &plug->mq_list);
904                         blk_mq_put_ctx(ctx);
905                         return;
906                 }
907         }
908 
909         spin_lock(&ctx->lock);
910 
911         if ((hctx->flags & BLK_MQ_F_SHOULD_MERGE) &&
912             blk_mq_attempt_merge(q, ctx, bio))
913                 __blk_mq_free_request(hctx, ctx, rq);
914         else {
915                 blk_mq_bio_to_request(rq, bio);
916                 __blk_mq_insert_request(hctx, rq, false);
917         }
918 
919         spin_unlock(&ctx->lock);
920         blk_mq_put_ctx(ctx);
921 
922         /*
923          * For a SYNC request, send it to the hardware immediately. For an
924          * ASYNC request, just ensure that we run it later on. The latter
925          * allows for merging opportunities and more efficient dispatching.
926          */
927 run_queue:
928         blk_mq_run_hw_queue(hctx, !is_sync || is_flush_fua);
929 }
930 
931 /*
932  * Default mapping to a software queue, since we use one per CPU.
933  */
934 struct blk_mq_hw_ctx *blk_mq_map_queue(struct request_queue *q, const int cpu)
935 {
936         return q->queue_hw_ctx[q->mq_map[cpu]];
937 }
938 EXPORT_SYMBOL(blk_mq_map_queue);
939 
940 struct blk_mq_hw_ctx *blk_mq_alloc_single_hw_queue(struct blk_mq_reg *reg,
941                                                    unsigned int hctx_index)
942 {
943         return kmalloc_node(sizeof(struct blk_mq_hw_ctx),
944                                 GFP_KERNEL | __GFP_ZERO, reg->numa_node);
945 }
946 EXPORT_SYMBOL(blk_mq_alloc_single_hw_queue);
947 
948 void blk_mq_free_single_hw_queue(struct blk_mq_hw_ctx *hctx,
949                                  unsigned int hctx_index)
950 {
951         kfree(hctx);
952 }
953 EXPORT_SYMBOL(blk_mq_free_single_hw_queue);
954 
955 static void blk_mq_hctx_notify(void *data, unsigned long action,
956                                unsigned int cpu)
957 {
958         struct blk_mq_hw_ctx *hctx = data;
959         struct request_queue *q = hctx->queue;
960         struct blk_mq_ctx *ctx;
961         LIST_HEAD(tmp);
962 
963         if (action != CPU_DEAD && action != CPU_DEAD_FROZEN)
964                 return;
965 
966         /*
967          * Move ctx entries to new CPU, if this one is going away.
968          */
969         ctx = __blk_mq_get_ctx(q, cpu);
970 
971         spin_lock(&ctx->lock);
972         if (!list_empty(&ctx->rq_list)) {
973                 list_splice_init(&ctx->rq_list, &tmp);
974                 clear_bit(ctx->index_hw, hctx->ctx_map);
975         }
976         spin_unlock(&ctx->lock);
977 
978         if (list_empty(&tmp))
979                 return;
980 
981         ctx = blk_mq_get_ctx(q);
982         spin_lock(&ctx->lock);
983 
984         while (!list_empty(&tmp)) {
985                 struct request *rq;
986 
987                 rq = list_first_entry(&tmp, struct request, queuelist);
988                 rq->mq_ctx = ctx;
989                 list_move_tail(&rq->queuelist, &ctx->rq_list);
990         }
991 
992         hctx = q->mq_ops->map_queue(q, ctx->cpu);
993         blk_mq_hctx_mark_pending(hctx, ctx);
994 
995         spin_unlock(&ctx->lock);
996         blk_mq_put_ctx(ctx);
997 
998         blk_mq_run_hw_queue(hctx, true);
999 }
1000 
1001 static int blk_mq_init_hw_commands(struct blk_mq_hw_ctx *hctx,
1002                                    int (*init)(void *, struct blk_mq_hw_ctx *,
1003                                         struct request *, unsigned int),
1004                                    void *data)
1005 {
1006         unsigned int i;
1007         int ret = 0;
1008 
1009         for (i = 0; i < hctx->queue_depth; i++) {
1010                 struct request *rq = hctx->rqs[i];
1011 
1012                 ret = init(data, hctx, rq, i);
1013                 if (ret)
1014                         break;
1015         }
1016 
1017         return ret;
1018 }
1019 
1020 int blk_mq_init_commands(struct request_queue *q,
1021                          int (*init)(void *, struct blk_mq_hw_ctx *,
1022                                         struct request *, unsigned int),
1023                          void *data)
1024 {
1025         struct blk_mq_hw_ctx *hctx;
1026         unsigned int i;
1027         int ret = 0;
1028 
1029         queue_for_each_hw_ctx(q, hctx, i) {
1030                 ret = blk_mq_init_hw_commands(hctx, init, data);
1031                 if (ret)
1032                         break;
1033         }
1034 
1035         return ret;
1036 }
1037 EXPORT_SYMBOL(blk_mq_init_commands);
1038 
1039 static void blk_mq_free_hw_commands(struct blk_mq_hw_ctx *hctx,
1040                                     void (*free)(void *, struct blk_mq_hw_ctx *,
1041                                         struct request *, unsigned int),
1042                                     void *data)
1043 {
1044         unsigned int i;
1045 
1046         for (i = 0; i < hctx->queue_depth; i++) {
1047                 struct request *rq = hctx->rqs[i];
1048 
1049                 free(data, hctx, rq, i);
1050         }
1051 }
1052 
1053 void blk_mq_free_commands(struct request_queue *q,
1054                           void (*free)(void *, struct blk_mq_hw_ctx *,
1055                                         struct request *, unsigned int),
1056                           void *data)
1057 {
1058         struct blk_mq_hw_ctx *hctx;
1059         unsigned int i;
1060 
1061         queue_for_each_hw_ctx(q, hctx, i)
1062                 blk_mq_free_hw_commands(hctx, free, data);
1063 }
1064 EXPORT_SYMBOL(blk_mq_free_commands);
1065 
1066 static void blk_mq_free_rq_map(struct blk_mq_hw_ctx *hctx)
1067 {
1068         struct page *page;
1069 
1070         while (!list_empty(&hctx->page_list)) {
1071                 page = list_first_entry(&hctx->page_list, struct page, lru);
1072                 list_del_init(&page->lru);
1073                 __free_pages(page, page->private);
1074         }
1075 
1076         kfree(hctx->rqs);
1077 
1078         if (hctx->tags)
1079                 blk_mq_free_tags(hctx->tags);
1080 }
1081 
1082 static size_t order_to_size(unsigned int order)
1083 {
1084         size_t ret = PAGE_SIZE;
1085 
1086         while (order--)
1087                 ret *= 2;
1088 
1089         return ret;
1090 }
1091 
1092 static int blk_mq_init_rq_map(struct blk_mq_hw_ctx *hctx,
1093                               unsigned int reserved_tags, int node)
1094 {
1095         unsigned int i, j, entries_per_page, max_order = 4;
1096         size_t rq_size, left;
1097 
1098         INIT_LIST_HEAD(&hctx->page_list);
1099 
1100         hctx->rqs = kmalloc_node(hctx->queue_depth * sizeof(struct request *),
1101                                         GFP_KERNEL, node);
1102         if (!hctx->rqs)
1103                 return -ENOMEM;
1104 
1105         /*
1106          * rq_size is the size of the request plus driver payload, rounded
1107          * to the cacheline size
1108          */
1109         rq_size = round_up(sizeof(struct request) + hctx->cmd_size,
1110                                 cache_line_size());
1111         left = rq_size * hctx->queue_depth;
1112 
1113         for (i = 0; i < hctx->queue_depth;) {
1114                 int this_order = max_order;
1115                 struct page *page;
1116                 int to_do;
1117                 void *p;
1118 
1119                 while (left < order_to_size(this_order - 1) && this_order)
1120                         this_order--;
1121 
1122                 do {
1123                         page = alloc_pages_node(node, GFP_KERNEL, this_order);
1124                         if (page)
1125                                 break;
1126                         if (!this_order--)
1127                                 break;
1128                         if (order_to_size(this_order) < rq_size)
1129                                 break;
1130                 } while (1);
1131 
1132                 if (!page)
1133                         break;
1134 
1135                 page->private = this_order;
1136                 list_add_tail(&page->lru, &hctx->page_list);
1137 
1138                 p = page_address(page);
1139                 entries_per_page = order_to_size(this_order) / rq_size;
1140                 to_do = min(entries_per_page, hctx->queue_depth - i);
1141                 left -= to_do * rq_size;
1142                 for (j = 0; j < to_do; j++) {
1143                         hctx->rqs[i] = p;
1144                         blk_mq_rq_init(hctx, hctx->rqs[i]);
1145                         p += rq_size;
1146                         i++;
1147                 }
1148         }
1149 
1150         if (i < (reserved_tags + BLK_MQ_TAG_MIN))
1151                 goto err_rq_map;
1152         else if (i != hctx->queue_depth) {
1153                 hctx->queue_depth = i;
1154                 pr_warn("%s: queue depth set to %u because of low memory\n",
1155                                         __func__, i);
1156         }
1157 
1158         hctx->tags = blk_mq_init_tags(hctx->queue_depth, reserved_tags, node);
1159         if (!hctx->tags) {
1160 err_rq_map:
1161                 blk_mq_free_rq_map(hctx);
1162                 return -ENOMEM;
1163         }
1164 
1165         return 0;
1166 }
1167 
1168 static int blk_mq_init_hw_queues(struct request_queue *q,
1169                                  struct blk_mq_reg *reg, void *driver_data)
1170 {
1171         struct blk_mq_hw_ctx *hctx;
1172         unsigned int i, j;
1173 
1174         /*
1175          * Initialize hardware queues
1176          */
1177         queue_for_each_hw_ctx(q, hctx, i) {
1178                 unsigned int num_maps;
1179                 int node;
1180 
1181                 node = hctx->numa_node;
1182                 if (node == NUMA_NO_NODE)
1183                         node = hctx->numa_node = reg->numa_node;
1184 
1185                 INIT_DELAYED_WORK(&hctx->delayed_work, blk_mq_work_fn);
1186                 spin_lock_init(&hctx->lock);
1187                 INIT_LIST_HEAD(&hctx->dispatch);
1188                 hctx->queue = q;
1189                 hctx->queue_num = i;
1190                 hctx->flags = reg->flags;
1191                 hctx->queue_depth = reg->queue_depth;
1192                 hctx->cmd_size = reg->cmd_size;
1193 
1194                 blk_mq_init_cpu_notifier(&hctx->cpu_notifier,
1195                                                 blk_mq_hctx_notify, hctx);
1196                 blk_mq_register_cpu_notifier(&hctx->cpu_notifier);
1197 
1198                 if (blk_mq_init_rq_map(hctx, reg->reserved_tags, node))
1199                         break;
1200 
1201                 /*
1202                  * Allocate space for all possible cpus to avoid allocation in
1203                  * runtime
1204                  */
1205                 hctx->ctxs = kmalloc_node(nr_cpu_ids * sizeof(void *),
1206                                                 GFP_KERNEL, node);
1207                 if (!hctx->ctxs)
1208                         break;
1209 
1210                 num_maps = ALIGN(nr_cpu_ids, BITS_PER_LONG) / BITS_PER_LONG;
1211                 hctx->ctx_map = kzalloc_node(num_maps * sizeof(unsigned long),
1212                                                 GFP_KERNEL, node);
1213                 if (!hctx->ctx_map)
1214                         break;
1215 
1216                 hctx->nr_ctx_map = num_maps;
1217                 hctx->nr_ctx = 0;
1218 
1219                 if (reg->ops->init_hctx &&
1220                     reg->ops->init_hctx(hctx, driver_data, i))
1221                         break;
1222         }
1223 
1224         if (i == q->nr_hw_queues)
1225                 return 0;
1226 
1227         /*
1228          * Init failed
1229          */
1230         queue_for_each_hw_ctx(q, hctx, j) {
1231                 if (i == j)
1232                         break;
1233 
1234                 if (reg->ops->exit_hctx)
1235                         reg->ops->exit_hctx(hctx, j);
1236 
1237                 blk_mq_unregister_cpu_notifier(&hctx->cpu_notifier);
1238                 blk_mq_free_rq_map(hctx);
1239                 kfree(hctx->ctxs);
1240         }
1241 
1242         return 1;
1243 }
1244 
1245 static void blk_mq_init_cpu_queues(struct request_queue *q,
1246                                    unsigned int nr_hw_queues)
1247 {
1248         unsigned int i;
1249 
1250         for_each_possible_cpu(i) {
1251                 struct blk_mq_ctx *__ctx = per_cpu_ptr(q->queue_ctx, i);
1252                 struct blk_mq_hw_ctx *hctx;
1253 
1254                 memset(__ctx, 0, sizeof(*__ctx));
1255                 __ctx->cpu = i;
1256                 spin_lock_init(&__ctx->lock);
1257                 INIT_LIST_HEAD(&__ctx->rq_list);
1258                 __ctx->queue = q;
1259 
1260                 /* If the cpu isn't online, the cpu is mapped to first hctx */
1261                 hctx = q->mq_ops->map_queue(q, i);
1262                 hctx->nr_ctx++;
1263 
1264                 if (!cpu_online(i))
1265                         continue;
1266 
1267                 /*
1268                  * Set local node, IFF we have more than one hw queue. If
1269                  * not, we remain on the home node of the device
1270                  */
1271                 if (nr_hw_queues > 1 && hctx->numa_node == NUMA_NO_NODE)
1272                         hctx->numa_node = cpu_to_node(i);
1273         }
1274 }
1275 
1276 static void blk_mq_map_swqueue(struct request_queue *q)
1277 {
1278         unsigned int i;
1279         struct blk_mq_hw_ctx *hctx;
1280         struct blk_mq_ctx *ctx;
1281 
1282         queue_for_each_hw_ctx(q, hctx, i) {
1283                 hctx->nr_ctx = 0;
1284         }
1285 
1286         /*
1287          * Map software to hardware queues
1288          */
1289         queue_for_each_ctx(q, ctx, i) {
1290                 /* If the cpu isn't online, the cpu is mapped to first hctx */
1291                 hctx = q->mq_ops->map_queue(q, i);
1292                 ctx->index_hw = hctx->nr_ctx;
1293                 hctx->ctxs[hctx->nr_ctx++] = ctx;
1294         }
1295 }
1296 
1297 struct request_queue *blk_mq_init_queue(struct blk_mq_reg *reg,
1298                                         void *driver_data)
1299 {
1300         struct blk_mq_hw_ctx **hctxs;
1301         struct blk_mq_ctx *ctx;
1302         struct request_queue *q;
1303         int i;
1304 
1305         if (!reg->nr_hw_queues ||
1306             !reg->ops->queue_rq || !reg->ops->map_queue ||
1307             !reg->ops->alloc_hctx || !reg->ops->free_hctx)
1308                 return ERR_PTR(-EINVAL);
1309 
1310         if (!reg->queue_depth)
1311                 reg->queue_depth = BLK_MQ_MAX_DEPTH;
1312         else if (reg->queue_depth > BLK_MQ_MAX_DEPTH) {
1313                 pr_err("blk-mq: queuedepth too large (%u)\n", reg->queue_depth);
1314                 reg->queue_depth = BLK_MQ_MAX_DEPTH;
1315         }
1316 
1317         if (reg->queue_depth < (reg->reserved_tags + BLK_MQ_TAG_MIN))
1318                 return ERR_PTR(-EINVAL);
1319 
1320         ctx = alloc_percpu(struct blk_mq_ctx);
1321         if (!ctx)
1322                 return ERR_PTR(-ENOMEM);
1323 
1324         hctxs = kmalloc_node(reg->nr_hw_queues * sizeof(*hctxs), GFP_KERNEL,
1325                         reg->numa_node);
1326 
1327         if (!hctxs)
1328                 goto err_percpu;
1329 
1330         for (i = 0; i < reg->nr_hw_queues; i++) {
1331                 hctxs[i] = reg->ops->alloc_hctx(reg, i);
1332                 if (!hctxs[i])
1333                         goto err_hctxs;
1334 
1335                 hctxs[i]->numa_node = NUMA_NO_NODE;
1336                 hctxs[i]->queue_num = i;
1337         }
1338 
1339         q = blk_alloc_queue_node(GFP_KERNEL, reg->numa_node);
1340         if (!q)
1341                 goto err_hctxs;
1342 
1343         q->mq_map = blk_mq_make_queue_map(reg);
1344         if (!q->mq_map)
1345                 goto err_map;
1346 
1347         setup_timer(&q->timeout, blk_mq_rq_timer, (unsigned long) q);
1348         blk_queue_rq_timeout(q, 30000);
1349 
1350         q->nr_queues = nr_cpu_ids;
1351         q->nr_hw_queues = reg->nr_hw_queues;
1352 
1353         q->queue_ctx = ctx;
1354         q->queue_hw_ctx = hctxs;
1355 
1356         q->mq_ops = reg->ops;
1357         q->queue_flags |= QUEUE_FLAG_MQ_DEFAULT;
1358 
1359         q->sg_reserved_size = INT_MAX;
1360 
1361         blk_queue_make_request(q, blk_mq_make_request);
1362         blk_queue_rq_timed_out(q, reg->ops->timeout);
1363         if (reg->timeout)
1364                 blk_queue_rq_timeout(q, reg->timeout);
1365 
1366         if (reg->ops->complete)
1367                 blk_queue_softirq_done(q, reg->ops->complete);
1368 
1369         blk_mq_init_flush(q);
1370         blk_mq_init_cpu_queues(q, reg->nr_hw_queues);
1371 
1372         q->flush_rq = kzalloc(round_up(sizeof(struct request) + reg->cmd_size,
1373                                 cache_line_size()), GFP_KERNEL);
1374         if (!q->flush_rq)
1375                 goto err_hw;
1376 
1377         if (blk_mq_init_hw_queues(q, reg, driver_data))
1378                 goto err_flush_rq;
1379 
1380         blk_mq_map_swqueue(q);
1381 
1382         mutex_lock(&all_q_mutex);
1383         list_add_tail(&q->all_q_node, &all_q_list);
1384         mutex_unlock(&all_q_mutex);
1385 
1386         return q;
1387 
1388 err_flush_rq:
1389         kfree(q->flush_rq);
1390 err_hw:
1391         kfree(q->mq_map);
1392 err_map:
1393         blk_cleanup_queue(q);
1394 err_hctxs:
1395         for (i = 0; i < reg->nr_hw_queues; i++) {
1396                 if (!hctxs[i])
1397                         break;
1398                 reg->ops->free_hctx(hctxs[i], i);
1399         }
1400         kfree(hctxs);
1401 err_percpu:
1402         free_percpu(ctx);
1403         return ERR_PTR(-ENOMEM);
1404 }
1405 EXPORT_SYMBOL(blk_mq_init_queue);
1406 
1407 void blk_mq_free_queue(struct request_queue *q)
1408 {
1409         struct blk_mq_hw_ctx *hctx;
1410         int i;
1411 
1412         queue_for_each_hw_ctx(q, hctx, i) {
1413                 kfree(hctx->ctx_map);
1414                 kfree(hctx->ctxs);
1415                 blk_mq_free_rq_map(hctx);
1416                 blk_mq_unregister_cpu_notifier(&hctx->cpu_notifier);
1417                 if (q->mq_ops->exit_hctx)
1418                         q->mq_ops->exit_hctx(hctx, i);
1419                 q->mq_ops->free_hctx(hctx, i);
1420         }
1421 
1422         free_percpu(q->queue_ctx);
1423         kfree(q->queue_hw_ctx);
1424         kfree(q->mq_map);
1425 
1426         q->queue_ctx = NULL;
1427         q->queue_hw_ctx = NULL;
1428         q->mq_map = NULL;
1429 
1430         mutex_lock(&all_q_mutex);
1431         list_del_init(&q->all_q_node);
1432         mutex_unlock(&all_q_mutex);
1433 }
1434 
1435 /* Basically redo blk_mq_init_queue with queue frozen */
1436 static void blk_mq_queue_reinit(struct request_queue *q)
1437 {
1438         blk_mq_freeze_queue(q);
1439 
1440         blk_mq_update_queue_map(q->mq_map, q->nr_hw_queues);
1441 
1442         /*
1443          * redo blk_mq_init_cpu_queues and blk_mq_init_hw_queues. FIXME: maybe
1444          * we should change hctx numa_node according to new topology (this
1445          * involves free and re-allocate memory, worthy doing?)
1446          */
1447 
1448         blk_mq_map_swqueue(q);
1449 
1450         blk_mq_unfreeze_queue(q);
1451 }
1452 
1453 static int blk_mq_queue_reinit_notify(struct notifier_block *nb,
1454                                       unsigned long action, void *hcpu)
1455 {
1456         struct request_queue *q;
1457 
1458         /*
1459          * Before new mapping is established, hotadded cpu might already start
1460          * handling requests. This doesn't break anything as we map offline
1461          * CPUs to first hardware queue. We will re-init queue below to get
1462          * optimal settings.
1463          */
1464         if (action != CPU_DEAD && action != CPU_DEAD_FROZEN &&
1465             action != CPU_ONLINE && action != CPU_ONLINE_FROZEN)
1466                 return NOTIFY_OK;
1467 
1468         mutex_lock(&all_q_mutex);
1469         list_for_each_entry(q, &all_q_list, all_q_node)
1470                 blk_mq_queue_reinit(q);
1471         mutex_unlock(&all_q_mutex);
1472         return NOTIFY_OK;
1473 }
1474 
1475 void blk_mq_disable_hotplug(void)
1476 {
1477         mutex_lock(&all_q_mutex);
1478 }
1479 
1480 void blk_mq_enable_hotplug(void)
1481 {
1482         mutex_unlock(&all_q_mutex);
1483 }
1484 
1485 static int __init blk_mq_init(void)
1486 {
1487         blk_mq_cpu_init();
1488 
1489         /* Must be called after percpu_counter_hotcpu_callback() */
1490         hotcpu_notifier(blk_mq_queue_reinit_notify, -10);
1491 
1492         return 0;
1493 }
1494 subsys_initcall(blk_mq_init);
1495 

~ [ source navigation ] ~ [ diff markup ] ~ [ identifier search ] ~

kernel.org | git.kernel.org | LWN.net | Project Home | Wiki (Japanese) | Wiki (English) | SVN repository | Mail admin

Linux® is a registered trademark of Linus Torvalds in the United States and other countries.
TOMOYO® is a registered trademark of NTT DATA CORPORATION.

osdn.jp