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author | Jens Axboe <axboe@fb.com> | 2016-12-07 08:41:17 -0700 |
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committer | Jens Axboe <axboe@fb.com> | 2016-12-09 09:03:02 -0700 |
commit | f04c3df3efeca0d226aeff7ef595e12a0b807ab2 (patch) | |
tree | 6f57ec6196eaeade6a93c181c6654d49283ca8a9 /block/blk-mq.c | |
parent | ae911c5e796d51cb2d1ed3a55e73b9cc88d176cf (diff) | |
download | linux-f04c3df3efeca0d226aeff7ef595e12a0b807ab2.tar.gz linux-f04c3df3efeca0d226aeff7ef595e12a0b807ab2.tar.bz2 linux-f04c3df3efeca0d226aeff7ef595e12a0b807ab2.zip |
blk-mq: abstract out blk_mq_dispatch_rq_list() helper
Takes a list of requests, and dispatches it. Moves any residual
requests to the dispatch list.
Signed-off-by: Jens Axboe <axboe@fb.com>
Reviewed-by: Hannes Reinecke <hare@suse.com>
Diffstat (limited to 'block/blk-mq.c')
-rw-r--r-- | block/blk-mq.c | 85 |
1 files changed, 47 insertions, 38 deletions
diff --git a/block/blk-mq.c b/block/blk-mq.c index c993476b630f..d79fdc11b1ee 100644 --- a/block/blk-mq.c +++ b/block/blk-mq.c @@ -821,41 +821,13 @@ static inline unsigned int queued_to_index(unsigned int queued) return min(BLK_MQ_MAX_DISPATCH_ORDER - 1, ilog2(queued) + 1); } -/* - * Run this hardware queue, pulling any software queues mapped to it in. - * Note that this function currently has various problems around ordering - * of IO. In particular, we'd like FIFO behaviour on handling existing - * items on the hctx->dispatch list. Ignore that for now. - */ -static void blk_mq_process_rq_list(struct blk_mq_hw_ctx *hctx) +bool blk_mq_dispatch_rq_list(struct blk_mq_hw_ctx *hctx, struct list_head *list) { struct request_queue *q = hctx->queue; struct request *rq; - LIST_HEAD(rq_list); LIST_HEAD(driver_list); struct list_head *dptr; - int queued; - - if (unlikely(blk_mq_hctx_stopped(hctx))) - return; - - hctx->run++; - - /* - * Touch any software queue that has pending entries. - */ - flush_busy_ctxs(hctx, &rq_list); - - /* - * If we have previous entries on our dispatch list, grab them - * and stuff them at the front for more fair dispatch. - */ - if (!list_empty_careful(&hctx->dispatch)) { - spin_lock(&hctx->lock); - if (!list_empty(&hctx->dispatch)) - list_splice_init(&hctx->dispatch, &rq_list); - spin_unlock(&hctx->lock); - } + int queued, ret = BLK_MQ_RQ_QUEUE_OK; /* * Start off with dptr being NULL, so we start the first request @@ -867,16 +839,15 @@ static void blk_mq_process_rq_list(struct blk_mq_hw_ctx *hctx) * Now process all the entries, sending them to the driver. */ queued = 0; - while (!list_empty(&rq_list)) { + while (!list_empty(list)) { struct blk_mq_queue_data bd; - int ret; - rq = list_first_entry(&rq_list, struct request, queuelist); + rq = list_first_entry(list, struct request, queuelist); list_del_init(&rq->queuelist); bd.rq = rq; bd.list = dptr; - bd.last = list_empty(&rq_list); + bd.last = list_empty(list); ret = q->mq_ops->queue_rq(hctx, &bd); switch (ret) { @@ -884,7 +855,7 @@ static void blk_mq_process_rq_list(struct blk_mq_hw_ctx *hctx) queued++; break; case BLK_MQ_RQ_QUEUE_BUSY: - list_add(&rq->queuelist, &rq_list); + list_add(&rq->queuelist, list); __blk_mq_requeue_request(rq); break; default: @@ -902,7 +873,7 @@ static void blk_mq_process_rq_list(struct blk_mq_hw_ctx *hctx) * We've done the first request. If we have more than 1 * left in the list, set dptr to defer issue. */ - if (!dptr && rq_list.next != rq_list.prev) + if (!dptr && list->next != list->prev) dptr = &driver_list; } @@ -912,10 +883,11 @@ static void blk_mq_process_rq_list(struct blk_mq_hw_ctx *hctx) * Any items that need requeuing? Stuff them into hctx->dispatch, * that is where we will continue on next queue run. */ - if (!list_empty(&rq_list)) { + if (!list_empty(list)) { spin_lock(&hctx->lock); - list_splice(&rq_list, &hctx->dispatch); + list_splice(list, &hctx->dispatch); spin_unlock(&hctx->lock); + /* * the queue is expected stopped with BLK_MQ_RQ_QUEUE_BUSY, but * it's possible the queue is stopped and restarted again @@ -927,6 +899,43 @@ static void blk_mq_process_rq_list(struct blk_mq_hw_ctx *hctx) **/ blk_mq_run_hw_queue(hctx, true); } + + return ret != BLK_MQ_RQ_QUEUE_BUSY; +} + +/* + * Run this hardware queue, pulling any software queues mapped to it in. + * Note that this function currently has various problems around ordering + * of IO. In particular, we'd like FIFO behaviour on handling existing + * items on the hctx->dispatch list. Ignore that for now. + */ +static void blk_mq_process_rq_list(struct blk_mq_hw_ctx *hctx) +{ + LIST_HEAD(rq_list); + LIST_HEAD(driver_list); + + if (unlikely(blk_mq_hctx_stopped(hctx))) + return; + + hctx->run++; + + /* + * Touch any software queue that has pending entries. + */ + flush_busy_ctxs(hctx, &rq_list); + + /* + * If we have previous entries on our dispatch list, grab them + * and stuff them at the front for more fair dispatch. + */ + if (!list_empty_careful(&hctx->dispatch)) { + spin_lock(&hctx->lock); + if (!list_empty(&hctx->dispatch)) + list_splice_init(&hctx->dispatch, &rq_list); + spin_unlock(&hctx->lock); + } + + blk_mq_dispatch_rq_list(hctx, &rq_list); } static void __blk_mq_run_hw_queue(struct blk_mq_hw_ctx *hctx) |