From 0809e3ac62319dc7534b64f95ac37e230d740e8a Mon Sep 17 00:00:00 2001 From: Jeff Moyer Date: Tue, 20 Oct 2015 23:13:51 +0800 Subject: [PATCH] block: fix plug list flushing for nomerge queues Request queues with merging disabled will not flush the plug list after BLK_MAX_REQUEST_COUNT requests have been queued, since the code relies on blk_attempt_plug_merge to compute the request_count. Fix this by computing the number of queued requests even for nomerge queues. Signed-off-by: Jeff Moyer Signed-off-by: Jens Axboe --- block/blk-core.c | 32 +++++++++++++++++++++++++++++--- block/blk-mq.c | 9 ++++++--- block/blk.h | 1 + 3 files changed, 36 insertions(+), 6 deletions(-) diff --git a/block/blk-core.c b/block/blk-core.c index 2eb722d48773..f0ae087ead06 100644 --- a/block/blk-core.c +++ b/block/blk-core.c @@ -1594,6 +1594,30 @@ out: return ret; } +unsigned int blk_plug_queued_count(struct request_queue *q) +{ + struct blk_plug *plug; + struct request *rq; + struct list_head *plug_list; + unsigned int ret = 0; + + plug = current->plug; + if (!plug) + goto out; + + if (q->mq_ops) + plug_list = &plug->mq_list; + else + plug_list = &plug->list; + + list_for_each_entry(rq, plug_list, queuelist) { + if (rq->q == q) + ret++; + } +out: + return ret; +} + void init_request_from_bio(struct request *req, struct bio *bio) { req->cmd_type = REQ_TYPE_FS; @@ -1641,9 +1665,11 @@ static void blk_queue_bio(struct request_queue *q, struct bio *bio) * Check if we can merge with the plugged list before grabbing * any locks. */ - if (!blk_queue_nomerges(q) && - blk_attempt_plug_merge(q, bio, &request_count, NULL)) - return; + if (!blk_queue_nomerges(q)) { + if (blk_attempt_plug_merge(q, bio, &request_count, NULL)) + return; + } else + request_count = blk_plug_queued_count(q); spin_lock_irq(q->queue_lock); diff --git a/block/blk-mq.c b/block/blk-mq.c index d921cd5177f5..9683a561efcd 100644 --- a/block/blk-mq.c +++ b/block/blk-mq.c @@ -1268,9 +1268,12 @@ static void blk_mq_make_request(struct request_queue *q, struct bio *bio) blk_queue_split(q, &bio, q->bio_split); - if (!is_flush_fua && !blk_queue_nomerges(q) && - blk_attempt_plug_merge(q, bio, &request_count, &same_queue_rq)) - return; + if (!is_flush_fua && !blk_queue_nomerges(q)) { + if (blk_attempt_plug_merge(q, bio, &request_count, + &same_queue_rq)) + return; + } else + request_count = blk_plug_queued_count(q); rq = blk_mq_map_request(q, bio, &data); if (unlikely(!rq)) diff --git a/block/blk.h b/block/blk.h index 98614ad37c81..aa27d0292af1 100644 --- a/block/blk.h +++ b/block/blk.h @@ -86,6 +86,7 @@ bool bio_attempt_back_merge(struct request_queue *q, struct request *req, bool blk_attempt_plug_merge(struct request_queue *q, struct bio *bio, unsigned int *request_count, struct request **same_queue_rq); +unsigned int blk_plug_queued_count(struct request_queue *q); void blk_account_io_start(struct request *req, bool new_io); void blk_account_io_completion(struct request *req, unsigned int bytes);