It is more reasonable to add requests to ->dispatch in way of FIFO style, instead of LIFO style.
Also in this way, we can allow to insert request at the front of hw queue, which function is needed to fix one bug in blk-mq's implementation of blk_execute_rq() Reported-by: Oleksandr Natalenko <[email protected]> Tested-by: Oleksandr Natalenko <[email protected]> Signed-off-by: Ming Lei <[email protected]> --- block/blk-mq-sched.c | 2 +- block/blk-mq.c | 2 +- 2 files changed, 2 insertions(+), 2 deletions(-) diff --git a/block/blk-mq-sched.c b/block/blk-mq-sched.c index 4ab69435708c..8d97df40fc28 100644 --- a/block/blk-mq-sched.c +++ b/block/blk-mq-sched.c @@ -272,7 +272,7 @@ static bool blk_mq_sched_bypass_insert(struct blk_mq_hw_ctx *hctx, * the dispatch list. */ spin_lock(&hctx->lock); - list_add(&rq->queuelist, &hctx->dispatch); + list_add_tail(&rq->queuelist, &hctx->dispatch); spin_unlock(&hctx->lock); return true; } diff --git a/block/blk-mq.c b/block/blk-mq.c index 4603b115e234..fed3d0c16266 100644 --- a/block/blk-mq.c +++ b/block/blk-mq.c @@ -1067,7 +1067,7 @@ bool blk_mq_dispatch_rq_list(struct request_queue *q, struct list_head *list) blk_mq_put_driver_tag(rq); spin_lock(&hctx->lock); - list_splice_init(list, &hctx->dispatch); + list_splice_tail_init(list, &hctx->dispatch); spin_unlock(&hctx->lock); /* -- 2.9.5
