Requests often need to be retried because of timeout, hardware busy or sort of reasons via blk_mq_requeue_request(), but at that time dispatch queue may have been stopped.
This patch starts the dispatch queue automatically in requeue's work handler, and fixes scsi-mq's timeout issue, which can be triggered if there are two or more requests timedout. Suggested-by: Christoph Hellwig <[email protected]> Signed-off-by: Ming Lei <[email protected]> --- block/blk-mq.c | 19 ++++++++++++++++--- 1 file changed, 16 insertions(+), 3 deletions(-) diff --git a/block/blk-mq.c b/block/blk-mq.c index 80ade9f..edd0ece 100644 --- a/block/blk-mq.c +++ b/block/blk-mq.c @@ -33,6 +33,8 @@ static DEFINE_MUTEX(all_q_mutex); static LIST_HEAD(all_q_list); static void __blk_mq_run_hw_queue(struct blk_mq_hw_ctx *hctx); +static void __blk_mq_run_queues(struct request_queue *q, bool async, + bool restart); /* * Check if any of the ctx's have pending work in this hardware queue @@ -473,7 +475,7 @@ static void blk_mq_requeue_work(struct work_struct *work) blk_mq_insert_request(rq, false, false, false); } - blk_mq_run_queues(q, false); + __blk_mq_run_queues(q, false, true); } void blk_mq_add_to_requeue_list(struct request *rq, bool at_head) @@ -806,15 +808,21 @@ void blk_mq_run_hw_queue(struct blk_mq_hw_ctx *hctx, bool async) } } -void blk_mq_run_queues(struct request_queue *q, bool async) +static void __blk_mq_run_queues(struct request_queue *q, bool async, + bool restart) { struct blk_mq_hw_ctx *hctx; int i; queue_for_each_hw_ctx(q, hctx, i) { + bool stopped = test_bit(BLK_MQ_S_STOPPED, &hctx->state); + + if (restart && stopped) + clear_bit(BLK_MQ_S_STOPPED, &hctx->state); + if ((!blk_mq_hctx_has_pending(hctx) && list_empty_careful(&hctx->dispatch)) || - test_bit(BLK_MQ_S_STOPPED, &hctx->state)) + (stopped && !restart)) continue; preempt_disable(); @@ -822,6 +830,11 @@ void blk_mq_run_queues(struct request_queue *q, bool async) preempt_enable(); } } + +void blk_mq_run_queues(struct request_queue *q, bool async) +{ + __blk_mq_run_queues(q, async, false); +} EXPORT_SYMBOL(blk_mq_run_queues); void blk_mq_stop_hw_queue(struct blk_mq_hw_ctx *hctx) -- 1.7.9.5 -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to [email protected] More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
