If a request queue is frozen there are no requests pending and hence it is not necessary to run a request queue. Signed-off-by: Bart Van Assche <bvanassche@xxxxxxx> --- block/blk-mq.c | 16 ++++++++-------- 1 file changed, 8 insertions(+), 8 deletions(-) diff --git a/block/blk-mq.c b/block/blk-mq.c index 7919607c1aeb..91b9fc1a7ddb 100644 --- a/block/blk-mq.c +++ b/block/blk-mq.c @@ -2298,16 +2298,16 @@ static inline bool blk_mq_hw_queue_need_run(struct blk_mq_hw_ctx *hctx) bool need_run; /* - * When queue is quiesced, we may be switching io scheduler, or - * updating nr_hw_queues, or other things, and we can't run queue - * any more, even blk_mq_hctx_has_pending() can't be called safely. - * - * And queue will be rerun in blk_mq_unquiesce_queue() if it is - * quiesced. + * The request queue is frozen when the e.g. the I/O scheduler is + * changed and also when nr_hw_queues is updated. Neither running the + * queue nor calling blk_mq_hctx_has_pending() is safe during these + * operations. Hence, check whether the queue is frozen before checking + * whether any requests are pending. */ __blk_mq_run_dispatch_ops(hctx->queue, false, - need_run = !blk_queue_quiesced(hctx->queue) && - blk_mq_hctx_has_pending(hctx)); + need_run = !blk_queue_frozen(hctx->queue) && + !blk_queue_quiesced(hctx->queue) && + blk_mq_hctx_has_pending(hctx)); return need_run; }
