bfq_has_work() is using busy_queues currently, which is not accurate because bfq_queue is busy doesn't represent that it has requests. Since bfqd aready has a counter 'queued' to record how many requests are in bfq, use it instead of busy_queues. Noted that bfq_has_work() can be called with 'bfqd->lock' held, thus the lock can't be held in bfq_has_work() to protect 'bfqd->queued'. Signed-off-by: Yu Kuai <yukuai3@xxxxxxxxxx> --- block/bfq-iosched.c | 4 ++-- 1 file changed, 2 insertions(+), 2 deletions(-) diff --git a/block/bfq-iosched.c b/block/bfq-iosched.c index 61750696e87f..1d2f8110c26b 100644 --- a/block/bfq-iosched.c +++ b/block/bfq-iosched.c @@ -5063,11 +5063,11 @@ static bool bfq_has_work(struct blk_mq_hw_ctx *hctx) struct bfq_data *bfqd = hctx->queue->elevator->elevator_data; /* - * Avoiding lock: a race on bfqd->busy_queues should cause at + * Avoiding lock: a race on bfqd->queued should cause at * most a call to dispatch for nothing */ return !list_empty_careful(&bfqd->dispatch) || - bfq_tot_busy_queues(bfqd) > 0; + READ_ONCE(bfqd->queued); } static struct request *__bfq_dispatch_request(struct blk_mq_hw_ctx *hctx) -- 2.31.1
