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Commit cd19181b authored by Ming Lei's avatar Ming Lei Committed by Jens Axboe
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blk-mq: enable IO poll if .nr_queues of type poll > 0 



The queue mapping of type poll only exists when set->map[HCTX_TYPE_POLL].nr_queues
is bigger than zero, so enhance the constraint by checking .nr_queues of type poll
before enabling IO poll.

Otherwise IO race & timeout can be observed when running block/007.

Cc: Jeff Moyer <jmoyer@redhat.com>
Cc: Christoph Hellwig <hch@lst.de>
Signed-off-by: default avatarMing Lei <ming.lei@redhat.com>
Signed-off-by: default avatarJens Axboe <axboe@kernel.dk>
parent 3c94d83c

block/blk-mq.c

+2 −1
Original line number Diff line number Diff line
@@ -2833,7 +2833,8 @@ struct request_queue *blk_mq_init_allocated_queue(struct blk_mq_tag_set *set, 
	q->tag_set = set;



	q->queue_flags |= QUEUE_FLAG_MQ_DEFAULT;

	if (set->nr_maps > HCTX_TYPE_POLL)

	if (set->nr_maps > HCTX_TYPE_POLL &&

	    set->map[HCTX_TYPE_POLL].nr_queues)

		blk_queue_flag_set(QUEUE_FLAG_POLL, q);



	if (!(set->flags & BLK_MQ_F_SG_MERGE))

block/blk-sysfs.c

+2 −1
Original line number Diff line number Diff line
@@ -402,7 +402,8 @@ static ssize_t queue_poll_store(struct request_queue *q, const char *page, 
	unsigned long poll_on;

	ssize_t ret;



	if (!q->tag_set || q->tag_set->nr_maps <= HCTX_TYPE_POLL)

	if (!q->tag_set || q->tag_set->nr_maps <= HCTX_TYPE_POLL ||

	    !q->tag_set->map[HCTX_TYPE_POLL].nr_queues)

		return -EINVAL;



	ret = queue_var_store(&poll_on, page, count);