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@xxxxxxxxxx> Cc: Christoph Hellwig <hch@xxxxxx> Signed-off-by: Ming Lei <ming.lei@xxxxxxxxxx> --- block/blk-mq.c | 3 ++- block/blk-sysfs.c | 3 ++- 2 files changed, 4 insertions(+), 2 deletions(-) diff --git a/block/blk-mq.c b/block/blk-mq.c index 6847f014606b..e45400da4180 100644 --- a/block/blk-mq.c +++ b/block/blk-mq.c @@ -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)) diff --git a/block/blk-sysfs.c b/block/blk-sysfs.c index bb7c642ffefa..0619c8922893 100644 --- a/block/blk-sysfs.c +++ b/block/blk-sysfs.c @@ -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); -- 2.9.5
