diff options
Diffstat (limited to 'block/blk-mq-tag.c')
| -rw-r--r-- | block/blk-mq-tag.c | 10 |
1 files changed, 9 insertions, 1 deletions
diff --git a/block/blk-mq-tag.c b/block/blk-mq-tag.c index a07ca3488d96..bf356de30134 100644 --- a/block/blk-mq-tag.c +++ b/block/blk-mq-tag.c @@ -481,6 +481,14 @@ void blk_mq_queue_tag_busy_iter(struct request_queue *q, busy_iter_fn *fn, struct blk_mq_hw_ctx *hctx; int i; + /* + * Avoid potential races with things like queue removal. + */ + rcu_read_lock(); + if (percpu_ref_is_zero(&q->q_usage_counter)) { + rcu_read_unlock(); + return; + } queue_for_each_hw_ctx(q, hctx, i) { struct blk_mq_tags *tags = hctx->tags; @@ -497,7 +505,7 @@ void blk_mq_queue_tag_busy_iter(struct request_queue *q, busy_iter_fn *fn, bt_for_each(hctx, &tags->bitmap_tags, tags->nr_reserved_tags, fn, priv, false); } - + rcu_read_unlock(); } static unsigned int bt_unused_tags(struct blk_mq_bitmap_tags *bt) |