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authoryangerkun <yangerkun@huawei.com>2020-09-19 06:54:25 +0300
committerJens Axboe <axboe@kernel.dk>2020-09-29 17:11:00 +0300
commit76cffccd606acffde1b91e8b029b39b5fd1a3117 (patch)
tree67bbb2d9c523f52e45957443fc03e87a05a1927d /block
parent8229cca8c3ea70bcb3b73aa105ae1d00aafbd3c8 (diff)
downloadlinux-76cffccd606acffde1b91e8b029b39b5fd1a3117.tar.xz
block-mq: fix comments in blk_mq_queue_tag_busy_iter
'f5bbbbe4d635 ("blk-mq: sync the update nr_hw_queues with blk_mq_queue_tag_busy_iter")' introduce a bug what we may sleep between rcu lock. Then '530ca2c9bd69 ("blk-mq: Allow blocking queue tag iter callbacks")' fix it by get request_queue's ref. And 'a9a808084d6a ("block: Remove the synchronize_rcu() call from __blk_mq_update_nr_hw_queues()")' remove the synchronize_rcu in __blk_mq_update_nr_hw_queues. We need update the confused comments in blk_mq_queue_tag_busy_iter. Signed-off-by: yangerkun <yangerkun@huawei.com> Signed-off-by: Jens Axboe <axboe@kernel.dk>
Diffstat (limited to 'block')
-rw-r--r--block/blk-mq-tag.c4
1 files changed, 1 insertions, 3 deletions
diff --git a/block/blk-mq-tag.c b/block/blk-mq-tag.c
index aacf10decdbd..9c92053e704d 100644
--- a/block/blk-mq-tag.c
+++ b/block/blk-mq-tag.c
@@ -416,9 +416,7 @@ void blk_mq_queue_tag_busy_iter(struct request_queue *q, busy_iter_fn *fn,
/*
* __blk_mq_update_nr_hw_queues() updates nr_hw_queues and queue_hw_ctx
* while the queue is frozen. So we can use q_usage_counter to avoid
- * racing with it. __blk_mq_update_nr_hw_queues() uses
- * synchronize_rcu() to ensure this function left the critical section
- * below.
+ * racing with it.
*/
if (!percpu_ref_tryget(&q->q_usage_counter))
return;