On Thu, 2018-01-11 at 15:14 -0500, Mike Snitzer wrote:
> blk_unregister_queue() must protect against any modifications of
> q->queue_flags (not just those performed in blk-sysfs.c). Therefore
> q->queue_lock needs to be used rather than q->sysfs_lock.
>
> Fixes: e9a823fb34a8b ("block: fix warning when I/O elevator is changed as
> request_queue is being removed")
> Cc: [email protected] # 4.14+
> Reported-by: Bart Van Assche <[email protected]>
> Signed-off-by: Mike Snitzer <[email protected]>
> ---
> block/blk-sysfs.c | 4 ++--
> 1 file changed, 2 insertions(+), 2 deletions(-)
>
> diff --git a/block/blk-sysfs.c b/block/blk-sysfs.c
> index 870484eaed1f..52f57539f1c7 100644
> --- a/block/blk-sysfs.c
> +++ b/block/blk-sysfs.c
> @@ -929,9 +929,9 @@ void blk_unregister_queue(struct gendisk *disk)
> if (WARN_ON(!q))
> return;
>
> - mutex_lock(&q->sysfs_lock);
> + spin_lock_irq(q->queue_lock);
> queue_flag_clear_unlocked(QUEUE_FLAG_REGISTERED, q);
> - mutex_unlock(&q->sysfs_lock);
> + spin_unlock_irq(q->queue_lock);
Hello Mike,
The function name queue_flag_clear_unlocked() means "clear a queue flag
without holding the queue lock". So at least to me the above code is confusing.
Please consider to change queue_flag_clear_unlocked() into queue_flag_clear().
Thanks,
Bart.
