On 06/20/2017 12:07 AM, Bart Van Assche wrote:
> From: Bart Van Assche <bart.vanassche@xxxxxxxxxxx>
>
> Add a comment above the queue_lockdep_assert_held() macro that
> explains the purpose of the q->queue_lock test.
>
> Signed-off-by: Bart Van Assche <bart.vanassche@xxxxxxxxxxx>
> Reviewed-by: Christoph Hellwig <hch@xxxxxx>
> Cc: Hannes Reinecke <hare@xxxxxxxx>
> Cc: Omar Sandoval <osandov@xxxxxx>
> Cc: Ming Lei <ming.lei@xxxxxxxxxx>
> ---
> include/linux/blkdev.h | 7 +++++++
> 1 file changed, 7 insertions(+)
>
> diff --git a/include/linux/blkdev.h b/include/linux/blkdev.h
> index ff0ae83235ea..c00a6b99e77c 100644
> --- a/include/linux/blkdev.h
> +++ b/include/linux/blkdev.h
> @@ -635,6 +635,13 @@ struct request_queue {
> (1 << QUEUE_FLAG_SAME_COMP) | \
> (1 << QUEUE_FLAG_POLL))
>
> +/*
> + * @q->queue_lock is set while a queue is being initialized. Since we know
> + * that no other threads access the queue object before @q->queue_lock has
> + * been set, it is safe to manipulate queue flags without holding the
> + * queue_lock if @q->queue_lock == NULL. See also blk_alloc_queue_node() and
> + * blk_init_allocated_queue().
> + */
> static inline void queue_lockdep_assert_held(struct request_queue *q)
> {
> if (q->queue_lock)
>
Reviewed-by: Hannes Reinecke <hare@xxxxxxxx>
Cheers,
Hannes
--
Dr. Hannes Reinecke Teamlead Storage & Networking
hare@xxxxxxx +49 911 74053 688
SUSE LINUX GmbH, Maxfeldstr. 5, 90409 Nürnberg
GF: F. Imendörffer, J. Smithard, J. Guild, D. Upmanyu, G. Norton
HRB 21284 (AG Nürnberg)
