From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: From: Bart Van Assche To: Jens Axboe CC: , Christoph Hellwig , "Bart Van Assche" , Hannes Reinecke , "Omar Sandoval" , Ming Lei Subject: [PATCH v3 07/12] block: Add a comment above queue_lockdep_assert_held() Date: Thu, 8 Jun 2017 10:33:50 -0700 Message-ID: <20170608173355.25898-8-bart.vanassche@sandisk.com> In-Reply-To: <20170608173355.25898-1-bart.vanassche@sandisk.com> References: <20170608173355.25898-1-bart.vanassche@sandisk.com> MIME-Version: 1.0 Content-Type: text/plain Return-Path: Bart.VanAssche@sandisk.com List-ID: 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 Reviewed-by: Christoph Hellwig Cc: Hannes Reinecke Cc: Omar Sandoval Cc: Ming Lei --- include/linux/blkdev.h | 7 +++++++ 1 file changed, 7 insertions(+) diff --git a/include/linux/blkdev.h b/include/linux/blkdev.h index cbc0028290e4..1e73b4df13a9 100644 --- a/include/linux/blkdev.h +++ b/include/linux/blkdev.h @@ -634,6 +634,13 @@ 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) -- 2.12.2