block: Complain if queue_flag_(set|clear)_unlocked() is abused

KAGA-KOKO · axboe · commit 1db2008b79a3 · 2018-03-08T14:13:48.000-07:00
Since it is not safe to use queue_flag_(set|clear)_unlocked()
without holding the queue lock after the sysfs entries for a
queue have been created, complain if this happens.

Cc: Mike Snitzer &lt;snitzer@redhat.com&gt;
Cc: Christoph Hellwig &lt;hch@lst.de&gt;
Cc: Hannes Reinecke &lt;hare@suse.de&gt;
Cc: Ming Lei &lt;ming.lei@redhat.com&gt;
Reviewed-by: Johannes Thumshirn &lt;jthumshirn@suse.de&gt;
Reviewed-by: Martin K. Petersen &lt;martin.petersen@oracle.com&gt;
Signed-off-by: Bart Van Assche &lt;bart.vanassche@wdc.com&gt;
Signed-off-by: Jens Axboe &lt;axboe@kernel.dk&gt;
diff --git a/include/linux/blkdev.h b/include/linux/blkdev.h
@@ -728,12 +728,18 @@ static inline void queue_lockdep_assert_held(struct request_queue *q)
 static inline void queue_flag_set_unlocked(unsigned int flag,
 					   struct request_queue *q)
 {
+	if (test_bit(QUEUE_FLAG_INIT_DONE, &q->queue_flags) &&
+	    kref_read(&q->kobj.kref))
+		lockdep_assert_held(q->queue_lock);
 	__set_bit(flag, &q->queue_flags);
 }
 
 static inline void queue_flag_clear_unlocked(unsigned int flag,
 					     struct request_queue *q)
 {
+	if (test_bit(QUEUE_FLAG_INIT_DONE, &q->queue_flags) &&
+	    kref_read(&q->kobj.kref))
+		lockdep_assert_held(q->queue_lock);
 	__clear_bit(flag, &q->queue_flags);
 }
 

Original file line number	Diff line number	Diff line change
`@@ -728,12 +728,18 @@ static inline void queue_lockdep_assert_held(struct request_queue *q)`
`728`	`728`	`static inline void queue_flag_set_unlocked(unsigned int flag,`
`729`	`729`	`struct request_queue *q)`
`730`	`730`	`{`
	`731`	`+ if (test_bit(QUEUE_FLAG_INIT_DONE, &q->queue_flags) &&`
	`732`	`+ kref_read(&q->kobj.kref))`
	`733`	`+ lockdep_assert_held(q->queue_lock);`
`731`	`734`	`__set_bit(flag, &q->queue_flags);`
`732`	`735`	`}`
`733`	`736`
`734`	`737`	`static inline void queue_flag_clear_unlocked(unsigned int flag,`
`735`	`738`	`struct request_queue *q)`
`736`	`739`	`{`
	`740`	`+ if (test_bit(QUEUE_FLAG_INIT_DONE, &q->queue_flags) &&`
	`741`	`+ kref_read(&q->kobj.kref))`
	`742`	`+ lockdep_assert_held(q->queue_lock);`
`737`	`743`	`__clear_bit(flag, &q->queue_flags);`
`738`	`744`	`}`
`739`	`745`