blk-mq: Add locking annotations to hctx_lock() and hctx_unlock()

KAGA-KOKO · axboe · commit b7435db8b8d1 · 2018-01-10T12:36:02.000-07:00
This patch avoids that sparse reports the following:

block/blk-mq.c:637:33: warning: context imbalance in 'hctx_unlock' - unexpected unlock
block/blk-mq.c:642:9: warning: context imbalance in 'hctx_lock' - wrong count at exit

Signed-off-by: Bart Van Assche &lt;bart.vanassche@wdc.com&gt;
Cc: Tejun Heo &lt;tj@kernel.org&gt;
Signed-off-by: Jens Axboe &lt;axboe@kernel.dk&gt;
diff --git a/block/blk-mq.c b/block/blk-mq.c
@@ -559,6 +559,7 @@ static void __blk_mq_complete_request(struct request *rq)
 }
 
 static void hctx_unlock(struct blk_mq_hw_ctx *hctx, int srcu_idx)
+	__releases(hctx->srcu)
 {
 	if (!(hctx->flags & BLK_MQ_F_BLOCKING))
 		rcu_read_unlock();
@@ -567,6 +568,7 @@ static void hctx_unlock(struct blk_mq_hw_ctx *hctx, int srcu_idx)
 }
 
 static void hctx_lock(struct blk_mq_hw_ctx *hctx, int *srcu_idx)
+	__acquires(hctx->srcu)
 {
 	if (!(hctx->flags & BLK_MQ_F_BLOCKING)) {
 		/* shut up gcc false positive */

Original file line number	Diff line number	Diff line change
`@@ -559,6 +559,7 @@ static void __blk_mq_complete_request(struct request *rq)`
`559`	`559`	`}`
`560`	`560`
`561`	`561`	`static void hctx_unlock(struct blk_mq_hw_ctx *hctx, int srcu_idx)`
	`562`	`+ __releases(hctx->srcu)`
`562`	`563`	`{`
`563`	`564`	`if (!(hctx->flags & BLK_MQ_F_BLOCKING))`
`564`	`565`	`rcu_read_unlock();`
`@@ -567,6 +568,7 @@ static void hctx_unlock(struct blk_mq_hw_ctx *hctx, int srcu_idx)`
`567`	`568`	`}`
`568`	`569`
`569`	`570`	`static void hctx_lock(struct blk_mq_hw_ctx hctx, int srcu_idx)`
	`571`	`+ __acquires(hctx->srcu)`
`570`	`572`	`{`
`571`	`573`	`if (!(hctx->flags & BLK_MQ_F_BLOCKING)) {`
`572`	`574`	`/* shut up gcc false positive */`