[PATCH v3 02/12] block/bdev: Annotate the blk_holder_ops callback invocations

[Bart Van Assche <bvanassche@acm.org>]

The four callback functions in blk_holder_ops all release the
bd_holder_lock. Add __release() annotations where appropriate to prepare
for enabling thread-safety analysis. Explicit __release() annotations have
been added since Clang does not support adding a __releases() annotation
to a function pointer.

Signed-off-by: Bart Van Assche <bvanassche@acm.org>
---
 block/bdev.c  | 10 ++++++++--
 block/ioctl.c |  6 ++++--
 2 files changed, 12 insertions(+), 4 deletions(-)

diff --git a/block/bdev.c b/block/bdev.c
index ed022f8c48c7..bab8f23ec7ec 100644
--- a/block/bdev.c
+++ b/block/bdev.c
@@ -312,7 +312,9 @@ int bdev_freeze(struct block_device *bdev)
 	mutex_lock(&bdev->bd_holder_lock);
 	if (bdev->bd_holder_ops && bdev->bd_holder_ops->freeze) {
 		error = bdev->bd_holder_ops->freeze(bdev);
+		/* bdev->bd_holder_ops->freeze() releases bd_holder_lock */
 		lockdep_assert_not_held(&bdev->bd_holder_lock);
+		__release(&bdev->bd_holder_lock);
 	} else {
 		mutex_unlock(&bdev->bd_holder_lock);
 		error = sync_blockdev(bdev);
@@ -355,7 +357,9 @@ int bdev_thaw(struct block_device *bdev)
 	mutex_lock(&bdev->bd_holder_lock);
 	if (bdev->bd_holder_ops && bdev->bd_holder_ops->thaw) {
 		error = bdev->bd_holder_ops->thaw(bdev);
+		/* bdev->bd_holder_ops->thaw() releases bd_holder_lock */
 		lockdep_assert_not_held(&bdev->bd_holder_lock);
+		__release(&bdev->bd_holder_lock);
 	} else {
 		mutex_unlock(&bdev->bd_holder_lock);
 	}
@@ -1254,9 +1258,11 @@ EXPORT_SYMBOL(lookup_bdev);
 void bdev_mark_dead(struct block_device *bdev, bool surprise)
 {
 	mutex_lock(&bdev->bd_holder_lock);
-	if (bdev->bd_holder_ops && bdev->bd_holder_ops->mark_dead)
+	if (bdev->bd_holder_ops && bdev->bd_holder_ops->mark_dead) {
 		bdev->bd_holder_ops->mark_dead(bdev, surprise);
-	else {
+		/* bdev->bd_holder_ops->mark_dead() releases bd_holder_lock */
+		__release(&bdev->bd_holder_lock);
+	} else {
 		mutex_unlock(&bdev->bd_holder_lock);
 		sync_blockdev(bdev);
 	}
diff --git a/block/ioctl.c b/block/ioctl.c
index 0b04661ac809..57c69ef0f2cd 100644
--- a/block/ioctl.c
+++ b/block/ioctl.c
@@ -523,9 +523,11 @@ static int blkdev_flushbuf(struct block_device *bdev, unsigned cmd,
 		return -EACCES;
 
 	mutex_lock(&bdev->bd_holder_lock);
-	if (bdev->bd_holder_ops && bdev->bd_holder_ops->sync)
+	if (bdev->bd_holder_ops && bdev->bd_holder_ops->sync) {
 		bdev->bd_holder_ops->sync(bdev);
-	else {
+		/* bdev->bd_holder_ops->sync() releases bd_holder_lock */
+		__release(&bdev->bd_holder_lock);
+	} else {
 		mutex_unlock(&bdev->bd_holder_lock);
 		sync_blockdev(bdev);
 	}