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-rw-r--r--block/ioctl.c9
1 files changed, 7 insertions, 2 deletions
diff --git a/block/ioctl.c b/block/ioctl.c
index 203cb4a..8061eba 100644
--- a/block/ioctl.c
+++ b/block/ioctl.c
@@ -174,13 +174,18 @@ EXPORT_SYMBOL(__blkdev_reread_part);
* This is an exported API for the block driver, and will
* try to acquire bd_mutex. If bd_mutex has been held already
* in current context, please call __blkdev_reread_part().
+ *
+ * Make sure the held locks in current context aren't required
+ * in open()/close() handler and I/O path for avoiding ABBA deadlock:
+ * - bd_mutex is held before calling block driver's open/close
+ * handler
+ * - reading partition table may submit I/O to the block device
*/
int blkdev_reread_part(struct block_device *bdev)
{
int res;
- if (!mutex_trylock(&bdev->bd_mutex))
- return -EBUSY;
+ mutex_lock(&bdev->bd_mutex);
res = __blkdev_reread_part(bdev);
mutex_unlock(&bdev->bd_mutex);
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