[PATCH] new bd_mutex lockdep annotation

Use the gendisk partition number to set a lock class.

Signed-off-by: Peter Zijlstra <a.p.zijlstra@chello.nl>
Cc: Neil Brown <neilb@cse.unsw.edu.au>
Cc: Ingo Molnar <mingo@elte.hu>
Acked-by: Arjan van de Ven <arjan@linux.intel.com>
Cc: Jason Baron <jbaron@redhat.com>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>

1 files changed, 9 insertions, 0 deletions

diff --git a/fs/block_dev.c b/fs/block_dev.c
index 36c38f48a4ed..528cf053ce96 100644
--- a/fs/block_dev.c
+++ b/fs/block_dev.c
@@ -355,10 +355,14 @@ static int bdev_set(struct inode *inode, void *data)
 
 static LIST_HEAD(all_bdevs);
 
+static struct lock_class_key bdev_part_lock_key;
+
 struct block_device *bdget(dev_t dev)
 {
         struct block_device *bdev;
         struct inode *inode;
+        struct gendisk *disk;
+        int part = 0;
 
         inode = iget5_locked(bd_mnt->mnt_sb, hash(dev),
                         bdev_test, bdev_set, &dev);
@@ -384,6 +388,11 @@ struct block_device *bdget(dev_t dev)
                 list_add(&bdev->bd_list, &all_bdevs);
                 spin_unlock(&bdev_lock);
                 unlock_new_inode(inode);
+                mutex_init(&bdev->bd_mutex);
+                disk = get_gendisk(dev, &part);
+                if (part)
+                        lockdep_set_class(&bdev->bd_mutex, &bdev_part_lock_key);
+                put_disk(disk);
         }
         return bdev;
 }