[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>

diff --git a/fs/block_dev.c b/fs/block_dev.c
index 36c38f4..528cf05 100644 (file)
--- 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;
 }