[PATCH] lockdep: annotate blkdev nesting

Teach special (recursive) locking code to the lock validator.

Effects on non-lockdep kernels:

- the introduction of the following function variants:

  extern struct block_device *open_partition_by_devnum(dev_t, unsigned);

  extern int blkdev_put_partition(struct block_device *);

  static int
  blkdev_get_whole(struct block_device *bdev, mode_t mode, unsigned flags);

 which on non-lockdep are the same as open_by_devnum(), blkdev_put()
 and blkdev_get().

- a subclass parameter to do_open(). [unused on non-lockdep]

- a subclass parameter to __blkdev_put(), which is a new internal
  function for the main blkdev_put*() functions. [parameter unused
  on non-lockdep kernels, except for two sanity check WARN_ON()s]

these functions carry no semantical difference - they only express
object dependencies towards the lockdep subsystem.

Signed-off-by: Ingo Molnar <mingo@elte.hu>
Signed-off-by: Arjan van de Ven <arjan@linux.intel.com>
Cc: Neil Brown <neilb@cse.unsw.edu.au>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>

1 files changed, 3 insertions, 3 deletions

diff --git a/drivers/md/md.c b/drivers/md/md.c
index 2fe32c261922..e4e161372a3e 100644
--- a/drivers/md/md.c
+++ b/drivers/md/md.c
@@ -1404,7 +1404,7 @@ static int lock_rdev(mdk_rdev_t *rdev, dev_t dev)
         struct block_device *bdev;
         char b[BDEVNAME_SIZE];
 
-        bdev = open_by_devnum(dev, FMODE_READ|FMODE_WRITE);
+        bdev = open_partition_by_devnum(dev, FMODE_READ|FMODE_WRITE);
         if (IS_ERR(bdev)) {
                 printk(KERN_ERR "md: could not open %s.\n",
                         __bdevname(dev, b));
@@ -1414,7 +1414,7 @@ static int lock_rdev(mdk_rdev_t *rdev, dev_t dev)
         if (err) {
                 printk(KERN_ERR "md: could not bd_claim %s.\n",
                         bdevname(bdev, b));
-                blkdev_put(bdev);
+                blkdev_put_partition(bdev);
                 return err;
         }
         rdev->bdev = bdev;
@@ -1428,7 +1428,7 @@ static void unlock_rdev(mdk_rdev_t *rdev)
         if (!bdev)
                 MD_BUG();
         bd_release(bdev);
-        blkdev_put(bdev);
+        blkdev_put_partition(bdev);
 }
 
 void md_autodetect_dev(dev_t dev);