[34-longterm 147/179] dm: fix idr leak on module removal

[Paul Gortmaker]

From: Alasdair G Kergon <agk@xxxxxxxxxx>

                   -------------------
    This is a commit scheduled for the next v2.6.34 longterm release.
    http://git.kernel.org/?p=linux/kernel/git/paulg/longterm-queue-2.6.34.git
    If you see a problem with using this for longterm, please comment.
                   -------------------

commit d15b774c2920d55e3d58275c97fbe3adc3afde38 upstream.

Destroy _minor_idr when unloading the core dm module.  (Found by kmemleak.)

Signed-off-by: Alasdair G Kergon <agk@xxxxxxxxxx>
Signed-off-by: Paul Gortmaker <paul.gortmaker@xxxxxxxxxxxxx>
---
 drivers/md/dm.c |   10 ++++++++--
 1 file changed, 8 insertions(+), 2 deletions(-)

diff --git a/drivers/md/dm.c b/drivers/md/dm.c
index c955f7f..6c65d49 100644
--- a/drivers/md/dm.c
+++ b/drivers/md/dm.c
@@ -36,6 +36,8 @@ static const char *_name = DM_NAME;
 static unsigned int major = 0;
 static unsigned int _major = 0;
 
+static DEFINE_IDR(_minor_idr);
+
 static DEFINE_SPINLOCK(_minor_lock);
 /*
  * For bio-based dm.
@@ -324,6 +326,12 @@ static void __exit dm_exit(void)
 
 	while (i--)
 		_exits[i]();
+
+	/*
+	 * Should be empty by this point.
+	 */
+	idr_remove_all(&_minor_idr);
+	idr_destroy(&_minor_idr);
 }
 
 /*
@@ -1772,8 +1780,6 @@ static int dm_any_congested(void *congested_data, int bdi_bits)
 /*-----------------------------------------------------------------
  * An IDR is used to keep track of allocated minor numbers.
  *---------------------------------------------------------------*/
-static DEFINE_IDR(_minor_idr);
-
 static void free_minor(int minor)
 {
 	spin_lock(&_minor_lock);
-- 
1.7.9.6

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