dm: fix idr leak on module removal

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

Cc: stable@kernel.org
Signed-off-by: Alasdair G Kergon <agk@redhat.com>

1 files changed, 8 insertions, 2 deletions

diff --git a/drivers/md/dm.c b/drivers/md/dm.c
index 0cf68b47887..41abc6dd481 100644
--- a/drivers/md/dm.c
+++ b/drivers/md/dm.c
@@ -37,6 +37,8 @@ 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.
@@ -313,6 +315,12 @@ 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);
 }
 
 /*
@@ -1705,8 +1713,6 @@ 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);