[PATCH] md: define and use safe_put_page for md

md sometimes call put_page on NULL pointers (treating it like kfree).  This is
not safe, so define and use a 'safe_put_page' which checks for NULL.

Signed-off-by: Neil Brown <neilb@suse.de>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>

1 files changed, 1 insertions, 2 deletions

diff --git a/drivers/md/raid6main.c b/drivers/md/raid6main.c
index 950e5fa6e1f2..06b32bd671a3 100644
--- a/drivers/md/raid6main.c
+++ b/drivers/md/raid6main.c
@@ -2072,8 +2072,7 @@ static int run(mddev_t *mddev)
 abort:
         if (conf) {
                 print_raid6_conf(conf);
-                if (conf->spare_page)
-                        put_page(conf->spare_page);
+                safe_put_page(conf->spare_page);
                 kfree(conf->stripe_hashtbl);
                 kfree(conf);
         }