[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/bitmap.c b/drivers/md/bitmap.c
index abe415f0c039..ee4a3424a8a3 100644
--- a/drivers/md/bitmap.c
+++ b/drivers/md/bitmap.c
@@ -626,8 +626,7 @@ static void bitmap_file_unmap(struct bitmap *bitmap)
         kfree(map);
         kfree(attr);
 
-        if (sb_page)
-                put_page(sb_page);
+        safe_put_page(sb_page);
 }
 
 static void bitmap_stop_daemon(struct bitmap *bitmap);