x86, pat: In rbt_memtype_check_insert(), update new->type only if valid

new->type should only change when there is a valid ret_type. Otherwise
the requested type and return type should be same.

Signed-off-by: Venkatesh Pallipadi <venkatesh.pallipadi@intel.com>
LKML-Reference: <20100224214355.GA16431@linux-os.sc.intel.com>
Tested-by: Jack Steiner <steiner@sgi.com>
Signed-off-by: H. Peter Anvin <hpa@zytor.com>

1 files changed, 3 insertions, 1 deletions

diff --git a/arch/x86/mm/pat_rbtree.c b/arch/x86/mm/pat_rbtree.c
index 9063f40b638b..07de4cb8cc30 100644
--- a/arch/x86/mm/pat_rbtree.c
+++ b/arch/x86/mm/pat_rbtree.c
@@ -223,7 +223,9 @@ int rbt_memtype_check_insert(struct memtype *new, unsigned long *ret_type)
                                                 new->type, ret_type);
 
         if (!err) {
-                new->type = *ret_type;
+                if (ret_type)
+                        new->type = *ret_type;
+
                 memtype_rb_insert(&memtype_rbroot, new);
         }
         return err;