1 files changed, 8 insertions, 12 deletions

diff --git a/arch/x86/lib/usercopy.c b/arch/x86/lib/usercopy.c
index d6ae30bbd7bb..2e4e4b02c37a 100644
--- a/arch/x86/lib/usercopy.c
+++ b/arch/x86/lib/usercopy.c
@@ -44,13 +44,6 @@ copy_from_user_nmi(void *to, const void __user *from, unsigned long n)
 }
 EXPORT_SYMBOL_GPL(copy_from_user_nmi);
 
-static inline unsigned long count_bytes(unsigned long mask)
-{
-        mask = (mask - 1) & ~mask;
-        mask >>= 7;
-        return count_masked_bytes(mask);
-}
-
 /*
  * Do a strncpy, return length of string without final '\0'.
  * 'count' is the user-supplied count (return 'count' if we
@@ -69,16 +62,19 @@ static inline long do_strncpy_from_user(char *dst, const char __user *src, long
                 max = count;
 
         while (max >= sizeof(unsigned long)) {
-                unsigned long c;
+                unsigned long c, mask;
 
                 /* Fall back to byte-at-a-time if we get a page fault */
                 if (unlikely(__get_user(c,(unsigned long __user *)(src+res))))
                         break;
-                /* This can write a few bytes past the NUL character, but that's ok */
+                mask = has_zero(c);
+                if (mask) {
+                        mask = (mask - 1) & ~mask;
+                        mask >>= 7;
+                        *(unsigned long *)(dst+res) = c & mask;
+                        return res + count_masked_bytes(mask);
+                }
                 *(unsigned long *)(dst+res) = c;
-                c = has_zero(c);
-                if (c)
-                        return res + count_bytes(c);
                 res += sizeof(unsigned long);
                 max -= sizeof(unsigned long);
         }