cris: don't rely upon __copy_user_zeroing() zeroing the tail

we want to get rid of it; unfortunately, it's tangled as hell, so
it'll take many steps, more's the pity.

Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>

diff --git a/arch/cris/include/asm/uaccess.h b/arch/cris/include/asm/uaccess.h
index f62f546720a93e0dea4be4114ebd6b8ca9ceef11..c8858e15d70969c813e9603c94ad00f39f6e9809 100644 (file)
--- a/arch/cris/include/asm/uaccess.h
+++ b/arch/cris/include/asm/uaccess.h
@@ -338,14 +338,16 @@ static inline size_t clear_user(void __user *to, size_t n)
 
 static inline size_t copy_from_user(void *to, const void __user *from, size_t n)
 {
-       if (unlikely(!access_ok(VERIFY_READ, from, n))) {
-               memset(to, 0, n);
-               return n;
+       size_t res = n;
+       if (likely(access_ok(VERIFY_READ, from, n))) {
+               if (__builtin_constant_p(n))
+                       res = __constant_copy_from_user(to, from, n);
+               else
+                       res = __copy_user_zeroing(to, from, n);
        }
-       if (__builtin_constant_p(n))
-               return __constant_copy_from_user(to, from, n);
-       else
-               return __copy_user_zeroing(to, from, n);
+       if (unlikely(res))
+               memset(to + n - res , 0, res);
+       return res;
 }
 
 static inline size_t copy_to_user(void __user *to, const void *from, size_t n)