blackfin: fix copy_from_user()

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

1 files changed, 5 insertions, 4 deletions

diff --git a/arch/blackfin/include/asm/uaccess.h b/arch/blackfin/include/asm/uaccess.h
index 12f5d6851bbc..0a2a70096d8b 100644
--- a/arch/blackfin/include/asm/uaccess.h
+++ b/arch/blackfin/include/asm/uaccess.h
@@ -171,11 +171,12 @@ static inline int bad_user_access_length(void)
 static inline unsigned long __must_check
 copy_from_user(void *to, const void __user *from, unsigned long n)
 {
-        if (access_ok(VERIFY_READ, from, n))
+        if (likely(access_ok(VERIFY_READ, from, n))) {
                 memcpy(to, (const void __force *)from, n);
-        else
-                return n;
-        return 0;
+                return 0;
+        }
+        memset(to, 0, n);
+        return n;
 }
 
 static inline unsigned long __must_check