blackfin: fix copy_from_user()

[ Upstream commit 8f035983dd826d7e04f67b28acf8e2f08c347e41 ]

Cc: stable@vger.kernel.org
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
Signed-off-by: Sasha Levin <alexander.levin@verizon.com>

diff --git a/arch/blackfin/include/asm/uaccess.h b/arch/blackfin/include/asm/uaccess.h
index 57701c3b8a591b35b60d88807c1d1f479b018423..a992a788409c1226a4d131ca9d51611efb1a1df4 100644 (file)
--- a/arch/blackfin/include/asm/uaccess.h
+++ b/arch/blackfin/include/asm/uaccess.h
@@ -177,11 +177,12 @@ 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