sparc: copy_from_user() should not return -EFAULT

From: Heiko Carstens <[e-mail]>

Callers of copy_from_user() expect it to return the number of bytes
it could not copy. In no case it is supposed to return -EFAULT.

In case of a detected buffer overflow just return the requested
length. In addition one could think of a memset that would clear
the size of the target object.

Signed-off-by: Heiko Carstens <[e-mail]>
Signed-off-by: David S. Miller <[e-mail]>

arch/sparc/include/asm/uaccess_32.h

···
 
 	if (unlikely(sz != -1 && sz < n)) {
 		copy_from_user_overflow();
-		return -EFAULT;
+		return n;
 	}
 
 	if (n && __access_ok((unsigned long) from, n))

arch/sparc/include/asm/uaccess_64.h

···
 static inline unsigned long __must_check
 copy_from_user(void *to, const void __user *from, unsigned long size)
 {
-	unsigned long ret = (unsigned long) -EFAULT;
 	int sz = __compiletime_object_size(to);
+	unsigned long ret = size;
 
 	if (likely(sz == -1 || sz >= size)) {
 		ret = ___copy_from_user(to, from, size);