uvc_v4l2: clean copyin/copyout up

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

drivers/media/usb/uvc/uvc_v4l2.c

@@ -1284,36 +1284,30 @@ struct uvc_xu_control_mapping32 {
 static int uvc_v4l2_get_xu_mapping(struct uvc_xu_control_mapping *kp,
 			const struct uvc_xu_control_mapping32 __user *up)
 {
-	compat_caddr_t p;
+	struct uvc_xu_control_mapping32 *p = (void *)kp;
+	compat_caddr_t info;
+	u32 count;
 
-	if (!access_ok(VERIFY_READ, up, sizeof(*up)) ||
-	    __copy_from_user(kp, up, offsetof(typeof(*up), menu_info)) ||
-	    __get_user(kp->menu_count, &up->menu_count))
+	if (copy_from_user(p, up, sizeof(*p)))
 		return -EFAULT;
 
+	count = p->menu_count;
+	info = p->menu_info;
+
 	memset(kp->reserved, 0, sizeof(kp->reserved));
-
-	if (kp->menu_count == 0) {
-		kp->menu_info = NULL;
-		return 0;
-	}
-
-	if (__get_user(p, &up->menu_info))
-		return -EFAULT;
-	kp->menu_info = compat_ptr(p);
-
+	kp->menu_info = count ? compat_ptr(info) : NULL;
+	kp->menu_count = count;
 	return 0;
 }
 
 static int uvc_v4l2_put_xu_mapping(const struct uvc_xu_control_mapping *kp,
 			struct uvc_xu_control_mapping32 __user *up)
 {
-	if (!access_ok(VERIFY_WRITE, up, sizeof(*up)) ||
-	    __copy_to_user(up, kp, offsetof(typeof(*up), menu_info)) ||
-	    __put_user(kp->menu_count, &up->menu_count))
+	if (copy_to_user(up, kp, offsetof(typeof(*up), menu_info)) ||
+	    put_user(kp->menu_count, &up->menu_count))
 		return -EFAULT;
 
-	if (__clear_user(up->reserved, sizeof(up->reserved)))
+	if (clear_user(up->reserved, sizeof(up->reserved)))
 		return -EFAULT;
 
 	return 0;
@@ -1330,31 +1324,26 @@ struct uvc_xu_control_query32 {
 static int uvc_v4l2_get_xu_query(struct uvc_xu_control_query *kp,
 			const struct uvc_xu_control_query32 __user *up)
 {
-	compat_caddr_t p;
+	struct uvc_xu_control_query32 v;
 
-	if (!access_ok(VERIFY_READ, up, sizeof(*up)) ||
-	    __copy_from_user(kp, up, offsetof(typeof(*up), data)))
+	if (copy_from_user(&v, up, sizeof(v)))
 		return -EFAULT;
 
-	if (kp->size == 0) {
-		kp->data = NULL;
-		return 0;
-	}
-
-	if (__get_user(p, &up->data))
-		return -EFAULT;
-	kp->data = compat_ptr(p);
-
+	*kp = (struct uvc_xu_control_query){
+		.unit = v.unit,
+		.selector = v.selector,
+		.query = v.query,
+		.size = v.size,
+		.data = v.size ? compat_ptr(v.data) : NULL
+	};
 	return 0;
 }
 
 static int uvc_v4l2_put_xu_query(const struct uvc_xu_control_query *kp,
 			struct uvc_xu_control_query32 __user *up)
 {
-	if (!access_ok(VERIFY_WRITE, up, sizeof(*up)) ||
-	    __copy_to_user(up, kp, offsetof(typeof(*up), data)))
+	if (copy_to_user(up, kp, offsetof(typeof(*up), data)))
 		return -EFAULT;
-
 	return 0;
 }