drbd: Add drbd_send_all(): Send an entire buffer

Signed-off-by: Philipp Reisner <philipp.reisner@linbit.com>
Signed-off-by: Lars Ellenberg <lars.ellenberg@linbit.com>

drivers/block/drbd/drbd_int.h

@@ -1161,6 +1161,9 @@ extern void _tl_add_barrier(struct drbd_tconn *, struct drbd_tl_epoch *);
 extern void drbd_free_sock(struct drbd_tconn *tconn);
 extern int drbd_send(struct drbd_tconn *tconn, struct socket *sock,
 		     void *buf, size_t size, unsigned msg_flags);
+extern int drbd_send_all(struct drbd_tconn *, struct socket *, void *, size_t,
+			 unsigned);
+
 extern int drbd_send_protocol(struct drbd_tconn *tconn);
 extern int drbd_send_uuids(struct drbd_conf *mdev);
 extern int drbd_send_uuids_skip_initial_sync(struct drbd_conf *mdev);

drivers/block/drbd/drbd_main.c

@@ -1764,6 +1764,24 @@ int drbd_send(struct drbd_tconn *tconn, struct socket *sock,
 	return sent;
 }
 
+/**
+ * drbd_send_all  -  Send an entire buffer
+ *
+ * Returns 0 upon success and a negative error value otherwise.
+ */
+int drbd_send_all(struct drbd_tconn *tconn, struct socket *sock, void *buffer,
+		  size_t size, unsigned msg_flags)
+{
+	int err;
+
+	err = drbd_send(tconn, sock, buffer, size, msg_flags);
+	if (err < 0)
+		return err;
+	if (err != size)
+		return -EIO;
+	return 0;
+}
+
 static int drbd_open(struct block_device *bdev, fmode_t mode)
 {
 	struct drbd_conf *mdev = bdev->bd_disk->private_data;