diff --git a/net/can/raw.c b/net/can/raw.c
index 1051eee82581..3aab7664933f 100644
--- a/net/can/raw.c
+++ b/net/can/raw.c
@@ -745,18 +745,19 @@ static int raw_sendmsg(struct socket *sock, struct msghdr *msg, size_t size)
 	} else
 		ifindex = ro->ifindex;
 
-	if (ro->fd_frames) {
-		if (unlikely(size != CANFD_MTU && size != CAN_MTU))
-			return -EINVAL;
-	} else {
-		if (unlikely(size != CAN_MTU))
-			return -EINVAL;
-	}
-
 	dev = dev_get_by_index(sock_net(sk), ifindex);
 	if (!dev)
 		return -ENXIO;
 
+	err = -EINVAL;
+	if (ro->fd_frames && dev->mtu == CANFD_MTU) {
+		if (unlikely(size != CANFD_MTU && size != CAN_MTU))
+			goto put_dev;
+	} else {
+		if (unlikely(size != CAN_MTU))
+			goto put_dev;
+	}
+
 	skb = sock_alloc_send_skb(sk, size + sizeof(struct can_skb_priv),
 				  msg->msg_flags & MSG_DONTWAIT, &err);
 	if (!skb)