nvmet-tcp: Add TOS for tcp transport

Set the outgoing packets type of service (TOS) according to the
receiving TOS.
Signed-off-by: Israel Rukshin <israelr@mellanox.com>
Suggested-by: Sagi Grimberg <sagi@grimberg.me>
Reviewed-by: Max Gurtovoy <maxg@mellanox.com>
Reviewed-by: Sagi Grimberg <sagi@grimberg.me>
Signed-off-by: Sagi Grimberg <sagi@grimberg.me>

drivers/nvme/target/tcp.c

@@ -1415,6 +1415,7 @@ static void nvmet_tcp_state_change(struct sock *sk)
 static int nvmet_tcp_set_queue_sock(struct nvmet_tcp_queue *queue)
 {
 	struct socket *sock = queue->sock;
+	struct inet_sock *inet = inet_sk(sock->sk);
 	struct linger sol = { .l_onoff = 1, .l_linger = 0 };
 	int ret;
 
@@ -1438,6 +1439,16 @@ static int nvmet_tcp_set_queue_sock(struct nvmet_tcp_queue *queue)
 	if (ret)
 		return ret;
 
+	/* Set socket type of service */
+	if (inet->rcv_tos > 0) {
+		int tos = inet->rcv_tos;
+
+		ret = kernel_setsockopt(sock, SOL_IP, IP_TOS,
+				(char *)&tos, sizeof(tos));
+		if (ret)
+			return ret;
+	}
+
 	write_lock_bh(&sock->sk->sk_callback_lock);
 	sock->sk->sk_user_data = queue;
 	queue->data_ready = sock->sk->sk_data_ready;