tcp: remove sk_can_gso() use

After previous commit, sk_can_gso() is always true.
Signed-off-by: NEric Dumazet <edumazet@google.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

net/ipv4/tcp.c

@@ -898,7 +898,7 @@ static unsigned int tcp_xmit_size_goal(struct sock *sk, u32 mss_now,
 	struct tcp_sock *tp = tcp_sk(sk);
 	u32 new_size_goal, size_goal;
 
-	if (!large_allowed || !sk_can_gso(sk))
+	if (!large_allowed)
 		return mss_now;
 
 	/* Note : tcp_tso_autosize() will eventually split this later */
@@ -1103,27 +1103,11 @@ static int linear_payload_sz(bool first_skb)
 	return 0;
 }
 
-static int select_size(const struct sock *sk, bool sg, bool first_skb, bool zc)
+static int select_size(bool first_skb, bool zc)
 {
-	const struct tcp_sock *tp = tcp_sk(sk);
-	int tmp = tp->mss_cache;
-
-	if (sg) {
-		if (zc)
-			return 0;
-
-		if (sk_can_gso(sk)) {
-			tmp = linear_payload_sz(first_skb);
-		} else {
-			int pgbreak = SKB_MAX_HEAD(MAX_TCP_HEADER);
-
-			if (tmp >= pgbreak &&
-			    tmp <= pgbreak + (MAX_SKB_FRAGS - 1) * PAGE_SIZE)
-				tmp = pgbreak;
-		}
-	}
-
-	return tmp;
+	if (zc)
+		return 0;
+	return linear_payload_sz(first_skb);
 }
 
 void tcp_free_fastopen_req(struct tcp_sock *tp)
@@ -1188,7 +1172,7 @@ int tcp_sendmsg_locked(struct sock *sk, struct msghdr *msg, size_t size)
 	int flags, err, copied = 0;
 	int mss_now = 0, size_goal, copied_syn = 0;
 	bool process_backlog = false;
-	bool sg, zc = false;
+	bool zc = false;
 	long timeo;
 
 	flags = msg->msg_flags;
@@ -1269,8 +1253,6 @@ int tcp_sendmsg_locked(struct sock *sk, struct msghdr *msg, size_t size)
 	if (sk->sk_err || (sk->sk_shutdown & SEND_SHUTDOWN))
 		goto do_error;
 
-	sg = !!(sk->sk_route_caps & NETIF_F_SG);
-
 	while (msg_data_left(msg)) {
 		int copy = 0;
 		int max = size_goal;
@@ -1298,7 +1280,7 @@ int tcp_sendmsg_locked(struct sock *sk, struct msghdr *msg, size_t size)
 				goto restart;
 			}
 			first_skb = tcp_rtx_and_write_queues_empty(sk);
-			linear = select_size(sk, sg, first_skb, zc);
+			linear = select_size(first_skb, zc);
 			skb = sk_stream_alloc_skb(sk, linear, sk->sk_allocation,
 						  first_skb);
 			if (!skb)
@@ -1344,7 +1326,7 @@ int tcp_sendmsg_locked(struct sock *sk, struct msghdr *msg, size_t size)
 
 			if (!skb_can_coalesce(skb, i, pfrag->page,
 					      pfrag->offset)) {
-				if (i >= sysctl_max_skb_frags || !sg) {
+				if (i >= sysctl_max_skb_frags) {
 					tcp_mark_push(tp, skb);
 					goto new_segment;
 				}

net/ipv4/tcp_input.c

@@ -1358,9 +1358,6 @@ static struct sk_buff *tcp_shift_skb_data(struct sock *sk, struct sk_buff *skb,
 	int len;
 	int in_sack;
 
-	if (!sk_can_gso(sk))
-		goto fallback;
-
 	/* Normally R but no L won't result in plain S */
 	if (!dup_sack &&
 	    (TCP_SKB_CB(skb)->sacked & (TCPCB_LOST|TCPCB_SACKED_RETRANS)) == TCPCB_SACKED_RETRANS)