net: tcp: Increase TCP_MIB_OUTRSTS even though fail to alloc skb

Because TCP_MIB_OUTRSTS is an important count, so always increase it
whatever send it successfully or not.

Now move the increment of TCP_MIB_OUTRSTS to the top of
tcp_send_active_reset to make sure it is increased always even though
fail to alloc skb.

Signed-off-by: Gao Feng <fgao@ikuai8.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

net/ipv4/tcp_output.c

@@ -2999,6 +2999,8 @@ void tcp_send_active_reset(struct sock *sk, gfp_t priority)
 {
 	struct sk_buff *skb;
 
+	TCP_INC_STATS(sock_net(sk), TCP_MIB_OUTRSTS);
+
 	/* NOTE: No TCP options attached and we never retransmit this. */
 	skb = alloc_skb(MAX_TCP_HEADER, priority);
 	if (!skb) {
@@ -3014,8 +3016,6 @@ void tcp_send_active_reset(struct sock *sk, gfp_t priority)
 	/* Send it off. */
 	if (tcp_transmit_skb(sk, skb, 0, priority))
 		NET_INC_STATS(sock_net(sk), LINUX_MIB_TCPABORTFAILED);
-
-	TCP_INC_STATS(sock_net(sk), TCP_MIB_OUTRSTS);
 }
 
 /* Send a crossed SYN-ACK during socket establishment.