tcp: purge write queue upon aborting the connection

When the connection is aborted, there is no point in
keeping the packets on the write queue until the connection
is closed.

Similar to a27fd7a8 ('tcp: purge write queue upon RST'),
this is essential for a correct MSG_ZEROCOPY implementation,
because userspace cannot call close(fd) before receiving
zerocopy signals even when the connection is aborted.

Fixes: f214f915 ("tcp: enable MSG_ZEROCOPY")
Signed-off-by: NSoheil Hassas Yeganeh <soheil@google.com>
Signed-off-by: NNeal Cardwell <ncardwell@google.com>
Reviewed-by: NEric Dumazet <edumazet@google.com>
Signed-off-by: NYuchung Cheng <ycheng@google.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

net/ipv4/tcp.c

@@ -3566,6 +3566,7 @@ int tcp_abort(struct sock *sk, int err)
 
 	bh_unlock_sock(sk);
 	local_bh_enable();
+	tcp_write_queue_purge(sk);
 	release_sock(sk);
 	return 0;
 }

net/ipv4/tcp_timer.c

@@ -34,6 +34,7 @@ static void tcp_write_err(struct sock *sk)
 	sk->sk_err = sk->sk_err_soft ? : ETIMEDOUT;
 	sk->sk_error_report(sk);
 
+	tcp_write_queue_purge(sk);
 	tcp_done(sk);
 	__NET_INC_STATS(sock_net(sk), LINUX_MIB_TCPABORTONTIMEOUT);
 }