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tcp: set TCP_LINGER2 locklessly

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tp->linger2 can be set locklessly as long as readers
use READ_ONCE().

Signed-off-by: Eric Dumazet <edumazet@google.com>
Acked-by: Soheil Hassas Yeganeh <soheil@google.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
This commit is contained in:
Eric Dumazet 2023-08-04 14:46:15 +00:00 committed by David S. Miller
parent 84485080cb
commit a81722ddd7
3 changed files with 11 additions and 12 deletions
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19
net/ipv4/tcp.c
View File

@ -2865,7 +2865,7 @@ adjudge_to_death:
if (sk->sk_state == TCP_FIN_WAIT2) {
struct tcp_sock *tp = tcp_sk(sk);
if (tp->linger2 < 0) {
if (READ_ONCE(tp->linger2) < 0) {
tcp_set_state(sk, TCP_CLOSE);
tcp_send_active_reset(sk, GFP_ATOMIC);
__NET_INC_STATS(sock_net(sk),
@ -3471,6 +3471,14 @@ int do_tcp_setsockopt(struct sock *sk, int level, int optname,
return tcp_sock_set_keepintvl(sk, val);
case TCP_KEEPCNT:
return tcp_sock_set_keepcnt(sk, val);
case TCP_LINGER2:
if (val < 0)
WRITE_ONCE(tp->linger2, -1);
else if (val > TCP_FIN_TIMEOUT_MAX / HZ)
WRITE_ONCE(tp->linger2, TCP_FIN_TIMEOUT_MAX);
else
WRITE_ONCE(tp->linger2, val * HZ);
return 0;
}
sockopt_lock_sock(sk);
@ -3576,15 +3584,6 @@ int do_tcp_setsockopt(struct sock *sk, int level, int optname,
tp->save_syn = val;
break;
case TCP_LINGER2:
if (val < 0)
WRITE_ONCE(tp->linger2, -1);
else if (val > TCP_FIN_TIMEOUT_MAX / HZ)
WRITE_ONCE(tp->linger2, TCP_FIN_TIMEOUT_MAX);
else
WRITE_ONCE(tp->linger2, val * HZ);
break;
case TCP_DEFER_ACCEPT:
/* Translate value in seconds to number of retransmits */
WRITE_ONCE(icsk->icsk_accept_queue.rskq_defer_accept,

2
net/ipv4/tcp_input.c
View File

@ -6624,7 +6624,7 @@ int tcp_rcv_state_process(struct sock *sk, struct sk_buff *skb)
break;
}
if (tp->linger2 < 0) {
if (READ_ONCE(tp->linger2) < 0) {
tcp_done(sk);
NET_INC_STATS(sock_net(sk), LINUX_MIB_TCPABORTONDATA);
return 1;

2
net/ipv4/tcp_timer.c
View File

@ -714,7 +714,7 @@ static void tcp_keepalive_timer (struct timer_list *t)
tcp_mstamp_refresh(tp);
if (sk->sk_state == TCP_FIN_WAIT2 && sock_flag(sk, SOCK_DEAD)) {
if (tp->linger2 >= 0) {
if (READ_ONCE(tp->linger2) >= 0) {
const int tmo = tcp_fin_time(sk) - TCP_TIMEWAIT_LEN;
if (tmo > 0) {