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Miller" , Jakub Kicinski , Paolo Abeni Cc: Neal Cardwell , netdev@vger.kernel.org, eric.dumazet@gmail.com, Eric Dumazet X-Patchwork-Delegate: kuba@kernel.org icsk->icsk_pending can be read locklessly already. Following patch in the series will add another lockless read. Add smp_load_acquire() and smp_store_release() annotations because following patch will add a test in tcp_write_timer(), and READ_ONCE()/WRITE_ONCE() alone would possibly lead to races. Signed-off-by: Eric Dumazet --- include/net/inet_connection_sock.h | 4 ++-- net/ipv4/inet_connection_sock.c | 6 ++++-- net/ipv4/inet_diag.c | 10 ++++++---- net/ipv4/tcp_ipv4.c | 10 ++++++---- net/ipv4/tcp_output.c | 4 ++-- net/ipv4/tcp_timer.c | 4 ++-- net/ipv6/tcp_ipv6.c | 10 ++++++---- 7 files changed, 28 insertions(+), 20 deletions(-) diff --git a/include/net/inet_connection_sock.h b/include/net/inet_connection_sock.h index c0deaafebfdc0bc5b7f9e1b2a881f797a1a82ace..914d1977270449241f6fc6da2055f3af02a75f99 100644 --- a/include/net/inet_connection_sock.h +++ b/include/net/inet_connection_sock.h @@ -197,7 +197,7 @@ static inline void inet_csk_clear_xmit_timer(struct sock *sk, const int what) struct inet_connection_sock *icsk = inet_csk(sk); if (what == ICSK_TIME_RETRANS || what == ICSK_TIME_PROBE0) { - icsk->icsk_pending = 0; + smp_store_release(&icsk->icsk_pending, 0); #ifdef INET_CSK_CLEAR_TIMERS sk_stop_timer(sk, &icsk->icsk_retransmit_timer); #endif @@ -229,7 +229,7 @@ static inline void inet_csk_reset_xmit_timer(struct sock *sk, const int what, if (what == ICSK_TIME_RETRANS || what == ICSK_TIME_PROBE0 || what == ICSK_TIME_LOSS_PROBE || what == ICSK_TIME_REO_TIMEOUT) { - icsk->icsk_pending = what; + smp_store_release(&icsk->icsk_pending, what); icsk->icsk_timeout = jiffies + when; sk_reset_timer(sk, &icsk->icsk_retransmit_timer, icsk->icsk_timeout); } else if (what == ICSK_TIME_DACK) { diff --git a/net/ipv4/inet_connection_sock.c b/net/ipv4/inet_connection_sock.c index 2c5632d4fddbe8ad96f6c35b9ed770d09126eb5d..8c53385cc808c61097898514fd91a322e3a08d31 100644 --- a/net/ipv4/inet_connection_sock.c +++ b/net/ipv4/inet_connection_sock.c @@ -775,7 +775,8 @@ void inet_csk_clear_xmit_timers(struct sock *sk) { struct inet_connection_sock *icsk = inet_csk(sk); - icsk->icsk_pending = icsk->icsk_ack.pending = 0; + smp_store_release(&icsk->icsk_pending, 0); + icsk->icsk_ack.pending = 0; sk_stop_timer(sk, &icsk->icsk_retransmit_timer); sk_stop_timer(sk, &icsk->icsk_delack_timer); @@ -790,7 +791,8 @@ void inet_csk_clear_xmit_timers_sync(struct sock *sk) /* ongoing timer handlers need to acquire socket lock. */ sock_not_owned_by_me(sk); - icsk->icsk_pending = icsk->icsk_ack.pending = 0; + smp_store_release(&icsk->icsk_pending, 0); + icsk->icsk_ack.pending = 0; sk_stop_timer_sync(sk, &icsk->icsk_retransmit_timer); sk_stop_timer_sync(sk, &icsk->icsk_delack_timer); diff --git a/net/ipv4/inet_diag.c b/net/ipv4/inet_diag.c index 67639309163d05c034fad80fc9a6096c3b79d42f..321acc8abf17e8c7d6a4e3326615123fff19deab 100644 --- a/net/ipv4/inet_diag.c +++ b/net/ipv4/inet_diag.c @@ -247,6 +247,7 @@ int inet_sk_diag_fill(struct sock *sk, struct inet_connection_sock *icsk, struct nlmsghdr *nlh; struct nlattr *attr; void *info = NULL; + u8 icsk_pending; int protocol; cb_data = cb->data; @@ -307,14 +308,15 @@ int inet_sk_diag_fill(struct sock *sk, struct inet_connection_sock *icsk, goto out; } - if (icsk->icsk_pending == ICSK_TIME_RETRANS || - icsk->icsk_pending == ICSK_TIME_REO_TIMEOUT || - icsk->icsk_pending == ICSK_TIME_LOSS_PROBE) { + icsk_pending = smp_load_acquire(&icsk->icsk_pending); + if (icsk_pending == ICSK_TIME_RETRANS || + icsk_pending == ICSK_TIME_REO_TIMEOUT || + icsk_pending == ICSK_TIME_LOSS_PROBE) { r->idiag_timer = 1; r->idiag_retrans = icsk->icsk_retransmits; r->idiag_expires = jiffies_delta_to_msecs(icsk->icsk_timeout - jiffies); - } else if (icsk->icsk_pending == ICSK_TIME_PROBE0) { + } else if (icsk_pending == ICSK_TIME_PROBE0) { r->idiag_timer = 4; r->idiag_retrans = icsk->icsk_probes_out; r->idiag_expires = diff --git a/net/ipv4/tcp_ipv4.c b/net/ipv4/tcp_ipv4.c index 5afe5e57c89b5c28dfada2bf2e01fa7b3afa61f0..985028434f644c399e51d12ba8d9c2c5740dc6e1 100644 --- a/net/ipv4/tcp_ipv4.c +++ b/net/ipv4/tcp_ipv4.c @@ -2900,15 +2900,17 @@ static void get_tcp4_sock(struct sock *sk, struct seq_file *f, int i) __be32 src = inet->inet_rcv_saddr; __u16 destp = ntohs(inet->inet_dport); __u16 srcp = ntohs(inet->inet_sport); + u8 icsk_pending; int rx_queue; int state; - if (icsk->icsk_pending == ICSK_TIME_RETRANS || - icsk->icsk_pending == ICSK_TIME_REO_TIMEOUT || - icsk->icsk_pending == ICSK_TIME_LOSS_PROBE) { + icsk_pending = smp_load_acquire(&icsk->icsk_pending); + if (icsk_pending == ICSK_TIME_RETRANS || + icsk_pending == ICSK_TIME_REO_TIMEOUT || + icsk_pending == ICSK_TIME_LOSS_PROBE) { timer_active = 1; timer_expires = icsk->icsk_timeout; - } else if (icsk->icsk_pending == ICSK_TIME_PROBE0) { + } else if (icsk_pending == ICSK_TIME_PROBE0) { timer_active = 4; timer_expires = icsk->icsk_timeout; } else if (timer_pending(&sk->sk_timer)) { diff --git a/net/ipv4/tcp_output.c b/net/ipv4/tcp_output.c index 4fd746bd4d54f621601b20c3821e71370a4a615a..4d04073016035dcf62ba5e0ad23aac86e54e65c7 100644 --- a/net/ipv4/tcp_output.c +++ b/net/ipv4/tcp_output.c @@ -2960,7 +2960,7 @@ void tcp_send_loss_probe(struct sock *sk) WARN_ONCE(tp->packets_out, "invalid inflight: %u state %u cwnd %u mss %d\n", tp->packets_out, sk->sk_state, tcp_snd_cwnd(tp), mss); - inet_csk(sk)->icsk_pending = 0; + smp_store_release(&inet_csk(sk)->icsk_pending, 0); return; } @@ -2993,7 +2993,7 @@ void tcp_send_loss_probe(struct sock *sk) NET_INC_STATS(sock_net(sk), LINUX_MIB_TCPLOSSPROBES); /* Reset s.t. tcp_rearm_rto will restart timer from now */ - inet_csk(sk)->icsk_pending = 0; + smp_store_release(&inet_csk(sk)->icsk_pending, 0); rearm_timer: tcp_rearm_rto(sk); } diff --git a/net/ipv4/tcp_timer.c b/net/ipv4/tcp_timer.c index 79064580c8c0d55daa2ab4dc6d27a5ab8802e599..56c597e763ac7a8cebeba324f84e57b1eeeae977 100644 --- a/net/ipv4/tcp_timer.c +++ b/net/ipv4/tcp_timer.c @@ -701,11 +701,11 @@ void tcp_write_timer_handler(struct sock *sk) tcp_send_loss_probe(sk); break; case ICSK_TIME_RETRANS: - icsk->icsk_pending = 0; + smp_store_release(&icsk->icsk_pending, 0); tcp_retransmit_timer(sk); break; case ICSK_TIME_PROBE0: - icsk->icsk_pending = 0; + smp_store_release(&icsk->icsk_pending, 0); tcp_probe_timer(sk); break; } diff --git a/net/ipv6/tcp_ipv6.c b/net/ipv6/tcp_ipv6.c index d71ab4e1efe1c6598cf3d3e4334adf0881064ce9..7634c0be6acbdb67bb378cc81bdbf184552d2afc 100644 --- a/net/ipv6/tcp_ipv6.c +++ b/net/ipv6/tcp_ipv6.c @@ -2177,6 +2177,7 @@ static void get_tcp6_sock(struct seq_file *seq, struct sock *sp, int i) const struct tcp_sock *tp = tcp_sk(sp); const struct inet_connection_sock *icsk = inet_csk(sp); const struct fastopen_queue *fastopenq = &icsk->icsk_accept_queue.fastopenq; + u8 icsk_pending; int rx_queue; int state; @@ -2185,12 +2186,13 @@ static void get_tcp6_sock(struct seq_file *seq, struct sock *sp, int i) destp = ntohs(inet->inet_dport); srcp = ntohs(inet->inet_sport); - if (icsk->icsk_pending == ICSK_TIME_RETRANS || - icsk->icsk_pending == ICSK_TIME_REO_TIMEOUT || - icsk->icsk_pending == ICSK_TIME_LOSS_PROBE) { + icsk_pending = smp_load_acquire(&icsk->icsk_pending); + if (icsk_pending == ICSK_TIME_RETRANS || + icsk_pending == ICSK_TIME_REO_TIMEOUT || + icsk_pending == ICSK_TIME_LOSS_PROBE) { timer_active = 1; timer_expires = icsk->icsk_timeout; - } else if (icsk->icsk_pending == ICSK_TIME_PROBE0) { + } else if (icsk_pending == ICSK_TIME_PROBE0) { timer_active = 4; timer_expires = icsk->icsk_timeout; } else if (timer_pending(&sp->sk_timer)) {