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| author | Eric Dumazet <edumazet@google.com> | 2023-08-04 14:46:11 +0000 |
|---|---|---|
| committer | David S. Miller <davem@davemloft.net> | 2023-08-06 08:24:55 +0100 |
| commit | d44fd4a767b3755899f8ad1df3e8eca3961ba708 (patch) | |
| tree | 9a3f8e02c87025cd2a6ac2d79a6e3a211de0b7e8 /net/ipv4/tcp_timer.c | |
| parent | 81083076a007d3af3f2216ad9be1374de0687d49 (diff) | |
| download | linux-d44fd4a767b3755899f8ad1df3e8eca3961ba708.tar.gz linux-d44fd4a767b3755899f8ad1df3e8eca3961ba708.tar.bz2 linux-d44fd4a767b3755899f8ad1df3e8eca3961ba708.zip | |
tcp: set TCP_SYNCNT locklessly
icsk->icsk_syn_retries can safely be set without locking the socket.
We have to add READ_ONCE() annotations in tcp_fastopen_synack_timer()
and tcp_write_timeout().
Signed-off-by: Eric Dumazet <edumazet@google.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
Diffstat (limited to 'net/ipv4/tcp_timer.c')
| -rw-r--r-- | net/ipv4/tcp_timer.c | 9 |
1 files changed, 6 insertions, 3 deletions
diff --git a/net/ipv4/tcp_timer.c b/net/ipv4/tcp_timer.c index 470f581eedd4..66040ab457d4 100644 --- a/net/ipv4/tcp_timer.c +++ b/net/ipv4/tcp_timer.c @@ -239,7 +239,8 @@ static int tcp_write_timeout(struct sock *sk) if ((1 << sk->sk_state) & (TCPF_SYN_SENT | TCPF_SYN_RECV)) { if (icsk->icsk_retransmits) __dst_negative_advice(sk); - retry_until = icsk->icsk_syn_retries ? : + /* Paired with WRITE_ONCE() in tcp_sock_set_syncnt() */ + retry_until = READ_ONCE(icsk->icsk_syn_retries) ? : READ_ONCE(net->ipv4.sysctl_tcp_syn_retries); max_retransmits = retry_until; @@ -421,8 +422,10 @@ static void tcp_fastopen_synack_timer(struct sock *sk, struct request_sock *req) req->rsk_ops->syn_ack_timeout(req); - /* add one more retry for fastopen */ - max_retries = icsk->icsk_syn_retries ? : + /* Add one more retry for fastopen. + * Paired with WRITE_ONCE() in tcp_sock_set_syncnt() + */ + max_retries = READ_ONCE(icsk->icsk_syn_retries) ? : READ_ONCE(sock_net(sk)->ipv4.sysctl_tcp_synack_retries) + 1; if (req->num_timeout >= max_retries) { |