From e08d0b3d172311e2bb500865c0d0038533d0ff11 Mon Sep 17 00:00:00 2001 From: Eric Dumazet Date: Fri, 22 Sep 2023 03:42:16 +0000 Subject: inet: implement lockless IP_TOS Some reads of inet->tos are racy. Add needed READ_ONCE() annotations and convert IP_TOS option lockless. v2: missing changes in include/net/route.h (David Ahern) Signed-off-by: Eric Dumazet Reviewed-by: David Ahern Signed-off-by: David S. Miller --- net/ipv4/tcp_ipv4.c | 9 +++++---- 1 file changed, 5 insertions(+), 4 deletions(-) (limited to 'net/ipv4/tcp_ipv4.c') diff --git a/net/ipv4/tcp_ipv4.c b/net/ipv4/tcp_ipv4.c index 95e972be0c05..a441740616d7 100644 --- a/net/ipv4/tcp_ipv4.c +++ b/net/ipv4/tcp_ipv4.c @@ -1024,10 +1024,11 @@ static int tcp_v4_send_synack(const struct sock *sk, struct dst_entry *dst, if (skb) { __tcp_v4_send_check(skb, ireq->ir_loc_addr, ireq->ir_rmt_addr); - tos = READ_ONCE(sock_net(sk)->ipv4.sysctl_tcp_reflect_tos) ? - (tcp_rsk(req)->syn_tos & ~INET_ECN_MASK) | - (inet_sk(sk)->tos & INET_ECN_MASK) : - inet_sk(sk)->tos; + tos = READ_ONCE(inet_sk(sk)->tos); + + if (READ_ONCE(sock_net(sk)->ipv4.sysctl_tcp_reflect_tos)) + tos = (tcp_rsk(req)->syn_tos & ~INET_ECN_MASK) | + (tos & INET_ECN_MASK); if (!INET_ECN_is_capable(tos) && tcp_bpf_ca_needs_ecn((struct sock *)req)) -- cgit v1.2.3