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authorEric Dumazet <edumazet@google.com>2023-09-22 05:42:16 +0200
committerDavid S. Miller <davem@davemloft.net>2023-10-01 20:39:18 +0200
commite08d0b3d172311e2bb500865c0d0038533d0ff11 (patch)
tree0c5343300213611a52bf2904f1aa129567929171 /net/ipv4/tcp_ipv4.c
parentinet: implement lockless IP_MTU_DISCOVER (diff)
downloadlinux-e08d0b3d172311e2bb500865c0d0038533d0ff11.tar.xz
linux-e08d0b3d172311e2bb500865c0d0038533d0ff11.zip
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 <edumazet@google.com> Reviewed-by: David Ahern <dsahern@kernel.org> Signed-off-by: David S. Miller <davem@davemloft.net>
Diffstat (limited to 'net/ipv4/tcp_ipv4.c')
-rw-r--r--net/ipv4/tcp_ipv4.c9
1 files changed, 5 insertions, 4 deletions
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))