diff options
| author | Eric Dumazet <edumazet@google.com> | 2023-09-12 16:02:11 +0000 |
|---|---|---|
| committer | David S. Miller <davem@davemloft.net> | 2023-09-15 10:33:48 +0100 |
| commit | 6b724bc4300b431443f3b99520994a5aece347cd (patch) | |
| tree | 02730c15dc86341705749df48ed87b7ca84688c1 /net/ipv6/ipv6_sockglue.c | |
| parent | 83cd5eb654b320c1972254f243531f3f3cebcccf (diff) | |
| download | lwn-6b724bc4300b431443f3b99520994a5aece347cd.tar.gz lwn-6b724bc4300b431443f3b99520994a5aece347cd.zip | |
ipv6: lockless IPV6_MTU_DISCOVER implementation
Most np->pmtudisc reads are racy.
Move this 3bit field on a full byte, add annotations
and make IPV6_MTU_DISCOVER setsockopt() lockless.
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/ipv6/ipv6_sockglue.c')
| -rw-r--r-- | net/ipv6/ipv6_sockglue.c | 17 |
1 files changed, 8 insertions, 9 deletions
diff --git a/net/ipv6/ipv6_sockglue.c b/net/ipv6/ipv6_sockglue.c index c22a492e0536..85ea42644dcb 100644 --- a/net/ipv6/ipv6_sockglue.c +++ b/net/ipv6/ipv6_sockglue.c @@ -493,6 +493,13 @@ int do_ipv6_setsockopt(struct sock *sk, int level, int optname, return -EINVAL; inet6_assign_bit(RTALERT_ISOLATE, sk, valbool); return 0; + case IPV6_MTU_DISCOVER: + if (optlen < sizeof(int)) + return -EINVAL; + if (val < IPV6_PMTUDISC_DONT || val > IPV6_PMTUDISC_OMIT) + return -EINVAL; + WRITE_ONCE(np->pmtudisc, val); + return 0; } if (needs_rtnl) rtnl_lock(); @@ -941,14 +948,6 @@ done: goto e_inval; retv = ip6_ra_control(sk, val); break; - case IPV6_MTU_DISCOVER: - if (optlen < sizeof(int)) - goto e_inval; - if (val < IPV6_PMTUDISC_DONT || val > IPV6_PMTUDISC_OMIT) - goto e_inval; - np->pmtudisc = val; - retv = 0; - break; case IPV6_FLOWINFO_SEND: if (optlen < sizeof(int)) goto e_inval; @@ -1374,7 +1373,7 @@ int do_ipv6_getsockopt(struct sock *sk, int level, int optname, break; case IPV6_MTU_DISCOVER: - val = np->pmtudisc; + val = READ_ONCE(np->pmtudisc); break; case IPV6_RECVERR: |