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| author | Eric Dumazet <edumazet@google.com> | 2021-10-25 18:48:22 +0200 |
|---|---|---|
| committer | Jakub Kicinski <kuba@kernel.org> | 2021-10-26 03:02:13 +0200 |
| commit | 790eb67374d43f66102a80821d22188b6a0bc3bb (patch) | |
| tree | 0f6306b5f3870c87d9075ca3738cbe636703affc /net/ipv6/ipv6_sockglue.c | |
| parent | ipv6: annotate data races around np->min_hopcount (diff) | |
| download | linux-790eb67374d43f66102a80821d22188b6a0bc3bb.tar.xz linux-790eb67374d43f66102a80821d22188b6a0bc3bb.zip | |
ipv6: guard IPV6_MINHOPCOUNT with a static key
RFC 5082 IPV6_MINHOPCOUNT is rarely used on hosts.
Add a static key to remove from TCP fast path useless code,
and potential cache line miss to fetch tcp_inet6_sk(sk)->min_hopcount
Note that once ip6_min_hopcount static key has been enabled,
it stays enabled until next boot.
Signed-off-by: Eric Dumazet <edumazet@google.com>
Acked-by: Soheil Hassas Yeganeh <soheil@google.com>
Signed-off-by: Jakub Kicinski <kuba@kernel.org>
Diffstat (limited to 'net/ipv6/ipv6_sockglue.c')
| -rw-r--r-- | net/ipv6/ipv6_sockglue.c | 6 |
1 files changed, 6 insertions, 0 deletions
diff --git a/net/ipv6/ipv6_sockglue.c b/net/ipv6/ipv6_sockglue.c index 9c3d28764b5c..41efca817db4 100644 --- a/net/ipv6/ipv6_sockglue.c +++ b/net/ipv6/ipv6_sockglue.c @@ -55,6 +55,8 @@ struct ip6_ra_chain *ip6_ra_chain; DEFINE_RWLOCK(ip6_ra_lock); +DEFINE_STATIC_KEY_FALSE(ip6_min_hopcount); + int ip6_ra_control(struct sock *sk, int sel) { struct ip6_ra_chain *ra, *new_ra, **rap; @@ -950,6 +952,10 @@ done: goto e_inval; if (val < 0 || val > 255) goto e_inval; + + if (val) + static_branch_enable(&ip6_min_hopcount); + /* tcp_v6_err() and tcp_v6_rcv() might read min_hopcount * while we are changing it. */ |