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authorEric Dumazet <edumazet@google.com>2023-03-13 20:17:32 +0000
committerJakub Kicinski <kuba@kernel.org>2023-03-15 00:37:33 -0700
commitc486640aa710ddd06c13a7f7162126e1552e8842 (patch)
tree0611835d7b618d97f31bdc1a592542c5352b636f /net/ipv6/route.c
parentb071af523579df7341cabf0f16fc661125e9a13f (diff)
ipv6: remove one read_lock()/read_unlock() pair in rt6_check_neigh()
rt6_check_neigh() uses read_lock() to protect n->nud_state reading. This seems overkill and causes false sharing. Signed-off-by: Eric Dumazet <edumazet@google.com> Reviewed-by: David Ahern <dsahern@kernel.org> Reviewed-by: Martin KaFai Lau <martin.lau@kernel.org> Signed-off-by: Jakub Kicinski <kuba@kernel.org>
Diffstat (limited to 'net/ipv6/route.c')
-rw-r--r--net/ipv6/route.c8
1 files changed, 4 insertions, 4 deletions
diff --git a/net/ipv6/route.c b/net/ipv6/route.c
index 25c00c6f5131..e829bd880384 100644
--- a/net/ipv6/route.c
+++ b/net/ipv6/route.c
@@ -687,16 +687,16 @@ static enum rt6_nud_state rt6_check_neigh(const struct fib6_nh *fib6_nh)
neigh = __ipv6_neigh_lookup_noref(fib6_nh->fib_nh_dev,
&fib6_nh->fib_nh_gw6);
if (neigh) {
- read_lock(&neigh->lock);
- if (neigh->nud_state & NUD_VALID)
+ u8 nud_state = READ_ONCE(neigh->nud_state);
+
+ if (nud_state & NUD_VALID)
ret = RT6_NUD_SUCCEED;
#ifdef CONFIG_IPV6_ROUTER_PREF
- else if (!(neigh->nud_state & NUD_FAILED))
+ else if (!(nud_state & NUD_FAILED))
ret = RT6_NUD_SUCCEED;
else
ret = RT6_NUD_FAIL_PROBE;
#endif
- read_unlock(&neigh->lock);
} else {
ret = IS_ENABLED(CONFIG_IPV6_ROUTER_PREF) ?
RT6_NUD_SUCCEED : RT6_NUD_FAIL_DO_RR;