From 1bd44b11e59f1e9ee7245f8de1f823bc5287b9ef Mon Sep 17 00:00:00 2001 From: "Alexander V. Chernikov" Date: Sun, 14 Feb 2021 10:11:06 +0000 Subject: [PATCH] Do not reference returned ifa in in6_ifawithifp(). The only place where in6_ifawithifp() is used is ip6_output(), which uses the returned ifa to bump traffic counters. Given ifa stability guarantees is provided by epoch, do not refcount ifa. This eliminates 2 atomic ops from IPv6 fast path. Reviewed By: rstone MFC after: 1 week Differential Revision: https://reviews.freebsd.org/D28649 --- sys/netinet6/in6.c | 14 +++----------- sys/netinet6/ip6_output.c | 1 - 2 files changed, 3 insertions(+), 12 deletions(-) diff --git a/sys/netinet6/in6.c b/sys/netinet6/in6.c index 48fa8dd2efc6..057c0ee91e02 100644 --- a/sys/netinet6/in6.c +++ b/sys/netinet6/in6.c @@ -1921,10 +1921,8 @@ in6_ifawithifp(struct ifnet *ifp, struct in6_addr *dst) besta = (struct in6_ifaddr *)ifa; } } - if (besta) { - ifa_ref(&besta->ia_ifa); + if (besta) return (besta); - } CK_STAILQ_FOREACH(ifa, &ifp->if_addrhead, ifa_link) { if (ifa->ifa_addr->sa_family != AF_INET6) @@ -1941,20 +1939,14 @@ in6_ifawithifp(struct ifnet *ifp, struct in6_addr *dst) continue; } - if (ifa != NULL) - ifa_ref(ifa); return (struct in6_ifaddr *)ifa; } /* use the last-resort values, that are, deprecated addresses */ - if (dep[0]) { - ifa_ref((struct ifaddr *)dep[0]); + if (dep[0]) return dep[0]; - } - if (dep[1]) { - ifa_ref((struct ifaddr *)dep[1]); + if (dep[1]) return dep[1]; - } return NULL; } diff --git a/sys/netinet6/ip6_output.c b/sys/netinet6/ip6_output.c index df1e9e6f2dcd..58334788b05b 100644 --- a/sys/netinet6/ip6_output.c +++ b/sys/netinet6/ip6_output.c @@ -1177,7 +1177,6 @@ ip6_output(struct mbuf *m0, struct ip6_pktopts *opt, counter_u64_add(ia6->ia_ifa.ifa_opackets, 1); counter_u64_add(ia6->ia_ifa.ifa_obytes, m->m_pkthdr.len); - ifa_free(&ia6->ia_ifa); } error = ip6_output_send(inp, ifp, origifp, m, dst, ro, (flags & IP_NO_SND_TAG_RL) ? false : true);