From cc429c8f6fa7cc1c9109bb4a1ad63a6d1f232f0e Mon Sep 17 00:00:00 2001 From: Eric Dumazet Date: Sat, 7 Oct 2017 19:30:28 -0700 Subject: [PATCH] ipv6: avoid cache line dirtying in ipv6_dev_get_saddr() By extending the rcu section a bit, we can avoid these very expensive in6_ifa_put()/in6_ifa_hold() calls done in __ipv6_dev_get_saddr() and ipv6_dev_get_saddr() Signed-off-by: Eric Dumazet Signed-off-by: David S. Miller --- net/ipv6/addrconf.c | 17 ++++++----------- 1 file changed, 6 insertions(+), 11 deletions(-) diff --git a/net/ipv6/addrconf.c b/net/ipv6/addrconf.c index 20c3ca7..cab3faa 100644 --- a/net/ipv6/addrconf.c +++ b/net/ipv6/addrconf.c @@ -1608,11 +1608,6 @@ static int __ipv6_dev_get_saddr(struct net *net, } break; } else if (minihiscore < miniscore) { - if (hiscore->ifa) - in6_ifa_put(hiscore->ifa); - - in6_ifa_hold(score->ifa); - swap(hiscore, score); hiscore_idx = 1 - hiscore_idx; @@ -1660,6 +1655,7 @@ int ipv6_dev_get_saddr(struct net *net, const struct net_device *dst_dev, int dst_type; bool use_oif_addr = false; int hiscore_idx = 0; + int ret = 0; dst_type = __ipv6_addr_type(daddr); dst.addr = daddr; @@ -1735,15 +1731,14 @@ int ipv6_dev_get_saddr(struct net *net, const struct net_device *dst_dev, } out: - rcu_read_unlock(); - hiscore = &scores[hiscore_idx]; if (!hiscore->ifa) - return -EADDRNOTAVAIL; + ret = -EADDRNOTAVAIL; + else + *saddr = hiscore->ifa->addr; - *saddr = hiscore->ifa->addr; - in6_ifa_put(hiscore->ifa); - return 0; + rcu_read_unlock(); + return ret; } EXPORT_SYMBOL(ipv6_dev_get_saddr); -- 2.7.4