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 <edumazet@google.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
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);