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Commit cc429c8f authored by Eric Dumazet's avatar Eric Dumazet Committed by David S. Miller
Browse files

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: default avatarEric Dumazet <edumazet@google.com>
Signed-off-by: default avatarDavid S. Miller <davem@davemloft.net>
parent f59c031e

net/ipv6/addrconf.c

+6 −11
Original line number Diff line number Diff line
@@ -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;

	in6_ifa_put(hiscore->ifa);

	return 0;



	rcu_read_unlock();

	return ret;

}

EXPORT_SYMBOL(ipv6_dev_get_saddr);