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ipv6: avoid cache line dirtying in ipv6_dev_get_saddr()

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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>
This commit is contained in:
Eric Dumazet 2017-10-07 19:30:28 -07:00 committed by David S. Miller
parent f59c031e91
commit cc429c8f6f
1 changed files with 6 additions and 11 deletions
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17
net/ipv6/addrconf.c
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@ -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);