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net: Abstract default MTU metric calculation behind an accessor.

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Like RTAX_ADVMSS, make the default calculation go through a dst_ops
method rather than caching the computation in the routing cache
entries.

Now dst metrics are pretty much left as-is when new entries are
created, thus optimizing metric sharing becomes a real possibility.

Signed-off-by: David S. Miller <davem@davemloft.net>
This commit is contained in:
David S. Miller 2010-12-14 13:01:14 -08:00
parent 9fe146aef4
commit d33e455337
6 changed files with 60 additions and 39 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

15
include/net/dst.h
View File

@ -113,7 +113,8 @@ static inline u32
dst_metric(const struct dst_entry *dst, const int metric)
{
WARN_ON_ONCE(metric == RTAX_HOPLIMIT ||
metric == RTAX_ADVMSS);
metric == RTAX_ADVMSS ||
metric == RTAX_MTU);
return dst_metric_raw(dst, metric);
}
@ -156,11 +157,11 @@ dst_feature(const struct dst_entry *dst, u32 feature)
static inline u32 dst_mtu(const struct dst_entry *dst)
{
u32 mtu = dst_metric(dst, RTAX_MTU);
/*
* Alexey put it here, so ask him about it :)
*/
barrier();
u32 mtu = dst_metric_raw(dst, RTAX_MTU);
if (!mtu)
mtu = dst->ops->default_mtu(dst);
return mtu;
}
@ -186,7 +187,7 @@ dst_allfrag(const struct dst_entry *dst)
}
static inline int
dst_metric_locked(struct dst_entry *dst, int metric)
dst_metric_locked(const struct dst_entry *dst, int metric)
{
return dst_metric(dst, RTAX_LOCK) & (1<<metric);
}

1
include/net/dst_ops.h
View File

@ -17,6 +17,7 @@ struct dst_ops {
int (*gc)(struct dst_ops *ops);
struct dst_entry * (*check)(struct dst_entry *, __u32 cookie);
unsigned int (*default_advmss)(const struct dst_entry *);
unsigned int (*default_mtu)(const struct dst_entry *);
void (*destroy)(struct dst_entry *);
void (*ifdown)(struct dst_entry *,
struct net_device *dev, int how);

10
net/decnet/dn_route.c
View File

@ -111,6 +111,7 @@ static unsigned long dn_rt_deadline;
static int dn_dst_gc(struct dst_ops *ops);
static struct dst_entry *dn_dst_check(struct dst_entry *, __u32);
static unsigned int dn_dst_default_advmss(const struct dst_entry *dst);
static unsigned int dn_dst_default_mtu(const struct dst_entry *dst);
static struct dst_entry *dn_dst_negative_advice(struct dst_entry *);
static void dn_dst_link_failure(struct sk_buff *);
static void dn_dst_update_pmtu(struct dst_entry *dst, u32 mtu);
@ -131,6 +132,7 @@ static struct dst_ops dn_dst_ops = {
.gc = dn_dst_gc,
.check = dn_dst_check,
.default_advmss = dn_dst_default_advmss,
.default_mtu = dn_dst_default_mtu,
.negative_advice = dn_dst_negative_advice,
.link_failure = dn_dst_link_failure,
.update_pmtu = dn_dst_update_pmtu,
@ -803,6 +805,11 @@ static unsigned int dn_dst_default_advmss(const struct dst_entry *dst)
return dn_mss_from_pmtu(dst->dev, dst_mtu(dst));
}
static unsigned int dn_dst_default_mtu(const struct dst_entry *dst)
{
return dst->dev->mtu;
}
static int dn_rt_set_next_hop(struct dn_route *rt, struct dn_fib_res *res)
{
struct dn_fib_info *fi = res->fi;
@ -825,8 +832,7 @@ static int dn_rt_set_next_hop(struct dn_route *rt, struct dn_fib_res *res)
rt->dst.neighbour = n;
}
if (dst_metric(&rt->dst, RTAX_MTU) == 0 ||
dst_metric(&rt->dst, RTAX_MTU) > rt->dst.dev->mtu)
if (dst_metric(&rt->dst, RTAX_MTU) > rt->dst.dev->mtu)
dst_metric_set(&rt->dst, RTAX_MTU, rt->dst.dev->mtu);
metric = dst_metric_raw(&rt->dst, RTAX_ADVMSS);
if (metric) {

29
net/ipv4/route.c
View File

@ -140,6 +140,7 @@ static unsigned long expires_ljiffies;
static struct dst_entry *ipv4_dst_check(struct dst_entry *dst, u32 cookie);
static unsigned int ipv4_default_advmss(const struct dst_entry *dst);
static unsigned int ipv4_default_mtu(const struct dst_entry *dst);
static void ipv4_dst_destroy(struct dst_entry *dst);
static struct dst_entry *ipv4_negative_advice(struct dst_entry *dst);
static void ipv4_link_failure(struct sk_buff *skb);
@ -157,6 +158,7 @@ static struct dst_ops ipv4_dst_ops = {
.gc = rt_garbage_collect,
.check = ipv4_dst_check,
.default_advmss = ipv4_default_advmss,
.default_mtu = ipv4_default_mtu,
.destroy = ipv4_dst_destroy,
.ifdown = ipv4_dst_ifdown,
.negative_advice = ipv4_negative_advice,
@ -1812,6 +1814,23 @@ static unsigned int ipv4_default_advmss(const struct dst_entry *dst)
return advmss;
}
static unsigned int ipv4_default_mtu(const struct dst_entry *dst)
{
unsigned int mtu = dst->dev->mtu;
if (unlikely(dst_metric_locked(dst, RTAX_MTU))) {
const struct rtable *rt = (const struct rtable *) dst;
if (rt->rt_gateway != rt->rt_dst && mtu > 576)
mtu = 576;
}
if (mtu > IP_MAX_MTU)
mtu = IP_MAX_MTU;
return mtu;
}
static void rt_set_nexthop(struct rtable *rt, struct fib_result *res, u32 itag)
{
struct dst_entry *dst = &rt->dst;
@ -1822,18 +1841,10 @@ static void rt_set_nexthop(struct rtable *rt, struct fib_result *res, u32 itag)
FIB_RES_NH(*res).nh_scope == RT_SCOPE_LINK)
rt->rt_gateway = FIB_RES_GW(*res);
dst_import_metrics(dst, fi->fib_metrics);
if (fi->fib_mtu == 0) {
dst_metric_set(dst, RTAX_MTU, dst->dev->mtu);
if (dst_metric_locked(dst, RTAX_MTU) &&
rt->rt_gateway != rt->rt_dst &&
dst->dev->mtu > 576)
dst_metric_set(dst, RTAX_MTU, 576);
}
#ifdef CONFIG_NET_CLS_ROUTE
dst->tclassid = FIB_RES_NH(*res).nh_tclassid;
#endif
} else
dst_metric_set(dst, RTAX_MTU, dst->dev->mtu);
}
if (dst_mtu(dst) > IP_MAX_MTU)
dst_metric_set(dst, RTAX_MTU, IP_MAX_MTU);

37
net/ipv6/route.c
View File

@ -77,6 +77,7 @@
static struct rt6_info * ip6_rt_copy(struct rt6_info *ort);
static struct dst_entry *ip6_dst_check(struct dst_entry *dst, u32 cookie);
static unsigned int ip6_default_advmss(const struct dst_entry *dst);
static unsigned int ip6_default_mtu(const struct dst_entry *dst);
static struct dst_entry *ip6_negative_advice(struct dst_entry *);
static void ip6_dst_destroy(struct dst_entry *);
static void ip6_dst_ifdown(struct dst_entry *,
@ -105,6 +106,7 @@ static struct dst_ops ip6_dst_ops_template = {
.gc_thresh = 1024,
.check = ip6_dst_check,
.default_advmss = ip6_default_advmss,
.default_mtu = ip6_default_mtu,
.destroy = ip6_dst_destroy,
.ifdown = ip6_dst_ifdown,
.negative_advice = ip6_negative_advice,
@ -937,8 +939,6 @@ static void ip6_rt_update_pmtu(struct dst_entry *dst, u32 mtu)
}
}
static int ipv6_get_mtu(struct net_device *dev);
static unsigned int ip6_default_advmss(const struct dst_entry *dst)
{
struct net_device *dev = dst->dev;
@ -961,6 +961,20 @@ static unsigned int ip6_default_advmss(const struct dst_entry *dst)
return mtu;
}
static unsigned int ip6_default_mtu(const struct dst_entry *dst)
{
unsigned int mtu = IPV6_MIN_MTU;
struct inet6_dev *idev;
rcu_read_lock();
idev = __in6_dev_get(dst->dev);
if (idev)
mtu = idev->cnf.mtu6;
rcu_read_unlock();
return mtu;
}
static struct dst_entry *icmp6_dst_gc_list;
static DEFINE_SPINLOCK(icmp6_dst_lock);
@ -995,7 +1009,6 @@ struct dst_entry *icmp6_dst_alloc(struct net_device *dev,
rt->rt6i_nexthop = neigh;
atomic_set(&rt->dst.__refcnt, 1);
dst_metric_set(&rt->dst, RTAX_HOPLIMIT, 255);
dst_metric_set(&rt->dst, RTAX_MTU, ipv6_get_mtu(rt->rt6i_dev));
rt->dst.output = ip6_output;
#if 0 /* there's no chance to use these for ndisc */
@ -1094,19 +1107,6 @@ out:
Remove it only when all the things will work!
*/
static int ipv6_get_mtu(struct net_device *dev)
{
int mtu = IPV6_MIN_MTU;
struct inet6_dev *idev;
rcu_read_lock();
idev = __in6_dev_get(dev);
if (idev)
mtu = idev->cnf.mtu6;
rcu_read_unlock();
return mtu;
}
int ip6_dst_hoplimit(struct dst_entry *dst)
{
int hoplimit = dst_metric_raw(dst, RTAX_HOPLIMIT);
@ -1315,8 +1315,6 @@ install_route:
}
}
if (!dst_mtu(&rt->dst))
dst_metric_set(&rt->dst, RTAX_MTU, ipv6_get_mtu(dev));
rt->dst.dev = dev;
rt->rt6i_idev = idev;
rt->rt6i_table = table;
@ -1541,8 +1539,6 @@ void rt6_redirect(struct in6_addr *dest, struct in6_addr *src,
ipv6_addr_copy(&nrt->rt6i_gateway, (struct in6_addr*)neigh->primary_key);
nrt->rt6i_nexthop = neigh_clone(neigh);
/* Reset pmtu, it may be better */
dst_metric_set(&nrt->dst, RTAX_MTU, ipv6_get_mtu(neigh->dev));
if (ip6_ins_rt(nrt))
goto out;
@ -1971,7 +1967,6 @@ struct rt6_info *addrconf_dst_alloc(struct inet6_dev *idev,
rt->dst.output = ip6_output;
rt->rt6i_dev = net->loopback_dev;
rt->rt6i_idev = idev;
dst_metric_set(&rt->dst, RTAX_MTU, ipv6_get_mtu(rt->rt6i_dev));
dst_metric_set(&rt->dst, RTAX_HOPLIMIT, -1);
rt->dst.obsolete = -1;

7
net/xfrm/xfrm_policy.c
View File

@ -2366,6 +2366,11 @@ static unsigned int xfrm_default_advmss(const struct dst_entry *dst)
return dst_metric_advmss(dst->path);
}
static unsigned int xfrm_default_mtu(const struct dst_entry *dst)
{
return dst_mtu(dst->path);
}
int xfrm_policy_register_afinfo(struct xfrm_policy_afinfo *afinfo)
{
struct net *net;
@ -2385,6 +2390,8 @@ int xfrm_policy_register_afinfo(struct xfrm_policy_afinfo *afinfo)
dst_ops->check = xfrm_dst_check;
if (likely(dst_ops->default_advmss == NULL))
dst_ops->default_advmss = xfrm_default_advmss;
if (likely(dst_ops->default_mtu == NULL))
dst_ops->default_mtu = xfrm_default_mtu;
if (likely(dst_ops->negative_advice == NULL))
dst_ops->negative_advice = xfrm_negative_advice;
if (likely(dst_ops->link_failure == NULL))