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Date: Tue, 14 Dec 2010 13:20:04 -0800 (PST)
From: David Miller <davem@...emloft.net>
To: netdev@...r.kernel.org
Subject: [PATCH] net: Abstract default MTU metric calculation behind an
accessor.
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@...emloft.net>
---
include/net/dst.h | 15 ++++++++-------
include/net/dst_ops.h | 1 +
net/decnet/dn_route.c | 10 ++++++++--
net/ipv4/route.c | 29 ++++++++++++++++++++---------
net/ipv6/route.c | 37 ++++++++++++++++---------------------
net/xfrm/xfrm_policy.c | 7 +++++++
6 files changed, 60 insertions(+), 39 deletions(-)
diff --git a/include/net/dst.h b/include/net/dst.h
index 03a1c3d..93b0310 100644
--- a/include/net/dst.h
+++ b/include/net/dst.h
@@ -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);
}
diff --git a/include/net/dst_ops.h b/include/net/dst_ops.h
index 15fb7af..21a320b 100644
--- a/include/net/dst_ops.h
+++ b/include/net/dst_ops.h
@@ -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);
diff --git a/net/decnet/dn_route.c b/net/decnet/dn_route.c
index b8a5c05..5e63636 100644
--- a/net/decnet/dn_route.c
+++ b/net/decnet/dn_route.c
@@ -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) {
diff --git a/net/ipv4/route.c b/net/ipv4/route.c
index 8099733..ae52096 100644
--- a/net/ipv4/route.c
+++ b/net/ipv4/route.c
@@ -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);
diff --git a/net/ipv6/route.c b/net/ipv6/route.c
index d9cb832..e7efb26 100644
--- a/net/ipv6/route.c
+++ b/net/ipv6/route.c
@@ -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;
diff --git a/net/xfrm/xfrm_policy.c b/net/xfrm/xfrm_policy.c
index 36936c8..8b3ef40 100644
--- a/net/xfrm/xfrm_policy.c
+++ b/net/xfrm/xfrm_policy.c
@@ -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))
--
1.7.3.2
--
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