[SRU][Trusty][PATCH 2/2] ipv6: remove rt6i_genid
Joseph Salisbury
joseph.salisbury at canonical.com
Fri Sep 16 14:20:04 UTC 2016
From: Hannes Frederic Sowa <hannes at stressinduktion.org>
BugLink: http://bugs.launchpad.net/bugs/1618299
Eric Dumazet noticed that all no-nonexthop or no-gateway routes which
are already marked DST_HOST (e.g. input routes routes) will always be
invalidated during sk_dst_check. Thus per-socket dst caching absolutely
had no effect and early demuxing had no effect.
Thus this patch removes rt6i_genid: fn_sernum already gets modified during
add operations, so we only must ensure we mutate fn_sernum during ipv6
address remove operations. This is a fairly cost extensive operations,
but address removal should not happen that often. Also our mtu update
functions do the same and we heard no complains so far. xfrm policy
changes also cause a call into fib6_flush_trees. Also plug a hole in
rt6_info (no cacheline changes).
I verified via tracing that this change has effect.
Cc: Eric Dumazet <eric.dumazet at gmail.com>
Cc: YOSHIFUJI Hideaki <hideaki at yoshifuji.org>
Cc: Vlad Yasevich <vyasevich at gmail.com>
Cc: Nicolas Dichtel <nicolas.dichtel at 6wind.com>
Cc: Martin Lau <kafai at fb.com>
Signed-off-by: Hannes Frederic Sowa <hannes at stressinduktion.org>
Signed-off-by: David S. Miller <davem at davemloft.net>
(cherry picked from commit 705f1c869d577c8055736dd02501f26a2507dd5b)
Signed-off-by: Joseph Salisbury <joseph.salisbury at canonical.com>
---
include/net/ip6_fib.h | 5 +----
include/net/net_namespace.h | 20 +++-----------------
net/ipv6/addrconf.c | 3 ++-
net/ipv6/addrconf_core.c | 7 +++++++
net/ipv6/ip6_fib.c | 20 ++++++++++++++++++++
net/ipv6/route.c | 4 ----
6 files changed, 33 insertions(+), 26 deletions(-)
diff --git a/include/net/ip6_fib.h b/include/net/ip6_fib.h
index aca0c27..aa0e6d7 100644
--- a/include/net/ip6_fib.h
+++ b/include/net/ip6_fib.h
@@ -114,16 +114,13 @@ struct rt6_info {
u32 rt6i_flags;
struct rt6key rt6i_src;
struct rt6key rt6i_prefsrc;
- u32 rt6i_metric;
struct inet6_dev *rt6i_idev;
unsigned long _rt6i_peer;
- u32 rt6i_genid;
-
+ u32 rt6i_metric;
/* more non-fragment space at head required */
unsigned short rt6i_nfheader_len;
-
u8 rt6i_protocol;
};
diff --git a/include/net/net_namespace.h b/include/net/net_namespace.h
index da68c9a..5cade18 100644
--- a/include/net/net_namespace.h
+++ b/include/net/net_namespace.h
@@ -347,26 +347,12 @@ static inline void rt_genid_bump_ipv4(struct net *net)
atomic_inc(&net->ipv4.rt_genid);
}
-#if IS_ENABLED(CONFIG_IPV6)
-static inline int rt_genid_ipv6(struct net *net)
-{
- return atomic_read(&net->ipv6.rt_genid);
-}
-
-static inline void rt_genid_bump_ipv6(struct net *net)
-{
- atomic_inc(&net->ipv6.rt_genid);
-}
-#else
-static inline int rt_genid_ipv6(struct net *net)
-{
- return 0;
-}
-
+extern void (*__fib6_flush_trees)(struct net *net);
static inline void rt_genid_bump_ipv6(struct net *net)
{
+ if (__fib6_flush_trees)
+ __fib6_flush_trees(net);
}
-#endif
/* For callers who don't really care about whether it's IPv4 or IPv6 */
static inline void rt_genid_bump_all(struct net *net)
diff --git a/net/ipv6/addrconf.c b/net/ipv6/addrconf.c
index 979606b..c61caab 100644
--- a/net/ipv6/addrconf.c
+++ b/net/ipv6/addrconf.c
@@ -4575,10 +4575,11 @@ static void __ipv6_ifa_notify(int event, struct inet6_ifaddr *ifp)
if (ip6_del_rt(ifp->rt))
dst_free(&ifp->rt->dst);
+
+ rt_genid_bump_ipv6(net);
break;
}
atomic_inc(&net->ipv6.dev_addr_genid);
- rt_genid_bump_ipv6(net);
}
static void ipv6_ifa_notify(int event, struct inet6_ifaddr *ifp)
diff --git a/net/ipv6/addrconf_core.c b/net/ipv6/addrconf_core.c
index 4c11cbc..8e32394 100644
--- a/net/ipv6/addrconf_core.c
+++ b/net/ipv6/addrconf_core.c
@@ -8,6 +8,13 @@
#include <net/addrconf.h>
#include <net/ip.h>
+/* if ipv6 module registers this function is used by xfrm to force all
+ * sockets to relookup their nodes - this is fairly expensive, be
+ * careful
+ */
+void (*__fib6_flush_trees)(struct net *);
+EXPORT_SYMBOL(__fib6_flush_trees);
+
#define IPV6_ADDR_SCOPE_TYPE(scope) ((scope) << 16)
static inline unsigned int ipv6_addr_scope2type(unsigned int scope)
diff --git a/net/ipv6/ip6_fib.c b/net/ipv6/ip6_fib.c
index d773910..c93b060 100644
--- a/net/ipv6/ip6_fib.c
+++ b/net/ipv6/ip6_fib.c
@@ -1608,6 +1608,24 @@ static void fib6_prune_clones(struct net *net, struct fib6_node *fn,
fib6_clean_tree(net, fn, fib6_prune_clone, 1, rt);
}
+static int fib6_update_sernum(struct rt6_info *rt, void *arg)
+{
+ __u32 sernum = *(__u32 *)arg;
+
+ if (rt->rt6i_node &&
+ rt->rt6i_node->fn_sernum != sernum)
+ rt->rt6i_node->fn_sernum = sernum;
+
+ return 0;
+}
+
+static void fib6_flush_trees(struct net *net)
+{
+ __u32 new_sernum = fib6_new_sernum();
+
+ fib6_clean_all(net, fib6_update_sernum, &new_sernum);
+}
+
/*
* Garbage collection
*/
@@ -1791,6 +1809,8 @@ int __init fib6_init(void)
NULL);
if (ret)
goto out_unregister_subsys;
+
+ __fib6_flush_trees = fib6_flush_trees;
out:
return ret;
diff --git a/net/ipv6/route.c b/net/ipv6/route.c
index 942ca87..11f6f8b 100644
--- a/net/ipv6/route.c
+++ b/net/ipv6/route.c
@@ -282,7 +282,6 @@ static inline struct rt6_info *ip6_dst_alloc(struct net *net,
memset(dst + 1, 0, sizeof(*rt) - sizeof(*dst));
rt6_init_peer(rt, table ? &table->tb6_peers : net->ipv6.peers);
- rt->rt6i_genid = rt_genid_ipv6(net);
INIT_LIST_HEAD(&rt->rt6i_siblings);
}
return rt;
@@ -1084,9 +1083,6 @@ static struct dst_entry *ip6_dst_check(struct dst_entry *dst, u32 cookie)
* DST_OBSOLETE_FORCE_CHK which forces validation calls down
* into this function always.
*/
- if (rt->rt6i_genid != rt_genid_ipv6(dev_net(rt->dst.dev)))
- return NULL;
-
if (!rt->rt6i_node || (rt->rt6i_node->fn_sernum != cookie))
return NULL;
--
2.7.4
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