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authorIdo Schimmel <idosch@mellanox.com>2016-12-03 16:45:06 +0100
committerDavid S. Miller <davem@davemloft.net>2016-12-03 19:29:35 -0500
commitcacaad11f43aefbbe5fca00af3b9c16e6aee1ba4 (patch)
treeca7600f9e865f6bfef8ce60a9c1d1ddd34acba96
parentd3f706f68e2fd93f1172fe7fd6f16ba70cc52b31 (diff)
downloadblackbird-op-linux-cacaad11f43aefbbe5fca00af3b9c16e6aee1ba4.tar.gz
blackbird-op-linux-cacaad11f43aefbbe5fca00af3b9c16e6aee1ba4.zip
ipv4: fib: Allow for consistent FIB dumping
The next patch will enable listeners of the FIB notification chain to request a dump of the FIB tables. However, since RTNL isn't taken during the dump, it's possible for the FIB tables to change mid-dump, which will result in inconsistency between the listener's table and the kernel's. Allow listeners to know about changes that occurred mid-dump, by adding a change sequence counter to each net namespace. The counter is incremented just before a notification is sent in the FIB chain. Signed-off-by: Ido Schimmel <idosch@mellanox.com> Signed-off-by: Jiri Pirko <jiri@mellanox.com> Signed-off-by: David S. Miller <davem@davemloft.net>
-rw-r--r--include/net/netns/ipv4.h3
-rw-r--r--net/ipv4/fib_frontend.c2
-rw-r--r--net/ipv4/fib_trie.c1
3 files changed, 6 insertions, 0 deletions
diff --git a/include/net/netns/ipv4.h b/include/net/netns/ipv4.h
index 7adf4386ac8f..f0cf5a1b777e 100644
--- a/include/net/netns/ipv4.h
+++ b/include/net/netns/ipv4.h
@@ -135,6 +135,9 @@ struct netns_ipv4 {
#ifdef CONFIG_IP_ROUTE_MULTIPATH
int sysctl_fib_multipath_use_neigh;
#endif
+
+ unsigned int fib_seq; /* protected by rtnl_mutex */
+
atomic_t rt_genid;
};
#endif
diff --git a/net/ipv4/fib_frontend.c b/net/ipv4/fib_frontend.c
index 121384bbb40b..dbad5a1c161a 100644
--- a/net/ipv4/fib_frontend.c
+++ b/net/ipv4/fib_frontend.c
@@ -1219,6 +1219,8 @@ static int __net_init ip_fib_net_init(struct net *net)
int err;
size_t size = sizeof(struct hlist_head) * FIB_TABLE_HASHSZ;
+ net->ipv4.fib_seq = 0;
+
/* Avoid false sharing : Use at least a full cache line */
size = max_t(size_t, size, L1_CACHE_BYTES);
diff --git a/net/ipv4/fib_trie.c b/net/ipv4/fib_trie.c
index 9bfce0df20dc..28913563e7cd 100644
--- a/net/ipv4/fib_trie.c
+++ b/net/ipv4/fib_trie.c
@@ -101,6 +101,7 @@ EXPORT_SYMBOL(unregister_fib_notifier);
int call_fib_notifiers(struct net *net, enum fib_event_type event_type,
struct fib_notifier_info *info)
{
+ net->ipv4.fib_seq++;
info->net = net;
return atomic_notifier_call_chain(&fib_chain, event_type, info);
}
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