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| author | David Ahern <dsa@cumulusnetworks.com> | 2017-03-10 14:11:39 -0800 |
|---|---|---|
| committer | David S. Miller <davem@davemloft.net> | 2017-03-12 23:45:36 -0700 |
| commit | 79099aab38c8f5c746748b066ae74ba984fe2cc8 (patch) | |
| tree | e54955acc8fead5a71eb675516aff2db3173099d | |
| parent | b17075d5c1988b83f840d272c795ac17d57ce804 (diff) | |
| download | linux-79099aab38c8f5c746748b066ae74ba984fe2cc8.tar.gz linux-79099aab38c8f5c746748b066ae74ba984fe2cc8.tar.bz2 linux-79099aab38c8f5c746748b066ae74ba984fe2cc8.zip | |
mpls: Do not decrement alive counter for unregister events
Multipath routes can be rendered usesless when a device in one of the
paths is deleted. For example:
$ ip -f mpls ro ls
100
nexthop as to 200 via inet 172.16.2.2 dev virt12
nexthop as to 300 via inet 172.16.3.2 dev br0
101
nexthop as to 201 via inet6 2000:2::2 dev virt12
nexthop as to 301 via inet6 2000:3::2 dev br0
$ ip li del br0
When br0 is deleted the other hop is not considered in
mpls_select_multipath because of the alive check -- rt_nhn_alive
is 0.
rt_nhn_alive is decremented once in mpls_ifdown when the device is taken
down (NETDEV_DOWN) and again when it is deleted (NETDEV_UNREGISTER). For
a 2 hop route, deleting one device drops the alive count to 0. Since
devices are taken down before unregistering, the decrement on
NETDEV_UNREGISTER is redundant.
Fixes: c89359a42e2a4 ("mpls: support for dead routes")
Signed-off-by: David Ahern <dsa@cumulusnetworks.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
| -rw-r--r-- | net/mpls/af_mpls.c | 3 |
1 files changed, 2 insertions, 1 deletions
diff --git a/net/mpls/af_mpls.c b/net/mpls/af_mpls.c index a1477989ed0b..33211f9a2656 100644 --- a/net/mpls/af_mpls.c +++ b/net/mpls/af_mpls.c @@ -1288,7 +1288,8 @@ static void mpls_ifdown(struct net_device *dev, int event) /* fall through */ case NETDEV_CHANGE: nh->nh_flags |= RTNH_F_LINKDOWN; - ACCESS_ONCE(rt->rt_nhn_alive) = rt->rt_nhn_alive - 1; + if (event != NETDEV_UNREGISTER) + ACCESS_ONCE(rt->rt_nhn_alive) = rt->rt_nhn_alive - 1; break; } if (event == NETDEV_UNREGISTER) |