Re: [PATCH net-next v4 2/2] vxlan: allow specifying multiple default destinations
From: Stephen Hemminger <stephen@networkplumber.org>
Date: 2013-06-24 00:14:45
On Sun, 23 Jun 2013 19:22:23 +0300 Mike Rapoport [off-list ref] wrote:
quoted hunk ↗ jump to hunk
A list of multiple default destinations can be used in environments that disable multicast on the infrastructure level, e.g. public clouds. Signed-off-by: Mike Rapoport <redacted> --- drivers/net/vxlan.c | 268 +++++++++++++++++++++++++++++++++++++++++-- include/uapi/linux/if_link.h | 17 +++ 2 files changed, 276 insertions(+), 9 deletions(-)diff --git a/drivers/net/vxlan.c b/drivers/net/vxlan.c index e5fb6568..f57a0d94 100644 --- a/drivers/net/vxlan.c +++ b/drivers/net/vxlan.c@@ -103,6 +103,7 @@ struct vxlan_rdst { u32 remote_vni; u32 remote_ifindex; struct list_head list; + struct rcu_head rcu; };
The use of remotes_cnt here is not SMP safe. You are using remotes_cnt to size the buffer for dumping, but then the list of remotes might change during the dump. There a a couple of alternatives here: 1. Put a hard limit on the number of remotes per MAC. 2. When there are multiple destnations, just dump multiple entries, like multipath routing does. I prefer #2 because it also allows for a cleaner API on creation.