From d217472410a033cdef5b8fba4393b466ee3c3bbc Mon Sep 17 00:00:00 2001 From: Kirill Tkhai Date: Mon, 5 Mar 2018 14:31:10 +0300 Subject: net: Convert caif_net_ops Init method just allocates memory for new cfg, and assigns net_generic(net, caif_net_id). Despite there is synchronize_rcu() on error path in cfcnfg_create(), in real this function does not use global lists, so it looks like this synchronize_rcu() is some legacy inheritance. Exit method removes caif devices under rtnl_lock(). There could be a problem, if someone from foreign net pernet_operations dereference caif_net_id of this net. It's dereferenced in get_cfcnfg() and caif_device_list(). get_cfcnfg() is used from netdevice notifiers, where they are called under rtnl_lock(). The notifiers can't be called from foreign nets pernet_operations. Also, it's used from caif_disconnect_client() and from caif_connect_client(). The both of the functions work with caif socket, and there is the only possibility to have a socket, when the net is dead. This may happen only of the socket was created as kern using sk_alloc(). Grep by PF_CAIF shows we do not create kern caif sockets, so get_cfcnfg() is safe. caif_device_list() is used in netdevice notifiers and exit method under rtnl lock. Also, from caif_get() used in the netdev notifiers and in caif_flow_cb(). The last item is skb destructor. Since there are no kernel caif sockets nobody can send net a packet in parallel with init/exit, so this is also safe. So, these pernet_operations are safe to be async. Signed-off-by: Kirill Tkhai Signed-off-by: David S. Miller --- net/caif/caif_dev.c | 1 + 1 file changed, 1 insertion(+) (limited to 'net/caif/caif_dev.c') diff --git a/net/caif/caif_dev.c b/net/caif/caif_dev.c index e0adcd123f48..7a78268cc572 100644 --- a/net/caif/caif_dev.c +++ b/net/caif/caif_dev.c @@ -544,6 +544,7 @@ static struct pernet_operations caif_net_ops = { .exit = caif_exit_net, .id = &caif_net_id, .size = sizeof(struct caif_net), + .async = true, }; /* Initialize Caif devices list */ -- cgit v1.2.3-55-g7522