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由 Kirill Tkhai 提交于
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: NKirill Tkhai <ktkhai@virtuozzo.com> Signed-off-by: NDavid S. Miller <davem@davemloft.net>
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