rtnetlink: add alloc() method to rtnl_link_ops

In order to make rtnetlink ops that can create different
kinds of devices, like what we want to add to the WWAN
framework, the priv_size and setup parameters aren't quite
sufficient. Make this easier to manage by allowing ops to
allocate their own netdev via an @alloc method that gets
the tb netlink data.

Signed-off-by: Johannes Berg <johannes.berg@intel.com>
Signed-off-by: Sergey Ryazanov <ryazanov.s.a@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

diff --git a/include/net/rtnetlink.h b/include/net/rtnetlink.h
index 479f60e..384e800 100644 (file)
--- a/include/net/rtnetlink.h
+++ b/include/net/rtnetlink.h
@@ -37,6 +37,9 @@ static inline int rtnl_msg_family(const struct nlmsghdr *nlh)
  *     @maxtype: Highest device specific netlink attribute number
  *     @policy: Netlink policy for device specific attribute validation
  *     @validate: Optional validation function for netlink/changelink parameters
+ *     @alloc: netdev allocation function, can be %NULL and is then used
+ *             in place of alloc_netdev_mqs(), in this case @priv_size
+ *             and @setup are unused. Returns a netdev or ERR_PTR().
  *     @priv_size: sizeof net_device private space
  *     @setup: net_device setup function
  *     @newlink: Function for configuring and registering a new device
@@ -63,6 +66,11 @@ struct rtnl_link_ops {
        const char              *kind;
 
        size_t                  priv_size;
+       struct net_device       *(*alloc)(struct nlattr *tb[],
+                                         const char *ifname,
+                                         unsigned char name_assign_type,
+                                         unsigned int num_tx_queues,
+                                         unsigned int num_rx_queues);
        void                    (*setup)(struct net_device *dev);
 
        bool                    netns_refund;

diff --git a/net/core/rtnetlink.c b/net/core/rtnetlink.c
index cd87c76..92c3e43 100644 (file)
--- a/net/core/rtnetlink.c
+++ b/net/core/rtnetlink.c
@@ -376,12 +376,12 @@ int __rtnl_link_register(struct rtnl_link_ops *ops)
        if (rtnl_link_ops_get(ops->kind))
                return -EEXIST;
 
-       /* The check for setup is here because if ops
+       /* The check for alloc/setup is here because if ops
         * does not have that filled up, it is not possible
         * to use the ops for creating device. So do not
         * fill up dellink as well. That disables rtnl_dellink.
         */
-       if (ops->setup && !ops->dellink)
+       if ((ops->alloc || ops->setup) && !ops->dellink)
                ops->dellink = unregister_netdevice_queue;
 
        list_add_tail(&ops->list, &link_ops);
@@ -3165,8 +3165,17 @@ struct net_device *rtnl_create_link(struct net *net, const char *ifname,
                return ERR_PTR(-EINVAL);
        }
 
-       dev = alloc_netdev_mqs(ops->priv_size, ifname, name_assign_type,
-                              ops->setup, num_tx_queues, num_rx_queues);
+       if (ops->alloc) {
+               dev = ops->alloc(tb, ifname, name_assign_type,
+                                num_tx_queues, num_rx_queues);
+               if (IS_ERR(dev))
+                       return dev;
+       } else {
+               dev = alloc_netdev_mqs(ops->priv_size, ifname,
+                                      name_assign_type, ops->setup,
+                                      num_tx_queues, num_rx_queues);
+       }
+
        if (!dev)
                return ERR_PTR(-ENOMEM);
 
@@ -3399,7 +3408,7 @@ replay:
                return -EOPNOTSUPP;
        }
 
-       if (!ops->setup)
+       if (!ops->alloc && !ops->setup)
                return -EOPNOTSUPP;
 
        if (!ifname[0]) {