wwan: core: add WWAN common private data for netdev

The WWAN core not only multiplex the netdev configuration data, but
process it too, and needs some space to store its private data
associated with the netdev. Add a structure to keep common WWAN core
data. The structure will be stored inside the netdev private data before
WWAN driver private data and have a field to make it easier to access
the driver data. Also add a helper function that simplifies drivers
access to their data.

At the moment we use the common WWAN private data to store the WWAN data
link (channel) id at the time the link is created, and report it back to
user using the .fill_info() RTNL callback. This should help the user to
be aware which network interface is bound to which WWAN device data
channel.

Signed-off-by: Sergey Ryazanov <ryazanov.s.a@gmail.com>
CC: M Chetan Kumar <m.chetan.kumar@intel.com>
CC: Intel Corporation <linuxwwan@intel.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

1 files changed, 28 insertions, 1 deletions

diff --git a/drivers/net/wwan/wwan_core.c b/drivers/net/wwan/wwan_core.c
index ef6ec641d877..3e16c318e705 100644
--- a/drivers/net/wwan/wwan_core.c
+++ b/drivers/net/wwan/wwan_core.c
@@ -815,6 +815,7 @@ static struct net_device *wwan_rtnl_alloc(struct nlattr *tb[],
 	const char *devname = nla_data(tb[IFLA_PARENT_DEV_NAME]);
 	struct wwan_device *wwandev = wwan_dev_get_by_name(devname);
 	struct net_device *dev;
+	unsigned int priv_size;
 
 	if (IS_ERR(wwandev))
 		return ERR_CAST(wwandev);
@@ -825,7 +826,8 @@ static struct net_device *wwan_rtnl_alloc(struct nlattr *tb[],
 		goto out;
 	}
 
-	dev = alloc_netdev_mqs(wwandev->ops->priv_size, ifname, name_assign_type,
+	priv_size = sizeof(struct wwan_netdev_priv) + wwandev->ops->priv_size;
+	dev = alloc_netdev_mqs(priv_size, ifname, name_assign_type,
 			       wwandev->ops->setup, num_tx_queues, num_rx_queues);
 
 	if (dev) {
@@ -845,6 +847,7 @@ static int wwan_rtnl_newlink(struct net *src_net, struct net_device *dev,
 {
 	struct wwan_device *wwandev = wwan_dev_get_by_parent(dev->dev.parent);
 	u32 link_id = nla_get_u32(data[IFLA_WWAN_LINK_ID]);
+	struct wwan_netdev_priv *priv = netdev_priv(dev);
 	int ret;
 
 	if (IS_ERR(wwandev))
@@ -856,6 +859,7 @@ static int wwan_rtnl_newlink(struct net *src_net, struct net_device *dev,
 		goto out;
 	}
 
+	priv->link_id = link_id;
 	if (wwandev->ops->newlink)
 		ret = wwandev->ops->newlink(wwandev->ops_ctxt, dev,
 					    link_id, extack);
@@ -889,6 +893,27 @@ out:
 	put_device(&wwandev->dev);
 }
 
+static size_t wwan_rtnl_get_size(const struct net_device *dev)
+{
+	return
+		nla_total_size(4) +	/* IFLA_WWAN_LINK_ID */
+		0;
+}
+
+static int wwan_rtnl_fill_info(struct sk_buff *skb,
+			       const struct net_device *dev)
+{
+	struct wwan_netdev_priv *priv = netdev_priv(dev);
+
+	if (nla_put_u32(skb, IFLA_WWAN_LINK_ID, priv->link_id))
+		goto nla_put_failure;
+
+	return 0;
+
+nla_put_failure:
+	return -EMSGSIZE;
+}
+
 static const struct nla_policy wwan_rtnl_policy[IFLA_WWAN_MAX + 1] = {
 	[IFLA_WWAN_LINK_ID] = { .type = NLA_U32 },
 };
@@ -900,6 +925,8 @@ static struct rtnl_link_ops wwan_rtnl_link_ops __read_mostly = {
 	.validate = wwan_rtnl_validate,
 	.newlink = wwan_rtnl_newlink,
 	.dellink = wwan_rtnl_dellink,
+	.get_size = wwan_rtnl_get_size,
+	.fill_info = wwan_rtnl_fill_info,
 	.policy = wwan_rtnl_policy,
 };