net: devres: provide devm_register_netdev()

Provide devm_register_netdev() - a device resource managed variant
of register_netdev(). This new helper will only work for net_device
structs that are also already managed by devres.

Signed-off-by: Bartosz Golaszewski <bgolaszewski@baylibre.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

diff --git a/Documentation/driver-api/driver-model/devres.rst b/Documentation/driver-api/driver-model/devres.rst
index 50df28d..fc242ed 100644 (file)
--- a/Documentation/driver-api/driver-model/devres.rst
+++ b/Documentation/driver-api/driver-model/devres.rst
@@ -375,6 +375,7 @@ MUX
 NET
   devm_alloc_etherdev()
   devm_alloc_etherdev_mqs()
+  devm_register_netdev()
 
 PER-CPU MEM
   devm_alloc_percpu()

diff --git a/include/linux/netdevice.h b/include/linux/netdevice.h
index a18f8fd..1a96e9c 100644 (file)
--- a/include/linux/netdevice.h
+++ b/include/linux/netdevice.h
@@ -4280,6 +4280,8 @@ struct net_device *alloc_netdev_mqs(int sizeof_priv, const char *name,
 int register_netdev(struct net_device *dev);
 void unregister_netdev(struct net_device *dev);
 
+int devm_register_netdev(struct device *dev, struct net_device *ndev);
+
 /* General hardware address lists handling functions */
 int __hw_addr_sync(struct netdev_hw_addr_list *to_list,
                   struct netdev_hw_addr_list *from_list, int addr_len);

diff --git a/net/devres.c b/net/devres.c
index b97b0c5..57a6a88 100644 (file)
--- a/net/devres.c
+++ b/net/devres.c
@@ -38,3 +38,58 @@ struct net_device *devm_alloc_etherdev_mqs(struct device *dev, int sizeof_priv,
        return dr->ndev;
 }
 EXPORT_SYMBOL(devm_alloc_etherdev_mqs);
+
+static void devm_netdev_release(struct device *dev, void *this)
+{
+       struct net_device_devres *res = this;
+
+       unregister_netdev(res->ndev);
+}
+
+static int netdev_devres_match(struct device *dev, void *this, void *match_data)
+{
+       struct net_device_devres *res = this;
+       struct net_device *ndev = match_data;
+
+       return ndev == res->ndev;
+}
+
+/**
+ *     devm_register_netdev - resource managed variant of register_netdev()
+ *     @dev: managing device for this netdev - usually the parent device
+ *     @ndev: device to register
+ *
+ *     This is a devres variant of register_netdev() for which the unregister
+ *     function will be call automatically when the managing device is
+ *     detached. Note: the net_device used must also be resource managed by
+ *     the same struct device.
+ */
+int devm_register_netdev(struct device *dev, struct net_device *ndev)
+{
+       struct net_device_devres *dr;
+       int ret;
+
+       /* struct net_device must itself be managed. For now a managed netdev
+        * can only be allocated by devm_alloc_etherdev_mqs() so the check is
+        * straightforward.
+        */
+       if (WARN_ON(!devres_find(dev, devm_free_netdev,
+                                netdev_devres_match, ndev)))
+               return -EINVAL;
+
+       dr = devres_alloc(devm_netdev_release, sizeof(*dr), GFP_KERNEL);
+       if (!dr)
+               return -ENOMEM;
+
+       ret = register_netdev(ndev);
+       if (ret) {
+               devres_free(dr);
+               return ret;
+       }
+
+       dr->ndev = ndev;
+       devres_add(ndev->dev.parent, dr);
+
+       return 0;
+}
+EXPORT_SYMBOL(devm_register_netdev);