[PATCH v2 4/5] net: devres: provide devm_register_netdev()

Bartosz Golaszewski
2020-05-23T13:27:39Z

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>
---
.../driver-api/driver-model/devres.rst | 1 +
include/linux/netdevice.h | 2 +
net/devres.c | 55 +++++++++++++++++++
3 files changed, 58 insertions(+)

diff --git a/Documentation/driver-api/driver-model/devres.rst b/Documentation/driver-api/driver-model/devres.rst
index 50df28d20fa7..fc242ed4bde5 100644
--- 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 a18f8fdf4260..1a96e9c4ec36 100644
--- 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 b97b0c5a8216..57a6a88d11f6 100644
--- 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);
--
2.25.0