[PATCH 05/11] net: core: provide devm_register_netdev()

Bartosz Golaszewski
2020-05-05T14:04:01Z

From: Bartosz Golaszewski <bgolaszewski@baylibre.com>

Provide devm_register_netdev() - a device resource managed variant
of register_netdev(). This new helper will only work for net_device
structs that have a parent device assigned and are devres managed too.

Signed-off-by: Bartosz Golaszewski <bgolaszewski@baylibre.com>
---
include/linux/netdevice.h | 4 ++++
net/core/dev.c | 48 +++++++++++++++++++++++++++++++++++++++
net/ethernet/eth.c | 1 +
3 files changed, 53 insertions(+)

diff --git a/include/linux/netdevice.h b/include/linux/netdevice.h
index 130a668049ab..433bd5ca2efc 100644
--- a/include/linux/netdevice.h
+++ b/include/linux/netdevice.h
@@ -1515,6 +1515,8 @@ struct net_device_ops {
* @IFF_FAILOVER_SLAVE: device is lower dev of a failover master device
* @IFF_L3MDEV_RX_HANDLER: only invoke the rx handler of L3 master device
* @IFF_LIVE_RENAME_OK: rename is allowed while device is up and running
+ * @IFF_IS_DEVRES: this structure was allocated dynamically and is managed by
+ * devres
*/
enum netdev_priv_flags {
IFF_802_1Q_VLAN = 1<<0,
@@ -1548,6 +1550,7 @@ enum netdev_priv_flags {
IFF_FAILOVER_SLAVE = 1<<28,
IFF_L3MDEV_RX_HANDLER = 1<<29,
IFF_LIVE_RENAME_OK = 1<<30,
+ IFF_IS_DEVRES = 1<<31,
};

#define IFF_802_1Q_VLAN IFF_802_1Q_VLAN
@@ -4206,6 +4209,7 @@ struct net_device *alloc_netdev_mqs(int sizeof_priv, const char *name,
count)

int register_netdev(struct net_device *dev);
+int devm_register_netdev(struct net_device *ndev);
void unregister_netdev(struct net_device *dev);

/* General hardware address lists handling functions */
diff --git a/net/core/dev.c b/net/core/dev.c
index 522288177bbd..99db537c9468 100644
--- a/net/core/dev.c
+++ b/net/core/dev.c
@@ -9519,6 +9519,54 @@ int register_netdev(struct net_device *dev)
}
EXPORT_SYMBOL(register_netdev);

+struct netdevice_devres {
+ struct net_device *ndev;
+};
+
+static void devm_netdev_release(struct device *dev, void *this)
+{
+ struct netdevice_devres *res = this;
+
+ unregister_netdev(res->ndev);
+}
+
+/**
+ * devm_register_netdev - resource managed variant of register_netdev()
+ * @ndev: device to register
+ *
+ * This is a devres variant of register_netdev() for which the unregister
+ * function will be call automatically when the parent device of ndev
+ * is detached.
+ */
+int devm_register_netdev(struct net_device *ndev)
+{
+ struct netdevice_devres *dr;
+ int ret;
+
+ /* struct net_device itself must be devres managed. */
+ BUG_ON(!(ndev->priv_flags & IFF_IS_DEVRES));
+ /* struct net_device must have a parent device - it will be the device
+ * managing this resource.
+ */
+ BUG_ON(!ndev->dev.parent);
+
+ 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);
+
int netdev_refcnt_read(const struct net_device *dev)
{
int i, refcnt = 0;
diff --git a/net/ethernet/eth.c b/net/ethernet/eth.c
index c8b903302ff2..ce9b5e576f20 100644
--- a/net/ethernet/eth.c
+++ b/net/ethernet/eth.c
@@ -423,6 +423,7 @@ struct net_device *devm_alloc_etherdev_mqs(struct device *dev, int sizeof_priv,

*dr = netdev;
devres_add(dev, dr);
+ netdev->priv_flags |= IFF_IS_DEVRES;

return netdev;
}
--
2.25.0