[netdevice] Allocate private data for each network upper-layer driver

Allow network upper-layer drivers (such as LLDP, which attaches to
each network device in order to provide a corresponding LLDP settings
block) to specify a size for private data, which will be allocated as
part of the network device structure (as with the existing private
data allocated for the underlying device driver).

This will allow network upper-layer drivers to be simplified by
omitting memory allocation and freeing code.  If the upper-layer
driver requires a reference counter (e.g. for interface
initialisation), then it may use the network device's existing
reference counter, since this is now the reference counter for the
containing block of memory.

Signed-off-by: Michael Brown <mcb30@ipxe.org>

1 files changed, 59 insertions, 13 deletions

diff --git a/src/net/netdevice.c b/src/net/netdevice.c
index 915178218..a9ed18134 100644
--- a/src/net/netdevice.c
+++ b/src/net/netdevice.c
@@ -110,16 +110,63 @@ static int netdev_has_ll_addr ( struct net_device *netdev ) {
 }
 
 /**
+ * Get offset of network device driver private data
+ *
+ * @v driver		Upper-layer driver, or NULL for device driver
+ * @ret offset		Offset of driver private data
+ */
+static size_t netdev_priv_offset ( struct net_driver *driver ) {
+	struct net_device *netdev;
+	unsigned int num_configs;
+	size_t offset;
+
+	/* Allow space for network device */
+	offset = sizeof ( *netdev );
+
+	/* Allow space for configurations */
+	num_configs = table_num_entries ( NET_DEVICE_CONFIGURATORS );
+	offset += ( num_configs * sizeof ( netdev->configs[0] ) );
+
+	/* Place variable-length device driver private data at end */
+	if ( ! driver )
+		driver = table_end ( NET_DRIVERS );
+
+	/* Allow space for preceding upper-layer drivers' private data */
+	for_each_table_entry_continue_reverse ( driver, NET_DRIVERS ) {
+		offset += driver->priv_len;
+	}
+
+	/* Sanity check */
+	assert ( ( offset & ( sizeof ( void * ) - 1 ) ) == 0 );
+
+	return offset;
+}
+
+/**
+ * Get network device driver private data
+ *
+ * @v netdev		Network device
+ * @v driver		Upper-layer driver, or NULL for device driver
+ * @ret priv		Driver private data
+ */
+void * netdev_priv ( struct net_device *netdev, struct net_driver *driver ) {
+
+	return ( ( ( void * ) netdev ) + netdev_priv_offset ( driver ) );
+}
+
+/**
  * Notify drivers of network device or link state change
  *
  * @v netdev		Network device
  */
 static void netdev_notify ( struct net_device *netdev ) {
 	struct net_driver *driver;
+	void *priv;
 
 	for_each_table_entry ( driver, NET_DRIVERS ) {
+		priv = netdev_priv ( netdev, driver );
 		if ( driver->notify )
-			driver->notify ( netdev );
+			driver->notify ( netdev, priv );
 	}
 }
 
@@ -675,14 +722,8 @@ struct net_device * alloc_netdev ( size_t priv_len ) {
 	struct net_device *netdev;
 	struct net_device_configurator *configurator;
 	struct net_device_configuration *config;
-	unsigned int num_configs;
-	size_t confs_len;
-	size_t total_len;
 
-	num_configs = table_num_entries ( NET_DEVICE_CONFIGURATORS );
-	confs_len = ( num_configs * sizeof ( netdev->configs[0] ) );
-	total_len = ( sizeof ( *netdev ) + confs_len + priv_len );
-	netdev = zalloc ( total_len );
+	netdev = zalloc ( netdev_priv_offset ( NULL ) + priv_len );
 	if ( netdev ) {
 		ref_init ( &netdev->refcnt, free_netdev );
 		netdev->link_rc = -EUNKNOWN_LINK_STATUS;
@@ -701,8 +742,7 @@ struct net_device * alloc_netdev ( size_t priv_len ) {
 				    &netdev->refcnt );
 			config++;
 		}
-		netdev->priv = ( ( ( void * ) netdev ) + sizeof ( *netdev ) +
-				 confs_len );
+		netdev->priv = netdev_priv ( netdev, NULL );
 	}
 	return netdev;
 }
@@ -722,6 +762,7 @@ int register_netdev ( struct net_device *netdev ) {
 	struct net_device *duplicate;
 	unsigned int i;
 	uint32_t seed;
+	void *priv;
 	int rc;
 
 	/* Set initial link-layer address, if not already set */
@@ -784,7 +825,9 @@ int register_netdev ( struct net_device *netdev ) {
 
 	/* Probe device */
 	for_each_table_entry ( driver, NET_DRIVERS ) {
-		if ( driver->probe && ( rc = driver->probe ( netdev ) ) != 0 ) {
+		priv = netdev_priv ( netdev, driver );
+		if ( driver->probe &&
+		     ( rc = driver->probe ( netdev, priv ) ) != 0 ) {
 			DBGC ( netdev, "NETDEV %s could not add %s device: "
 			       "%s\n", netdev->name, driver->name,
 			       strerror ( rc ) );
@@ -796,8 +839,9 @@ int register_netdev ( struct net_device *netdev ) {
 
  err_probe:
 	for_each_table_entry_continue_reverse ( driver, NET_DRIVERS ) {
+		priv = netdev_priv ( netdev, driver );
 		if ( driver->remove )
-			driver->remove ( netdev );
+			driver->remove ( netdev, priv );
 	}
 	clear_settings ( netdev_settings ( netdev ) );
 	unregister_settings ( netdev_settings ( netdev ) );
@@ -896,14 +940,16 @@ void netdev_close ( struct net_device *netdev ) {
  */
 void unregister_netdev ( struct net_device *netdev ) {
 	struct net_driver *driver;
+	void *priv;
 
 	/* Ensure device is closed */
 	netdev_close ( netdev );
 
 	/* Remove device */
 	for_each_table_entry_reverse ( driver, NET_DRIVERS ) {
+		priv = netdev_priv ( netdev, driver );
 		if ( driver->remove )
-			driver->remove ( netdev );
+			driver->remove ( netdev, priv );
 	}
 
 	/* Unregister per-netdev configuration settings */