netdev: network device operations infrastructure

This patch changes the network device internal API to move adminstrative
operations out of the network device structure and into a separate structure.

This patch involves some hackery to maintain compatablity between the
new and old model, so all 300+ drivers don't have to be changed at once.
For drivers that aren't converted yet, the netdevice_ops virt function list
still resides in the net_device structure. For old protocols, the new
net_device_ops are copied out to the old net_device pointers.

After the transistion is completed the nag message can be changed to
an WARN_ON, and the compatiablity code can be made configurable.

Some function pointers aren't moved:
* destructor can't be in net_device_ops because
  it may need to be referenced after the module is unloaded.
* neighbor setup is manipulated in a couple of places that need special
  consideration
* hard_start_xmit is in the fast path for transmit.

Signed-off-by: Stephen Hemminger <[email protected]>
Signed-off-by: David S. Miller <[email protected]>

Author: Stephen Hemminger

include/linux/netdevice.h

@@ -451,6 +451,131 @@ struct netdev_queue {
 	struct Qdisc		*qdisc_sleeping;
 } ____cacheline_aligned_in_smp;
 
+
+/*
+ * This structure defines the management hooks for network devices.
+ * The following hooks can bed defined and are optonal (can be null)
+ * unless otherwise noted.
+ *
+ * int (*ndo_init)(struct net_device *dev);
+ *     This function is called once when network device is registered.
+ *     The network device can use this to any late stage initializaton
+ *     or semantic validattion. It can fail with an error code which will
+ *     be propogated back to register_netdev
+ *
+ * void (*ndo_uninit)(struct net_device *dev);
+ *     This function is called when device is unregistered or when registration
+ *     fails. It is not called if init fails.
+ *
+ * int (*ndo_open)(struct net_device *dev);
+ *     This function is called when network device transistions to the up
+ *     state.
+ *
+ * int (*ndo_stop)(struct net_device *dev);
+ *     This function is called when network device transistions to the down
+ *     state.
+ *
+ * void (*ndo_change_rx_flags)(struct net_device *dev, int flags);
+ *	This function is called to allow device receiver to make
+ *	changes to configuration when multicast or promiscious is enabled.
+ *
+ * void (*ndo_set_rx_mode)(struct net_device *dev);
+ *	This function is called device changes address list filtering.
+ *
+ * void (*ndo_set_multicast_list)(struct net_device *dev);
+ *	This function is called when the multicast address list changes.
+ *
+ * int (*ndo_set_mac_address)(struct net_device *dev, void *addr);
+ *	This function  is called when the Media Access Control address
+ *	needs to be changed. If not this interface is not defined, the
+ *	mac address can not be changed.
+ *
+ * int (*ndo_validate_addr)(struct net_device *dev);
+ *	Test if Media Access Control address is valid for the device.
+ *
+ * int (*ndo_do_ioctl)(struct net_device *dev, struct ifreq *ifr, int cmd);
+ *	Called when a user request an ioctl which can't be handled by
+ *	the generic interface code. If not defined ioctl's return
+ *	not supported error code.
+ *
+ * int (*ndo_set_config)(struct net_device *dev, struct ifmap *map);
+ *	Used to set network devices bus interface parameters. This interface
+ *	is retained for legacy reason, new devices should use the bus
+ *	interface (PCI) for low level management.
+ *
+ * int (*ndo_change_mtu)(struct net_device *dev, int new_mtu);
+ *	Called when a user wants to change the Maximum Transfer Unit
+ *	of a device. If not defined, any request to change MTU will
+ *	will return an error.
+ *
+ * void (*ndo_tx_timeout) (struct net_device *dev);
+ *	Callback uses when the transmitter has not made any progress
+ *	for dev->watchdog ticks.
+ *
+ * struct net_device_stats* (*get_stats)(struct net_device *dev);
+ *	Called when a user wants to get the network device usage
+ *	statistics. If not defined, the counters in dev->stats will
+ *	be used.
+ *
+ * void (*ndo_vlan_rx_register)(struct net_device *dev, struct vlan_group *grp);
+ *	If device support VLAN receive accleration
+ *	(ie. dev->features & NETIF_F_HW_VLAN_RX), then this function is called
+ *	when vlan groups for the device changes.  Note: grp is NULL
+ *	if no vlan's groups are being used.
+ *
+ * void (*ndo_vlan_rx_add_vid)(struct net_device *dev, unsigned short vid);
+ *	If device support VLAN filtering (dev->features & NETIF_F_HW_VLAN_FILTER)
+ *	this function is called when a VLAN id is registered.
+ *
+ * void (*ndo_vlan_rx_kill_vid)(struct net_device *dev, unsigned short vid);
+ *	If device support VLAN filtering (dev->features & NETIF_F_HW_VLAN_FILTER)
+ *	this function is called when a VLAN id is unregistered.
+ *
+ * void (*ndo_poll_controller)(struct net_device *dev);
+ */
+struct net_device_ops {
+	int			(*ndo_init)(struct net_device *dev);
+	void			(*ndo_uninit)(struct net_device *dev);
+	int			(*ndo_open)(struct net_device *dev);
+	int			(*ndo_stop)(struct net_device *dev);
+#define HAVE_CHANGE_RX_FLAGS
+	void			(*ndo_change_rx_flags)(struct net_device *dev,
+						       int flags);
+#define HAVE_SET_RX_MODE
+	void			(*ndo_set_rx_mode)(struct net_device *dev);
+#define HAVE_MULTICAST
+	void			(*ndo_set_multicast_list)(struct net_device *dev);
+#define HAVE_SET_MAC_ADDR
+	int			(*ndo_set_mac_address)(struct net_device *dev,
+						       void *addr);
+#define HAVE_VALIDATE_ADDR
+	int			(*ndo_validate_addr)(struct net_device *dev);
+#define HAVE_PRIVATE_IOCTL
+	int			(*ndo_do_ioctl)(struct net_device *dev,
+					        struct ifreq *ifr, int cmd);
+#define HAVE_SET_CONFIG
+	int			(*ndo_set_config)(struct net_device *dev,
+					          struct ifmap *map);
+#define HAVE_CHANGE_MTU
+	int			(*ndo_change_mtu)(struct net_device *dev, int new_mtu);
+
+#define HAVE_TX_TIMEOUT
+	void			(*ndo_tx_timeout) (struct net_device *dev);
+
+	struct net_device_stats* (*ndo_get_stats)(struct net_device *dev);
+
+	void			(*ndo_vlan_rx_register)(struct net_device *dev,
+						        struct vlan_group *grp);
+	void			(*ndo_vlan_rx_add_vid)(struct net_device *dev,
+						       unsigned short vid);
+	void			(*ndo_vlan_rx_kill_vid)(struct net_device *dev,
+						        unsigned short vid);
+#ifdef CONFIG_NET_POLL_CONTROLLER
+#define HAVE_NETDEV_POLL
+	void                    (*ndo_poll_controller)(struct net_device *dev);
+#endif
+};
+
 /*
  *	The DEVICE structure.
  *	Actually, this whole structure is a big mistake.  It mixes I/O
@@ -498,11 +623,6 @@ struct net_device
 #ifdef CONFIG_NETPOLL
 	struct list_head	napi_list;
 #endif
-	
-	/* The device initialization function. Called only once. */
-	int			(*init)(struct net_device *dev);
-
-	/* ------- Fields preinitialized in Space.c finish here ------- */
 
 	/* Net device features */
 	unsigned long		features;
@@ -546,15 +666,13 @@ struct net_device
 	 * for all in netdev_increment_features.
 	 */
 #define NETIF_F_ONE_FOR_ALL	(NETIF_F_GSO_SOFTWARE | NETIF_F_GSO_ROBUST | \
-				 NETIF_F_SG | NETIF_F_HIGHDMA | \
+				 NETIF_F_SG | NETIF_F_HIGHDMA |		\
 				 NETIF_F_FRAGLIST)
 
 	/* Interface index. Unique device identifier	*/
 	int			ifindex;
 	int			iflink;
 
-
-	struct net_device_stats* (*get_stats)(struct net_device *dev);
 	struct net_device_stats	stats;
 
 #ifdef CONFIG_WIRELESS_EXT
@@ -564,18 +682,13 @@ struct net_device
 	/* Instance data managed by the core of Wireless Extensions. */
 	struct iw_public_data *	wireless_data;
 #endif
+	/* Management operations */
+	const struct net_device_ops *netdev_ops;
 	const struct ethtool_ops *ethtool_ops;
 
 	/* Hardware header description */
 	const struct header_ops *header_ops;
 
-	/*
-	 * This marks the end of the "visible" part of the structure. All
-	 * fields hereafter are internal to the system, and may change at
-	 * will (read: may be cleaned up at will).
-	 */
-
-
 	unsigned int		flags;	/* interface flags (a la BSD)	*/
 	unsigned short		gflags;
         unsigned short          priv_flags; /* Like 'flags' but invisible to userspace. */
@@ -634,7 +747,7 @@ struct net_device
 	unsigned long		last_rx;	/* Time of last Rx	*/
 	/* Interface address info used in eth_type_trans() */
 	unsigned char		dev_addr[MAX_ADDR_LEN];	/* hw address, (before bcast 
-							because most packets are unicast) */
+							   because most packets are unicast) */
 
 	unsigned char		broadcast[MAX_ADDR_LEN];	/* hw bcast add	*/
 
@@ -648,6 +761,10 @@ struct net_device
 	/* Number of TX queues currently active in device  */
 	unsigned int		real_num_tx_queues;
 
+	/* Map buffer to appropriate transmit queue */
+	u16			(*select_queue)(struct net_device *dev,
+						struct sk_buff *skb);
+
 	unsigned long		tx_queue_len;	/* Max frames per queue allowed */
 	spinlock_t		tx_global_lock;
 /*
@@ -662,9 +779,6 @@ struct net_device
 	int			watchdog_timeo; /* used by dev_watchdog() */
 	struct timer_list	watchdog_timer;
 
-/*
- * refcnt is a very hot point, so align it on SMP
- */
 	/* Number of references to this device */
 	atomic_t		refcnt ____cacheline_aligned_in_smp;
 
@@ -683,56 +797,14 @@ struct net_device
 	       NETREG_RELEASED,		/* called free_netdev */
 	} reg_state;
 
-	/* Called after device is detached from network. */
-	void			(*uninit)(struct net_device *dev);
-	/* Called after last user reference disappears. */
-	void			(*destructor)(struct net_device *dev);
+	/* Called from unregister, can be used to call free_netdev */
+	void (*destructor)(struct net_device *dev);
 
-	/* Pointers to interface service routines.	*/
-	int			(*open)(struct net_device *dev);
-	int			(*stop)(struct net_device *dev);
-#define HAVE_NETDEV_POLL
-#define HAVE_CHANGE_RX_FLAGS
-	void			(*change_rx_flags)(struct net_device *dev,
-						   int flags);
-#define HAVE_SET_RX_MODE
-	void			(*set_rx_mode)(struct net_device *dev);
-#define HAVE_MULTICAST			 
-	void			(*set_multicast_list)(struct net_device *dev);
-#define HAVE_SET_MAC_ADDR  		 
-	int			(*set_mac_address)(struct net_device *dev,
-						   void *addr);
-#define HAVE_VALIDATE_ADDR
-	int			(*validate_addr)(struct net_device *dev);
-#define HAVE_PRIVATE_IOCTL
-	int			(*do_ioctl)(struct net_device *dev,
-					    struct ifreq *ifr, int cmd);
-#define HAVE_SET_CONFIG
-	int			(*set_config)(struct net_device *dev,
-					      struct ifmap *map);
-#define HAVE_CHANGE_MTU
-	int			(*change_mtu)(struct net_device *dev, int new_mtu);
+	int (*neigh_setup)(struct net_device *dev, struct neigh_parms *);
 
-#define HAVE_TX_TIMEOUT
-	void			(*tx_timeout) (struct net_device *dev);
-
-	void			(*vlan_rx_register)(struct net_device *dev,
-						    struct vlan_group *grp);
-	void			(*vlan_rx_add_vid)(struct net_device *dev,
-						   unsigned short vid);
-	void			(*vlan_rx_kill_vid)(struct net_device *dev,
-						    unsigned short vid);
-
-	int			(*neigh_setup)(struct net_device *dev, struct neigh_parms *);
 #ifdef CONFIG_NETPOLL
 	struct netpoll_info	*npinfo;
 #endif
-#ifdef CONFIG_NET_POLL_CONTROLLER
-	void                    (*poll_controller)(struct net_device *dev);
-#endif
-
-	u16			(*select_queue)(struct net_device *dev,
-						struct sk_buff *skb);
 
 #ifdef CONFIG_NET_NS
 	/* Network namespace this network device is inside */
@@ -763,6 +835,38 @@ struct net_device
 	/* for setting kernel sock attribute on TCP connection setup */
 #define GSO_MAX_SIZE		65536
 	unsigned int		gso_max_size;
+
+#ifdef CONFIG_COMPAT_NET_DEV_OPS
+	struct {
+		int			(*init)(struct net_device *dev);
+		void			(*uninit)(struct net_device *dev);
+		int			(*open)(struct net_device *dev);
+		int			(*stop)(struct net_device *dev);
+		void			(*change_rx_flags)(struct net_device *dev,
+							   int flags);
+		void			(*set_rx_mode)(struct net_device *dev);
+		void			(*set_multicast_list)(struct net_device *dev);
+		int			(*set_mac_address)(struct net_device *dev,
+							   void *addr);
+		int			(*validate_addr)(struct net_device *dev);
+		int			(*do_ioctl)(struct net_device *dev,
+						    struct ifreq *ifr, int cmd);
+		int			(*set_config)(struct net_device *dev,
+						      struct ifmap *map);
+		int			(*change_mtu)(struct net_device *dev, int new_mtu);
+		void			(*tx_timeout) (struct net_device *dev);
+		struct net_device_stats* (*get_stats)(struct net_device *dev);
+		void			(*vlan_rx_register)(struct net_device *dev,
+							    struct vlan_group *grp);
+		void			(*vlan_rx_add_vid)(struct net_device *dev,
+							   unsigned short vid);
+		void			(*vlan_rx_kill_vid)(struct net_device *dev,
+							    unsigned short vid);
+#ifdef CONFIG_NET_POLL_CONTROLLER
+		void                    (*poll_controller)(struct net_device *dev);
+#endif
+#endif
+	};
 };
 #define to_net_dev(d) container_of(d, struct net_device, dev)
 

net/Kconfig

@@ -32,6 +32,9 @@ config NET_NS
 	  Allow user space to create what appear to be multiple instances
 	  of the network stack.
 
+config COMPAT_NET_DEV_OPS
+       def_bool y
+
 source "net/packet/Kconfig"
 source "net/unix/Kconfig"
 source "net/xfrm/Kconfig"