[NET]: Inline net_device_stats

Network drivers which keep stats allocate their own stats structure
then write a get_stats() function to return them.  It would be nice if
this were done by default.

1) Add a new "stats" field to "struct net_device".
2) Add a new feature field to say "this driver uses the internal one"
3) Have a default "get_stats" which returns NULL if that feature not set.
4) Change callers to check result of get_stats call for NULL, not if
   ->get_stats is set.

This should not break backwards compatibility with older drivers, yet
allow modern drivers to shed some boilerplate code.

Lightly tested: works for a modified lguest network driver.

Signed-off-by: Rusty Russell <rusty@rustcorp.com.au>
Signed-off-by: David S. Miller <davem@davemloft.net>

1 files changed, 2 insertions, 0 deletions

diff --git a/include/linux/netdevice.h b/include/linux/netdevice.h
index 1a528548cd1d..71fc8ff4888b 100644
--- a/include/linux/netdevice.h
+++ b/include/linux/netdevice.h
@@ -323,6 +323,7 @@ struct net_device
 #define NETIF_F_VLAN_CHALLENGED 1024    /* Device cannot handle VLAN packets */
 #define NETIF_F_GSO             2048    /* Enable software GSO. */
 #define NETIF_F_LLTX            4096    /* LockLess TX */
+#define NETIF_F_INTERNAL_STATS  8192    /* Use stats structure in net_device */
 
         /* Segmentation offload features */
 #define NETIF_F_GSO_SHIFT       16
@@ -347,6 +348,7 @@ struct net_device
 
 
         struct net_device_stats* (*get_stats)(struct net_device *dev);
+        struct net_device_stats stats;
 
         /* List of functions to handle Wireless Extensions (instead of ioctl).
          * See <net/iw_handler.h> for details. Jean II */