[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, 3 deletions

diff --git a/drivers/net/bonding/bond_main.c b/drivers/net/bonding/bond_main.c
index 76d3504505bd..cea3783c92c5 100644
--- a/drivers/net/bonding/bond_main.c
+++ b/drivers/net/bonding/bond_main.c
@@ -3640,9 +3640,8 @@ static struct net_device_stats *bond_get_stats(struct net_device *bond_dev)
         read_lock_bh(&bond->lock);
 
         bond_for_each_slave(bond, slave, i) {
-                if (slave->dev->get_stats) {
-                        sstats = slave->dev->get_stats(slave->dev);
-
+                sstats = slave->dev->get_stats(slave->dev);
+                if (sstats) {
                         stats->rx_packets += sstats->rx_packets;
                         stats->rx_bytes += sstats->rx_bytes;
                         stats->rx_errors += sstats->rx_errors;