[ETHTOOL] Provide default behaviors for a few ethtool sub-ioctls

For the operations
	get-tx-csum
	get-sg
	get-tso
	get-ufo
the default ethtool_op_xxx behavior is fine for all drivers, so we
permit op==NULL to imply the default behavior.

This provides a more uniform behavior across all drivers, eliminating
ethtool(8) "ioctl not supported" errors on older drivers that had
not been updated for the latest sub-ioctls.

The ethtool_op_xxx() functions are left exported, in case anyone
wishes to call them directly from a driver-private implementation --
a not-uncommon case.  Should an ethtool_op_xxx() helper remain unused
for a while, except by net/core/ethtool.c, we can un-export it at a
later date.

[ Resolved conflicts with set/get value ethtool patch... -DaveM ]

Signed-off-by: Jeff Garzik <jeff@garzik.org>
Signed-off-by: David S. Miller <davem@davemloft.net>

2 files changed, 12 insertions, 7 deletions

diff --git a/net/bridge/br_device.c b/net/bridge/br_device.c
index f803e39eee28..c07bac5e3e10 100644
--- a/net/bridge/br_device.c
+++ b/net/bridge/br_device.c
@@ -150,11 +150,8 @@ static int br_set_tx_csum(struct net_device *dev, u32 data)
 static struct ethtool_ops br_ethtool_ops = {
         .get_drvinfo = br_getinfo,
         .get_link = ethtool_op_get_link,
-        .get_sg = ethtool_op_get_sg,
         .set_sg = br_set_sg,
-        .get_tx_csum = ethtool_op_get_tx_csum,
         .set_tx_csum = br_set_tx_csum,
-        .get_tso = ethtool_op_get_tso,
         .set_tso = br_set_tso,
 };
 
diff --git a/net/core/ethtool.c b/net/core/ethtool.c
index 0d0b13cc1dd3..1163eb2256d0 100644
--- a/net/core/ethtool.c
+++ b/net/core/ethtool.c
@@ -893,21 +893,27 @@ int dev_ethtool(struct net *net, struct ifreq *ifr)
                 break;
         case ETHTOOL_GTXCSUM:
                 rc = ethtool_get_value(dev, useraddr, ethcmd,
-                                       dev->ethtool_ops->get_tx_csum);
+                                       (dev->ethtool_ops->get_tx_csum ?
+                                        dev->ethtool_ops->get_tx_csum :
+                                        ethtool_op_get_tx_csum));
                 break;
         case ETHTOOL_STXCSUM:
                 rc = ethtool_set_tx_csum(dev, useraddr);
                 break;
         case ETHTOOL_GSG:
                 rc = ethtool_get_value(dev, useraddr, ethcmd,
-                                       dev->ethtool_ops->get_sg);
+                                       (dev->ethtool_ops->get_sg ?
+                                        dev->ethtool_ops->get_sg :
+                                        ethtool_op_get_sg));
                 break;
         case ETHTOOL_SSG:
                 rc = ethtool_set_sg(dev, useraddr);
                 break;
         case ETHTOOL_GTSO:
                 rc = ethtool_get_value(dev, useraddr, ethcmd,
-                                       dev->ethtool_ops->get_tso);
+                                       (dev->ethtool_ops->get_tso ?
+                                        dev->ethtool_ops->get_tso :
+                                        ethtool_op_get_tso));
                 break;
         case ETHTOOL_STSO:
                 rc = ethtool_set_tso(dev, useraddr);
@@ -929,7 +935,9 @@ int dev_ethtool(struct net *net, struct ifreq *ifr)
                 break;
         case ETHTOOL_GUFO:
                 rc = ethtool_get_value(dev, useraddr, ethcmd,
-                                       dev->ethtool_ops->get_ufo);
+                                       (dev->ethtool_ops->get_ufo ?
+                                        dev->ethtool_ops->get_ufo :
+                                        ethtool_op_get_ufo));
                 break;
         case ETHTOOL_SUFO:
                 rc = ethtool_set_ufo(dev, useraddr);