net: introduce NETIF_F_RXCSUM

Introduce NETIF_F_RXCSUM to replace device-private flags for RX checksum
offload. Integrate it with ndo_fix_features.

ethtool_op_get_rx_csum() is removed altogether as nothing in-tree uses it.

Signed-off-by: Michał Mirosław <mirq-linux@rere.qmqm.pl>
Signed-off-by: David S. Miller <davem@davemloft.net>
diff --git a/include/linux/netdevice.h b/include/linux/netdevice.h
index 85f67e2..ffe56c1 100644
--- a/include/linux/netdevice.h
+++ b/include/linux/netdevice.h
@@ -977,6 +977,7 @@
 #define NETIF_F_FCOE_MTU	(1 << 26) /* Supports max FCoE MTU, 2158 bytes*/
 #define NETIF_F_NTUPLE		(1 << 27) /* N-tuple filters supported */
 #define NETIF_F_RXHASH		(1 << 28) /* Receive hashing offload */
+#define NETIF_F_RXCSUM		(1 << 29) /* Receive checksumming offload */
 
 	/* Segmentation offload features */
 #define NETIF_F_GSO_SHIFT	16
@@ -992,7 +993,7 @@
 	/* = all defined minus driver/device-class-related */
 #define NETIF_F_NEVER_CHANGE	(NETIF_F_HIGHDMA | NETIF_F_VLAN_CHALLENGED | \
 				  NETIF_F_LLTX | NETIF_F_NETNS_LOCAL)
-#define NETIF_F_ETHTOOL_BITS	(0x1f3fffff & ~NETIF_F_NEVER_CHANGE)
+#define NETIF_F_ETHTOOL_BITS	(0x3f3fffff & ~NETIF_F_NEVER_CHANGE)
 
 	/* List of features with software fallbacks. */
 #define NETIF_F_GSO_SOFTWARE	(NETIF_F_TSO | NETIF_F_TSO_ECN | \
@@ -2510,6 +2511,8 @@
 
 static inline u32 dev_ethtool_get_rx_csum(struct net_device *dev)
 {
+	if (dev->hw_features & NETIF_F_RXCSUM)
+		return !!(dev->features & NETIF_F_RXCSUM);
 	if (!dev->ethtool_ops || !dev->ethtool_ops->get_rx_csum)
 		return 0;
 	return dev->ethtool_ops->get_rx_csum(dev);