net: Remove gso_send_check as an offload callback

The send_check logic was only interesting in cases of TCP offload and
UDP UFO where the checksum needed to be initialized to the pseudo
header checksum. Now we've moved that logic into the related
gso_segment functions so gso_send_check is no longer needed.

Signed-off-by: Tom Herbert <[e-mail]>
Signed-off-by: David S. Miller <[e-mail]>

include/linux/netdevice.h

···
 struct offload_callbacks {
 	struct sk_buff		*(*gso_segment)(struct sk_buff *skb,
 						netdev_features_t features);
-	int			(*gso_send_check)(struct sk_buff *skb);
 	struct sk_buff		**(*gro_receive)(struct sk_buff **head,
 					       struct sk_buff *skb);
 	int			(*gro_complete)(struct sk_buff *skb, int nhoff);

net/core/dev.c

···
 	rcu_read_lock();
 	list_for_each_entry_rcu(ptype, &offload_base, list) {
 		if (ptype->type == type && ptype->callbacks.gso_segment) {
-			if (unlikely(skb->ip_summed != CHECKSUM_PARTIAL)) {
-				int err;
-
-				err = ptype->callbacks.gso_send_check(skb);
-				segs = ERR_PTR(err);
-				if (err || skb_gso_ok(skb, features))
-					break;
-				__skb_push(skb, (skb->data -
-						 skb_network_header(skb)));
-			}
 			segs = ptype->callbacks.gso_segment(skb, features);
 			break;
 		}

net/ipv4/af_inet.c

···
 }
 EXPORT_SYMBOL(inet_sk_rebuild_header);
 
-static int inet_gso_send_check(struct sk_buff *skb)
-{
-	const struct net_offload *ops;
-	const struct iphdr *iph;
-	int proto;
-	int ihl;
-	int err = -EINVAL;
-
-	if (unlikely(!pskb_may_pull(skb, sizeof(*iph))))
-		goto out;
-
-	iph = ip_hdr(skb);
-	ihl = iph->ihl * 4;
-	if (ihl < sizeof(*iph))
-		goto out;
-
-	proto = iph->protocol;
-
-	/* Warning: after this point, iph might be no longer valid */
-	if (unlikely(!pskb_may_pull(skb, ihl)))
-		goto out;
-	__skb_pull(skb, ihl);
-
-	skb_reset_transport_header(skb);
-	err = -EPROTONOSUPPORT;
-
-	ops = rcu_dereference(inet_offloads[proto]);
-	if (likely(ops && ops->callbacks.gso_send_check))
-		err = ops->callbacks.gso_send_check(skb);
-
-out:
-	return err;
-}
-
 static struct sk_buff *inet_gso_segment(struct sk_buff *skb,
 					netdev_features_t features)
 {
···
 static struct packet_offload ip_packet_offload __read_mostly = {
 	.type = cpu_to_be16(ETH_P_IP),
 	.callbacks = {
-		.gso_send_check = inet_gso_send_check,
 		.gso_segment = inet_gso_segment,
 		.gro_receive = inet_gro_receive,
 		.gro_complete = inet_gro_complete,
···
 
 static const struct net_offload ipip_offload = {
 	.callbacks = {
-		.gso_send_check = inet_gso_send_check,
 		.gso_segment	= inet_gso_segment,
 		.gro_receive	= inet_gro_receive,
 		.gro_complete	= inet_gro_complete,

net/ipv4/gre_offload.c

···
 #include <net/protocol.h>
 #include <net/gre.h>
 
-static int gre_gso_send_check(struct sk_buff *skb)
-{
-	if (!skb->encapsulation)
-		return -EINVAL;
-	return 0;
-}
-
 static struct sk_buff *gre_gso_segment(struct sk_buff *skb,
 				       netdev_features_t features)
 {
···
 				  SKB_GSO_GRE |
 				  SKB_GSO_GRE_CSUM |
 				  SKB_GSO_IPIP)))
+		goto out;
+
+	if (!skb->encapsulation)
 		goto out;
 
 	if (unlikely(!pskb_may_pull(skb, sizeof(*greh))))
···
 
 static const struct net_offload gre_offload = {
 	.callbacks = {
-		.gso_send_check = gre_gso_send_check,
 		.gso_segment = gre_gso_segment,
 		.gro_receive = gre_gro_receive,
 		.gro_complete = gre_gro_complete,

net/ipv4/tcp_offload.c

···
 }
 EXPORT_SYMBOL(tcp_gro_complete);
 
-static int tcp_v4_gso_send_check(struct sk_buff *skb)
-{
-	return 0;
-}
-
 static struct sk_buff **tcp4_gro_receive(struct sk_buff **head, struct sk_buff *skb)
 {
 	/* Don't bother verifying checksum if we're going to flush anyway. */
···
 
 static const struct net_offload tcpv4_offload = {
 	.callbacks = {
-		.gso_send_check	=	tcp_v4_gso_send_check,
 		.gso_segment	=	tcp4_gso_segment,
 		.gro_receive	=	tcp4_gro_receive,
 		.gro_complete	=	tcp4_gro_complete,

net/ipv4/udp_offload.c

···
 	struct udp_offload_priv __rcu *next;
 };
 
-static int udp4_ufo_send_check(struct sk_buff *skb)
-{
-	return 0;
-}
-
 struct sk_buff *skb_udp_tunnel_segment(struct sk_buff *skb,
 				       netdev_features_t features)
 {
···
 
 static const struct net_offload udpv4_offload = {
 	.callbacks = {
-		.gso_send_check = udp4_ufo_send_check,
 		.gso_segment = udp4_ufo_fragment,
 		.gro_receive  =	udp4_gro_receive,
 		.gro_complete =	udp4_gro_complete,

net/ipv6/ip6_offload.c

···
 	return proto;
 }
 
-static int ipv6_gso_send_check(struct sk_buff *skb)
-{
-	const struct ipv6hdr *ipv6h;
-	const struct net_offload *ops;
-	int err = -EINVAL;
-
-	if (unlikely(!pskb_may_pull(skb, sizeof(*ipv6h))))
-		goto out;
-
-	ipv6h = ipv6_hdr(skb);
-	__skb_pull(skb, sizeof(*ipv6h));
-	err = -EPROTONOSUPPORT;
-
-	ops = rcu_dereference(inet6_offloads[
-		ipv6_gso_pull_exthdrs(skb, ipv6h->nexthdr)]);
-
-	if (likely(ops && ops->callbacks.gso_send_check)) {
-		skb_reset_transport_header(skb);
-		err = ops->callbacks.gso_send_check(skb);
-	}
-
-out:
-	return err;
-}
-
 static struct sk_buff *ipv6_gso_segment(struct sk_buff *skb,
 	netdev_features_t features)
 {
···
 static struct packet_offload ipv6_packet_offload __read_mostly = {
 	.type = cpu_to_be16(ETH_P_IPV6),
 	.callbacks = {
-		.gso_send_check = ipv6_gso_send_check,
 		.gso_segment = ipv6_gso_segment,
 		.gro_receive = ipv6_gro_receive,
 		.gro_complete = ipv6_gro_complete,
···
 
 static const struct net_offload sit_offload = {
 	.callbacks = {
-		.gso_send_check = ipv6_gso_send_check,
 		.gso_segment	= ipv6_gso_segment,
 		.gro_receive	= ipv6_gro_receive,
 		.gro_complete	= ipv6_gro_complete,

net/ipv6/tcpv6_offload.c

···
 #include <net/ip6_checksum.h>
 #include "ip6_offload.h"
 
-static int tcp_v6_gso_send_check(struct sk_buff *skb)
-{
-	return 0;
-}
-
 static struct sk_buff **tcp6_gro_receive(struct sk_buff **head,
 					 struct sk_buff *skb)
 {
···
 }
 static const struct net_offload tcpv6_offload = {
 	.callbacks = {
-		.gso_send_check	=	tcp_v6_gso_send_check,
 		.gso_segment	=	tcp6_gso_segment,
 		.gro_receive	=	tcp6_gro_receive,
 		.gro_complete	=	tcp6_gro_complete,

net/ipv6/udp_offload.c

···
 #include <net/ip6_checksum.h>
 #include "ip6_offload.h"
 
-static int udp6_ufo_send_check(struct sk_buff *skb)
-{
-	return 0;
-}
-
 static struct sk_buff *udp6_ufo_fragment(struct sk_buff *skb,
 					 netdev_features_t features)
 {
···
 
 static const struct net_offload udpv6_offload = {
 	.callbacks = {
-		.gso_send_check =	udp6_ufo_send_check,
 		.gso_segment	=	udp6_ufo_fragment,
 		.gro_receive	=	udp6_gro_receive,
 		.gro_complete	=	udp6_gro_complete,

net/mpls/mpls_gso.c

···
 	return segs;
 }
 
-static int mpls_gso_send_check(struct sk_buff *skb)
-{
-	return 0;
-}
-
 static struct packet_offload mpls_mc_offload = {
 	.type = cpu_to_be16(ETH_P_MPLS_MC),
 	.callbacks = {
-		.gso_send_check =	mpls_gso_send_check,
 		.gso_segment    =	mpls_gso_segment,
 	},
 };
···
 static struct packet_offload mpls_uc_offload = {
 	.type = cpu_to_be16(ETH_P_MPLS_UC),
 	.callbacks = {
-		.gso_send_check =	mpls_gso_send_check,
 		.gso_segment    =	mpls_gso_segment,
 	},
 };