net: Make gro complete function to return void

tcp_gro_complete() function only updates the skb fields related to GRO
and it always returns zero. All the 3 drivers which are using it
do not check for the return value either.

Change it to return void instead which simplifies its callers as
error handing becomes unnecessary.
Signed-off-by: Parav Pandit <parav@nvidia.com>
Reviewed-by: Simon Horman <simon.horman@corigine.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

include/net/tcp.h

@@ -2041,7 +2041,7 @@ INDIRECT_CALLABLE_DECLARE(int tcp4_gro_complete(struct sk_buff *skb, int thoff))
 INDIRECT_CALLABLE_DECLARE(struct sk_buff *tcp4_gro_receive(struct list_head *head, struct sk_buff *skb));
 INDIRECT_CALLABLE_DECLARE(int tcp6_gro_complete(struct sk_buff *skb, int thoff));
 INDIRECT_CALLABLE_DECLARE(struct sk_buff *tcp6_gro_receive(struct list_head *head, struct sk_buff *skb));
-int tcp_gro_complete(struct sk_buff *skb);
+void tcp_gro_complete(struct sk_buff *skb);
 
 void __tcp_v4_send_check(struct sk_buff *skb, __be32 saddr, __be32 daddr);
 

net/ipv4/tcp_offload.c

@@ -296,7 +296,7 @@ struct sk_buff *tcp_gro_receive(struct list_head *head, struct sk_buff *skb)
 	return pp;
 }
 
-int tcp_gro_complete(struct sk_buff *skb)
+void tcp_gro_complete(struct sk_buff *skb)
 {
 	struct tcphdr *th = tcp_hdr(skb);
 
@@ -311,8 +311,6 @@ int tcp_gro_complete(struct sk_buff *skb)
 
 	if (skb->encapsulation)
 		skb->inner_transport_header = skb->transport_header;
-
-	return 0;
 }
 EXPORT_SYMBOL(tcp_gro_complete);
 
@@ -342,7 +340,8 @@ INDIRECT_CALLABLE_SCOPE int tcp4_gro_complete(struct sk_buff *skb, int thoff)
 	if (NAPI_GRO_CB(skb)->is_atomic)
 		skb_shinfo(skb)->gso_type |= SKB_GSO_TCP_FIXEDID;
 
-	return tcp_gro_complete(skb);
+	tcp_gro_complete(skb);
+	return 0;
 }
 
 static const struct net_offload tcpv4_offload = {

net/ipv6/tcpv6_offload.c

@@ -36,7 +36,8 @@ INDIRECT_CALLABLE_SCOPE int tcp6_gro_complete(struct sk_buff *skb, int thoff)
 				  &iph->daddr, 0);
 	skb_shinfo(skb)->gso_type |= SKB_GSO_TCPV6;
 
-	return tcp_gro_complete(skb);
+	tcp_gro_complete(skb);
+	return 0;
 }
 
 static struct sk_buff *tcp6_gso_segment(struct sk_buff *skb,