Commit 8f78010b authored by Eric Dumazet's avatar Eric Dumazet Committed by Paolo Abeni
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tcp: gro: micro optimizations in tcp[4]_gro_complete() 



In tcp_gro_complete() :

Moving the skb->inner_transport_header setting
allows the compiler to reuse the previously loaded value
of skb->transport_header.

Caching skb_shinfo() avoids duplications as well.

In tcp4_gro_complete(), doing a single change on
skb_shinfo(skb)->gso_type also generates better code.

Signed-off-by: default avatarEric Dumazet <edumazet@google.com>
Acked-by: default avatarPaolo Abeni <pabeni@redhat.com>
Signed-off-by: default avatarPaolo Abeni <pabeni@redhat.com>
parent c7583e9f

net/ipv4/tcp_offload.c

+9 −8
Original line number Diff line number Diff line
@@ -299,18 +299,20 @@ struct sk_buff *tcp_gro_receive(struct list_head *head, struct sk_buff *skb) 
void tcp_gro_complete(struct sk_buff *skb)

{

	struct tcphdr *th = tcp_hdr(skb);

	struct skb_shared_info *shinfo;



	if (skb->encapsulation)

		skb->inner_transport_header = skb->transport_header;



	skb->csum_start = (unsigned char *)th - skb->head;

	skb->csum_offset = offsetof(struct tcphdr, check);

	skb->ip_summed = CHECKSUM_PARTIAL;



	skb_shinfo(skb)->gso_segs = NAPI_GRO_CB(skb)->count;

	shinfo = skb_shinfo(skb);

	shinfo->gso_segs = NAPI_GRO_CB(skb)->count;



	if (th->cwr)

		skb_shinfo(skb)->gso_type |= SKB_GSO_TCP_ECN;



	if (skb->encapsulation)

		skb->inner_transport_header = skb->transport_header;

		shinfo->gso_type |= SKB_GSO_TCP_ECN;

}

EXPORT_SYMBOL(tcp_gro_complete);
@@ -335,10 +337,9 @@ INDIRECT_CALLABLE_SCOPE int tcp4_gro_complete(struct sk_buff *skb, int thoff) 


	th->check = ~tcp_v4_check(skb->len - thoff, iph->saddr,

				  iph->daddr, 0);

	skb_shinfo(skb)->gso_type |= SKB_GSO_TCPV4;



	if (NAPI_GRO_CB(skb)->is_atomic)

		skb_shinfo(skb)->gso_type |= SKB_GSO_TCP_FIXEDID;

	skb_shinfo(skb)->gso_type |= SKB_GSO_TCPV4 |

			(NAPI_GRO_CB(skb)->is_atomic * SKB_GSO_TCP_FIXEDID);



	tcp_gro_complete(skb);

	return 0;