net-gro: avoid reorders (d61d072e) · Commits · 戴 / test

Receiving a GSO packet in dev_gro_receive() is not uncommon in stacked devices, or devices partially implementing LRO/GRO like bnx2x. GRO is implementing the aggregation the device was not able to do itself. Current code causes reorders, like in following case : For a given flow where sender sent 3 packets P1,P2,P3,P4 Receiver might receive P1 as a single packet, stored in GRO engine. Then P2-P4 are received as a single GSO packet, immediately given to upper stack, while P1 is held in GRO engine. This patch will make sure P1 is given to upper stack, then P2-P4 immediately after. Signed-off-by:

Eric Dumazet <edumazet@google.com> Signed-off-by:

David S. Miller <davem@davemloft.net>

net/core/dev.c

+2 −2

Original line number	Original line	Diff line number	Diff line
	@@ -4482,7 +4482,7 @@ static enum gro_result dev_gro_receive(struct napi_struct *napi, struct sk_buff
	if (!(skb->dev->features & NETIF_F_GRO))		if (!(skb->dev->features & NETIF_F_GRO))
	goto normal;		goto normal;

	if (skb_is_gso(skb) \|\| skb_has_frag_list(skb) \|\| skb->csum_bad)		if (skb->csum_bad)
	goto normal;		goto normal;

	gro_list_prepare(napi, skb);		gro_list_prepare(napi, skb);
	@@ -4495,7 +4495,7 @@ static enum gro_result dev_gro_receive(struct napi_struct *napi, struct sk_buff
	skb_set_network_header(skb, skb_gro_offset(skb));		skb_set_network_header(skb, skb_gro_offset(skb));
	skb_reset_mac_len(skb);		skb_reset_mac_len(skb);
	NAPI_GRO_CB(skb)->same_flow = 0;		NAPI_GRO_CB(skb)->same_flow = 0;
	NAPI_GRO_CB(skb)->flush = 0;		NAPI_GRO_CB(skb)->flush = skb_is_gso(skb) \|\| skb_has_frag_list(skb);
	NAPI_GRO_CB(skb)->free = 0;		NAPI_GRO_CB(skb)->free = 0;
	NAPI_GRO_CB(skb)->encap_mark = 0;		NAPI_GRO_CB(skb)->encap_mark = 0;
	NAPI_GRO_CB(skb)->recursion_counter = 0;		NAPI_GRO_CB(skb)->recursion_counter = 0;

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