gro: Optimise IPv4 packet reception
As this function can be called more than half a million times for 10GbE, it's important to optimise it as much as we can. This patch does some obvious changes to use 2-byte and 4-byte operations instead of byte-oriented ones where possible. Bit ops are also used to replace logical ops to reduce branching. Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au> Signed-off-by: David S. Miller <davem@davemloft.net>
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@ -1263,7 +1263,7 @@ static struct sk_buff **inet_gro_receive(struct sk_buff **head,
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if (!ops || !ops->gro_receive)
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if (!ops || !ops->gro_receive)
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goto out_unlock;
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goto out_unlock;
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if (iph->version != 4 || iph->ihl != 5)
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if (*(u8 *)iph != 0x45)
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goto out_unlock;
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goto out_unlock;
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if (unlikely(ip_fast_csum((u8 *)iph, iph->ihl)))
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if (unlikely(ip_fast_csum((u8 *)iph, iph->ihl)))
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@ -1281,17 +1281,18 @@ static struct sk_buff **inet_gro_receive(struct sk_buff **head,
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iph2 = ip_hdr(p);
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iph2 = ip_hdr(p);
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if (iph->protocol != iph2->protocol ||
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if ((iph->protocol ^ iph2->protocol) |
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iph->tos != iph2->tos ||
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(iph->tos ^ iph2->tos) |
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memcmp(&iph->saddr, &iph2->saddr, 8)) {
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(iph->saddr ^ iph2->saddr) |
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(iph->daddr ^ iph2->daddr)) {
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NAPI_GRO_CB(p)->same_flow = 0;
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NAPI_GRO_CB(p)->same_flow = 0;
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continue;
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continue;
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}
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}
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/* All fields must match except length and checksum. */
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/* All fields must match except length and checksum. */
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NAPI_GRO_CB(p)->flush |=
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NAPI_GRO_CB(p)->flush |=
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memcmp(&iph->frag_off, &iph2->frag_off, 4) ||
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(iph->ttl ^ iph2->ttl) |
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(u16)(ntohs(iph2->id) + NAPI_GRO_CB(p)->count) != id;
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((u16)(ntohs(iph2->id) + NAPI_GRO_CB(p)->count) ^ id);
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NAPI_GRO_CB(p)->flush |= flush;
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NAPI_GRO_CB(p)->flush |= flush;
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}
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}
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