From mboxrd@z Thu Jan 1 00:00:00 1970 From: Yafang Shao Subject: [PATCH net-next 1/2] ipv4: replace ip_hdr() with skb->data for optimization Date: Tue, 5 Jun 2018 08:04:21 -0400 Message-ID: <1528200262-11834-1-git-send-email-laoar.shao@gmail.com> Cc: netdev@vger.kernel.org, inux-kernel@vger.kernel.org, Yafang Shao To: edumazet@google.com, davem@davemloft.net Return-path: Received: from mail-pf0-f193.google.com ([209.85.192.193]:33691 "EHLO mail-pf0-f193.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751625AbeFEMEo (ORCPT ); Tue, 5 Jun 2018 08:04:44 -0400 Sender: netdev-owner@vger.kernel.org List-ID: In ip receive path, when ip header hasn't been pulled yet, ip_hdr() and skb->data are pointing to the same byte. In ip output path, when ip header is just pushed, ip_hdr() and skb->data are pointing to the same byte. As ip_hdr() is more expensive than using skb->data, so replace ip_hdr() with skb->data in these situations for optimization. Signed-off-by: Yafang Shao --- net/ipv4/ip_input.c | 8 ++++---- net/ipv4/ip_output.c | 8 ++++---- 2 files changed, 8 insertions(+), 8 deletions(-) diff --git a/net/ipv4/ip_input.c b/net/ipv4/ip_input.c index 7582713..7a03e8c 100644 --- a/net/ipv4/ip_input.c +++ b/net/ipv4/ip_input.c @@ -309,7 +309,7 @@ static inline bool ip_rcv_options(struct sk_buff *skb) static int ip_rcv_finish(struct net *net, struct sock *sk, struct sk_buff *skb) { - const struct iphdr *iph = ip_hdr(skb); + const struct iphdr *iph = (const struct iphdr *)skb->data; int (*edemux)(struct sk_buff *skb); struct net_device *dev = skb->dev; struct rtable *rt; @@ -335,7 +335,7 @@ static int ip_rcv_finish(struct net *net, struct sock *sk, struct sk_buff *skb) if (unlikely(err)) goto drop_error; /* must reload iph, skb->head might have changed */ - iph = ip_hdr(skb); + iph = (const struct iphdr *)skb->data; } } @@ -433,7 +433,7 @@ int ip_rcv(struct sk_buff *skb, struct net_device *dev, struct packet_type *pt, if (!pskb_may_pull(skb, sizeof(struct iphdr))) goto inhdr_error; - iph = ip_hdr(skb); + iph = (const struct iphdr *)skb->data; /* * RFC1122: 3.2.1.2 MUST silently discard any IP frame that fails the checksum. @@ -459,7 +459,7 @@ int ip_rcv(struct sk_buff *skb, struct net_device *dev, struct packet_type *pt, if (!pskb_may_pull(skb, iph->ihl*4)) goto inhdr_error; - iph = ip_hdr(skb); + iph = (const struct iphdr *)skb->data; if (unlikely(ip_fast_csum((u8 *)iph, iph->ihl))) goto csum_error; diff --git a/net/ipv4/ip_output.c b/net/ipv4/ip_output.c index af5a830..f5014cd 100644 --- a/net/ipv4/ip_output.c +++ b/net/ipv4/ip_output.c @@ -96,7 +96,7 @@ void ip_send_check(struct iphdr *iph) int __ip_local_out(struct net *net, struct sock *sk, struct sk_buff *skb) { - struct iphdr *iph = ip_hdr(skb); + struct iphdr *iph = (struct iphdr *)skb->data; iph->tot_len = htons(skb->len); ip_send_check(iph); @@ -151,7 +151,7 @@ int ip_build_and_send_pkt(struct sk_buff *skb, const struct sock *sk, /* Build the IP header. */ skb_push(skb, sizeof(struct iphdr) + (opt ? opt->opt.optlen : 0)); skb_reset_network_header(skb); - iph = ip_hdr(skb); + iph = (struct iphdr *)skb->data; iph->version = 4; iph->ihl = 5; iph->tos = inet->tos; @@ -477,7 +477,7 @@ int ip_queue_xmit(struct sock *sk, struct sk_buff *skb, struct flowi *fl) /* OK, we know where to send it, allocate and build IP header. */ skb_push(skb, sizeof(struct iphdr) + (inet_opt ? inet_opt->opt.optlen : 0)); skb_reset_network_header(skb); - iph = ip_hdr(skb); + iph = (struct iphdr *)skb->data; *((__be16 *)iph) = htons((4 << 12) | (5 << 8) | (inet->tos & 0xff)); if (ip_dont_fragment(sk, &rt->dst) && !skb->ignore_df) iph->frag_off = htons(IP_DF); @@ -659,7 +659,7 @@ int ip_do_fragment(struct net *net, struct sock *sk, struct sk_buff *skb, __skb_push(frag, hlen); skb_reset_network_header(frag); memcpy(skb_network_header(frag), iph, hlen); - iph = ip_hdr(frag); + iph = (struct iphdr *)skb->data; iph->tot_len = htons(frag->len); ip_copy_metadata(frag, skb); if (offset == 0) -- 1.8.3.1