91 lines
2.5 KiB
Diff
91 lines
2.5 KiB
Diff
From: Eric Dumazet <eric.dumazet@gmail.com>
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Date: Mon, 28 Nov 2011 20:30:35 +0000
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Subject: [PATCH 2/3] flow_dissector: use a 64bit load/store
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MIME-Version: 1.0
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Content-Type: text/plain; charset=UTF-8
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Content-Transfer-Encoding: 8bit
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commit 4d77d2b567ec66a443792d99e96ac760991d80d0 upstream.
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Le lundi 28 novembre 2011 à 19:06 -0500, David Miller a écrit :
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> From: Dimitris Michailidis <dm@chelsio.com>
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> Date: Mon, 28 Nov 2011 08:25:39 -0800
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>
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> >> +bool skb_flow_dissect(const struct sk_buff *skb, struct flow_keys
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> >> *flow)
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> >> +{
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> >> + int poff, nhoff = skb_network_offset(skb);
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> >> + u8 ip_proto;
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> >> + u16 proto = skb->protocol;
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> >
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> > __be16 instead of u16 for proto?
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>
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> I'll take care of this when I apply these patches.
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( CC trimmed )
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Thanks David !
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Here is a small patch to use one 64bit load/store on x86_64 instead of
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two 32bit load/stores.
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[PATCH net-next] flow_dissector: use a 64bit load/store
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gcc compiler is smart enough to use a single load/store if we
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memcpy(dptr, sptr, 8) on x86_64, regardless of
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CONFIG_CC_OPTIMIZE_FOR_SIZE
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In IP header, daddr immediately follows saddr, this wont change in the
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future. We only need to make sure our flow_keys (src,dst) fields wont
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break the rule.
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Signed-off-by: Eric Dumazet <eric.dumazet@gmail.com>
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Signed-off-by: David S. Miller <davem@davemloft.net>
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diff --git a/include/net/flow_keys.h b/include/net/flow_keys.h
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index e4cb285..80461c1 100644
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--- a/include/net/flow_keys.h
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+++ b/include/net/flow_keys.h
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@@ -2,6 +2,7 @@
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#define _NET_FLOW_KEYS_H
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struct flow_keys {
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+ /* (src,dst) must be grouped, in the same way than in IP header */
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__be32 src;
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__be32 dst;
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union {
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diff --git a/net/core/flow_dissector.c b/net/core/flow_dissector.c
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index f0516d9..0985b9b 100644
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--- a/net/core/flow_dissector.c
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+++ b/net/core/flow_dissector.c
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@@ -8,6 +8,16 @@
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#include <linux/ppp_defs.h>
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#include <net/flow_keys.h>
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+/* copy saddr & daddr, possibly using 64bit load/store
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+ * Equivalent to : flow->src = iph->saddr;
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+ * flow->dst = iph->daddr;
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+ */
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+static void iph_to_flow_copy_addrs(struct flow_keys *flow, const struct iphdr *iph)
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+{
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+ BUILD_BUG_ON(offsetof(typeof(*flow), dst) !=
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+ offsetof(typeof(*flow), src) + sizeof(flow->src));
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+ memcpy(&flow->src, &iph->saddr, sizeof(flow->src) + sizeof(flow->dst));
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+}
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bool skb_flow_dissect(const struct sk_buff *skb, struct flow_keys *flow)
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{
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@@ -31,8 +41,7 @@ ip:
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ip_proto = 0;
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else
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ip_proto = iph->protocol;
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- flow->src = iph->saddr;
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- flow->dst = iph->daddr;
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+ iph_to_flow_copy_addrs(flow, iph);
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nhoff += iph->ihl * 4;
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break;
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}
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--
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1.7.10
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