From: Eric Dumazet <eric.dumazet@gmail.com>
Date: Wed, 11 Apr 2012 23:05:28 +0000 (+0000)
Subject: udp: intoduce udp_encap_needed static_key
X-Git-Tag: v3.5-rc1~109^2~472
X-Git-Url: http://git.openpandora.org/cgi-bin/gitweb.cgi?a=commitdiff_plain;h=447167bf565a474ff0cfb0f41d54936937479e97;p=pandora-kernel.git

udp: intoduce udp_encap_needed static_key

Most machines dont use UDP encapsulation (L2TP)

Adds a static_key so that udp_queue_rcv_skb() doesnt have to perform a
test if L2TP never setup the encap_rcv on a socket.

Idea of this patch came after Simon Horman proposal to add a hook on TCP
as well.

If static_key is not yet enabled, the fast path does a single JMP .

When static_key is enabled, JMP destination is patched to reach the real
encap_type/encap_rcv logic, possibly adding cache misses.

Signed-off-by: Eric Dumazet <eric.dumazet@gmail.com>
Cc: Simon Horman <horms@verge.net.au>
Cc: dev@openvswitch.org
Signed-off-by: David S. Miller <davem@davemloft.net>
---

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