03d4f879b9
As IPPROTO_TCP is 6, it makes sense to make sure inet_protos[] array is properly cache line aligned to avoid false sharing on SMP. c0680540 b peer_total c0680544 b inet_peer_unused_head c0680560 B inet_protos On i386 this example, we can see that inet_protos[IPPROTO_TCP] shares a potentially hot (and modified) cache line. Signed-off-by: Eric Dumazet <dada1@cosmosbay.com> Signed-off-by: David S. Miller <davem@davemloft.net>
99 lines
2.3 KiB
C
99 lines
2.3 KiB
C
/*
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* INET An implementation of the TCP/IP protocol suite for the LINUX
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* operating system. INET is implemented using the BSD Socket
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* interface as the means of communication with the user level.
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*
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* INET protocol dispatch tables.
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*
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* Version: $Id: protocol.c,v 1.14 2001/05/18 02:25:49 davem Exp $
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*
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* Authors: Ross Biro
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* Fred N. van Kempen, <waltje@uWalt.NL.Mugnet.ORG>
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*
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* Fixes:
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* Alan Cox : Ahah! udp icmp errors don't work because
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* udp_err is never called!
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* Alan Cox : Added new fields for init and ready for
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* proper fragmentation (_NO_ 4K limits!)
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* Richard Colella : Hang on hash collision
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* Vince Laviano : Modified inet_del_protocol() to correctly
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* maintain copy bit.
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*
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* This program is free software; you can redistribute it and/or
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* modify it under the terms of the GNU General Public License
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* as published by the Free Software Foundation; either version
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* 2 of the License, or (at your option) any later version.
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*/
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#include <asm/uaccess.h>
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#include <asm/system.h>
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#include <linux/module.h>
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#include <linux/types.h>
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#include <linux/kernel.h>
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#include <linux/string.h>
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#include <linux/socket.h>
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#include <linux/in.h>
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#include <linux/inet.h>
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#include <linux/netdevice.h>
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#include <linux/timer.h>
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#include <net/ip.h>
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#include <net/protocol.h>
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#include <linux/skbuff.h>
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#include <net/sock.h>
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#include <net/icmp.h>
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#include <net/udp.h>
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#include <net/ipip.h>
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#include <linux/igmp.h>
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struct net_protocol *inet_protos[MAX_INET_PROTOS] ____cacheline_aligned_in_smp;
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static DEFINE_SPINLOCK(inet_proto_lock);
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/*
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* Add a protocol handler to the hash tables
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*/
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int inet_add_protocol(struct net_protocol *prot, unsigned char protocol)
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{
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int hash, ret;
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hash = protocol & (MAX_INET_PROTOS - 1);
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spin_lock_bh(&inet_proto_lock);
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if (inet_protos[hash]) {
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ret = -1;
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} else {
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inet_protos[hash] = prot;
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ret = 0;
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}
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spin_unlock_bh(&inet_proto_lock);
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return ret;
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}
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/*
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* Remove a protocol from the hash tables.
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*/
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int inet_del_protocol(struct net_protocol *prot, unsigned char protocol)
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{
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int hash, ret;
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hash = protocol & (MAX_INET_PROTOS - 1);
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spin_lock_bh(&inet_proto_lock);
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if (inet_protos[hash] == prot) {
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inet_protos[hash] = NULL;
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ret = 0;
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} else {
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ret = -1;
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}
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spin_unlock_bh(&inet_proto_lock);
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synchronize_net();
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return ret;
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}
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EXPORT_SYMBOL(inet_add_protocol);
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EXPORT_SYMBOL(inet_del_protocol);
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