forked from Minki/linux
e0386005ff
Use cmpxchg() to get rid of spinlocks in inet_add_protocol() and friends. inet_protos[] & inet6_protos[] are moved to read_mostly section Signed-off-by: Eric Dumazet <eric.dumazet@gmail.com> Signed-off-by: David S. Miller <davem@davemloft.net>
60 lines
1.7 KiB
C
60 lines
1.7 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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* 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 <linux/cache.h>
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#include <linux/module.h>
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#include <linux/netdevice.h>
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#include <linux/spinlock.h>
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#include <net/protocol.h>
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const struct net_protocol *inet_protos[MAX_INET_PROTOS] __read_mostly;
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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(const struct net_protocol *prot, unsigned char protocol)
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{
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int hash = protocol & (MAX_INET_PROTOS - 1);
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return !cmpxchg(&inet_protos[hash], NULL, prot) ? 0 : -1;
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}
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EXPORT_SYMBOL(inet_add_protocol);
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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(const struct net_protocol *prot, unsigned char protocol)
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{
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int ret, hash = protocol & (MAX_INET_PROTOS - 1);
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ret = (cmpxchg(&inet_protos[hash], prot, NULL) == prot) ? 0 : -1;
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synchronize_net();
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return ret;
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}
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EXPORT_SYMBOL(inet_del_protocol);
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