linux/net/ipv4/multipath_drr.c
Tim Schmielau cd354f1ae7 [PATCH] remove many unneeded #includes of sched.h
After Al Viro (finally) succeeded in removing the sched.h #include in module.h
recently, it makes sense again to remove other superfluous sched.h includes.
There are quite a lot of files which include it but don't actually need
anything defined in there.  Presumably these includes were once needed for
macros that used to live in sched.h, but moved to other header files in the
course of cleaning it up.

To ease the pain, this time I did not fiddle with any header files and only
removed #includes from .c-files, which tend to cause less trouble.

Compile tested against 2.6.20-rc2 and 2.6.20-rc2-mm2 (with offsets) on alpha,
arm, i386, ia64, mips, powerpc, and x86_64 with allnoconfig, defconfig,
allmodconfig, and allyesconfig as well as a few randconfigs on x86_64 and all
configs in arch/arm/configs on arm.  I also checked that no new warnings were
introduced by the patch (actually, some warnings are removed that were emitted
by unnecessarily included header files).

Signed-off-by: Tim Schmielau <tim@physik3.uni-rostock.de>
Acked-by: Russell King <rmk+kernel@arm.linux.org.uk>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2007-02-14 08:09:54 -08:00

250 lines
5.3 KiB
C

/*
* Device round robin policy for multipath.
*
*
* Version: $Id: multipath_drr.c,v 1.1.2.1 2004/09/16 07:42:34 elueck Exp $
*
* Authors: Einar Lueck <elueck@de.ibm.com><lkml@einar-lueck.de>
*
* This program is free software; you can redistribute it and/or
* modify it under the terms of the GNU General Public License
* as published by the Free Software Foundation; either version
* 2 of the License, or (at your option) any later version.
*/
#include <asm/system.h>
#include <asm/uaccess.h>
#include <linux/types.h>
#include <linux/errno.h>
#include <linux/timer.h>
#include <linux/mm.h>
#include <linux/kernel.h>
#include <linux/fcntl.h>
#include <linux/stat.h>
#include <linux/socket.h>
#include <linux/in.h>
#include <linux/inet.h>
#include <linux/netdevice.h>
#include <linux/inetdevice.h>
#include <linux/igmp.h>
#include <linux/proc_fs.h>
#include <linux/seq_file.h>
#include <linux/module.h>
#include <linux/mroute.h>
#include <linux/init.h>
#include <net/ip.h>
#include <net/protocol.h>
#include <linux/skbuff.h>
#include <net/sock.h>
#include <net/icmp.h>
#include <net/udp.h>
#include <net/raw.h>
#include <linux/notifier.h>
#include <linux/if_arp.h>
#include <linux/netfilter_ipv4.h>
#include <net/ipip.h>
#include <net/checksum.h>
#include <net/ip_mp_alg.h>
struct multipath_device {
int ifi; /* interface index of device */
atomic_t usecount;
int allocated;
};
#define MULTIPATH_MAX_DEVICECANDIDATES 10
static struct multipath_device state[MULTIPATH_MAX_DEVICECANDIDATES];
static DEFINE_SPINLOCK(state_lock);
static int inline __multipath_findslot(void)
{
int i;
for (i = 0; i < MULTIPATH_MAX_DEVICECANDIDATES; i++) {
if (state[i].allocated == 0)
return i;
}
return -1;
}
static int inline __multipath_finddev(int ifindex)
{
int i;
for (i = 0; i < MULTIPATH_MAX_DEVICECANDIDATES; i++) {
if (state[i].allocated != 0 &&
state[i].ifi == ifindex)
return i;
}
return -1;
}
static int drr_dev_event(struct notifier_block *this,
unsigned long event, void *ptr)
{
struct net_device *dev = ptr;
int devidx;
switch (event) {
case NETDEV_UNREGISTER:
case NETDEV_DOWN:
spin_lock_bh(&state_lock);
devidx = __multipath_finddev(dev->ifindex);
if (devidx != -1) {
state[devidx].allocated = 0;
state[devidx].ifi = 0;
atomic_set(&state[devidx].usecount, 0);
}
spin_unlock_bh(&state_lock);
break;
};
return NOTIFY_DONE;
}
static struct notifier_block drr_dev_notifier = {
.notifier_call = drr_dev_event,
};
static void drr_safe_inc(atomic_t *usecount)
{
int n;
atomic_inc(usecount);
n = atomic_read(usecount);
if (n <= 0) {
int i;
spin_lock_bh(&state_lock);
for (i = 0; i < MULTIPATH_MAX_DEVICECANDIDATES; i++)
atomic_set(&state[i].usecount, 0);
spin_unlock_bh(&state_lock);
}
}
static void drr_select_route(const struct flowi *flp,
struct rtable *first, struct rtable **rp)
{
struct rtable *nh, *result, *cur_min;
int min_usecount = -1;
int devidx = -1;
int cur_min_devidx = -1;
/* 1. make sure all alt. nexthops have the same GC related data */
/* 2. determine the new candidate to be returned */
result = NULL;
cur_min = NULL;
for (nh = rcu_dereference(first); nh;
nh = rcu_dereference(nh->u.dst.rt_next)) {
if ((nh->u.dst.flags & DST_BALANCED) != 0 &&
multipath_comparekeys(&nh->fl, flp)) {
int nh_ifidx = nh->u.dst.dev->ifindex;
nh->u.dst.lastuse = jiffies;
nh->u.dst.__use++;
if (result != NULL)
continue;
/* search for the output interface */
/* this is not SMP safe, only add/remove are
* SMP safe as wrong usecount updates have no big
* impact
*/
devidx = __multipath_finddev(nh_ifidx);
if (devidx == -1) {
/* add the interface to the array
* SMP safe
*/
spin_lock_bh(&state_lock);
/* due to SMP: search again */
devidx = __multipath_finddev(nh_ifidx);
if (devidx == -1) {
/* add entry for device */
devidx = __multipath_findslot();
if (devidx == -1) {
/* unlikely but possible */
continue;
}
state[devidx].allocated = 1;
state[devidx].ifi = nh_ifidx;
atomic_set(&state[devidx].usecount, 0);
min_usecount = 0;
}
spin_unlock_bh(&state_lock);
}
if (min_usecount == 0) {
/* if the device has not been used it is
* the primary target
*/
drr_safe_inc(&state[devidx].usecount);
result = nh;
} else {
int count =
atomic_read(&state[devidx].usecount);
if (min_usecount == -1 ||
count < min_usecount) {
cur_min = nh;
cur_min_devidx = devidx;
min_usecount = count;
}
}
}
}
if (!result) {
if (cur_min) {
drr_safe_inc(&state[cur_min_devidx].usecount);
result = cur_min;
} else {
result = first;
}
}
*rp = result;
}
static struct ip_mp_alg_ops drr_ops = {
.mp_alg_select_route = drr_select_route,
};
static int __init drr_init(void)
{
int err = register_netdevice_notifier(&drr_dev_notifier);
if (err)
return err;
err = multipath_alg_register(&drr_ops, IP_MP_ALG_DRR);
if (err)
goto fail;
return 0;
fail:
unregister_netdevice_notifier(&drr_dev_notifier);
return err;
}
static void __exit drr_exit(void)
{
unregister_netdevice_notifier(&drr_dev_notifier);
multipath_alg_unregister(&drr_ops, IP_MP_ALG_DRR);
}
module_init(drr_init);
module_exit(drr_exit);
MODULE_LICENSE("GPL");