kernel-ark/net/ipv4/multipath.c

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/* multipath.c: IPV4 multipath algorithm support.
*
* Copyright (C) 2004, 2005 Einar Lueck <elueck@de.ibm.com>
* Copyright (C) 2005 David S. Miller <davem@davemloft.net>
*/
#include <linux/module.h>
#include <linux/errno.h>
#include <linux/netdevice.h>
#include <linux/spinlock.h>
#include <net/ip_mp_alg.h>
static DEFINE_SPINLOCK(alg_table_lock);
struct ip_mp_alg_ops *ip_mp_alg_table[IP_MP_ALG_MAX + 1];
int multipath_alg_register(struct ip_mp_alg_ops *ops, enum ip_mp_alg n)
{
struct ip_mp_alg_ops **slot;
int err;
if (n < IP_MP_ALG_NONE || n > IP_MP_ALG_MAX ||
!ops->mp_alg_select_route)
return -EINVAL;
spin_lock(&alg_table_lock);
slot = &ip_mp_alg_table[n];
if (*slot != NULL) {
err = -EBUSY;
} else {
*slot = ops;
err = 0;
}
spin_unlock(&alg_table_lock);
return err;
}
EXPORT_SYMBOL(multipath_alg_register);
void multipath_alg_unregister(struct ip_mp_alg_ops *ops, enum ip_mp_alg n)
{
struct ip_mp_alg_ops **slot;
if (n < IP_MP_ALG_NONE || n > IP_MP_ALG_MAX)
return;
spin_lock(&alg_table_lock);
slot = &ip_mp_alg_table[n];
if (*slot == ops)
*slot = NULL;
spin_unlock(&alg_table_lock);
synchronize_net();
}
EXPORT_SYMBOL(multipath_alg_unregister);