/* 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);