/*
* IPVS An implementation of the IP virtual server support for the
* LINUX operating system. IPVS is now implemented as a module
* over the Netfilter framework. IPVS can be used to build a
* high-performance and highly available server based on a
* cluster of servers.
*
* Version: $Id: ip_vs_sched.c,v 1.13 2003/05/10 03:05:23 wensong Exp $
*
* Authors: Wensong Zhang <wensong@linuxvirtualserver.org>
* Peter Kese <peter.kese@ijs.si>
*
* 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.
*
* Changes:
*
*/
#include <linux/module.h>
#include <linux/spinlock.h>
#include <linux/interrupt.h>
#include <asm/string.h>
#include <linux/kmod.h>
#include <linux/sysctl.h>
#include <net/ip_vs.h>
/*
* IPVS scheduler list
*/
static LIST_HEAD(ip_vs_schedulers);
/* lock for service table */
static DEFINE_RWLOCK(__ip_vs_sched_lock);
/*
* Bind a service with a scheduler
*/
int ip_vs_bind_scheduler(struct ip_vs_service *svc,
struct ip_vs_scheduler *scheduler)
{
int ret;
if (svc == NULL) {
IP_VS_ERR("ip_vs_bind_scheduler(): svc arg NULL\n");
return -EINVAL;
}
if (scheduler == NULL) {
IP_VS_ERR("ip_vs_bind_scheduler(): scheduler arg NULL\n");
return -EINVAL;
}
svc->scheduler = scheduler;
if (scheduler->init_service) {
ret = scheduler->init_service(svc);
if (ret) {
IP_VS_ERR("ip_vs_bind_scheduler(): init error\n");
return ret;
}
}
return 0;
}
/*
* Unbind a service with its scheduler
*/
int ip_vs_unbind_scheduler(struct ip_vs_service *svc)
{
struct ip_vs_scheduler *sched;
if (svc == NULL) {
IP_VS_ERR("ip_vs_unbind_scheduler(): svc arg NULL\n");
return -EINVAL;
}
sched = svc->scheduler;
if (sched == NULL) {
IP_VS_ERR("ip_vs_unbind_scheduler(): svc isn't bound\n");
return -EINVAL;
}
if (sched->done_service) {
if (sched->done_service(svc) != 0) {
IP_VS_ERR("ip_vs_unbind_scheduler(): done error\n");
return -EINVAL;
}
}
svc->scheduler = NULL;
return 0;
}
/*
* Get scheduler in the scheduler list by name
*/
static struct ip_vs_scheduler *ip_vs_sched_getbyname(const char *sched_name)
{
struct ip_vs_scheduler *sched;
IP_VS_DBG(2, "ip_vs_sched_getbyname(): sched_name \"%s\"\n",
sched_name);
read_lock_bh(&__ip_vs_sched_lock);
list_for_each_entry(sched, &ip_vs_schedulers, n_list) {
/*
* Test and get the modules atomically
*/
if (sched->module && !try_module_get(sched->module)) {
/*
* This scheduler is just deleted
*/
continue;
}
if (strcmp(sched_name, sched->name)==0) {
/* HIT */
read_unlock_bh(&__ip_vs_sched_lock);
return sched;
}
if (sched->module)
module_put(sched->module);
}
read_unlock_bh(&__ip_vs_sched_lock);
return NULL;
}
/*
* Lookup scheduler and try to load it if it doesn't exist
*/
struct ip_vs_scheduler *ip_vs_scheduler_get(const char *sched_name)
{
struct ip_vs_scheduler *sched;
/*
* Search for the scheduler by sched_name
*/
sched = ip_vs_sched_getbyname(sched_name);
/*
* If scheduler not found, load the module and search again
*/
if (sched == NULL) {
request_module("ip_vs_%s", sched_name);
sched = ip_vs_sched_getbyname(sched_name);
}
return sched;
}
void ip_vs_scheduler_put(struct ip_vs_scheduler *scheduler)
{
if (scheduler->module)
module_put(scheduler->module);
}
/*
* Register a scheduler in the scheduler list
*/
int register_ip_vs_scheduler(struct ip_vs_scheduler *scheduler)
{
struct ip_vs_scheduler *sched;
if (!scheduler) {
IP_VS_ERR("register_ip_vs_scheduler(): NULL arg\n");
return -EINVAL;
}
if (!scheduler->name) {
IP_VS_ERR("register_ip_vs_scheduler(): NULL scheduler_name\n");
return -EINVAL;
}
/* increase the module use count */
ip_vs_use_count_inc();
write_lock_bh(&__ip_vs_sched_lock);
if (scheduler->n_list.next != &scheduler->n_list) {
write_unlock_bh(&__ip_vs_sched_lock);
ip_vs_use_count_dec();
IP_VS_ERR("register_ip_vs_scheduler(): [%s] scheduler "
"already linked\n", scheduler->name);
return -EINVAL;
}
/*
* Make sure that the scheduler with this name doesn't exist
* in the scheduler list.
*/
list_for_each_entry(sched, &ip_vs_schedulers, n_list) {
if (strcmp(scheduler->name, sched->name) == 0) {
write_unlock_bh(&__ip_vs_sched_lock);
ip_vs_use_count_dec();
IP_VS_ERR("register_ip_vs_scheduler(): [%s] scheduler "
"already existed in the system\n",
scheduler->name);
return -EINVAL;
}
}
/*
* Add it into the d-linked scheduler list
*/
list_add(&scheduler->n_list, &ip_vs_schedulers);
write_unlock_bh(&__ip_vs_sched_lock);
IP_VS_INFO("[%s] scheduler registered.\n", scheduler->name);
return 0;
}
/*
* Unregister a scheduler from the scheduler list
*/
int unregister_ip_vs_scheduler(struct ip_vs_scheduler *scheduler)
{
if (!scheduler) {
IP_VS_ERR( "unregister_ip_vs_scheduler(): NULL arg\n");
return -EINVAL;
}
write_lock_bh(&__ip_vs_sched_lock);
if (scheduler->n_list.next == &scheduler->n_list) {
write_unlock_bh(&__ip_vs_sched_lock);
IP_VS_ERR("unregister_ip_vs_scheduler(): [%s] scheduler "
"is not in the list. failed\n", scheduler->name);
return -EINVAL;
}
/*
* Remove it from the d-linked scheduler list
*/
list_del(&scheduler->n_list);
write_unlock_bh(&__ip_vs_sched_lock);
/* decrease the module use count */
ip_vs_use_count_dec();
IP_VS_INFO("[%s] scheduler unregistered.\n", scheduler->name);
return 0;
}
