2 * IPVS An implementation of the IP virtual server support for the
3 * LINUX operating system. IPVS is now implemented as a module
4 * over the Netfilter framework. IPVS can be used to build a
5 * high-performance and highly available server based on a
8 * Authors: Wensong Zhang <wensong@linuxvirtualserver.org>
9 * Peter Kese <peter.kese@ijs.si>
11 * This program is free software; you can redistribute it and/or
12 * modify it under the terms of the GNU General Public License
13 * as published by the Free Software Foundation; either version
14 * 2 of the License, or (at your option) any later version.
20 #define KMSG_COMPONENT "IPVS"
21 #define pr_fmt(fmt) KMSG_COMPONENT ": " fmt
23 #include <linux/module.h>
24 #include <linux/spinlock.h>
25 #include <linux/interrupt.h>
26 #include <asm/string.h>
27 #include <linux/kmod.h>
28 #include <linux/sysctl.h>
30 #include <net/ip_vs.h>
35 static LIST_HEAD(ip_vs_schedulers);
37 /* lock for service table */
38 static DEFINE_SPINLOCK(ip_vs_sched_lock);
42 * Bind a service with a scheduler
44 int ip_vs_bind_scheduler(struct ip_vs_service *svc,
45 struct ip_vs_scheduler *scheduler)
49 svc->scheduler = scheduler;
51 if (scheduler->init_service) {
52 ret = scheduler->init_service(svc);
54 pr_err("%s(): init error\n", __func__);
64 * Unbind a service with its scheduler
66 int ip_vs_unbind_scheduler(struct ip_vs_service *svc)
68 struct ip_vs_scheduler *sched = svc->scheduler;
73 if (sched->done_service) {
74 if (sched->done_service(svc) != 0) {
75 pr_err("%s(): done error\n", __func__);
80 svc->scheduler = NULL;
86 * Get scheduler in the scheduler list by name
88 static struct ip_vs_scheduler *ip_vs_sched_getbyname(const char *sched_name)
90 struct ip_vs_scheduler *sched;
92 IP_VS_DBG(2, "%s(): sched_name \"%s\"\n", __func__, sched_name);
94 spin_lock_bh(&ip_vs_sched_lock);
96 list_for_each_entry(sched, &ip_vs_schedulers, n_list) {
98 * Test and get the modules atomically
100 if (sched->module && !try_module_get(sched->module)) {
102 * This scheduler is just deleted
106 if (strcmp(sched_name, sched->name)==0) {
108 spin_unlock_bh(&ip_vs_sched_lock);
112 module_put(sched->module);
115 spin_unlock_bh(&ip_vs_sched_lock);
121 * Lookup scheduler and try to load it if it doesn't exist
123 struct ip_vs_scheduler *ip_vs_scheduler_get(const char *sched_name)
125 struct ip_vs_scheduler *sched;
128 * Search for the scheduler by sched_name
130 sched = ip_vs_sched_getbyname(sched_name);
133 * If scheduler not found, load the module and search again
136 request_module("ip_vs_%s", sched_name);
137 sched = ip_vs_sched_getbyname(sched_name);
143 void ip_vs_scheduler_put(struct ip_vs_scheduler *scheduler)
145 if (scheduler && scheduler->module)
146 module_put(scheduler->module);
151 * Register a scheduler in the scheduler list
153 int register_ip_vs_scheduler(struct ip_vs_scheduler *scheduler)
155 struct ip_vs_scheduler *sched;
158 pr_err("%s(): NULL arg\n", __func__);
162 if (!scheduler->name) {
163 pr_err("%s(): NULL scheduler_name\n", __func__);
167 /* increase the module use count */
168 ip_vs_use_count_inc();
170 spin_lock_bh(&ip_vs_sched_lock);
172 if (!list_empty(&scheduler->n_list)) {
173 spin_unlock_bh(&ip_vs_sched_lock);
174 ip_vs_use_count_dec();
175 pr_err("%s(): [%s] scheduler already linked\n",
176 __func__, scheduler->name);
181 * Make sure that the scheduler with this name doesn't exist
182 * in the scheduler list.
184 list_for_each_entry(sched, &ip_vs_schedulers, n_list) {
185 if (strcmp(scheduler->name, sched->name) == 0) {
186 spin_unlock_bh(&ip_vs_sched_lock);
187 ip_vs_use_count_dec();
188 pr_err("%s(): [%s] scheduler already existed "
189 "in the system\n", __func__, scheduler->name);
194 * Add it into the d-linked scheduler list
196 list_add(&scheduler->n_list, &ip_vs_schedulers);
197 spin_unlock_bh(&ip_vs_sched_lock);
199 pr_info("[%s] scheduler registered.\n", scheduler->name);
206 * Unregister a scheduler from the scheduler list
208 int unregister_ip_vs_scheduler(struct ip_vs_scheduler *scheduler)
211 pr_err("%s(): NULL arg\n", __func__);
215 spin_lock_bh(&ip_vs_sched_lock);
216 if (list_empty(&scheduler->n_list)) {
217 spin_unlock_bh(&ip_vs_sched_lock);
218 pr_err("%s(): [%s] scheduler is not in the list. failed\n",
219 __func__, scheduler->name);
224 * Remove it from the d-linked scheduler list
226 list_del(&scheduler->n_list);
227 spin_unlock_bh(&ip_vs_sched_lock);
229 /* decrease the module use count */
230 ip_vs_use_count_dec();
232 pr_info("[%s] scheduler unregistered.\n", scheduler->name);