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_RWLOCK(__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
)
50 pr_err("%s(): svc arg NULL\n", __func__
);
53 if (scheduler
== NULL
) {
54 pr_err("%s(): scheduler arg NULL\n", __func__
);
58 svc
->scheduler
= scheduler
;
60 if (scheduler
->init_service
) {
61 ret
= scheduler
->init_service(svc
);
63 pr_err("%s(): init error\n", __func__
);
73 * Unbind a service with its scheduler
75 int ip_vs_unbind_scheduler(struct ip_vs_service
*svc
)
77 struct ip_vs_scheduler
*sched
;
80 pr_err("%s(): svc arg NULL\n", __func__
);
84 sched
= svc
->scheduler
;
86 pr_err("%s(): svc isn't bound\n", __func__
);
90 if (sched
->done_service
) {
91 if (sched
->done_service(svc
) != 0) {
92 pr_err("%s(): done error\n", __func__
);
97 svc
->scheduler
= NULL
;
103 * Get scheduler in the scheduler list by name
105 static struct ip_vs_scheduler
*ip_vs_sched_getbyname(const char *sched_name
)
107 struct ip_vs_scheduler
*sched
;
109 IP_VS_DBG(2, "%s(): sched_name \"%s\"\n", __func__
, sched_name
);
111 read_lock_bh(&__ip_vs_sched_lock
);
113 list_for_each_entry(sched
, &ip_vs_schedulers
, n_list
) {
115 * Test and get the modules atomically
117 if (sched
->module
&& !try_module_get(sched
->module
)) {
119 * This scheduler is just deleted
123 if (strcmp(sched_name
, sched
->name
)==0) {
125 read_unlock_bh(&__ip_vs_sched_lock
);
129 module_put(sched
->module
);
132 read_unlock_bh(&__ip_vs_sched_lock
);
138 * Lookup scheduler and try to load it if it doesn't exist
140 struct ip_vs_scheduler
*ip_vs_scheduler_get(const char *sched_name
)
142 struct ip_vs_scheduler
*sched
;
145 * Search for the scheduler by sched_name
147 sched
= ip_vs_sched_getbyname(sched_name
);
150 * If scheduler not found, load the module and search again
153 request_module("ip_vs_%s", sched_name
);
154 sched
= ip_vs_sched_getbyname(sched_name
);
160 void ip_vs_scheduler_put(struct ip_vs_scheduler
*scheduler
)
162 if (scheduler
->module
)
163 module_put(scheduler
->module
);
168 * Register a scheduler in the scheduler list
170 int register_ip_vs_scheduler(struct ip_vs_scheduler
*scheduler
)
172 struct ip_vs_scheduler
*sched
;
175 pr_err("%s(): NULL arg\n", __func__
);
179 if (!scheduler
->name
) {
180 pr_err("%s(): NULL scheduler_name\n", __func__
);
184 /* increase the module use count */
185 ip_vs_use_count_inc();
187 write_lock_bh(&__ip_vs_sched_lock
);
189 if (!list_empty(&scheduler
->n_list
)) {
190 write_unlock_bh(&__ip_vs_sched_lock
);
191 ip_vs_use_count_dec();
192 pr_err("%s(): [%s] scheduler already linked\n",
193 __func__
, scheduler
->name
);
198 * Make sure that the scheduler with this name doesn't exist
199 * in the scheduler list.
201 list_for_each_entry(sched
, &ip_vs_schedulers
, n_list
) {
202 if (strcmp(scheduler
->name
, sched
->name
) == 0) {
203 write_unlock_bh(&__ip_vs_sched_lock
);
204 ip_vs_use_count_dec();
205 pr_err("%s(): [%s] scheduler already existed "
206 "in the system\n", __func__
, scheduler
->name
);
211 * Add it into the d-linked scheduler list
213 list_add(&scheduler
->n_list
, &ip_vs_schedulers
);
214 write_unlock_bh(&__ip_vs_sched_lock
);
216 pr_info("[%s] scheduler registered.\n", scheduler
->name
);
223 * Unregister a scheduler from the scheduler list
225 int unregister_ip_vs_scheduler(struct ip_vs_scheduler
*scheduler
)
228 pr_err("%s(): NULL arg\n", __func__
);
232 write_lock_bh(&__ip_vs_sched_lock
);
233 if (list_empty(&scheduler
->n_list
)) {
234 write_unlock_bh(&__ip_vs_sched_lock
);
235 pr_err("%s(): [%s] scheduler is not in the list. failed\n",
236 __func__
, scheduler
->name
);
241 * Remove it from the d-linked scheduler list
243 list_del(&scheduler
->n_list
);
244 write_unlock_bh(&__ip_vs_sched_lock
);
246 /* decrease the module use count */
247 ip_vs_use_count_dec();
249 pr_info("[%s] scheduler unregistered.\n", scheduler
->name
);