patch-2.4.23 linux-2.4.23/net/ipv4/ipvs/ip_vs_sched.c

• Lines: 261
• Date: 2003-11-28 10:26:21.000000000 -0800
• Orig file: linux-2.4.22/net/ipv4/ipvs/ip_vs_sched.c
• Orig date: 1969-12-31 16:00:00.000000000 -0800

diff -urN linux-2.4.22/net/ipv4/ipvs/ip_vs_sched.c linux-2.4.23/net/ipv4/ipvs/ip_vs_sched.c
@@ -0,0 +1,260 @@
+/*
+ * 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 1.11 2001/11/04 08:58:43 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/config.h>
+#include <linux/module.h>
+#include <linux/kernel.h>
+#include <linux/errno.h>
+#include <linux/sched.h>
+#include <linux/spinlock.h>
+#include <asm/softirq.h>                /* for local_bh_* */
+#include <asm/string.h>
+#include <linux/kmod.h>
+
+#include <net/ip_vs.h>
+
+/*
+ *  IPVS scheduler list
+ */
+static LIST_HEAD(ip_vs_schedulers);
+
+/* lock for service table */
+static rwlock_t __ip_vs_sched_lock = RW_LOCK_UNLOCKED;
+
+
+/*
+ *  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;
+	struct list_head *l, *e;
+
+	IP_VS_DBG(2, "ip_vs_sched_getbyname(): sched_name \"%s\"\n",
+		  sched_name);
+
+	l = &ip_vs_schedulers;
+
+	read_lock_bh(&__ip_vs_sched_lock);
+
+	for (e=l->next; e!=l; e=e->next) {
+		sched = list_entry(e, struct ip_vs_scheduler, n_list);
+
+		/*
+		 * Test and MOD_INC_USE_COUNT atomically
+		 */
+		if (sched->module && !try_inc_mod_count(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)
+			__MOD_DEC_USE_COUNT(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) {
+		char module_name[IP_VS_SCHEDNAME_MAXLEN+8];
+		sprintf(module_name,"ip_vs_%s", sched_name);
+		request_module(module_name);
+		sched = ip_vs_sched_getbyname(sched_name);
+	}
+
+	return sched;
+}
+
+void ip_vs_scheduler_put(struct ip_vs_scheduler *scheduler)
+{
+	if (scheduler->module)
+		__MOD_DEC_USE_COUNT(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;
+	}
+
+	MOD_INC_USE_COUNT;
+
+	/*
+	 *  Make sure that the scheduler with this name doesn't exist
+	 *  in the scheduler list.
+	 */
+	sched = ip_vs_sched_getbyname(scheduler->name);
+	if (sched) {
+		ip_vs_scheduler_put(sched);
+		MOD_DEC_USE_COUNT;
+		IP_VS_ERR("register_ip_vs_scheduler(): [%s] scheduler "
+			  "already existed in the system\n", scheduler->name);
+		return -EINVAL;
+	}
+
+	write_lock_bh(&__ip_vs_sched_lock);
+
+	if (scheduler->n_list.next != &scheduler->n_list) {
+		write_unlock_bh(&__ip_vs_sched_lock);
+		MOD_DEC_USE_COUNT;
+		IP_VS_ERR("register_ip_vs_scheduler(): [%s] scheduler "
+			  "already linked\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);
+
+	MOD_DEC_USE_COUNT;
+
+	IP_VS_INFO("[%s] scheduler unregistered.\n", scheduler->name);
+
+	return 0;
+}