// SPDX-License-Identifier: GPL-2.0-or-later
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/*
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* IPVS An implementation of the IP virtual server support for the
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* LINUX operating system. IPVS is now implemented as a module
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* over the Netfilter framework. IPVS can be used to build a
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* high-performance and highly available server based on a
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* cluster of servers.
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*
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* Authors: Wensong Zhang <wensong@linuxvirtualserver.org>
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* Peter Kese <peter.kese@ijs.si>
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*
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* Changes:
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*/
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#define KMSG_COMPONENT "IPVS"
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#define pr_fmt(fmt) KMSG_COMPONENT ": " fmt
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#include <linux/module.h>
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#include <linux/spinlock.h>
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#include <linux/interrupt.h>
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#include <asm/string.h>
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#include <linux/kmod.h>
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#include <linux/sysctl.h>
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#include <net/ip_vs.h>
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EXPORT_SYMBOL(ip_vs_scheduler_err);
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/*
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* IPVS scheduler list
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*/
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static LIST_HEAD(ip_vs_schedulers);
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/* semaphore for schedulers */
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static DEFINE_MUTEX(ip_vs_sched_mutex);
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/*
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* Bind a service with a scheduler
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*/
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int ip_vs_bind_scheduler(struct ip_vs_service *svc,
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struct ip_vs_scheduler *scheduler)
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{
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int ret;
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if (scheduler->init_service) {
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ret = scheduler->init_service(svc);
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if (ret) {
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pr_err("%s(): init error\n", __func__);
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return ret;
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}
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}
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rcu_assign_pointer(svc->scheduler, scheduler);
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return 0;
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}
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/*
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* Unbind a service with its scheduler
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*/
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void ip_vs_unbind_scheduler(struct ip_vs_service *svc,
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struct ip_vs_scheduler *sched)
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{
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struct ip_vs_scheduler *cur_sched;
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cur_sched = rcu_dereference_protected(svc->scheduler, 1);
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/* This check proves that old 'sched' was installed */
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if (!cur_sched)
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return;
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if (sched->done_service)
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sched->done_service(svc);
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/* svc->scheduler can be set to NULL only by caller */
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}
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/*
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* Get scheduler in the scheduler list by name
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*/
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static struct ip_vs_scheduler *ip_vs_sched_getbyname(const char *sched_name)
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{
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struct ip_vs_scheduler *sched;
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IP_VS_DBG(2, "%s(): sched_name \"%s\"\n", __func__, sched_name);
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mutex_lock(&ip_vs_sched_mutex);
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list_for_each_entry(sched, &ip_vs_schedulers, n_list) {
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/*
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* Test and get the modules atomically
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*/
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if (sched->module && !try_module_get(sched->module)) {
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/*
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* This scheduler is just deleted
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*/
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continue;
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}
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if (strcmp(sched_name, sched->name)==0) {
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/* HIT */
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mutex_unlock(&ip_vs_sched_mutex);
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return sched;
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}
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module_put(sched->module);
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}
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mutex_unlock(&ip_vs_sched_mutex);
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return NULL;
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}
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/*
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* Lookup scheduler and try to load it if it doesn't exist
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*/
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struct ip_vs_scheduler *ip_vs_scheduler_get(const char *sched_name)
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{
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struct ip_vs_scheduler *sched;
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/*
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* Search for the scheduler by sched_name
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*/
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sched = ip_vs_sched_getbyname(sched_name);
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/*
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* If scheduler not found, load the module and search again
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*/
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if (sched == NULL) {
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request_module("ip_vs_%s", sched_name);
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sched = ip_vs_sched_getbyname(sched_name);
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}
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return sched;
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}
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void ip_vs_scheduler_put(struct ip_vs_scheduler *scheduler)
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{
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if (scheduler)
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module_put(scheduler->module);
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}
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/*
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* Common error output helper for schedulers
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*/
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void ip_vs_scheduler_err(struct ip_vs_service *svc, const char *msg)
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{
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struct ip_vs_scheduler *sched = rcu_dereference(svc->scheduler);
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char *sched_name = sched ? sched->name : "none";
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if (svc->fwmark) {
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IP_VS_ERR_RL("%s: FWM %u 0x%08X - %s\n",
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sched_name, svc->fwmark, svc->fwmark, msg);
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#ifdef CONFIG_IP_VS_IPV6
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} else if (svc->af == AF_INET6) {
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IP_VS_ERR_RL("%s: %s [%pI6c]:%d - %s\n",
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sched_name, ip_vs_proto_name(svc->protocol),
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&svc->addr.in6, ntohs(svc->port), msg);
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#endif
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} else {
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IP_VS_ERR_RL("%s: %s %pI4:%d - %s\n",
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sched_name, ip_vs_proto_name(svc->protocol),
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&svc->addr.ip, ntohs(svc->port), msg);
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}
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}
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/*
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* Register a scheduler in the scheduler list
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*/
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int register_ip_vs_scheduler(struct ip_vs_scheduler *scheduler)
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{
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struct ip_vs_scheduler *sched;
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if (!scheduler) {
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pr_err("%s(): NULL arg\n", __func__);
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return -EINVAL;
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}
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if (!scheduler->name) {
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pr_err("%s(): NULL scheduler_name\n", __func__);
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return -EINVAL;
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}
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/* increase the module use count */
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if (!ip_vs_use_count_inc())
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return -ENOENT;
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mutex_lock(&ip_vs_sched_mutex);
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if (!list_empty(&scheduler->n_list)) {
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mutex_unlock(&ip_vs_sched_mutex);
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ip_vs_use_count_dec();
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pr_err("%s(): [%s] scheduler already linked\n",
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__func__, scheduler->name);
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return -EINVAL;
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}
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/*
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* Make sure that the scheduler with this name doesn't exist
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* in the scheduler list.
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*/
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list_for_each_entry(sched, &ip_vs_schedulers, n_list) {
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if (strcmp(scheduler->name, sched->name) == 0) {
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mutex_unlock(&ip_vs_sched_mutex);
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ip_vs_use_count_dec();
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pr_err("%s(): [%s] scheduler already existed "
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"in the system\n", __func__, scheduler->name);
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return -EINVAL;
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}
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}
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/*
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* Add it into the d-linked scheduler list
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*/
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list_add(&scheduler->n_list, &ip_vs_schedulers);
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mutex_unlock(&ip_vs_sched_mutex);
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pr_info("[%s] scheduler registered.\n", scheduler->name);
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return 0;
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}
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/*
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* Unregister a scheduler from the scheduler list
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*/
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int unregister_ip_vs_scheduler(struct ip_vs_scheduler *scheduler)
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{
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if (!scheduler) {
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pr_err("%s(): NULL arg\n", __func__);
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return -EINVAL;
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}
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mutex_lock(&ip_vs_sched_mutex);
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if (list_empty(&scheduler->n_list)) {
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mutex_unlock(&ip_vs_sched_mutex);
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pr_err("%s(): [%s] scheduler is not in the list. failed\n",
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__func__, scheduler->name);
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return -EINVAL;
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}
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/*
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* Remove it from the d-linked scheduler list
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*/
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list_del(&scheduler->n_list);
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mutex_unlock(&ip_vs_sched_mutex);
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/* decrease the module use count */
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ip_vs_use_count_dec();
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pr_info("[%s] scheduler unregistered.\n", scheduler->name);
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return 0;
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}
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