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Based on 1 normalized pattern(s): 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 extracted by the scancode license scanner the SPDX license identifier GPL-2.0-or-later has been chosen to replace the boilerplate/reference in 3029 file(s). Signed-off-by: Thomas Gleixner <tglx@linutronix.de> Reviewed-by: Allison Randal <allison@lohutok.net> Cc: linux-spdx@vger.kernel.org Link: https://lkml.kernel.org/r/20190527070032.746973796@linutronix.de Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
126 lines
3.2 KiB
C
126 lines
3.2 KiB
C
// SPDX-License-Identifier: GPL-2.0-or-later
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/*
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* IPVS: Round-Robin Scheduling module
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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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* Fixes/Changes:
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* Wensong Zhang : changed the ip_vs_rr_schedule to return dest
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* Julian Anastasov : fixed the NULL pointer access bug in debugging
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* Wensong Zhang : changed some comestics things for debugging
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* Wensong Zhang : changed for the d-linked destination list
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* Wensong Zhang : added the ip_vs_rr_update_svc
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* Wensong Zhang : added any dest with weight=0 is quiesced
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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/kernel.h>
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#include <net/ip_vs.h>
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static int ip_vs_rr_init_svc(struct ip_vs_service *svc)
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{
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svc->sched_data = &svc->destinations;
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return 0;
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}
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static int ip_vs_rr_del_dest(struct ip_vs_service *svc, struct ip_vs_dest *dest)
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{
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struct list_head *p;
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spin_lock_bh(&svc->sched_lock);
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p = (struct list_head *) svc->sched_data;
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/* dest is already unlinked, so p->prev is not valid but
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* p->next is valid, use it to reach previous entry.
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*/
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if (p == &dest->n_list)
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svc->sched_data = p->next->prev;
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spin_unlock_bh(&svc->sched_lock);
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return 0;
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}
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/*
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* Round-Robin Scheduling
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*/
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static struct ip_vs_dest *
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ip_vs_rr_schedule(struct ip_vs_service *svc, const struct sk_buff *skb,
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struct ip_vs_iphdr *iph)
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{
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struct list_head *p;
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struct ip_vs_dest *dest, *last;
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int pass = 0;
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IP_VS_DBG(6, "%s(): Scheduling...\n", __func__);
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spin_lock_bh(&svc->sched_lock);
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p = (struct list_head *) svc->sched_data;
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last = dest = list_entry(p, struct ip_vs_dest, n_list);
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do {
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list_for_each_entry_continue_rcu(dest,
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&svc->destinations,
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n_list) {
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if (!(dest->flags & IP_VS_DEST_F_OVERLOAD) &&
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atomic_read(&dest->weight) > 0)
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/* HIT */
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goto out;
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if (dest == last)
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goto stop;
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}
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pass++;
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/* Previous dest could be unlinked, do not loop forever.
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* If we stay at head there is no need for 2nd pass.
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*/
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} while (pass < 2 && p != &svc->destinations);
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stop:
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spin_unlock_bh(&svc->sched_lock);
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ip_vs_scheduler_err(svc, "no destination available");
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return NULL;
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out:
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svc->sched_data = &dest->n_list;
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spin_unlock_bh(&svc->sched_lock);
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IP_VS_DBG_BUF(6, "RR: server %s:%u "
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"activeconns %d refcnt %d weight %d\n",
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IP_VS_DBG_ADDR(dest->af, &dest->addr), ntohs(dest->port),
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atomic_read(&dest->activeconns),
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refcount_read(&dest->refcnt), atomic_read(&dest->weight));
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return dest;
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}
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static struct ip_vs_scheduler ip_vs_rr_scheduler = {
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.name = "rr", /* name */
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.refcnt = ATOMIC_INIT(0),
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.module = THIS_MODULE,
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.n_list = LIST_HEAD_INIT(ip_vs_rr_scheduler.n_list),
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.init_service = ip_vs_rr_init_svc,
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.add_dest = NULL,
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.del_dest = ip_vs_rr_del_dest,
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.schedule = ip_vs_rr_schedule,
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};
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static int __init ip_vs_rr_init(void)
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{
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return register_ip_vs_scheduler(&ip_vs_rr_scheduler);
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}
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static void __exit ip_vs_rr_cleanup(void)
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{
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unregister_ip_vs_scheduler(&ip_vs_rr_scheduler);
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synchronize_rcu();
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}
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module_init(ip_vs_rr_init);
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module_exit(ip_vs_rr_cleanup);
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MODULE_LICENSE("GPL");
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