Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1 | /* |
| 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 |
| 6 | * cluster of servers. |
| 7 | * |
| 8 | * Version: $Id: ip_vs_sched.c,v 1.13 2003/05/10 03:05:23 wensong Exp $ |
| 9 | * |
| 10 | * Authors: Wensong Zhang <wensong@linuxvirtualserver.org> |
| 11 | * Peter Kese <peter.kese@ijs.si> |
| 12 | * |
| 13 | * This program is free software; you can redistribute it and/or |
| 14 | * modify it under the terms of the GNU General Public License |
| 15 | * as published by the Free Software Foundation; either version |
| 16 | * 2 of the License, or (at your option) any later version. |
| 17 | * |
| 18 | * Changes: |
| 19 | * |
| 20 | */ |
| 21 | |
| 22 | #include <linux/module.h> |
| 23 | #include <linux/sched.h> |
| 24 | #include <linux/spinlock.h> |
| 25 | #include <asm/string.h> |
| 26 | #include <linux/kmod.h> |
| 27 | |
| 28 | #include <net/ip_vs.h> |
| 29 | |
| 30 | /* |
| 31 | * IPVS scheduler list |
| 32 | */ |
| 33 | static LIST_HEAD(ip_vs_schedulers); |
| 34 | |
| 35 | /* lock for service table */ |
| 36 | static DEFINE_RWLOCK(__ip_vs_sched_lock); |
| 37 | |
| 38 | |
| 39 | /* |
| 40 | * Bind a service with a scheduler |
| 41 | */ |
| 42 | int ip_vs_bind_scheduler(struct ip_vs_service *svc, |
| 43 | struct ip_vs_scheduler *scheduler) |
| 44 | { |
| 45 | int ret; |
| 46 | |
| 47 | if (svc == NULL) { |
| 48 | IP_VS_ERR("ip_vs_bind_scheduler(): svc arg NULL\n"); |
| 49 | return -EINVAL; |
| 50 | } |
| 51 | if (scheduler == NULL) { |
| 52 | IP_VS_ERR("ip_vs_bind_scheduler(): scheduler arg NULL\n"); |
| 53 | return -EINVAL; |
| 54 | } |
| 55 | |
| 56 | svc->scheduler = scheduler; |
| 57 | |
| 58 | if (scheduler->init_service) { |
| 59 | ret = scheduler->init_service(svc); |
| 60 | if (ret) { |
| 61 | IP_VS_ERR("ip_vs_bind_scheduler(): init error\n"); |
| 62 | return ret; |
| 63 | } |
| 64 | } |
| 65 | |
| 66 | return 0; |
| 67 | } |
| 68 | |
| 69 | |
| 70 | /* |
| 71 | * Unbind a service with its scheduler |
| 72 | */ |
| 73 | int ip_vs_unbind_scheduler(struct ip_vs_service *svc) |
| 74 | { |
| 75 | struct ip_vs_scheduler *sched; |
| 76 | |
| 77 | if (svc == NULL) { |
| 78 | IP_VS_ERR("ip_vs_unbind_scheduler(): svc arg NULL\n"); |
| 79 | return -EINVAL; |
| 80 | } |
| 81 | |
| 82 | sched = svc->scheduler; |
| 83 | if (sched == NULL) { |
| 84 | IP_VS_ERR("ip_vs_unbind_scheduler(): svc isn't bound\n"); |
| 85 | return -EINVAL; |
| 86 | } |
| 87 | |
| 88 | if (sched->done_service) { |
| 89 | if (sched->done_service(svc) != 0) { |
| 90 | IP_VS_ERR("ip_vs_unbind_scheduler(): done error\n"); |
| 91 | return -EINVAL; |
| 92 | } |
| 93 | } |
| 94 | |
| 95 | svc->scheduler = NULL; |
| 96 | return 0; |
| 97 | } |
| 98 | |
| 99 | |
| 100 | /* |
| 101 | * Get scheduler in the scheduler list by name |
| 102 | */ |
| 103 | static struct ip_vs_scheduler *ip_vs_sched_getbyname(const char *sched_name) |
| 104 | { |
| 105 | struct ip_vs_scheduler *sched; |
| 106 | |
| 107 | IP_VS_DBG(2, "ip_vs_sched_getbyname(): sched_name \"%s\"\n", |
| 108 | sched_name); |
| 109 | |
| 110 | read_lock_bh(&__ip_vs_sched_lock); |
| 111 | |
| 112 | list_for_each_entry(sched, &ip_vs_schedulers, n_list) { |
| 113 | /* |
| 114 | * Test and get the modules atomically |
| 115 | */ |
| 116 | if (sched->module && !try_module_get(sched->module)) { |
| 117 | /* |
| 118 | * This scheduler is just deleted |
| 119 | */ |
| 120 | continue; |
| 121 | } |
| 122 | if (strcmp(sched_name, sched->name)==0) { |
| 123 | /* HIT */ |
| 124 | read_unlock_bh(&__ip_vs_sched_lock); |
| 125 | return sched; |
| 126 | } |
| 127 | if (sched->module) |
| 128 | module_put(sched->module); |
| 129 | } |
| 130 | |
| 131 | read_unlock_bh(&__ip_vs_sched_lock); |
| 132 | return NULL; |
| 133 | } |
| 134 | |
| 135 | |
| 136 | /* |
| 137 | * Lookup scheduler and try to load it if it doesn't exist |
| 138 | */ |
| 139 | struct ip_vs_scheduler *ip_vs_scheduler_get(const char *sched_name) |
| 140 | { |
| 141 | struct ip_vs_scheduler *sched; |
| 142 | |
| 143 | /* |
| 144 | * Search for the scheduler by sched_name |
| 145 | */ |
| 146 | sched = ip_vs_sched_getbyname(sched_name); |
| 147 | |
| 148 | /* |
| 149 | * If scheduler not found, load the module and search again |
| 150 | */ |
| 151 | if (sched == NULL) { |
| 152 | request_module("ip_vs_%s", sched_name); |
| 153 | sched = ip_vs_sched_getbyname(sched_name); |
| 154 | } |
| 155 | |
| 156 | return sched; |
| 157 | } |
| 158 | |
| 159 | void ip_vs_scheduler_put(struct ip_vs_scheduler *scheduler) |
| 160 | { |
| 161 | if (scheduler->module) |
| 162 | module_put(scheduler->module); |
| 163 | } |
| 164 | |
| 165 | |
| 166 | /* |
| 167 | * Register a scheduler in the scheduler list |
| 168 | */ |
| 169 | int register_ip_vs_scheduler(struct ip_vs_scheduler *scheduler) |
| 170 | { |
| 171 | struct ip_vs_scheduler *sched; |
| 172 | |
| 173 | if (!scheduler) { |
| 174 | IP_VS_ERR("register_ip_vs_scheduler(): NULL arg\n"); |
| 175 | return -EINVAL; |
| 176 | } |
| 177 | |
| 178 | if (!scheduler->name) { |
| 179 | IP_VS_ERR("register_ip_vs_scheduler(): NULL scheduler_name\n"); |
| 180 | return -EINVAL; |
| 181 | } |
| 182 | |
| 183 | /* increase the module use count */ |
| 184 | ip_vs_use_count_inc(); |
| 185 | |
| 186 | /* |
| 187 | * Make sure that the scheduler with this name doesn't exist |
| 188 | * in the scheduler list. |
| 189 | */ |
| 190 | sched = ip_vs_sched_getbyname(scheduler->name); |
| 191 | if (sched) { |
| 192 | ip_vs_scheduler_put(sched); |
| 193 | ip_vs_use_count_dec(); |
| 194 | IP_VS_ERR("register_ip_vs_scheduler(): [%s] scheduler " |
| 195 | "already existed in the system\n", scheduler->name); |
| 196 | return -EINVAL; |
| 197 | } |
| 198 | |
| 199 | write_lock_bh(&__ip_vs_sched_lock); |
| 200 | |
| 201 | if (scheduler->n_list.next != &scheduler->n_list) { |
| 202 | write_unlock_bh(&__ip_vs_sched_lock); |
| 203 | ip_vs_use_count_dec(); |
| 204 | IP_VS_ERR("register_ip_vs_scheduler(): [%s] scheduler " |
| 205 | "already linked\n", scheduler->name); |
| 206 | return -EINVAL; |
| 207 | } |
| 208 | |
| 209 | /* |
| 210 | * Add it into the d-linked scheduler list |
| 211 | */ |
| 212 | list_add(&scheduler->n_list, &ip_vs_schedulers); |
| 213 | write_unlock_bh(&__ip_vs_sched_lock); |
| 214 | |
| 215 | IP_VS_INFO("[%s] scheduler registered.\n", scheduler->name); |
| 216 | |
| 217 | return 0; |
| 218 | } |
| 219 | |
| 220 | |
| 221 | /* |
| 222 | * Unregister a scheduler from the scheduler list |
| 223 | */ |
| 224 | int unregister_ip_vs_scheduler(struct ip_vs_scheduler *scheduler) |
| 225 | { |
| 226 | if (!scheduler) { |
| 227 | IP_VS_ERR( "unregister_ip_vs_scheduler(): NULL arg\n"); |
| 228 | return -EINVAL; |
| 229 | } |
| 230 | |
| 231 | write_lock_bh(&__ip_vs_sched_lock); |
| 232 | if (scheduler->n_list.next == &scheduler->n_list) { |
| 233 | write_unlock_bh(&__ip_vs_sched_lock); |
| 234 | IP_VS_ERR("unregister_ip_vs_scheduler(): [%s] scheduler " |
| 235 | "is not in the list. failed\n", scheduler->name); |
| 236 | return -EINVAL; |
| 237 | } |
| 238 | |
| 239 | /* |
| 240 | * Remove it from the d-linked scheduler list |
| 241 | */ |
| 242 | list_del(&scheduler->n_list); |
| 243 | write_unlock_bh(&__ip_vs_sched_lock); |
| 244 | |
| 245 | /* decrease the module use count */ |
| 246 | ip_vs_use_count_dec(); |
| 247 | |
| 248 | IP_VS_INFO("[%s] scheduler unregistered.\n", scheduler->name); |
| 249 | |
| 250 | return 0; |
| 251 | } |