net/mac80211/ieee80211_rate.c

   1 /*
   2  * Copyright 2002-2005, Instant802 Networks, Inc.
   3  * Copyright 2005-2006, Devicescape Software, Inc.
   4  * Copyright (c) 2006 Jiri Benc <jbenc@suse.cz>
   5  *
   6  * This program is free software; you can redistribute it and/or modify
   7  * it under the terms of the GNU General Public License version 2 as
   8  * published by the Free Software Foundation.
   9  */
  10
  11 #include <linux/kernel.h>
  12 #include <linux/rtnetlink.h>
  13 #include "ieee80211_rate.h"
  14 #include "ieee80211_i.h"
  15
  16 struct rate_control_alg {
  17         struct list_head list;
  18         struct rate_control_ops *ops;
  19 };
  20
  21 static LIST_HEAD(rate_ctrl_algs);
  22 static DEFINE_MUTEX(rate_ctrl_mutex);
  23
  24 int ieee80211_rate_control_register(struct rate_control_ops *ops)
  25 {
  26         struct rate_control_alg *alg;
  27
  28         if (!ops->name)
  29                 return -EINVAL;
  30
  31         mutex_lock(&rate_ctrl_mutex);
  32         list_for_each_entry(alg, &rate_ctrl_algs, list) {
  33                 if (!strcmp(alg->ops->name, ops->name)) {
  34                         /* don't register an algorithm twice */
  35                         WARN_ON(1);
  36                         mutex_unlock(&rate_ctrl_mutex);
  37                         return -EALREADY;
  38                 }
  39         }
  40
  41         alg = kzalloc(sizeof(*alg), GFP_KERNEL);
  42         if (alg == NULL) {
  43                 mutex_unlock(&rate_ctrl_mutex);
  44                 return -ENOMEM;
  45         }
  46         alg->ops = ops;
  47
  48         list_add_tail(&alg->list, &rate_ctrl_algs);
  49         mutex_unlock(&rate_ctrl_mutex);
  50
  51         return 0;
  52 }
  53 EXPORT_SYMBOL(ieee80211_rate_control_register);
  54
  55 void ieee80211_rate_control_unregister(struct rate_control_ops *ops)
  56 {
  57         struct rate_control_alg *alg;
  58
  59         mutex_lock(&rate_ctrl_mutex);
  60         list_for_each_entry(alg, &rate_ctrl_algs, list) {
  61                 if (alg->ops == ops) {
  62                         list_del(&alg->list);
  63                         kfree(alg);
  64                         break;
  65                 }
  66         }
  67         mutex_unlock(&rate_ctrl_mutex);
  68 }
  69 EXPORT_SYMBOL(ieee80211_rate_control_unregister);
  70
  71 static struct rate_control_ops *
  72 ieee80211_try_rate_control_ops_get(const char *name)
  73 {
  74         struct rate_control_alg *alg;
  75         struct rate_control_ops *ops = NULL;
  76
  77         if (!name)
  78                 return NULL;
  79
  80         mutex_lock(&rate_ctrl_mutex);
  81         list_for_each_entry(alg, &rate_ctrl_algs, list) {
  82                 if (!strcmp(alg->ops->name, name))
  83                         if (try_module_get(alg->ops->module)) {
  84                                 ops = alg->ops;
  85                                 break;
  86                         }
  87         }
  88         mutex_unlock(&rate_ctrl_mutex);
  89         return ops;
  90 }
  91
  92 /* Get the rate control algorithm. If `name' is NULL, get the first
  93  * available algorithm. */
  94 static struct rate_control_ops *
  95 ieee80211_rate_control_ops_get(const char *name)
  96 {
  97         struct rate_control_ops *ops;
  98
  99         if (!name)
 100                 name = "simple";
 101
 102         ops = ieee80211_try_rate_control_ops_get(name);
 103         if (!ops) {
 104                 request_module("rc80211_%s", name);
 105                 ops = ieee80211_try_rate_control_ops_get(name);
 106         }
 107         return ops;
 108 }
 109
 110 static void ieee80211_rate_control_ops_put(struct rate_control_ops *ops)
 111 {
 112         module_put(ops->module);
 113 }
 114
 115 struct rate_control_ref *rate_control_alloc(const char *name,
 116                                             struct ieee80211_local *local)
 117 {
 118         struct rate_control_ref *ref;
 119
 120         ref = kmalloc(sizeof(struct rate_control_ref), GFP_KERNEL);
 121         if (!ref)
 122                 goto fail_ref;
 123         kref_init(&ref->kref);
 124         ref->ops = ieee80211_rate_control_ops_get(name);
 125         if (!ref->ops)
 126                 goto fail_ops;
 127         ref->priv = ref->ops->alloc(local);
 128         if (!ref->priv)
 129                 goto fail_priv;
 130         return ref;
 131
 132 fail_priv:
 133         ieee80211_rate_control_ops_put(ref->ops);
 134 fail_ops:
 135         kfree(ref);
 136 fail_ref:
 137         return NULL;
 138 }
 139
 140 static void rate_control_release(struct kref *kref)
 141 {
 142         struct rate_control_ref *ctrl_ref;
 143
 144         ctrl_ref = container_of(kref, struct rate_control_ref, kref);
 145         ctrl_ref->ops->free(ctrl_ref->priv);
 146         ieee80211_rate_control_ops_put(ctrl_ref->ops);
 147         kfree(ctrl_ref);
 148 }
 149
 150 struct rate_control_ref *rate_control_get(struct rate_control_ref *ref)
 151 {
 152         kref_get(&ref->kref);
 153         return ref;
 154 }
 155
 156 void rate_control_put(struct rate_control_ref *ref)
 157 {
 158         kref_put(&ref->kref, rate_control_release);
 159 }
 160
 161 int ieee80211_init_rate_ctrl_alg(struct ieee80211_local *local,
 162                                  const char *name)
 163 {
 164         struct rate_control_ref *ref, *old;
 165
 166         ASSERT_RTNL();
 167         if (local->open_count || netif_running(local->mdev))
 168                 return -EBUSY;
 169
 170         ref = rate_control_alloc(name, local);
 171         if (!ref) {
 172                 printk(KERN_WARNING "%s: Failed to select rate control "
 173                        "algorithm\n", wiphy_name(local->hw.wiphy));
 174                 return -ENOENT;
 175         }
 176
 177         old = local->rate_ctrl;
 178         local->rate_ctrl = ref;
 179         if (old) {
 180                 rate_control_put(old);
 181                 sta_info_flush(local, NULL);
 182         }
 183
 184         printk(KERN_DEBUG "%s: Selected rate control "
 185                "algorithm '%s'\n", wiphy_name(local->hw.wiphy),
 186                ref->ops->name);
 187
 188
 189         return 0;
 190 }
 191
 192 void rate_control_deinitialize(struct ieee80211_local *local)
 193 {
 194         struct rate_control_ref *ref;
 195
 196         ref = local->rate_ctrl;
 197         local->rate_ctrl = NULL;
 198         rate_control_put(ref);
 199 }