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                         return -EALREADY;
  37                 }
  38         }
  39
  40         alg = kzalloc(sizeof(*alg), GFP_KERNEL);
  41         if (alg == NULL) {
  42                 mutex_unlock(&rate_ctrl_mutex);
  43                 return -ENOMEM;
  44         }
  45         alg->ops = ops;
  46
  47         list_add_tail(&alg->list, &rate_ctrl_algs);
  48         mutex_unlock(&rate_ctrl_mutex);
  49
  50         return 0;
  51 }
  52 EXPORT_SYMBOL(ieee80211_rate_control_register);
  53
  54 void ieee80211_rate_control_unregister(struct rate_control_ops *ops)
  55 {
  56         struct rate_control_alg *alg;
  57
  58         mutex_lock(&rate_ctrl_mutex);
  59         list_for_each_entry(alg, &rate_ctrl_algs, list) {
  60                 if (alg->ops == ops) {
  61                         list_del(&alg->list);
  62                         break;
  63                 }
  64         }
  65         mutex_unlock(&rate_ctrl_mutex);
  66         kfree(alg);
  67 }
  68 EXPORT_SYMBOL(ieee80211_rate_control_unregister);
  69
  70 static struct rate_control_ops *
  71 ieee80211_try_rate_control_ops_get(const char *name)
  72 {
  73         struct rate_control_alg *alg;
  74         struct rate_control_ops *ops = NULL;
  75
  76         if (!name)
  77                 return NULL;
  78
  79         mutex_lock(&rate_ctrl_mutex);
  80         list_for_each_entry(alg, &rate_ctrl_algs, list) {
  81                 if (!strcmp(alg->ops->name, name))
  82                         if (try_module_get(alg->ops->module)) {
  83                                 ops = alg->ops;
  84                                 break;
  85                         }
  86         }
  87         mutex_unlock(&rate_ctrl_mutex);
  88         return ops;
  89 }
  90
  91 /* Get the rate control algorithm. If `name' is NULL, get the first
  92  * available algorithm. */
  93 static struct rate_control_ops *
  94 ieee80211_rate_control_ops_get(const char *name)
  95 {
  96         struct rate_control_ops *ops;
  97
  98         if (!name)
  99                 name = "simple";
 100
 101         ops = ieee80211_try_rate_control_ops_get(name);
 102         if (!ops) {
 103                 request_module("rc80211_%s", name);
 104                 ops = ieee80211_try_rate_control_ops_get(name);
 105         }
 106         return ops;
 107 }
 108
 109 static void ieee80211_rate_control_ops_put(struct rate_control_ops *ops)
 110 {
 111         module_put(ops->module);
 112 }
 113
 114 struct rate_control_ref *rate_control_alloc(const char *name,
 115                                             struct ieee80211_local *local)
 116 {
 117         struct rate_control_ref *ref;
 118
 119         ref = kmalloc(sizeof(struct rate_control_ref), GFP_KERNEL);
 120         if (!ref)
 121                 goto fail_ref;
 122         kref_init(&ref->kref);
 123         ref->ops = ieee80211_rate_control_ops_get(name);
 124         if (!ref->ops)
 125                 goto fail_ops;
 126         ref->priv = ref->ops->alloc(local);
 127         if (!ref->priv)
 128                 goto fail_priv;
 129         return ref;
 130
 131 fail_priv:
 132         ieee80211_rate_control_ops_put(ref->ops);
 133 fail_ops:
 134         kfree(ref);
 135 fail_ref:
 136         return NULL;
 137 }
 138
 139 static void rate_control_release(struct kref *kref)
 140 {
 141         struct rate_control_ref *ctrl_ref;
 142
 143         ctrl_ref = container_of(kref, struct rate_control_ref, kref);
 144         ctrl_ref->ops->free(ctrl_ref->priv);
 145         ieee80211_rate_control_ops_put(ctrl_ref->ops);
 146         kfree(ctrl_ref);
 147 }
 148
 149 struct rate_control_ref *rate_control_get(struct rate_control_ref *ref)
 150 {
 151         kref_get(&ref->kref);
 152         return ref;
 153 }
 154
 155 void rate_control_put(struct rate_control_ref *ref)
 156 {
 157         kref_put(&ref->kref, rate_control_release);
 158 }
 159
 160 int ieee80211_init_rate_ctrl_alg(struct ieee80211_local *local,
 161                                  const char *name)
 162 {
 163         struct rate_control_ref *ref, *old;
 164
 165         ASSERT_RTNL();
 166         if (local->open_count || netif_running(local->mdev))
 167                 return -EBUSY;
 168
 169         ref = rate_control_alloc(name, local);
 170         if (!ref) {
 171                 printk(KERN_WARNING "%s: Failed to select rate control "
 172                        "algorithm\n", wiphy_name(local->hw.wiphy));
 173                 return -ENOENT;
 174         }
 175
 176         old = local->rate_ctrl;
 177         local->rate_ctrl = ref;
 178         if (old) {
 179                 rate_control_put(old);
 180                 sta_info_flush(local, NULL);
 181         }
 182
 183         printk(KERN_DEBUG "%s: Selected rate control "
 184                "algorithm '%s'\n", wiphy_name(local->hw.wiphy),
 185                ref->ops->name);
 186
 187
 188         return 0;
 189 }
 190
 191 void rate_control_deinitialize(struct ieee80211_local *local)
 192 {
 193         struct rate_control_ref *ref;
 194
 195         ref = local->rate_ctrl;
 196         local->rate_ctrl = NULL;
 197         rate_control_put(ref);
 198 }