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 "ieee80211_rate.h"
  13 #include "ieee80211_i.h"
  14
  15 struct rate_control_alg {
  16         struct list_head list;
  17         struct rate_control_ops *ops;
  18 };
  19
  20 static LIST_HEAD(rate_ctrl_algs);
  21 static DEFINE_MUTEX(rate_ctrl_mutex);
  22
  23 int ieee80211_rate_control_register(struct rate_control_ops *ops)
  24 {
  25         struct rate_control_alg *alg;
  26
  27         alg = kzalloc(sizeof(*alg), GFP_KERNEL);
  28         if (alg == NULL) {
  29                 return -ENOMEM;
  30         }
  31         alg->ops = ops;
  32
  33         mutex_lock(&rate_ctrl_mutex);
  34         list_add_tail(&alg->list, &rate_ctrl_algs);
  35         mutex_unlock(&rate_ctrl_mutex);
  36
  37         return 0;
  38 }
  39 EXPORT_SYMBOL(ieee80211_rate_control_register);
  40
  41 void ieee80211_rate_control_unregister(struct rate_control_ops *ops)
  42 {
  43         struct rate_control_alg *alg;
  44
  45         mutex_lock(&rate_ctrl_mutex);
  46         list_for_each_entry(alg, &rate_ctrl_algs, list) {
  47                 if (alg->ops == ops) {
  48                         list_del(&alg->list);
  49                         break;
  50                 }
  51         }
  52         mutex_unlock(&rate_ctrl_mutex);
  53         kfree(alg);
  54 }
  55 EXPORT_SYMBOL(ieee80211_rate_control_unregister);
  56
  57 static struct rate_control_ops *
  58 ieee80211_try_rate_control_ops_get(const char *name)
  59 {
  60         struct rate_control_alg *alg;
  61         struct rate_control_ops *ops = NULL;
  62
  63         mutex_lock(&rate_ctrl_mutex);
  64         list_for_each_entry(alg, &rate_ctrl_algs, list) {
  65                 if (!name || !strcmp(alg->ops->name, name))
  66                         if (try_module_get(alg->ops->module)) {
  67                                 ops = alg->ops;
  68                                 break;
  69                         }
  70         }
  71         mutex_unlock(&rate_ctrl_mutex);
  72         return ops;
  73 }
  74
  75 /* Get the rate control algorithm. If `name' is NULL, get the first
  76  * available algorithm. */
  77 static struct rate_control_ops *
  78 ieee80211_rate_control_ops_get(const char *name)
  79 {
  80         struct rate_control_ops *ops;
  81
  82         ops = ieee80211_try_rate_control_ops_get(name);
  83         if (!ops) {
  84                 request_module("rc80211_%s", name ? name : "default");
  85                 ops = ieee80211_try_rate_control_ops_get(name);
  86         }
  87         return ops;
  88 }
  89
  90 static void ieee80211_rate_control_ops_put(struct rate_control_ops *ops)
  91 {
  92         module_put(ops->module);
  93 }
  94
  95 struct rate_control_ref *rate_control_alloc(const char *name,
  96                                             struct ieee80211_local *local)
  97 {
  98         struct rate_control_ref *ref;
  99
 100         ref = kmalloc(sizeof(struct rate_control_ref), GFP_KERNEL);
 101         if (!ref)
 102                 goto fail_ref;
 103         kref_init(&ref->kref);
 104         ref->ops = ieee80211_rate_control_ops_get(name);
 105         if (!ref->ops)
 106                 goto fail_ops;
 107         ref->priv = ref->ops->alloc(local);
 108         if (!ref->priv)
 109                 goto fail_priv;
 110         return ref;
 111
 112 fail_priv:
 113         ieee80211_rate_control_ops_put(ref->ops);
 114 fail_ops:
 115         kfree(ref);
 116 fail_ref:
 117         return NULL;
 118 }
 119
 120 static void rate_control_release(struct kref *kref)
 121 {
 122         struct rate_control_ref *ctrl_ref;
 123
 124         ctrl_ref = container_of(kref, struct rate_control_ref, kref);
 125         ctrl_ref->ops->free(ctrl_ref->priv);
 126         ieee80211_rate_control_ops_put(ctrl_ref->ops);
 127         kfree(ctrl_ref);
 128 }
 129
 130 struct rate_control_ref *rate_control_get(struct rate_control_ref *ref)
 131 {
 132         kref_get(&ref->kref);
 133         return ref;
 134 }
 135
 136 void rate_control_put(struct rate_control_ref *ref)
 137 {
 138         kref_put(&ref->kref, rate_control_release);
 139 }