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 = kmalloc(sizeof(*alg), GFP_KERNEL);
  28         if (alg == NULL) {
  29                 return -ENOMEM;
  30         }
  31         memset(alg, 0, sizeof(*alg));
  32         alg->ops = ops;
  33
  34         mutex_lock(&rate_ctrl_mutex);
  35         list_add_tail(&alg->list, &rate_ctrl_algs);
  36         mutex_unlock(&rate_ctrl_mutex);
  37
  38         return 0;
  39 }
  40 EXPORT_SYMBOL(ieee80211_rate_control_register);
  41
  42 void ieee80211_rate_control_unregister(struct rate_control_ops *ops)
  43 {
  44         struct rate_control_alg *alg;
  45
  46         mutex_lock(&rate_ctrl_mutex);
  47         list_for_each_entry(alg, &rate_ctrl_algs, list) {
  48                 if (alg->ops == ops) {
  49                         list_del(&alg->list);
  50                         break;
  51                 }
  52         }
  53         mutex_unlock(&rate_ctrl_mutex);
  54         kfree(alg);
  55 }
  56 EXPORT_SYMBOL(ieee80211_rate_control_unregister);
  57
  58 static struct rate_control_ops *
  59 ieee80211_try_rate_control_ops_get(const char *name)
  60 {
  61         struct rate_control_alg *alg;
  62         struct rate_control_ops *ops = NULL;
  63
  64         mutex_lock(&rate_ctrl_mutex);
  65         list_for_each_entry(alg, &rate_ctrl_algs, list) {
  66                 if (!name || !strcmp(alg->ops->name, name))
  67                         if (try_module_get(alg->ops->module)) {
  68                                 ops = alg->ops;
  69                                 break;
  70                         }
  71         }
  72         mutex_unlock(&rate_ctrl_mutex);
  73         return ops;
  74 }
  75
  76 /* Get the rate control algorithm. If `name' is NULL, get the first
  77  * available algorithm. */
  78 static struct rate_control_ops *
  79 ieee80211_rate_control_ops_get(const char *name)
  80 {
  81         struct rate_control_ops *ops;
  82
  83         ops = ieee80211_try_rate_control_ops_get(name);
  84         if (!ops) {
  85                 request_module("rc80211_%s", name ? name : "default");
  86                 ops = ieee80211_try_rate_control_ops_get(name);
  87         }
  88         return ops;
  89 }
  90
  91 static void ieee80211_rate_control_ops_put(struct rate_control_ops *ops)
  92 {
  93         module_put(ops->module);
  94 }
  95
  96 struct rate_control_ref *rate_control_alloc(const char *name,
  97                                             struct ieee80211_local *local)
  98 {
  99         struct rate_control_ref *ref;
 100
 101         ref = kmalloc(sizeof(struct rate_control_ref), GFP_KERNEL);
 102         if (!ref)
 103                 goto fail_ref;
 104         kref_init(&ref->kref);
 105         ref->ops = ieee80211_rate_control_ops_get(name);
 106         if (!ref->ops)
 107                 goto fail_ops;
 108         ref->priv = ref->ops->alloc(local);
 109         if (!ref->priv)
 110                 goto fail_priv;
 111         return ref;
 112
 113 fail_priv:
 114         ieee80211_rate_control_ops_put(ref->ops);
 115 fail_ops:
 116         kfree(ref);
 117 fail_ref:
 118         return NULL;
 119 }
 120
 121 static void rate_control_release(struct kref *kref)
 122 {
 123         struct rate_control_ref *ctrl_ref;
 124
 125         ctrl_ref = container_of(kref, struct rate_control_ref, kref);
 126         ctrl_ref->ops->free(ctrl_ref->priv);
 127         ieee80211_rate_control_ops_put(ctrl_ref->ops);
 128         kfree(ctrl_ref);
 129 }
 130
 131 struct rate_control_ref *rate_control_get(struct rate_control_ref *ref)
 132 {
 133         kref_get(&ref->kref);
 134         return ref;
 135 }
 136
 137 void rate_control_put(struct rate_control_ref *ref)
 138 {
 139         kref_put(&ref->kref, rate_control_release);
 140 }