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
15struct rate_control_alg {
16	struct list_head list;
17	struct rate_control_ops *ops;
18};
19
20static LIST_HEAD(rate_ctrl_algs);
21static DEFINE_MUTEX(rate_ctrl_mutex);
22
23int 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}
40EXPORT_SYMBOL(ieee80211_rate_control_register);
41
42void 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}
56EXPORT_SYMBOL(ieee80211_rate_control_unregister);
57
58static struct rate_control_ops *
59ieee80211_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. */
78static struct rate_control_ops *
79ieee80211_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
91static void ieee80211_rate_control_ops_put(struct rate_control_ops *ops)
92{
93	module_put(ops->module);
94}
95
96struct 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
113fail_priv:
114	ieee80211_rate_control_ops_put(ref->ops);
115fail_ops:
116	kfree(ref);
117fail_ref:
118	return NULL;
119}
120
121static 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
131struct rate_control_ref *rate_control_get(struct rate_control_ref *ref)
132{
133	kref_get(&ref->kref);
134	return ref;
135}
136
137void rate_control_put(struct rate_control_ref *ref)
138{
139	kref_put(&ref->kref, rate_control_release);
140}
141