1/*
2 *	cn_queue.c
3 *
4 * 2004+ Copyright (c) Evgeniy Polyakov <zbr@ioremap.net>
5 * All rights reserved.
6 *
7 * This program is free software; you can redistribute it and/or modify
8 * it under the terms of the GNU General Public License as published by
9 * the Free Software Foundation; either version 2 of the License, or
10 * (at your option) any later version.
11 *
12 * This program is distributed in the hope that it will be useful,
13 * but WITHOUT ANY WARRANTY; without even the implied warranty of
14 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
15 * GNU General Public License for more details.
16 *
17 * You should have received a copy of the GNU General Public License
18 * along with this program; if not, write to the Free Software
19 * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA
20 *
21 */
22
23#include <linux/kernel.h>
24#include <linux/module.h>
25#include <linux/list.h>
26#include <linux/workqueue.h>
27#include <linux/spinlock.h>
28#include <linux/slab.h>
29#include <linux/skbuff.h>
30#include <linux/suspend.h>
31#include <linux/connector.h>
32#include <linux/delay.h>
33
34static struct cn_callback_entry *
35cn_queue_alloc_callback_entry(struct cn_queue_dev *dev, const char *name,
36			      struct cb_id *id,
37			      void (*callback)(struct cn_msg *,
38					       struct netlink_skb_parms *))
39{
40	struct cn_callback_entry *cbq;
41
42	cbq = kzalloc(sizeof(*cbq), GFP_KERNEL);
43	if (!cbq) {
44		pr_err("Failed to create new callback queue.\n");
45		return NULL;
46	}
47
48	atomic_set(&cbq->refcnt, 1);
49
50	atomic_inc(&dev->refcnt);
51	cbq->pdev = dev;
52
53	snprintf(cbq->id.name, sizeof(cbq->id.name), "%s", name);
54	memcpy(&cbq->id.id, id, sizeof(struct cb_id));
55	cbq->callback = callback;
56	return cbq;
57}
58
59void cn_queue_release_callback(struct cn_callback_entry *cbq)
60{
61	if (!atomic_dec_and_test(&cbq->refcnt))
62		return;
63
64	atomic_dec(&cbq->pdev->refcnt);
65	kfree(cbq);
66}
67
68int cn_cb_equal(struct cb_id *i1, struct cb_id *i2)
69{
70	return ((i1->idx == i2->idx) && (i1->val == i2->val));
71}
72
73int cn_queue_add_callback(struct cn_queue_dev *dev, const char *name,
74			  struct cb_id *id,
75			  void (*callback)(struct cn_msg *,
76					   struct netlink_skb_parms *))
77{
78	struct cn_callback_entry *cbq, *__cbq;
79	int found = 0;
80
81	cbq = cn_queue_alloc_callback_entry(dev, name, id, callback);
82	if (!cbq)
83		return -ENOMEM;
84
85	spin_lock_bh(&dev->queue_lock);
86	list_for_each_entry(__cbq, &dev->queue_list, callback_entry) {
87		if (cn_cb_equal(&__cbq->id.id, id)) {
88			found = 1;
89			break;
90		}
91	}
92	if (!found)
93		list_add_tail(&cbq->callback_entry, &dev->queue_list);
94	spin_unlock_bh(&dev->queue_lock);
95
96	if (found) {
97		cn_queue_release_callback(cbq);
98		return -EINVAL;
99	}
100
101	cbq->seq = 0;
102	cbq->group = cbq->id.id.idx;
103
104	return 0;
105}
106
107void cn_queue_del_callback(struct cn_queue_dev *dev, struct cb_id *id)
108{
109	struct cn_callback_entry *cbq, *n;
110	int found = 0;
111
112	spin_lock_bh(&dev->queue_lock);
113	list_for_each_entry_safe(cbq, n, &dev->queue_list, callback_entry) {
114		if (cn_cb_equal(&cbq->id.id, id)) {
115			list_del(&cbq->callback_entry);
116			found = 1;
117			break;
118		}
119	}
120	spin_unlock_bh(&dev->queue_lock);
121
122	if (found)
123		cn_queue_release_callback(cbq);
124}
125
126struct cn_queue_dev *cn_queue_alloc_dev(const char *name, struct sock *nls)
127{
128	struct cn_queue_dev *dev;
129
130	dev = kzalloc(sizeof(*dev), GFP_KERNEL);
131	if (!dev)
132		return NULL;
133
134	snprintf(dev->name, sizeof(dev->name), "%s", name);
135	atomic_set(&dev->refcnt, 0);
136	INIT_LIST_HEAD(&dev->queue_list);
137	spin_lock_init(&dev->queue_lock);
138
139	dev->nls = nls;
140
141	return dev;
142}
143
144void cn_queue_free_dev(struct cn_queue_dev *dev)
145{
146	struct cn_callback_entry *cbq, *n;
147
148	spin_lock_bh(&dev->queue_lock);
149	list_for_each_entry_safe(cbq, n, &dev->queue_list, callback_entry)
150		list_del(&cbq->callback_entry);
151	spin_unlock_bh(&dev->queue_lock);
152
153	while (atomic_read(&dev->refcnt)) {
154		pr_info("Waiting for %s to become free: refcnt=%d.\n",
155		       dev->name, atomic_read(&dev->refcnt));
156		msleep(1000);
157	}
158
159	kfree(dev);
160	dev = NULL;
161}
162