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
34 static struct cn_callback_entry *
cn_queue_alloc_callback_entry(struct cn_queue_dev * dev,const char * name,struct cb_id * id,void (* callback)(struct cn_msg *,struct netlink_skb_parms *))35 cn_queue_alloc_callback_entry(struct cn_queue_dev *dev, const char *name,
36 struct cb_id *id,
37 void (*callback)(struct cn_msg *, struct netlink_skb_parms *))
38 {
39 struct cn_callback_entry *cbq;
40
41 cbq = kzalloc(sizeof(*cbq), GFP_KERNEL);
42 if (!cbq) {
43 printk(KERN_ERR "Failed to create new callback queue.\n");
44 return NULL;
45 }
46
47 atomic_set(&cbq->refcnt, 1);
48
49 atomic_inc(&dev->refcnt);
50 cbq->pdev = dev;
51
52 snprintf(cbq->id.name, sizeof(cbq->id.name), "%s", name);
53 memcpy(&cbq->id.id, id, sizeof(struct cb_id));
54 cbq->callback = callback;
55 return cbq;
56 }
57
cn_queue_release_callback(struct cn_callback_entry * cbq)58 void cn_queue_release_callback(struct cn_callback_entry *cbq)
59 {
60 if (!atomic_dec_and_test(&cbq->refcnt))
61 return;
62
63 atomic_dec(&cbq->pdev->refcnt);
64 kfree(cbq);
65 }
66
cn_cb_equal(struct cb_id * i1,struct cb_id * i2)67 int cn_cb_equal(struct cb_id *i1, struct cb_id *i2)
68 {
69 return ((i1->idx == i2->idx) && (i1->val == i2->val));
70 }
71
cn_queue_add_callback(struct cn_queue_dev * dev,const char * name,struct cb_id * id,void (* callback)(struct cn_msg *,struct netlink_skb_parms *))72 int cn_queue_add_callback(struct cn_queue_dev *dev, const char *name,
73 struct cb_id *id,
74 void (*callback)(struct cn_msg *, struct netlink_skb_parms *))
75 {
76 struct cn_callback_entry *cbq, *__cbq;
77 int found = 0;
78
79 cbq = cn_queue_alloc_callback_entry(dev, name, id, callback);
80 if (!cbq)
81 return -ENOMEM;
82
83 spin_lock_bh(&dev->queue_lock);
84 list_for_each_entry(__cbq, &dev->queue_list, callback_entry) {
85 if (cn_cb_equal(&__cbq->id.id, id)) {
86 found = 1;
87 break;
88 }
89 }
90 if (!found)
91 list_add_tail(&cbq->callback_entry, &dev->queue_list);
92 spin_unlock_bh(&dev->queue_lock);
93
94 if (found) {
95 cn_queue_release_callback(cbq);
96 return -EINVAL;
97 }
98
99 cbq->seq = 0;
100 cbq->group = cbq->id.id.idx;
101
102 return 0;
103 }
104
cn_queue_del_callback(struct cn_queue_dev * dev,struct cb_id * id)105 void cn_queue_del_callback(struct cn_queue_dev *dev, struct cb_id *id)
106 {
107 struct cn_callback_entry *cbq, *n;
108 int found = 0;
109
110 spin_lock_bh(&dev->queue_lock);
111 list_for_each_entry_safe(cbq, n, &dev->queue_list, callback_entry) {
112 if (cn_cb_equal(&cbq->id.id, id)) {
113 list_del(&cbq->callback_entry);
114 found = 1;
115 break;
116 }
117 }
118 spin_unlock_bh(&dev->queue_lock);
119
120 if (found)
121 cn_queue_release_callback(cbq);
122 }
123
cn_queue_alloc_dev(const char * name,struct sock * nls)124 struct cn_queue_dev *cn_queue_alloc_dev(const char *name, struct sock *nls)
125 {
126 struct cn_queue_dev *dev;
127
128 dev = kzalloc(sizeof(*dev), GFP_KERNEL);
129 if (!dev)
130 return NULL;
131
132 snprintf(dev->name, sizeof(dev->name), "%s", name);
133 atomic_set(&dev->refcnt, 0);
134 INIT_LIST_HEAD(&dev->queue_list);
135 spin_lock_init(&dev->queue_lock);
136
137 dev->nls = nls;
138
139 return dev;
140 }
141
cn_queue_free_dev(struct cn_queue_dev * dev)142 void cn_queue_free_dev(struct cn_queue_dev *dev)
143 {
144 struct cn_callback_entry *cbq, *n;
145
146 spin_lock_bh(&dev->queue_lock);
147 list_for_each_entry_safe(cbq, n, &dev->queue_list, callback_entry)
148 list_del(&cbq->callback_entry);
149 spin_unlock_bh(&dev->queue_lock);
150
151 while (atomic_read(&dev->refcnt)) {
152 printk(KERN_INFO "Waiting for %s to become free: refcnt=%d.\n",
153 dev->name, atomic_read(&dev->refcnt));
154 msleep(1000);
155 }
156
157 kfree(dev);
158 dev = NULL;
159 }
160