1 /*
2 * cn_queue.c
3 *
4 * 2004-2005 Copyright (c) Evgeniy Polyakov <johnpol@2ka.mipt.ru>
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 void cn_queue_wrapper(struct work_struct *work)
35 {
36 struct cn_callback_entry *cbq =
37 container_of(work, struct cn_callback_entry, work);
38 struct cn_callback_data *d = &cbq->data;
39
40 d->callback(d->callback_priv);
41
42 d->destruct_data(d->ddata);
43 d->ddata = NULL;
44
45 kfree(d->free);
46 }
47
48 static struct cn_callback_entry *cn_queue_alloc_callback_entry(char *name, struct cb_id *id, void (*callback)(void *))
49 {
50 struct cn_callback_entry *cbq;
51
52 cbq = kzalloc(sizeof(*cbq), GFP_KERNEL);
53 if (!cbq) {
54 printk(KERN_ERR "Failed to create new callback queue.\n");
55 return NULL;
56 }
57
58 snprintf(cbq->id.name, sizeof(cbq->id.name), "%s", name);
59 memcpy(&cbq->id.id, id, sizeof(struct cb_id));
60 cbq->data.callback = callback;
61
62 INIT_WORK(&cbq->work, &cn_queue_wrapper);
63 return cbq;
64 }
65
66 static void cn_queue_free_callback(struct cn_callback_entry *cbq)
67 {
68 flush_workqueue(cbq->pdev->cn_queue);
69
70 kfree(cbq);
71 }
72
73 int cn_cb_equal(struct cb_id *i1, struct cb_id *i2)
74 {
75 return ((i1->idx == i2->idx) && (i1->val == i2->val));
76 }
77
78 int cn_queue_add_callback(struct cn_queue_dev *dev, char *name, struct cb_id *id, void (*callback)(void *))
79 {
80 struct cn_callback_entry *cbq, *__cbq;
81 int found = 0;
82
83 cbq = cn_queue_alloc_callback_entry(name, id, callback);
84 if (!cbq)
85 return -ENOMEM;
86
87 atomic_inc(&dev->refcnt);
88 cbq->pdev = dev;
89
90 spin_lock_bh(&dev->queue_lock);
91 list_for_each_entry(__cbq, &dev->queue_list, callback_entry) {
92 if (cn_cb_equal(&__cbq->id.id, id)) {
93 found = 1;
94 break;
95 }
96 }
97 if (!found)
98 list_add_tail(&cbq->callback_entry, &dev->queue_list);
99 spin_unlock_bh(&dev->queue_lock);
100
101 if (found) {
102 cn_queue_free_callback(cbq);
103 atomic_dec(&dev->refcnt);
104 return -EINVAL;
105 }
106
107 cbq->seq = 0;
108 cbq->group = cbq->id.id.idx;
109
110 return 0;
111 }
112
113 void cn_queue_del_callback(struct cn_queue_dev *dev, struct cb_id *id)
114 {
115 struct cn_callback_entry *cbq, *n;
116 int found = 0;
117
118 spin_lock_bh(&dev->queue_lock);
119 list_for_each_entry_safe(cbq, n, &dev->queue_list, callback_entry) {
120 if (cn_cb_equal(&cbq->id.id, id)) {
121 list_del(&cbq->callback_entry);
122 found = 1;
123 break;
124 }
125 }
126 spin_unlock_bh(&dev->queue_lock);
127
128 if (found) {
129 cn_queue_free_callback(cbq);
130 atomic_dec(&dev->refcnt);
131 }
132 }
133
134 struct cn_queue_dev *cn_queue_alloc_dev(char *name, struct sock *nls)
135 {
136 struct cn_queue_dev *dev;
137
138 dev = kzalloc(sizeof(*dev), GFP_KERNEL);
139 if (!dev)
140 return NULL;
141
142 snprintf(dev->name, sizeof(dev->name), "%s", name);
143 atomic_set(&dev->refcnt, 0);
144 INIT_LIST_HEAD(&dev->queue_list);
145 spin_lock_init(&dev->queue_lock);
146
147 dev->nls = nls;
148
149 dev->cn_queue = create_singlethread_workqueue(dev->name);
150 if (!dev->cn_queue) {
151 kfree(dev);
152 return NULL;
153 }
154
155 return dev;
156 }
157
158 void cn_queue_free_dev(struct cn_queue_dev *dev)
159 {
160 struct cn_callback_entry *cbq, *n;
161
162 flush_workqueue(dev->cn_queue);
163 destroy_workqueue(dev->cn_queue);
164
165 spin_lock_bh(&dev->queue_lock);
166 list_for_each_entry_safe(cbq, n, &dev->queue_list, callback_entry)
167 list_del(&cbq->callback_entry);
168 spin_unlock_bh(&dev->queue_lock);
169
170 while (atomic_read(&dev->refcnt)) {
171 printk(KERN_INFO "Waiting for %s to become free: refcnt=%d.\n",
172 dev->name, atomic_read(&dev->refcnt));
173 msleep(1000);
174 }
175
176 kfree(dev);
177 dev = NULL;
178 }
179
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