4 * 2004+ Copyright (c) Evgeniy Polyakov <zbr@ioremap.net>
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.
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.
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
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>
36 * This job is sent to the kevent workqueue.
37 * While no event is once sent to any callback, the connector workqueue
38 * is not created to avoid a useless waiting kernel task.
39 * Once the first event is received, we create this dedicated workqueue which
40 * is necessary because the flow of data can be high and we don't want
41 * to encumber keventd with that.
43 static void cn_queue_create(struct work_struct *work)
45 struct cn_queue_dev *dev;
47 dev = container_of(work, struct cn_queue_dev, wq_creation);
49 dev->cn_queue = create_singlethread_workqueue(dev->name);
50 /* If we fail, we will use keventd for all following connector jobs */
51 WARN_ON(!dev->cn_queue);
55 * Queue a data sent to a callback.
56 * If the connector workqueue is already created, we queue the job on it.
57 * Otherwise, we queue the job to kevent and queue the connector workqueue
60 int queue_cn_work(struct cn_callback_entry *cbq, struct work_struct *work)
62 struct cn_queue_dev *pdev = cbq->pdev;
64 if (likely(pdev->cn_queue))
65 return queue_work(pdev->cn_queue, work);
67 /* Don't create the connector workqueue twice */
68 if (atomic_inc_return(&pdev->wq_requested) == 1)
69 schedule_work(&pdev->wq_creation);
71 atomic_dec(&pdev->wq_requested);
73 return schedule_work(work);
76 void cn_queue_wrapper(struct work_struct *work)
78 struct cn_callback_entry *cbq =
79 container_of(work, struct cn_callback_entry, work);
80 struct cn_callback_data *d = &cbq->data;
82 d->callback(d->callback_priv);
84 d->destruct_data(d->ddata);
90 static struct cn_callback_entry *cn_queue_alloc_callback_entry(char *name, struct cb_id *id, void (*callback)(void *))
92 struct cn_callback_entry *cbq;
94 cbq = kzalloc(sizeof(*cbq), GFP_KERNEL);
96 printk(KERN_ERR "Failed to create new callback queue.\n");
100 snprintf(cbq->id.name, sizeof(cbq->id.name), "%s", name);
101 memcpy(&cbq->id.id, id, sizeof(struct cb_id));
102 cbq->data.callback = callback;
104 INIT_WORK(&cbq->work, &cn_queue_wrapper);
108 static void cn_queue_free_callback(struct cn_callback_entry *cbq)
110 /* The first jobs have been sent to kevent, flush them too */
111 flush_scheduled_work();
112 if (cbq->pdev->cn_queue)
113 flush_workqueue(cbq->pdev->cn_queue);
118 int cn_cb_equal(struct cb_id *i1, struct cb_id *i2)
120 return ((i1->idx == i2->idx) && (i1->val == i2->val));
123 int cn_queue_add_callback(struct cn_queue_dev *dev, char *name, struct cb_id *id, void (*callback)(void *))
125 struct cn_callback_entry *cbq, *__cbq;
128 cbq = cn_queue_alloc_callback_entry(name, id, callback);
132 atomic_inc(&dev->refcnt);
135 spin_lock_bh(&dev->queue_lock);
136 list_for_each_entry(__cbq, &dev->queue_list, callback_entry) {
137 if (cn_cb_equal(&__cbq->id.id, id)) {
143 list_add_tail(&cbq->callback_entry, &dev->queue_list);
144 spin_unlock_bh(&dev->queue_lock);
147 cn_queue_free_callback(cbq);
148 atomic_dec(&dev->refcnt);
153 cbq->group = cbq->id.id.idx;
158 void cn_queue_del_callback(struct cn_queue_dev *dev, struct cb_id *id)
160 struct cn_callback_entry *cbq, *n;
163 spin_lock_bh(&dev->queue_lock);
164 list_for_each_entry_safe(cbq, n, &dev->queue_list, callback_entry) {
165 if (cn_cb_equal(&cbq->id.id, id)) {
166 list_del(&cbq->callback_entry);
171 spin_unlock_bh(&dev->queue_lock);
174 cn_queue_free_callback(cbq);
175 atomic_dec(&dev->refcnt);
179 struct cn_queue_dev *cn_queue_alloc_dev(char *name, struct sock *nls)
181 struct cn_queue_dev *dev;
183 dev = kzalloc(sizeof(*dev), GFP_KERNEL);
187 snprintf(dev->name, sizeof(dev->name), "%s", name);
188 atomic_set(&dev->refcnt, 0);
189 INIT_LIST_HEAD(&dev->queue_list);
190 spin_lock_init(&dev->queue_lock);
191 init_waitqueue_head(&dev->wq_created);
195 INIT_WORK(&dev->wq_creation, cn_queue_create);
200 void cn_queue_free_dev(struct cn_queue_dev *dev)
202 struct cn_callback_entry *cbq, *n;
206 /* Flush the first pending jobs queued on kevent */
207 flush_scheduled_work();
209 /* If the connector workqueue creation is still pending, wait for it */
210 prepare_to_wait(&dev->wq_created, &wait, TASK_UNINTERRUPTIBLE);
211 if (atomic_read(&dev->wq_requested) && !dev->cn_queue) {
212 timeout = schedule_timeout(HZ * 2);
213 if (!timeout && !dev->cn_queue)
216 finish_wait(&dev->wq_created, &wait);
219 flush_workqueue(dev->cn_queue);
220 destroy_workqueue(dev->cn_queue);
223 spin_lock_bh(&dev->queue_lock);
224 list_for_each_entry_safe(cbq, n, &dev->queue_list, callback_entry)
225 list_del(&cbq->callback_entry);
226 spin_unlock_bh(&dev->queue_lock);
228 while (atomic_read(&dev->refcnt)) {
229 printk(KERN_INFO "Waiting for %s to become free: refcnt=%d.\n",
230 dev->name, atomic_read(&dev->refcnt));