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7672d0b5 EP |
1 | /* |
2 | * cn_queue.c | |
1a5645bc | 3 | * |
acb9c1b2 | 4 | * 2004+ Copyright (c) Evgeniy Polyakov <zbr@ioremap.net> |
7672d0b5 | 5 | * All rights reserved. |
1a5645bc | 6 | * |
7672d0b5 EP |
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 | ||
1a5645bc FW |
34 | |
35 | /* | |
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. | |
42 | */ | |
43 | static void cn_queue_create(struct work_struct *work) | |
44 | { | |
45 | struct cn_queue_dev *dev; | |
46 | ||
47 | dev = container_of(work, struct cn_queue_dev, wq_creation); | |
48 | ||
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); | |
52 | } | |
53 | ||
54 | /* | |
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 | |
58 | * creation too. | |
59 | */ | |
60 | int queue_cn_work(struct cn_callback_entry *cbq, struct work_struct *work) | |
61 | { | |
62 | struct cn_queue_dev *pdev = cbq->pdev; | |
63 | ||
64 | if (likely(pdev->cn_queue)) | |
65 | return queue_work(pdev->cn_queue, work); | |
66 | ||
67 | /* Don't create the connector workqueue twice */ | |
68 | if (atomic_inc_return(&pdev->wq_requested) == 1) | |
69 | schedule_work(&pdev->wq_creation); | |
70 | else | |
71 | atomic_dec(&pdev->wq_requested); | |
72 | ||
73 | return schedule_work(work); | |
74 | } | |
75 | ||
c4028958 | 76 | void cn_queue_wrapper(struct work_struct *work) |
7672d0b5 | 77 | { |
c4028958 | 78 | struct cn_callback_entry *cbq = |
a240d9f1 | 79 | container_of(work, struct cn_callback_entry, work); |
c4028958 | 80 | struct cn_callback_data *d = &cbq->data; |
7672d0b5 | 81 | |
acd042bb EP |
82 | d->callback(d->callback_priv); |
83 | ||
84 | d->destruct_data(d->ddata); | |
85 | d->ddata = NULL; | |
86 | ||
87 | kfree(d->free); | |
7672d0b5 EP |
88 | } |
89 | ||
0741241c MF |
90 | static struct cn_callback_entry * |
91 | cn_queue_alloc_callback_entry(char *name, struct cb_id *id, | |
92 | void (*callback)(struct cn_msg *)) | |
7672d0b5 EP |
93 | { |
94 | struct cn_callback_entry *cbq; | |
95 | ||
96 | cbq = kzalloc(sizeof(*cbq), GFP_KERNEL); | |
97 | if (!cbq) { | |
98 | printk(KERN_ERR "Failed to create new callback queue.\n"); | |
99 | return NULL; | |
100 | } | |
101 | ||
acd042bb EP |
102 | snprintf(cbq->id.name, sizeof(cbq->id.name), "%s", name); |
103 | memcpy(&cbq->id.id, id, sizeof(struct cb_id)); | |
104 | cbq->data.callback = callback; | |
1a5645bc | 105 | |
a240d9f1 | 106 | INIT_WORK(&cbq->work, &cn_queue_wrapper); |
7672d0b5 EP |
107 | return cbq; |
108 | } | |
109 | ||
110 | static void cn_queue_free_callback(struct cn_callback_entry *cbq) | |
111 | { | |
1a5645bc FW |
112 | /* The first jobs have been sent to kevent, flush them too */ |
113 | flush_scheduled_work(); | |
114 | if (cbq->pdev->cn_queue) | |
115 | flush_workqueue(cbq->pdev->cn_queue); | |
7672d0b5 EP |
116 | |
117 | kfree(cbq); | |
118 | } | |
119 | ||
120 | int cn_cb_equal(struct cb_id *i1, struct cb_id *i2) | |
121 | { | |
122 | return ((i1->idx == i2->idx) && (i1->val == i2->val)); | |
123 | } | |
124 | ||
0741241c MF |
125 | int cn_queue_add_callback(struct cn_queue_dev *dev, char *name, struct cb_id *id, |
126 | void (*callback)(struct cn_msg *)) | |
7672d0b5 EP |
127 | { |
128 | struct cn_callback_entry *cbq, *__cbq; | |
129 | int found = 0; | |
130 | ||
acd042bb | 131 | cbq = cn_queue_alloc_callback_entry(name, id, callback); |
7672d0b5 EP |
132 | if (!cbq) |
133 | return -ENOMEM; | |
134 | ||
135 | atomic_inc(&dev->refcnt); | |
136 | cbq->pdev = dev; | |
137 | ||
138 | spin_lock_bh(&dev->queue_lock); | |
139 | list_for_each_entry(__cbq, &dev->queue_list, callback_entry) { | |
acd042bb | 140 | if (cn_cb_equal(&__cbq->id.id, id)) { |
7672d0b5 EP |
141 | found = 1; |
142 | break; | |
143 | } | |
144 | } | |
145 | if (!found) | |
146 | list_add_tail(&cbq->callback_entry, &dev->queue_list); | |
147 | spin_unlock_bh(&dev->queue_lock); | |
148 | ||
149 | if (found) { | |
7672d0b5 | 150 | cn_queue_free_callback(cbq); |
cf585ae8 | 151 | atomic_dec(&dev->refcnt); |
7672d0b5 EP |
152 | return -EINVAL; |
153 | } | |
154 | ||
7672d0b5 | 155 | cbq->seq = 0; |
acd042bb | 156 | cbq->group = cbq->id.id.idx; |
7672d0b5 EP |
157 | |
158 | return 0; | |
159 | } | |
160 | ||
161 | void cn_queue_del_callback(struct cn_queue_dev *dev, struct cb_id *id) | |
162 | { | |
163 | struct cn_callback_entry *cbq, *n; | |
164 | int found = 0; | |
165 | ||
166 | spin_lock_bh(&dev->queue_lock); | |
167 | list_for_each_entry_safe(cbq, n, &dev->queue_list, callback_entry) { | |
acd042bb | 168 | if (cn_cb_equal(&cbq->id.id, id)) { |
7672d0b5 EP |
169 | list_del(&cbq->callback_entry); |
170 | found = 1; | |
171 | break; | |
172 | } | |
173 | } | |
174 | spin_unlock_bh(&dev->queue_lock); | |
175 | ||
176 | if (found) { | |
177 | cn_queue_free_callback(cbq); | |
cec6f7f3 | 178 | atomic_dec(&dev->refcnt); |
7672d0b5 EP |
179 | } |
180 | } | |
181 | ||
182 | struct cn_queue_dev *cn_queue_alloc_dev(char *name, struct sock *nls) | |
183 | { | |
184 | struct cn_queue_dev *dev; | |
185 | ||
186 | dev = kzalloc(sizeof(*dev), GFP_KERNEL); | |
187 | if (!dev) | |
188 | return NULL; | |
189 | ||
190 | snprintf(dev->name, sizeof(dev->name), "%s", name); | |
191 | atomic_set(&dev->refcnt, 0); | |
192 | INIT_LIST_HEAD(&dev->queue_list); | |
193 | spin_lock_init(&dev->queue_lock); | |
1a5645bc | 194 | init_waitqueue_head(&dev->wq_created); |
7672d0b5 EP |
195 | |
196 | dev->nls = nls; | |
7672d0b5 | 197 | |
1a5645bc | 198 | INIT_WORK(&dev->wq_creation, cn_queue_create); |
7672d0b5 EP |
199 | |
200 | return dev; | |
201 | } | |
202 | ||
203 | void cn_queue_free_dev(struct cn_queue_dev *dev) | |
204 | { | |
205 | struct cn_callback_entry *cbq, *n; | |
1a5645bc FW |
206 | long timeout; |
207 | DEFINE_WAIT(wait); | |
208 | ||
209 | /* Flush the first pending jobs queued on kevent */ | |
210 | flush_scheduled_work(); | |
211 | ||
212 | /* If the connector workqueue creation is still pending, wait for it */ | |
213 | prepare_to_wait(&dev->wq_created, &wait, TASK_UNINTERRUPTIBLE); | |
214 | if (atomic_read(&dev->wq_requested) && !dev->cn_queue) { | |
215 | timeout = schedule_timeout(HZ * 2); | |
216 | if (!timeout && !dev->cn_queue) | |
217 | WARN_ON(1); | |
218 | } | |
219 | finish_wait(&dev->wq_created, &wait); | |
7672d0b5 | 220 | |
1a5645bc FW |
221 | if (dev->cn_queue) { |
222 | flush_workqueue(dev->cn_queue); | |
223 | destroy_workqueue(dev->cn_queue); | |
224 | } | |
7672d0b5 EP |
225 | |
226 | spin_lock_bh(&dev->queue_lock); | |
227 | list_for_each_entry_safe(cbq, n, &dev->queue_list, callback_entry) | |
228 | list_del(&cbq->callback_entry); | |
229 | spin_unlock_bh(&dev->queue_lock); | |
230 | ||
231 | while (atomic_read(&dev->refcnt)) { | |
232 | printk(KERN_INFO "Waiting for %s to become free: refcnt=%d.\n", | |
233 | dev->name, atomic_read(&dev->refcnt)); | |
234 | msleep(1000); | |
235 | } | |
236 | ||
237 | kfree(dev); | |
238 | dev = NULL; | |
239 | } |