linux/drivers/connector/cn_queue.c
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   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
  34void 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
  48static 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
  66static void cn_queue_free_callback(struct cn_callback_entry *cbq)
  67{
  68        flush_workqueue(cbq->pdev->cn_queue);
  69
  70        kfree(cbq);
  71}
  72
  73int cn_cb_equal(struct cb_id *i1, struct cb_id *i2)
  74{
  75        return ((i1->idx == i2->idx) && (i1->val == i2->val));
  76}
  77
  78int 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
 113void 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
 134struct 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
 158void 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