drivers/connector/cn_queue.c

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