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 void cn_queue_wrapper(void *data)
  35 {
  36         struct cn_callback_data *d = data;
  37
  38         d->callback(d->callback_priv);
  39
  40         d->destruct_data(d->ddata);
  41         d->ddata = NULL;
  42
  43         kfree(d->free);
  44 }
  45
  46 static struct cn_callback_entry *cn_queue_alloc_callback_entry(char *name, struct cb_id *id, void (*callback)(void *))
  47 {
  48         struct cn_callback_entry *cbq;
  49
  50         cbq = kzalloc(sizeof(*cbq), GFP_KERNEL);
  51         if (!cbq) {
  52                 printk(KERN_ERR "Failed to create new callback queue.\n");
  53                 return NULL;
  54         }
  55
  56         snprintf(cbq->id.name, sizeof(cbq->id.name), "%s", name);
  57         memcpy(&cbq->id.id, id, sizeof(struct cb_id));
  58         cbq->data.callback = callback;
  59
  60         INIT_WORK(&cbq->work, &cn_queue_wrapper, &cbq->data);
  61         return cbq;
  62 }
  63
  64 static void cn_queue_free_callback(struct cn_callback_entry *cbq)
  65 {
  66         cancel_delayed_work(&cbq->work);
  67         flush_workqueue(cbq->pdev->cn_queue);
  68
  69         kfree(cbq);
  70 }
  71
  72 int cn_cb_equal(struct cb_id *i1, struct cb_id *i2)
  73 {
  74         return ((i1->idx == i2->idx) && (i1->val == i2->val));
  75 }
  76
  77 int cn_queue_add_callback(struct cn_queue_dev *dev, char *name, struct cb_id *id, void (*callback)(void *))
  78 {
  79         struct cn_callback_entry *cbq, *__cbq;
  80         int found = 0;
  81
  82         cbq = cn_queue_alloc_callback_entry(name, id, callback);
  83         if (!cbq)
  84                 return -ENOMEM;
  85
  86         atomic_inc(&dev->refcnt);
  87         cbq->pdev = dev;
  88
  89         spin_lock_bh(&dev->queue_lock);
  90         list_for_each_entry(__cbq, &dev->queue_list, callback_entry) {
  91                 if (cn_cb_equal(&__cbq->id.id, id)) {
  92                         found = 1;
  93                         break;
  94                 }
  95         }
  96         if (!found)
  97                 list_add_tail(&cbq->callback_entry, &dev->queue_list);
  98         spin_unlock_bh(&dev->queue_lock);
  99
 100         if (found) {
 101                 atomic_dec(&dev->refcnt);
 102                 cn_queue_free_callback(cbq);
 103                 return -EINVAL;
 104         }
 105
 106         cbq->nls = dev->nls;
 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         dev->netlink_groups = 0;
 149
 150         dev->cn_queue = create_workqueue(dev->name);
 151         if (!dev->cn_queue) {
 152                 kfree(dev);
 153                 return NULL;
 154         }
 155
 156         return dev;
 157 }
 158
 159 void cn_queue_free_dev(struct cn_queue_dev *dev)
 160 {
 161         struct cn_callback_entry *cbq, *n;
 162
 163         flush_workqueue(dev->cn_queue);
 164         destroy_workqueue(dev->cn_queue);
 165
 166         spin_lock_bh(&dev->queue_lock);
 167         list_for_each_entry_safe(cbq, n, &dev->queue_list, callback_entry)
 168                 list_del(&cbq->callback_entry);
 169         spin_unlock_bh(&dev->queue_lock);
 170
 171         while (atomic_read(&dev->refcnt)) {
 172                 printk(KERN_INFO "Waiting for %s to become free: refcnt=%d.\n",
 173                        dev->name, atomic_read(&dev->refcnt));
 174                 msleep(1000);
 175         }
 176
 177         kfree(dev);
 178         dev = NULL;
 179 }