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