LXR linux/drivers/connector/cn

   1/*
   2 *      cn_queue.c
   3 *
   4 * 2004+ Copyright (c) Evgeniy Polyakov <zbr@ioremap.net>
   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
  34static struct cn_callback_entry *
  35cn_queue_alloc_callback_entry(struct cn_queue_dev *dev, const char *name,
  36                              struct cb_id *id,
  37                              void (*callback)(struct cn_msg *, struct netlink_skb_parms *))
  38{
  39        struct cn_callback_entry *cbq;
  40
  41        cbq = kzalloc(sizeof(*cbq), GFP_KERNEL);
  42        if (!cbq) {
  43                printk(KERN_ERR "Failed to create new callback queue.\n");
  44                return NULL;
  45        }
  46
  47        atomic_set(&cbq->refcnt, 1);
  48
  49        atomic_inc(&dev->refcnt);
  50        cbq->pdev = dev;
  51
  52        snprintf(cbq->id.name, sizeof(cbq->id.name), "%s", name);
  53        memcpy(&cbq->id.id, id, sizeof(struct cb_id));
  54        cbq->callback = callback;
  55        return cbq;
  56}
  57
  58void cn_queue_release_callback(struct cn_callback_entry *cbq)
  59{
  60        if (!atomic_dec_and_test(&cbq->refcnt))
  61                return;
  62
  63        atomic_dec(&cbq->pdev->refcnt);
  64        kfree(cbq);
  65}
  66
  67int cn_cb_equal(struct cb_id *i1, struct cb_id *i2)
  68{
  69        return ((i1->idx == i2->idx) && (i1->val == i2->val));
  70}
  71
  72int cn_queue_add_callback(struct cn_queue_dev *dev, const char *name,
  73                          struct cb_id *id,
  74                          void (*callback)(struct cn_msg *, struct netlink_skb_parms *))
  75{
  76        struct cn_callback_entry *cbq, *__cbq;
  77        int found = 0;
  78
  79        cbq = cn_queue_alloc_callback_entry(dev, name, id, callback);
  80        if (!cbq)
  81                return -ENOMEM;
  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->id.id, 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                cn_queue_release_callback(cbq);
  96                return -EINVAL;
  97        }
  98
  99        cbq->seq = 0;
 100        cbq->group = cbq->id.id.idx;
 101
 102        return 0;
 103}
 104
 105void cn_queue_del_callback(struct cn_queue_dev *dev, struct cb_id *id)
 106{
 107        struct cn_callback_entry *cbq, *n;
 108        int found = 0;
 109
 110        spin_lock_bh(&dev->queue_lock);
 111        list_for_each_entry_safe(cbq, n, &dev->queue_list, callback_entry) {
 112                if (cn_cb_equal(&cbq->id.id, id)) {
 113                        list_del(&cbq->callback_entry);
 114                        found = 1;
 115                        break;
 116                }
 117        }
 118        spin_unlock_bh(&dev->queue_lock);
 119
 120        if (found)
 121                cn_queue_release_callback(cbq);
 122}
 123
 124struct cn_queue_dev *cn_queue_alloc_dev(const char *name, struct sock *nls)
 125{
 126        struct cn_queue_dev *dev;
 127
 128        dev = kzalloc(sizeof(*dev), GFP_KERNEL);
 129        if (!dev)
 130                return NULL;
 131
 132        snprintf(dev->name, sizeof(dev->name), "%s", name);
 133        atomic_set(&dev->refcnt, 0);
 134        INIT_LIST_HEAD(&dev->queue_list);
 135        spin_lock_init(&dev->queue_lock);
 136
 137        dev->nls = nls;
 138
 139        return dev;
 140}
 141
 142void cn_queue_free_dev(struct cn_queue_dev *dev)
 143{
 144        struct cn_callback_entry *cbq, *n;
 145
 146        spin_lock_bh(&dev->queue_lock);
 147        list_for_each_entry_safe(cbq, n, &dev->queue_list, callback_entry)
 148                list_del(&cbq->callback_entry);
 149        spin_unlock_bh(&dev->queue_lock);
 150
 151        while (atomic_read(&dev->refcnt)) {
 152                printk(KERN_INFO "Waiting for %s to become free: refcnt=%d.\n",
 153                       dev->name, atomic_read(&dev->refcnt));
 154                msleep(1000);
 155        }
 156
 157        kfree(dev);
 158        dev = NULL;
 159}
 160