drivers/connector/cn_queue.c

   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
  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         struct cn_msg *msg = NLMSG_DATA(nlmsg_hdr(d->skb));
  40         struct netlink_skb_parms *nsp = &NETLINK_CB(d->skb);
  41
  42         d->callback(msg, nsp);
  43
  44         kfree_skb(d->skb);
  45         d->skb = NULL;
  46
  47         kfree(d->free);
  48 }
  49
  50 static struct cn_callback_entry *
  51 cn_queue_alloc_callback_entry(char *name, struct cb_id *id,
  52                               void (*callback)(struct cn_msg *, struct netlink_skb_parms *))
  53 {
  54         struct cn_callback_entry *cbq;
  55
  56         cbq = kzalloc(sizeof(*cbq), GFP_KERNEL);
  57         if (!cbq) {
  58                 printk(KERN_ERR "Failed to create new callback queue.\n");
  59                 return NULL;
  60         }
  61
  62         snprintf(cbq->id.name, sizeof(cbq->id.name), "%s", name);
  63         memcpy(&cbq->id.id, id, sizeof(struct cb_id));
  64         cbq->data.callback = callback;
  65
  66         INIT_WORK(&cbq->work, &cn_queue_wrapper);
  67         return cbq;
  68 }
  69
  70 static void cn_queue_free_callback(struct cn_callback_entry *cbq)
  71 {
  72         flush_workqueue(cbq->pdev->cn_queue);
  73         kfree(cbq);
  74 }
  75
  76 int cn_cb_equal(struct cb_id *i1, struct cb_id *i2)
  77 {
  78         return ((i1->idx == i2->idx) && (i1->val == i2->val));
  79 }
  80
  81 int cn_queue_add_callback(struct cn_queue_dev *dev, char *name, struct cb_id *id,
  82                           void (*callback)(struct cn_msg *, struct netlink_skb_parms *))
  83 {
  84         struct cn_callback_entry *cbq, *__cbq;
  85         int found = 0;
  86
  87         cbq = cn_queue_alloc_callback_entry(name, id, callback);
  88         if (!cbq)
  89                 return -ENOMEM;
  90
  91         atomic_inc(&dev->refcnt);
  92         cbq->pdev = dev;
  93
  94         spin_lock_bh(&dev->queue_lock);
  95         list_for_each_entry(__cbq, &dev->queue_list, callback_entry) {
  96                 if (cn_cb_equal(&__cbq->id.id, id)) {
  97                         found = 1;
  98                         break;
  99                 }
 100         }
 101         if (!found)
 102                 list_add_tail(&cbq->callback_entry, &dev->queue_list);
 103         spin_unlock_bh(&dev->queue_lock);
 104
 105         if (found) {
 106                 cn_queue_free_callback(cbq);
 107                 atomic_dec(&dev->refcnt);
 108                 return -EINVAL;
 109         }
 110
 111         cbq->seq = 0;
 112         cbq->group = cbq->id.id.idx;
 113
 114         return 0;
 115 }
 116
 117 void cn_queue_del_callback(struct cn_queue_dev *dev, struct cb_id *id)
 118 {
 119         struct cn_callback_entry *cbq, *n;
 120         int found = 0;
 121
 122         spin_lock_bh(&dev->queue_lock);
 123         list_for_each_entry_safe(cbq, n, &dev->queue_list, callback_entry) {
 124                 if (cn_cb_equal(&cbq->id.id, id)) {
 125                         list_del(&cbq->callback_entry);
 126                         found = 1;
 127                         break;
 128                 }
 129         }
 130         spin_unlock_bh(&dev->queue_lock);
 131
 132         if (found) {
 133                 cn_queue_free_callback(cbq);
 134                 atomic_dec(&dev->refcnt);
 135         }
 136 }
 137
 138 struct cn_queue_dev *cn_queue_alloc_dev(char *name, struct sock *nls)
 139 {
 140         struct cn_queue_dev *dev;
 141
 142         dev = kzalloc(sizeof(*dev), GFP_KERNEL);
 143         if (!dev)
 144                 return NULL;
 145
 146         snprintf(dev->name, sizeof(dev->name), "%s", name);
 147         atomic_set(&dev->refcnt, 0);
 148         INIT_LIST_HEAD(&dev->queue_list);
 149         spin_lock_init(&dev->queue_lock);
 150
 151         dev->nls = nls;
 152
 153         dev->cn_queue = alloc_ordered_workqueue(dev->name, 0);
 154         if (!dev->cn_queue) {
 155                 kfree(dev);
 156                 return NULL;
 157         }
 158
 159         return dev;
 160 }
 161
 162 void cn_queue_free_dev(struct cn_queue_dev *dev)
 163 {
 164         struct cn_callback_entry *cbq, *n;
 165
 166         flush_workqueue(dev->cn_queue);
 167         destroy_workqueue(dev->cn_queue);
 168
 169         spin_lock_bh(&dev->queue_lock);
 170         list_for_each_entry_safe(cbq, n, &dev->queue_list, callback_entry)
 171                 list_del(&cbq->callback_entry);
 172         spin_unlock_bh(&dev->queue_lock);
 173
 174         while (atomic_read(&dev->refcnt)) {
 175                 printk(KERN_INFO "Waiting for %s to become free: refcnt=%d.\n",
 176                        dev->name, atomic_read(&dev->refcnt));
 177                 msleep(1000);
 178         }
 179
 180         kfree(dev);
 181         dev = NULL;
 182 }