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 static struct cn_callback_entry * 35 cn_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 58 void 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 67 int cn_cb_equal(struct cb_id *i1, struct cb_id *i2) 68 { 69 return ((i1->idx == i2->idx) && (i1->val == i2->val)); 70 } 71 72 int 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 } 104 105 void 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 } 123 124 struct 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 } 141 142 void 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