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 *, 38 struct netlink_skb_parms *)) 39 { 40 struct cn_callback_entry *cbq; 41 42 cbq = kzalloc(sizeof(*cbq), GFP_KERNEL); 43 if (!cbq) { 44 pr_err("Failed to create new callback queue.\n"); 45 return NULL; 46 } 47 48 atomic_set(&cbq->refcnt, 1); 49 50 atomic_inc(&dev->refcnt); 51 cbq->pdev = dev; 52 53 snprintf(cbq->id.name, sizeof(cbq->id.name), "%s", name); 54 memcpy(&cbq->id.id, id, sizeof(struct cb_id)); 55 cbq->callback = callback; 56 return cbq; 57 } 58 59 void cn_queue_release_callback(struct cn_callback_entry *cbq) 60 { 61 if (!atomic_dec_and_test(&cbq->refcnt)) 62 return; 63 64 atomic_dec(&cbq->pdev->refcnt); 65 kfree(cbq); 66 } 67 68 int cn_cb_equal(struct cb_id *i1, struct cb_id *i2) 69 { 70 return ((i1->idx == i2->idx) && (i1->val == i2->val)); 71 } 72 73 int cn_queue_add_callback(struct cn_queue_dev *dev, const char *name, 74 struct cb_id *id, 75 void (*callback)(struct cn_msg *, 76 struct netlink_skb_parms *)) 77 { 78 struct cn_callback_entry *cbq, *__cbq; 79 int found = 0; 80 81 cbq = cn_queue_alloc_callback_entry(dev, name, id, callback); 82 if (!cbq) 83 return -ENOMEM; 84 85 spin_lock_bh(&dev->queue_lock); 86 list_for_each_entry(__cbq, &dev->queue_list, callback_entry) { 87 if (cn_cb_equal(&__cbq->id.id, id)) { 88 found = 1; 89 break; 90 } 91 } 92 if (!found) 93 list_add_tail(&cbq->callback_entry, &dev->queue_list); 94 spin_unlock_bh(&dev->queue_lock); 95 96 if (found) { 97 cn_queue_release_callback(cbq); 98 return -EINVAL; 99 } 100 101 cbq->seq = 0; 102 cbq->group = cbq->id.id.idx; 103 104 return 0; 105 } 106 107 void cn_queue_del_callback(struct cn_queue_dev *dev, struct cb_id *id) 108 { 109 struct cn_callback_entry *cbq, *n; 110 int found = 0; 111 112 spin_lock_bh(&dev->queue_lock); 113 list_for_each_entry_safe(cbq, n, &dev->queue_list, callback_entry) { 114 if (cn_cb_equal(&cbq->id.id, id)) { 115 list_del(&cbq->callback_entry); 116 found = 1; 117 break; 118 } 119 } 120 spin_unlock_bh(&dev->queue_lock); 121 122 if (found) 123 cn_queue_release_callback(cbq); 124 } 125 126 struct cn_queue_dev *cn_queue_alloc_dev(const char *name, struct sock *nls) 127 { 128 struct cn_queue_dev *dev; 129 130 dev = kzalloc(sizeof(*dev), GFP_KERNEL); 131 if (!dev) 132 return NULL; 133 134 snprintf(dev->name, sizeof(dev->name), "%s", name); 135 atomic_set(&dev->refcnt, 0); 136 INIT_LIST_HEAD(&dev->queue_list); 137 spin_lock_init(&dev->queue_lock); 138 139 dev->nls = nls; 140 141 return dev; 142 } 143 144 void cn_queue_free_dev(struct cn_queue_dev *dev) 145 { 146 struct cn_callback_entry *cbq, *n; 147 148 spin_lock_bh(&dev->queue_lock); 149 list_for_each_entry_safe(cbq, n, &dev->queue_list, callback_entry) 150 list_del(&cbq->callback_entry); 151 spin_unlock_bh(&dev->queue_lock); 152 153 while (atomic_read(&dev->refcnt)) { 154 pr_info("Waiting for %s to become free: refcnt=%d.\n", 155 dev->name, atomic_read(&dev->refcnt)); 156 msleep(1000); 157 } 158 159 kfree(dev); 160 dev = NULL; 161 } 162