1 // SPDX-License-Identifier: GPL-2.0-or-later 2 /* 3 * cn_queue.c 4 * 5 * 2004+ Copyright (c) Evgeniy Polyakov <zbr@ioremap.net> 6 * All rights reserved. 7 */ 8 9 #include <linux/kernel.h> 10 #include <linux/module.h> 11 #include <linux/list.h> 12 #include <linux/workqueue.h> 13 #include <linux/spinlock.h> 14 #include <linux/slab.h> 15 #include <linux/skbuff.h> 16 #include <linux/suspend.h> 17 #include <linux/connector.h> 18 #include <linux/delay.h> 19 20 static struct cn_callback_entry * 21 cn_queue_alloc_callback_entry(struct cn_queue_dev *dev, const char *name, 22 const struct cb_id *id, 23 void (*callback)(struct cn_msg *, 24 struct netlink_skb_parms *)) 25 { 26 struct cn_callback_entry *cbq; 27 28 cbq = kzalloc(sizeof(*cbq), GFP_KERNEL); 29 if (!cbq) { 30 pr_err("Failed to create new callback queue.\n"); 31 return NULL; 32 } 33 34 refcount_set(&cbq->refcnt, 1); 35 36 atomic_inc(&dev->refcnt); 37 cbq->pdev = dev; 38 39 snprintf(cbq->id.name, sizeof(cbq->id.name), "%s", name); 40 memcpy(&cbq->id.id, id, sizeof(struct cb_id)); 41 cbq->callback = callback; 42 return cbq; 43 } 44 45 void cn_queue_release_callback(struct cn_callback_entry *cbq) 46 { 47 if (!refcount_dec_and_test(&cbq->refcnt)) 48 return; 49 50 atomic_dec(&cbq->pdev->refcnt); 51 kfree(cbq); 52 } 53 54 int cn_cb_equal(const struct cb_id *i1, const struct cb_id *i2) 55 { 56 return ((i1->idx == i2->idx) && (i1->val == i2->val)); 57 } 58 59 int cn_queue_add_callback(struct cn_queue_dev *dev, const char *name, 60 const struct cb_id *id, 61 void (*callback)(struct cn_msg *, 62 struct netlink_skb_parms *)) 63 { 64 struct cn_callback_entry *cbq, *__cbq; 65 int found = 0; 66 67 cbq = cn_queue_alloc_callback_entry(dev, name, id, callback); 68 if (!cbq) 69 return -ENOMEM; 70 71 spin_lock_bh(&dev->queue_lock); 72 list_for_each_entry(__cbq, &dev->queue_list, callback_entry) { 73 if (cn_cb_equal(&__cbq->id.id, id)) { 74 found = 1; 75 break; 76 } 77 } 78 if (!found) 79 list_add_tail(&cbq->callback_entry, &dev->queue_list); 80 spin_unlock_bh(&dev->queue_lock); 81 82 if (found) { 83 cn_queue_release_callback(cbq); 84 return -EINVAL; 85 } 86 87 cbq->seq = 0; 88 cbq->group = cbq->id.id.idx; 89 90 return 0; 91 } 92 93 void cn_queue_del_callback(struct cn_queue_dev *dev, const struct cb_id *id) 94 { 95 struct cn_callback_entry *cbq, *n; 96 int found = 0; 97 98 spin_lock_bh(&dev->queue_lock); 99 list_for_each_entry_safe(cbq, n, &dev->queue_list, callback_entry) { 100 if (cn_cb_equal(&cbq->id.id, id)) { 101 list_del(&cbq->callback_entry); 102 found = 1; 103 break; 104 } 105 } 106 spin_unlock_bh(&dev->queue_lock); 107 108 if (found) 109 cn_queue_release_callback(cbq); 110 } 111 112 struct cn_queue_dev *cn_queue_alloc_dev(const char *name, struct sock *nls) 113 { 114 struct cn_queue_dev *dev; 115 116 dev = kzalloc(sizeof(*dev), GFP_KERNEL); 117 if (!dev) 118 return NULL; 119 120 snprintf(dev->name, sizeof(dev->name), "%s", name); 121 atomic_set(&dev->refcnt, 0); 122 INIT_LIST_HEAD(&dev->queue_list); 123 spin_lock_init(&dev->queue_lock); 124 125 dev->nls = nls; 126 127 return dev; 128 } 129 130 void cn_queue_free_dev(struct cn_queue_dev *dev) 131 { 132 struct cn_callback_entry *cbq, *n; 133 134 spin_lock_bh(&dev->queue_lock); 135 list_for_each_entry_safe(cbq, n, &dev->queue_list, callback_entry) 136 list_del(&cbq->callback_entry); 137 spin_unlock_bh(&dev->queue_lock); 138 139 while (atomic_read(&dev->refcnt)) { 140 pr_info("Waiting for %s to become free: refcnt=%d.\n", 141 dev->name, atomic_read(&dev->refcnt)); 142 msleep(1000); 143 } 144 145 kfree(dev); 146 dev = NULL; 147 } 148