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 *
cn_queue_alloc_callback_entry(struct cn_queue_dev * dev,const char * name,const struct cb_id * id,void (* callback)(struct cn_msg *,struct netlink_skb_parms *))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
cn_queue_release_callback(struct cn_callback_entry * cbq)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
cn_cb_equal(const struct cb_id * i1,const struct cb_id * i2)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
cn_queue_add_callback(struct cn_queue_dev * dev,const char * name,const struct cb_id * id,void (* callback)(struct cn_msg *,struct netlink_skb_parms *))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
cn_queue_del_callback(struct cn_queue_dev * dev,const struct cb_id * id)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
cn_queue_alloc_dev(const char * name,struct sock * nls)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
cn_queue_free_dev(struct cn_queue_dev * dev)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