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
20static struct cn_callback_entry *
21cn_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(r: &cbq->refcnt, n: 1);
35
36 atomic_inc(v: &dev->refcnt);
37 cbq->pdev = dev;
38
39 snprintf(buf: cbq->id.name, size: sizeof(cbq->id.name), fmt: "%s", name);
40 memcpy(to: &cbq->id.id, from: id, len: sizeof(struct cb_id));
41 cbq->callback = callback;
42 return cbq;
43}
44
45void cn_queue_release_callback(struct cn_callback_entry *cbq)
46{
47 if (!refcount_dec_and_test(r: &cbq->refcnt))
48 return;
49
50 atomic_dec(v: &cbq->pdev->refcnt);
51 kfree(objp: cbq);
52}
53
54int 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
59int 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(lock: &dev->queue_lock);
72 list_for_each_entry(__cbq, &dev->queue_list, callback_entry) {
73 if (cn_cb_equal(i1: &__cbq->id.id, i2: id)) {
74 found = 1;
75 break;
76 }
77 }
78 if (!found)
79 list_add_tail(new: &cbq->callback_entry, head: &dev->queue_list);
80 spin_unlock_bh(lock: &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
93void 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(lock: &dev->queue_lock);
99 list_for_each_entry_safe(cbq, n, &dev->queue_list, callback_entry) {
100 if (cn_cb_equal(i1: &cbq->id.id, i2: id)) {
101 list_del(entry: &cbq->callback_entry);
102 found = 1;
103 break;
104 }
105 }
106 spin_unlock_bh(lock: &dev->queue_lock);
107
108 if (found)
109 cn_queue_release_callback(cbq);
110}
111
112struct 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(buf: dev->name, size: sizeof(dev->name), fmt: "%s", name);
121 atomic_set(v: &dev->refcnt, i: 0);
122 INIT_LIST_HEAD(list: &dev->queue_list);
123 spin_lock_init(&dev->queue_lock);
124
125 dev->nls = nls;
126
127 return dev;
128}
129
130void cn_queue_free_dev(struct cn_queue_dev *dev)
131{
132 struct cn_callback_entry *cbq, *n;
133
134 spin_lock_bh(lock: &dev->queue_lock);
135 list_for_each_entry_safe(cbq, n, &dev->queue_list, callback_entry)
136 list_del(entry: &cbq->callback_entry);
137 spin_unlock_bh(lock: &dev->queue_lock);
138
139 while (atomic_read(v: &dev->refcnt)) {
140 pr_info("Waiting for %s to become free: refcnt=%d.\n",
141 dev->name, atomic_read(&dev->refcnt));
142 msleep(msecs: 1000);
143 }
144
145 kfree(objp: dev);
146 dev = NULL;
147}
148