projects/linux·blob master · refs

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1// SPDX-License-Identifier: GPL-2.0-or-later
2/*
3 * Misc and compatibility things
4 * Copyright (c) by Jaroslav Kysela <[email protected]>
5 */
6
7#include <linux/init.h>
8#include <linux/export.h>
9#include <linux/moduleparam.h>
10#include <linux/time.h>
11#include <linux/slab.h>
12#include <linux/ioport.h>
13#include <linux/fs.h>
14#include <sound/core.h>
15
16void release_and_free_resource(struct resource *res)
17{
18 if (res) {
19 release_resource(res);
20 kfree(res);
21 }
22}
23EXPORT_SYMBOL(release_and_free_resource);
24
25#ifdef CONFIG_PCI
26#include <linux/pci.h>
27/**
28 * snd_pci_quirk_lookup_id - look up a PCI SSID quirk list
29 * @vendor: PCI SSV id
30 * @device: PCI SSD id
31 * @list: quirk list, terminated by a null entry
32 *
33 * Look through the given quirk list and finds a matching entry
34 * with the same PCI SSID. When subdevice is 0, all subdevice
35 * values may match.
36 *
37 * Returns the matched entry pointer, or NULL if nothing matched.
38 */
39const struct snd_pci_quirk *
40snd_pci_quirk_lookup_id(u16 vendor, u16 device,
41 const struct snd_pci_quirk *list)
42{
43 const struct snd_pci_quirk *q;
44
45 for (q = list; q->subvendor || q->subdevice; q++) {
46 if (q->subvendor != vendor)
47 continue;
48 if (!q->subdevice ||
49 (device & q->subdevice_mask) == q->subdevice)
50 return q;
51 }
52 return NULL;
53}
54EXPORT_SYMBOL(snd_pci_quirk_lookup_id);
55
56/**
57 * snd_pci_quirk_lookup - look up a PCI SSID quirk list
58 * @pci: pci_dev handle
59 * @list: quirk list, terminated by a null entry
60 *
61 * Look through the given quirk list and finds a matching entry
62 * with the same PCI SSID. When subdevice is 0, all subdevice
63 * values may match.
64 *
65 * Returns the matched entry pointer, or NULL if nothing matched.
66 */
67const struct snd_pci_quirk *
68snd_pci_quirk_lookup(struct pci_dev *pci, const struct snd_pci_quirk *list)
69{
70 if (!pci)
71 return NULL;
72 return snd_pci_quirk_lookup_id(pci->subsystem_vendor,
73 pci->subsystem_device,
74 list);
75}
76EXPORT_SYMBOL(snd_pci_quirk_lookup);
77#endif
78
79/*
80 * Deferred async signal helpers
81 *
82 * Below are a few helper functions to wrap the async signal handling
83 * in the deferred work. The main purpose is to avoid the messy deadlock
84 * around tasklist_lock and co at the kill_fasync() invocation.
85 * fasync_helper() and kill_fasync() are replaced with snd_fasync_helper()
86 * and snd_kill_fasync(), respectively. In addition, snd_fasync_free() has
87 * to be called at releasing the relevant file object.
88 */
89struct snd_fasync {
90 struct fasync_struct *fasync;
91 int signal;
92 int poll;
93 int on;
94 struct list_head list;
95};
96
97static DEFINE_SPINLOCK(snd_fasync_lock);
98static LIST_HEAD(snd_fasync_list);
99
100static void snd_fasync_work_fn(struct work_struct *work)
101{
102 struct snd_fasync *fasync;
103 int signal, poll;
104
105 spin_lock_irq(&snd_fasync_lock);
106 while (!list_empty(&snd_fasync_list)) {
107 fasync = list_first_entry(&snd_fasync_list, struct snd_fasync, list);
108 list_del_init(&fasync->list);
109 if (!fasync->on)
110 continue;
111 signal = fasync->signal;
112 poll = fasync->poll;
113 spin_unlock_irq(&snd_fasync_lock);
114 kill_fasync(&fasync->fasync, signal, poll);
115 spin_lock_irq(&snd_fasync_lock);
116 }
117 spin_unlock_irq(&snd_fasync_lock);
118}
119
120static DECLARE_WORK(snd_fasync_work, snd_fasync_work_fn);
121
122int snd_fasync_helper(int fd, struct file *file, int on,
123 struct snd_fasync **fasyncp)
124{
125 struct snd_fasync *fasync = NULL;
126
127 if (on) {
128 fasync = kzalloc_obj(*fasync);
129 if (!fasync)
130 return -ENOMEM;
131 INIT_LIST_HEAD(&fasync->list);
132 }
133
134 scoped_guard(spinlock_irq, &snd_fasync_lock) {
135 if (*fasyncp) {
136 kfree(fasync);
137 fasync = *fasyncp;
138 } else {
139 if (!fasync)
140 return 0;
141 *fasyncp = fasync;
142 }
143 fasync->on = on;
144 }
145 return fasync_helper(fd, file, on, &fasync->fasync);
146}
147EXPORT_SYMBOL_GPL(snd_fasync_helper);
148
149void snd_kill_fasync(struct snd_fasync *fasync, int signal, int poll)
150{
151 if (!fasync)
152 return;
153 guard(spinlock_irqsave)(&snd_fasync_lock);
154 if (!fasync->on)
155 return;
156 fasync->signal = signal;
157 fasync->poll = poll;
158 list_move(&fasync->list, &snd_fasync_list);
159 schedule_work(&snd_fasync_work);
160}
161EXPORT_SYMBOL_GPL(snd_kill_fasync);
162
163void snd_fasync_free(struct snd_fasync *fasync)
164{
165 if (!fasync)
166 return;
167
168 scoped_guard(spinlock_irq, &snd_fasync_lock) {
169 fasync->on = 0;
170 list_del_init(&fasync->list);
171 }
172
173 flush_work(&snd_fasync_work);
174 kfree(fasync);
175}
176EXPORT_SYMBOL_GPL(snd_fasync_free);
177
178/*
179 * generic refcount helper
180 */
181
182void snd_refcount_init(struct snd_refcount *ref)
183{
184 atomic_set(&ref->count, 0);
185 init_waitqueue_head(&ref->waiter);
186}
187EXPORT_SYMBOL_GPL(snd_refcount_init);
188
189void snd_refcount_put(struct snd_refcount *ref)
190{
191 if (atomic_dec_and_test(&ref->count))
192 wake_up(&ref->waiter);
193}
194EXPORT_SYMBOL_GPL(snd_refcount_put);
195
196void snd_refcount_sync(struct snd_refcount *ref)
197{
198 wait_event(ref->waiter, !atomic_read(&ref->count));
199}
200EXPORT_SYMBOL_GPL(snd_refcount_sync);