1// SPDX-License-Identifier: GPL-2.0-or-later
2/*
3 * Misc and compatibility things
4 * Copyright (c) by Jaroslav Kysela <perex@perex.cz>
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(new: res);
20 kfree(objp: 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
104 spin_lock_irq(lock: &snd_fasync_lock);
105 while (!list_empty(head: &snd_fasync_list)) {
106 fasync = list_first_entry(&snd_fasync_list, struct snd_fasync, list);
107 list_del_init(entry: &fasync->list);
108 spin_unlock_irq(lock: &snd_fasync_lock);
109 if (fasync->on)
110 kill_fasync(&fasync->fasync, fasync->signal, fasync->poll);
111 spin_lock_irq(lock: &snd_fasync_lock);
112 }
113 spin_unlock_irq(lock: &snd_fasync_lock);
114}
115
116static DECLARE_WORK(snd_fasync_work, snd_fasync_work_fn);
117
118int snd_fasync_helper(int fd, struct file *file, int on,
119 struct snd_fasync **fasyncp)
120{
121 struct snd_fasync *fasync = NULL;
122
123 if (on) {
124 fasync = kzalloc(sizeof(*fasync), GFP_KERNEL);
125 if (!fasync)
126 return -ENOMEM;
127 INIT_LIST_HEAD(list: &fasync->list);
128 }
129
130 scoped_guard(spinlock_irq, &snd_fasync_lock) {
131 if (*fasyncp) {
132 kfree(objp: fasync);
133 fasync = *fasyncp;
134 } else {
135 if (!fasync)
136 return 0;
137 *fasyncp = fasync;
138 }
139 fasync->on = on;
140 }
141 return fasync_helper(fd, file, on, &fasync->fasync);
142}
143EXPORT_SYMBOL_GPL(snd_fasync_helper);
144
145void snd_kill_fasync(struct snd_fasync *fasync, int signal, int poll)
146{
147 if (!fasync || !fasync->on)
148 return;
149 guard(spinlock_irqsave)(l: &snd_fasync_lock);
150 fasync->signal = signal;
151 fasync->poll = poll;
152 list_move(list: &fasync->list, head: &snd_fasync_list);
153 schedule_work(work: &snd_fasync_work);
154}
155EXPORT_SYMBOL_GPL(snd_kill_fasync);
156
157void snd_fasync_free(struct snd_fasync *fasync)
158{
159 if (!fasync)
160 return;
161 fasync->on = 0;
162 flush_work(work: &snd_fasync_work);
163 kfree(objp: fasync);
164}
165EXPORT_SYMBOL_GPL(snd_fasync_free);
166

source code of linux/sound/core/misc.c