linux/sound/core/pcm.c

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// SPDX-License-Identifier: GPL-2.0-or-later
/*
* Digital Audio (PCM) abstract layer
* Copyright (c) by Jaroslav Kysela <perex@perex.cz>
*/
#include <linux/init.h>
#include <linux/slab.h>
#include <linux/module.h>
#include <linux/time.h>
#include <linux/mutex.h>
#include <linux/device.h>
#include <linux/nospec.h>
#include <sound/core.h>
#include <sound/minors.h>
#include <sound/pcm.h>
#include <sound/timer.h>
#include <sound/control.h>
#include <sound/info.h>
#include "pcm_local.h"
MODULE_AUTHOR("Jaroslav Kysela <perex@perex.cz>, Abramo Bagnara <abramo@alsa-project.org>");
MODULE_DESCRIPTION("Midlevel PCM code for ALSA.");
MODULE_LICENSE("GPL");
static LIST_HEAD(snd_pcm_devices);
static DEFINE_MUTEX(register_mutex);
#if IS_ENABLED(CONFIG_SND_PCM_OSS)
static LIST_HEAD(snd_pcm_notify_list);
#endif
static int snd_pcm_free(struct snd_pcm *pcm);
static int snd_pcm_dev_free(struct snd_device *device);
static int snd_pcm_dev_register(struct snd_device *device);
static int snd_pcm_dev_disconnect(struct snd_device *device);
static struct snd_pcm *snd_pcm_get(struct snd_card *card, int device)
{
struct snd_pcm *pcm;
list_for_each_entry(pcm, &snd_pcm_devices, list) {
if (pcm->card == card && pcm->device == device)
return pcm;
}
return NULL;
}
static int snd_pcm_next(struct snd_card *card, int device)
{
struct snd_pcm *pcm;
list_for_each_entry(pcm, &snd_pcm_devices, list) {
if (pcm->card == card && pcm->device > device)
return pcm->device;
else if (pcm->card->number > card->number)
return -1;
}
return -1;
}
static int snd_pcm_add(struct snd_pcm *newpcm)
{
struct snd_pcm *pcm;
if (newpcm->internal)
return 0;
list_for_each_entry(pcm, &snd_pcm_devices, list) {
if (pcm->card == newpcm->card && pcm->device == newpcm->device)
return -EBUSY;
if (pcm->card->number > newpcm->card->number ||
(pcm->card == newpcm->card &&
pcm->device > newpcm->device)) {
list_add(&newpcm->list, pcm->list.prev);
return 0;
}
}
list_add_tail(&newpcm->list, &snd_pcm_devices);
return 0;
}
static int snd_pcm_control_ioctl(struct snd_card *card,
struct snd_ctl_file *control,
unsigned int cmd, unsigned long arg)
{
switch (cmd) {
case SNDRV_CTL_IOCTL_PCM_NEXT_DEVICE:
{
int device;
if (get_user(device, (int __user *)arg))
return -EFAULT;
mutex_lock(&register_mutex);
device = snd_pcm_next(card, device);
mutex_unlock(&register_mutex);
if (put_user(device, (int __user *)arg))
return -EFAULT;
return 0;
}
case SNDRV_CTL_IOCTL_PCM_INFO:
{
struct snd_pcm_info __user *info;
unsigned int device, subdevice;
int stream;
struct snd_pcm *pcm;
struct snd_pcm_str *pstr;
struct snd_pcm_substream *substream;
int err;
info = (struct snd_pcm_info __user *)arg;
if (get_user(device, &info->device))
return -EFAULT;
if (get_user(stream, &info->stream))
return -EFAULT;
if (stream < 0 || stream > 1)
return -EINVAL;
stream = array_index_nospec(stream, 2);
if (get_user(subdevice, &info->subdevice))
return -EFAULT;
mutex_lock(&register_mutex);
pcm = snd_pcm_get(card, device);
if (pcm == NULL) {
err = -ENXIO;
goto _error;
}
pstr = &pcm->streams[stream];
if (pstr->substream_count == 0) {
err = -ENOENT;
goto _error;
}
if (subdevice >= pstr->substream_count) {
err = -ENXIO;
goto _error;
}
for (substream = pstr->substream; substream;
substream = substream->next)
if (substream->number == (int)subdevice)
break;
if (substream == NULL) {
err = -ENXIO;
goto _error;
}
mutex_lock(&pcm->open_mutex);
err = snd_pcm_info_user(substream, info);
mutex_unlock(&pcm->open_mutex);
_error:
mutex_unlock(&register_mutex);
return err;
}
case SNDRV_CTL_IOCTL_PCM_PREFER_SUBDEVICE:
{
int val;
if (get_user(val, (int __user *)arg))
return -EFAULT;
control->preferred_subdevice[SND_CTL_SUBDEV_PCM] = val;
return 0;
}
}
return -ENOIOCTLCMD;
}
#define FORMAT(v) [SNDRV_PCM_FORMAT_##v] = #v
static const char * const snd_pcm_format_names[] = {
FORMAT(S8),
FORMAT(U8),
FORMAT(S16_LE),
FORMAT(S16_BE),
FORMAT(U16_LE),
FORMAT(U16_BE),
FORMAT(S24_LE),
FORMAT(S24_BE),
FORMAT(U24_LE),
FORMAT(U24_BE),
FORMAT(S32_LE),
FORMAT(S32_BE),
FORMAT(U32_LE),
FORMAT(U32_BE),
FORMAT(FLOAT_LE),
FORMAT(FLOAT_BE),
FORMAT(FLOAT64_LE),
FORMAT(FLOAT64_BE),
FORMAT(IEC958_SUBFRAME_LE),
FORMAT(IEC958_SUBFRAME_BE),
FORMAT(MU_LAW),
FORMAT(A_LAW),
FORMAT(IMA_ADPCM),
FORMAT(MPEG),
FORMAT(GSM),
FORMAT(SPECIAL),
FORMAT(S24_3LE),
FORMAT(S24_3BE),
FORMAT(U24_3LE),
FORMAT(U24_3BE),
FORMAT(S20_3LE),
FORMAT(S20_3BE),
FORMAT(U20_3LE),
FORMAT(U20_3BE),
FORMAT(S18_3LE),
FORMAT(S18_3BE),
FORMAT(U18_3LE),
FORMAT(U18_3BE),
FORMAT(G723_24),
FORMAT(G723_24_1B),
FORMAT(G723_40),
FORMAT(G723_40_1B),
FORMAT(DSD_U8),
FORMAT(DSD_U16_LE),
FORMAT(DSD_U32_LE),
FORMAT(DSD_U16_BE),
FORMAT(DSD_U32_BE),
};
/**
* snd_pcm_format_name - Return a name string for the given PCM format
* @format: PCM format
*
* Return: the format name string
*/
const char *snd_pcm_format_name(snd_pcm_format_t format)
{
if ((__force unsigned int)format >= ARRAY_SIZE(snd_pcm_format_names))
return "Unknown";
return snd_pcm_format_names[(__force unsigned int)format];
}
EXPORT_SYMBOL_GPL(snd_pcm_format_name);
#ifdef CONFIG_SND_VERBOSE_PROCFS
#define STATE(v) [SNDRV_PCM_STATE_##v] = #v
#define STREAM(v) [SNDRV_PCM_STREAM_##v] = #v
#define READY(v) [SNDRV_PCM_READY_##v] = #v
#define XRUN(v) [SNDRV_PCM_XRUN_##v] = #v
#define SILENCE(v) [SNDRV_PCM_SILENCE_##v] = #v
#define TSTAMP(v) [SNDRV_PCM_TSTAMP_##v] = #v
#define ACCESS(v) [SNDRV_PCM_ACCESS_##v] = #v
#define START(v) [SNDRV_PCM_START_##v] = #v
#define SUBFORMAT(v) [SNDRV_PCM_SUBFORMAT_##v] = #v
static const char * const snd_pcm_stream_names[] = {
STREAM(PLAYBACK),
STREAM(CAPTURE),
};
static const char * const snd_pcm_state_names[] = {
STATE(OPEN),
STATE(SETUP),
STATE(PREPARED),
STATE(RUNNING),
STATE(XRUN),
STATE(DRAINING),
STATE(PAUSED),
STATE(SUSPENDED),
};
static const char * const snd_pcm_access_names[] = {
ACCESS(MMAP_INTERLEAVED),
ACCESS(MMAP_NONINTERLEAVED),
ACCESS(MMAP_COMPLEX),
ACCESS(RW_INTERLEAVED),
ACCESS(RW_NONINTERLEAVED),
};
static const char * const snd_pcm_subformat_names[] = {
SUBFORMAT(STD),
};
static const char * const snd_pcm_tstamp_mode_names[] = {
TSTAMP(NONE),
TSTAMP(ENABLE),
};
static const char *snd_pcm_stream_name(int stream)
{
return snd_pcm_stream_names[stream];
}
static const char *snd_pcm_access_name(snd_pcm_access_t access)
{
return snd_pcm_access_names[(__force int)access];
}
static const char *snd_pcm_subformat_name(snd_pcm_subformat_t subformat)
{
return snd_pcm_subformat_names[(__force int)subformat];
}
static const char *snd_pcm_tstamp_mode_name(int mode)
{
return snd_pcm_tstamp_mode_names[mode];
}
static const char *snd_pcm_state_name(snd_pcm_state_t state)
{
return snd_pcm_state_names[(__force int)state];
}
#if IS_ENABLED(CONFIG_SND_PCM_OSS)
#include <linux/soundcard.h>
static const char *snd_pcm_oss_format_name(int format)
{
switch (format) {
case AFMT_MU_LAW:
return "MU_LAW";
case AFMT_A_LAW:
return "A_LAW";
case AFMT_IMA_ADPCM:
return "IMA_ADPCM";
case AFMT_U8:
return "U8";
case AFMT_S16_LE:
return "S16_LE";
case AFMT_S16_BE:
return "S16_BE";
case AFMT_S8:
return "S8";
case AFMT_U16_LE:
return "U16_LE";
case AFMT_U16_BE:
return "U16_BE";
case AFMT_MPEG:
return "MPEG";
default:
return "unknown";
}
}
#endif
static void snd_pcm_proc_info_read(struct snd_pcm_substream *substream,
struct snd_info_buffer *buffer)
{
struct snd_pcm_info *info;
int err;
if (! substream)
return;
info = kmalloc(sizeof(*info), GFP_KERNEL);
if (!info)
return;
err = snd_pcm_info(substream, info);
if (err < 0) {
snd_iprintf(buffer, "error %d\n", err);
kfree(info);
return;
}
snd_iprintf(buffer, "card: %d\n", info->card);
snd_iprintf(buffer, "device: %d\n", info->device);
snd_iprintf(buffer, "subdevice: %d\n", info->subdevice);
snd_iprintf(buffer, "stream: %s\n", snd_pcm_stream_name(info->stream));
snd_iprintf(buffer, "id: %s\n", info->id);
snd_iprintf(buffer, "name: %s\n", info->name);
snd_iprintf(buffer, "subname: %s\n", info->subname);
snd_iprintf(buffer, "class: %d\n", info->dev_class);
snd_iprintf(buffer, "subclass: %d\n", info->dev_subclass);
snd_iprintf(buffer, "subdevices_count: %d\n", info->subdevices_count);
snd_iprintf(buffer, "subdevices_avail: %d\n", info->subdevices_avail);
kfree(info);
}
static void snd_pcm_stream_proc_info_read(struct snd_info_entry *entry,
struct snd_info_buffer *buffer)
{
snd_pcm_proc_info_read(((struct snd_pcm_str *)entry->private_data)->substream,
buffer);
}
static void snd_pcm_substream_proc_info_read(struct snd_info_entry *entry,
struct snd_info_buffer *buffer)
{
snd_pcm_proc_info_read(entry->private_data, buffer);
}
static void snd_pcm_substream_proc_hw_params_read(struct snd_info_entry *entry,
struct snd_info_buffer *buffer)
{
struct snd_pcm_substream *substream = entry->private_data;
struct snd_pcm_runtime *runtime;
mutex_lock(&substream->pcm->open_mutex);
runtime = substream->runtime;
if (!runtime) {
snd_iprintf(buffer, "closed\n");
goto unlock;
}
if (runtime->state == SNDRV_PCM_STATE_OPEN) {
snd_iprintf(buffer, "no setup\n");
goto unlock;
}
snd_iprintf(buffer, "access: %s\n", snd_pcm_access_name(runtime->access));
snd_iprintf(buffer, "format: %s\n", snd_pcm_format_name(runtime->format));
snd_iprintf(buffer, "subformat: %s\n", snd_pcm_subformat_name(runtime->subformat));
snd_iprintf(buffer, "channels: %u\n", runtime->channels);
snd_iprintf(buffer, "rate: %u (%u/%u)\n", runtime->rate, runtime->rate_num, runtime->rate_den);
snd_iprintf(buffer, "period_size: %lu\n", runtime->period_size);
snd_iprintf(buffer, "buffer_size: %lu\n", runtime->buffer_size);
#if IS_ENABLED(CONFIG_SND_PCM_OSS)
if (substream->oss.oss) {
snd_iprintf(buffer, "OSS format: %s\n", snd_pcm_oss_format_name(runtime->oss.format));
snd_iprintf(buffer, "OSS channels: %u\n", runtime->oss.channels);
snd_iprintf(buffer, "OSS rate: %u\n", runtime->oss.rate);
snd_iprintf(buffer, "OSS period bytes: %lu\n", (unsigned long)runtime->oss.period_bytes);
snd_iprintf(buffer, "OSS periods: %u\n", runtime->oss.periods);
snd_iprintf(buffer, "OSS period frames: %lu\n", (unsigned long)runtime->oss.period_frames);
}
#endif
unlock:
mutex_unlock(&substream->pcm->open_mutex);
}
static void snd_pcm_substream_proc_sw_params_read(struct snd_info_entry *entry,
struct snd_info_buffer *buffer)
{
struct snd_pcm_substream *substream = entry->private_data;
struct snd_pcm_runtime *runtime;
mutex_lock(&substream->pcm->open_mutex);
runtime = substream->runtime;
if (!runtime) {
snd_iprintf(buffer, "closed\n");
goto unlock;
}
if (runtime->state == SNDRV_PCM_STATE_OPEN) {
snd_iprintf(buffer, "no setup\n");
goto unlock;
}
snd_iprintf(buffer, "tstamp_mode: %s\n", snd_pcm_tstamp_mode_name(runtime->tstamp_mode));
snd_iprintf(buffer, "period_step: %u\n", runtime->period_step);
snd_iprintf(buffer, "avail_min: %lu\n", runtime->control->avail_min);
snd_iprintf(buffer, "start_threshold: %lu\n", runtime->start_threshold);
snd_iprintf(buffer, "stop_threshold: %lu\n", runtime->stop_threshold);
snd_iprintf(buffer, "silence_threshold: %lu\n", runtime->silence_threshold);
snd_iprintf(buffer, "silence_size: %lu\n", runtime->silence_size);
snd_iprintf(buffer, "boundary: %lu\n", runtime->boundary);
unlock:
mutex_unlock(&substream->pcm->open_mutex);
}
static void snd_pcm_substream_proc_status_read(struct snd_info_entry *entry,
struct snd_info_buffer *buffer)
{
struct snd_pcm_substream *substream = entry->private_data;
struct snd_pcm_runtime *runtime;
ALSA: Avoid using timespec for struct snd_pcm_status The struct snd_pcm_status will use 'timespec' type variables to record timestamp, which is not year 2038 safe on 32bits system. Userspace will use SNDRV_PCM_IOCTL_STATUS and SNDRV_PCM_IOCTL_STATUS_EXT as commands to issue ioctl() to fill the 'snd_pcm_status' structure in userspace. The command number is always defined through _IOR/_IOW/IORW, so when userspace changes the definition of 'struct timespec' to use 64-bit types, the command number also changes. Thus in the kernel, we now need to define two versions of each such ioctl and corresponding ioctl commands to handle 32bit time_t and 64bit time_t in native mode: struct snd_pcm_status32 { ...... s32 trigger_tstamp_sec; s32 trigger_tstamp_nsec; ...... s32 audio_tstamp_sec; s32 audio_tstamp_nsec; ...... }; struct snd_pcm_status64 { ...... s32 trigger_tstamp_sec; s32 trigger_tstamp_nsec; ...... s32 audio_tstamp_sec; s32 audio_tstamp_nsec; ...... }; Moreover in compat file, we renamed or introduced new structures to handle 32bit/64bit time_t in compatible mode. The 'struct snd_pcm_status32' and snd_pcm_status_user32() are used to handle 32bit time_t in compat mode. 'struct compat_snd_pcm_status64' and snd_pcm_status_user_compat64() are used to handle 64bit time_t. The implicit padding before timespec is made explicit to avoid incompatible structure layout between 32-bit and 64-bit x86 due to the different alignment requirements, and the snd_pcm_status structure is now hidden from the kernel to avoid relying on the timespec definitio definitionn Finally we can replace SNDRV_PCM_IOCTL_STATUS and SNDRV_PCM_IOCTL_STATUS_EXT with new commands and introduce new functions to fill new 'struct snd_pcm_status64' instead of using unsafe 'struct snd_pcm_status'. Then in future, the new commands can be matched when userspace changes 'timespec' to 64bit type to make a size change of 'struct snd_pcm_status'. When glibc changes time_t to 64-bit, any recompiled program will issue ioctl commands that the kernel does not understand without this patch. Signed-off-by: Baolin Wang <baolin.wang@linaro.org> Signed-off-by: Arnd Bergmann <arnd@arndb.de>
2018-04-24 15:06:11 +03:00
struct snd_pcm_status64 status;
int err;
mutex_lock(&substream->pcm->open_mutex);
runtime = substream->runtime;
if (!runtime) {
snd_iprintf(buffer, "closed\n");
goto unlock;
}
memset(&status, 0, sizeof(status));
ALSA: Avoid using timespec for struct snd_pcm_status The struct snd_pcm_status will use 'timespec' type variables to record timestamp, which is not year 2038 safe on 32bits system. Userspace will use SNDRV_PCM_IOCTL_STATUS and SNDRV_PCM_IOCTL_STATUS_EXT as commands to issue ioctl() to fill the 'snd_pcm_status' structure in userspace. The command number is always defined through _IOR/_IOW/IORW, so when userspace changes the definition of 'struct timespec' to use 64-bit types, the command number also changes. Thus in the kernel, we now need to define two versions of each such ioctl and corresponding ioctl commands to handle 32bit time_t and 64bit time_t in native mode: struct snd_pcm_status32 { ...... s32 trigger_tstamp_sec; s32 trigger_tstamp_nsec; ...... s32 audio_tstamp_sec; s32 audio_tstamp_nsec; ...... }; struct snd_pcm_status64 { ...... s32 trigger_tstamp_sec; s32 trigger_tstamp_nsec; ...... s32 audio_tstamp_sec; s32 audio_tstamp_nsec; ...... }; Moreover in compat file, we renamed or introduced new structures to handle 32bit/64bit time_t in compatible mode. The 'struct snd_pcm_status32' and snd_pcm_status_user32() are used to handle 32bit time_t in compat mode. 'struct compat_snd_pcm_status64' and snd_pcm_status_user_compat64() are used to handle 64bit time_t. The implicit padding before timespec is made explicit to avoid incompatible structure layout between 32-bit and 64-bit x86 due to the different alignment requirements, and the snd_pcm_status structure is now hidden from the kernel to avoid relying on the timespec definitio definitionn Finally we can replace SNDRV_PCM_IOCTL_STATUS and SNDRV_PCM_IOCTL_STATUS_EXT with new commands and introduce new functions to fill new 'struct snd_pcm_status64' instead of using unsafe 'struct snd_pcm_status'. Then in future, the new commands can be matched when userspace changes 'timespec' to 64bit type to make a size change of 'struct snd_pcm_status'. When glibc changes time_t to 64-bit, any recompiled program will issue ioctl commands that the kernel does not understand without this patch. Signed-off-by: Baolin Wang <baolin.wang@linaro.org> Signed-off-by: Arnd Bergmann <arnd@arndb.de>
2018-04-24 15:06:11 +03:00
err = snd_pcm_status64(substream, &status);
if (err < 0) {
snd_iprintf(buffer, "error %d\n", err);
goto unlock;
}
snd_iprintf(buffer, "state: %s\n", snd_pcm_state_name(status.state));
snd_iprintf(buffer, "owner_pid : %d\n", pid_vnr(substream->pid));
ALSA: Avoid using timespec for struct snd_pcm_status The struct snd_pcm_status will use 'timespec' type variables to record timestamp, which is not year 2038 safe on 32bits system. Userspace will use SNDRV_PCM_IOCTL_STATUS and SNDRV_PCM_IOCTL_STATUS_EXT as commands to issue ioctl() to fill the 'snd_pcm_status' structure in userspace. The command number is always defined through _IOR/_IOW/IORW, so when userspace changes the definition of 'struct timespec' to use 64-bit types, the command number also changes. Thus in the kernel, we now need to define two versions of each such ioctl and corresponding ioctl commands to handle 32bit time_t and 64bit time_t in native mode: struct snd_pcm_status32 { ...... s32 trigger_tstamp_sec; s32 trigger_tstamp_nsec; ...... s32 audio_tstamp_sec; s32 audio_tstamp_nsec; ...... }; struct snd_pcm_status64 { ...... s32 trigger_tstamp_sec; s32 trigger_tstamp_nsec; ...... s32 audio_tstamp_sec; s32 audio_tstamp_nsec; ...... }; Moreover in compat file, we renamed or introduced new structures to handle 32bit/64bit time_t in compatible mode. The 'struct snd_pcm_status32' and snd_pcm_status_user32() are used to handle 32bit time_t in compat mode. 'struct compat_snd_pcm_status64' and snd_pcm_status_user_compat64() are used to handle 64bit time_t. The implicit padding before timespec is made explicit to avoid incompatible structure layout between 32-bit and 64-bit x86 due to the different alignment requirements, and the snd_pcm_status structure is now hidden from the kernel to avoid relying on the timespec definitio definitionn Finally we can replace SNDRV_PCM_IOCTL_STATUS and SNDRV_PCM_IOCTL_STATUS_EXT with new commands and introduce new functions to fill new 'struct snd_pcm_status64' instead of using unsafe 'struct snd_pcm_status'. Then in future, the new commands can be matched when userspace changes 'timespec' to 64bit type to make a size change of 'struct snd_pcm_status'. When glibc changes time_t to 64-bit, any recompiled program will issue ioctl commands that the kernel does not understand without this patch. Signed-off-by: Baolin Wang <baolin.wang@linaro.org> Signed-off-by: Arnd Bergmann <arnd@arndb.de>
2018-04-24 15:06:11 +03:00
snd_iprintf(buffer, "trigger_time: %lld.%09lld\n",
status.trigger_tstamp_sec, status.trigger_tstamp_nsec);
snd_iprintf(buffer, "tstamp : %lld.%09lld\n",
status.tstamp_sec, status.tstamp_nsec);
snd_iprintf(buffer, "delay : %ld\n", status.delay);
snd_iprintf(buffer, "avail : %ld\n", status.avail);
snd_iprintf(buffer, "avail_max : %ld\n", status.avail_max);
snd_iprintf(buffer, "-----\n");
snd_iprintf(buffer, "hw_ptr : %ld\n", runtime->status->hw_ptr);
snd_iprintf(buffer, "appl_ptr : %ld\n", runtime->control->appl_ptr);
unlock:
mutex_unlock(&substream->pcm->open_mutex);
}
#ifdef CONFIG_SND_PCM_XRUN_DEBUG
static void snd_pcm_xrun_injection_write(struct snd_info_entry *entry,
struct snd_info_buffer *buffer)
{
struct snd_pcm_substream *substream = entry->private_data;
snd_pcm_stop_xrun(substream);
}
static void snd_pcm_xrun_debug_read(struct snd_info_entry *entry,
struct snd_info_buffer *buffer)
{
struct snd_pcm_str *pstr = entry->private_data;
snd_iprintf(buffer, "%d\n", pstr->xrun_debug);
}
static void snd_pcm_xrun_debug_write(struct snd_info_entry *entry,
struct snd_info_buffer *buffer)
{
struct snd_pcm_str *pstr = entry->private_data;
char line[64];
if (!snd_info_get_line(buffer, line, sizeof(line)))
pstr->xrun_debug = simple_strtoul(line, NULL, 10);
}
#endif
static int snd_pcm_stream_proc_init(struct snd_pcm_str *pstr)
{
struct snd_pcm *pcm = pstr->pcm;
struct snd_info_entry *entry;
char name[16];
sprintf(name, "pcm%i%c", pcm->device,
pstr->stream == SNDRV_PCM_STREAM_PLAYBACK ? 'p' : 'c');
entry = snd_info_create_card_entry(pcm->card, name,
pcm->card->proc_root);
if (!entry)
return -ENOMEM;
entry->mode = S_IFDIR | 0555;
pstr->proc_root = entry;
entry = snd_info_create_card_entry(pcm->card, "info", pstr->proc_root);
if (entry)
snd_info_set_text_ops(entry, pstr, snd_pcm_stream_proc_info_read);
#ifdef CONFIG_SND_PCM_XRUN_DEBUG
entry = snd_info_create_card_entry(pcm->card, "xrun_debug",
pstr->proc_root);
if (entry) {
snd_info_set_text_ops(entry, pstr, snd_pcm_xrun_debug_read);
entry->c.text.write = snd_pcm_xrun_debug_write;
entry->mode |= 0200;
}
#endif
return 0;
}
static int snd_pcm_stream_proc_done(struct snd_pcm_str *pstr)
{
snd_info_free_entry(pstr->proc_root);
pstr->proc_root = NULL;
return 0;
}
static struct snd_info_entry *
create_substream_info_entry(struct snd_pcm_substream *substream,
const char *name,
void (*read)(struct snd_info_entry *,
struct snd_info_buffer *))
{
struct snd_info_entry *entry;
entry = snd_info_create_card_entry(substream->pcm->card, name,
substream->proc_root);
if (entry)
snd_info_set_text_ops(entry, substream, read);
return entry;
}
static int snd_pcm_substream_proc_init(struct snd_pcm_substream *substream)
{
struct snd_info_entry *entry;
struct snd_card *card;
char name[16];
card = substream->pcm->card;
sprintf(name, "sub%i", substream->number);
entry = snd_info_create_card_entry(card, name,
substream->pstr->proc_root);
if (!entry)
return -ENOMEM;
entry->mode = S_IFDIR | 0555;
substream->proc_root = entry;
create_substream_info_entry(substream, "info",
snd_pcm_substream_proc_info_read);
create_substream_info_entry(substream, "hw_params",
snd_pcm_substream_proc_hw_params_read);
create_substream_info_entry(substream, "sw_params",
snd_pcm_substream_proc_sw_params_read);
create_substream_info_entry(substream, "status",
snd_pcm_substream_proc_status_read);
#ifdef CONFIG_SND_PCM_XRUN_DEBUG
entry = create_substream_info_entry(substream, "xrun_injection", NULL);
if (entry) {
entry->c.text.write = snd_pcm_xrun_injection_write;
entry->mode = S_IFREG | 0200;
}
#endif /* CONFIG_SND_PCM_XRUN_DEBUG */
return 0;
}
#else /* !CONFIG_SND_VERBOSE_PROCFS */
static inline int snd_pcm_stream_proc_init(struct snd_pcm_str *pstr) { return 0; }
static inline int snd_pcm_stream_proc_done(struct snd_pcm_str *pstr) { return 0; }
static inline int snd_pcm_substream_proc_init(struct snd_pcm_substream *substream) { return 0; }
#endif /* CONFIG_SND_VERBOSE_PROCFS */
static const struct attribute_group *pcm_dev_attr_groups[];
/*
* PM callbacks: we need to deal only with suspend here, as the resume is
* triggered either from user-space or the driver's resume callback
*/
#ifdef CONFIG_PM_SLEEP
static int do_pcm_suspend(struct device *dev)
{
struct snd_pcm_str *pstr = container_of(dev, struct snd_pcm_str, dev);
if (!pstr->pcm->no_device_suspend)
snd_pcm_suspend_all(pstr->pcm);
return 0;
}
#endif
static const struct dev_pm_ops pcm_dev_pm_ops = {
SET_SYSTEM_SLEEP_PM_OPS(do_pcm_suspend, NULL)
};
/* device type for PCM -- basically only for passing PM callbacks */
static const struct device_type pcm_dev_type = {
.name = "pcm",
.pm = &pcm_dev_pm_ops,
};
/**
* snd_pcm_new_stream - create a new PCM stream
* @pcm: the pcm instance
* @stream: the stream direction, SNDRV_PCM_STREAM_XXX
* @substream_count: the number of substreams
*
* Creates a new stream for the pcm.
* The corresponding stream on the pcm must have been empty before
* calling this, i.e. zero must be given to the argument of
* snd_pcm_new().
*
* Return: Zero if successful, or a negative error code on failure.
*/
int snd_pcm_new_stream(struct snd_pcm *pcm, int stream, int substream_count)
{
int idx, err;
struct snd_pcm_str *pstr = &pcm->streams[stream];
struct snd_pcm_substream *substream, *prev;
#if IS_ENABLED(CONFIG_SND_PCM_OSS)
mutex_init(&pstr->oss.setup_mutex);
#endif
pstr->stream = stream;
pstr->pcm = pcm;
pstr->substream_count = substream_count;
if (!substream_count)
return 0;
snd_device_initialize(&pstr->dev, pcm->card);
pstr->dev.groups = pcm_dev_attr_groups;
pstr->dev.type = &pcm_dev_type;
dev_set_name(&pstr->dev, "pcmC%iD%i%c", pcm->card->number, pcm->device,
stream == SNDRV_PCM_STREAM_PLAYBACK ? 'p' : 'c');
if (!pcm->internal) {
err = snd_pcm_stream_proc_init(pstr);
if (err < 0) {
pcm_err(pcm, "Error in snd_pcm_stream_proc_init\n");
return err;
}
}
prev = NULL;
for (idx = 0, prev = NULL; idx < substream_count; idx++) {
substream = kzalloc(sizeof(*substream), GFP_KERNEL);
if (!substream)
return -ENOMEM;
substream->pcm = pcm;
substream->pstr = pstr;
substream->number = idx;
substream->stream = stream;
sprintf(substream->name, "subdevice #%i", idx);
substream->buffer_bytes_max = UINT_MAX;
if (prev == NULL)
pstr->substream = substream;
else
prev->next = substream;
if (!pcm->internal) {
err = snd_pcm_substream_proc_init(substream);
if (err < 0) {
pcm_err(pcm,
"Error in snd_pcm_stream_proc_init\n");
if (prev == NULL)
pstr->substream = NULL;
else
prev->next = NULL;
kfree(substream);
return err;
}
}
substream->group = &substream->self_group;
snd_pcm_group_init(&substream->self_group);
list_add_tail(&substream->link_list, &substream->self_group.substreams);
atomic_set(&substream->mmap_count, 0);
prev = substream;
}
return 0;
}
EXPORT_SYMBOL(snd_pcm_new_stream);
static int _snd_pcm_new(struct snd_card *card, const char *id, int device,
int playback_count, int capture_count, bool internal,
struct snd_pcm **rpcm)
{
struct snd_pcm *pcm;
int err;
static const struct snd_device_ops ops = {
.dev_free = snd_pcm_dev_free,
.dev_register = snd_pcm_dev_register,
.dev_disconnect = snd_pcm_dev_disconnect,
};
static const struct snd_device_ops internal_ops = {
.dev_free = snd_pcm_dev_free,
};
if (snd_BUG_ON(!card))
return -ENXIO;
if (rpcm)
*rpcm = NULL;
pcm = kzalloc(sizeof(*pcm), GFP_KERNEL);
if (!pcm)
return -ENOMEM;
pcm->card = card;
pcm->device = device;
pcm->internal = internal;
mutex_init(&pcm->open_mutex);
init_waitqueue_head(&pcm->open_wait);
INIT_LIST_HEAD(&pcm->list);
if (id)
strscpy(pcm->id, id, sizeof(pcm->id));
err = snd_pcm_new_stream(pcm, SNDRV_PCM_STREAM_PLAYBACK,
playback_count);
if (err < 0)
goto free_pcm;
err = snd_pcm_new_stream(pcm, SNDRV_PCM_STREAM_CAPTURE, capture_count);
if (err < 0)
goto free_pcm;
err = snd_device_new(card, SNDRV_DEV_PCM, pcm,
internal ? &internal_ops : &ops);
if (err < 0)
goto free_pcm;
if (rpcm)
*rpcm = pcm;
return 0;
free_pcm:
snd_pcm_free(pcm);
return err;
}
/**
* snd_pcm_new - create a new PCM instance
* @card: the card instance
* @id: the id string
* @device: the device index (zero based)
* @playback_count: the number of substreams for playback
* @capture_count: the number of substreams for capture
* @rpcm: the pointer to store the new pcm instance
*
* Creates a new PCM instance.
*
* The pcm operators have to be set afterwards to the new instance
* via snd_pcm_set_ops().
*
* Return: Zero if successful, or a negative error code on failure.
*/
int snd_pcm_new(struct snd_card *card, const char *id, int device,
int playback_count, int capture_count, struct snd_pcm **rpcm)
{
return _snd_pcm_new(card, id, device, playback_count, capture_count,
false, rpcm);
}
EXPORT_SYMBOL(snd_pcm_new);
/**
* snd_pcm_new_internal - create a new internal PCM instance
* @card: the card instance
* @id: the id string
* @device: the device index (zero based - shared with normal PCMs)
* @playback_count: the number of substreams for playback
* @capture_count: the number of substreams for capture
* @rpcm: the pointer to store the new pcm instance
*
* Creates a new internal PCM instance with no userspace device or procfs
* entries. This is used by ASoC Back End PCMs in order to create a PCM that
* will only be used internally by kernel drivers. i.e. it cannot be opened
* by userspace. It provides existing ASoC components drivers with a substream
* and access to any private data.
*
* The pcm operators have to be set afterwards to the new instance
* via snd_pcm_set_ops().
*
* Return: Zero if successful, or a negative error code on failure.
*/
int snd_pcm_new_internal(struct snd_card *card, const char *id, int device,
int playback_count, int capture_count,
struct snd_pcm **rpcm)
{
return _snd_pcm_new(card, id, device, playback_count, capture_count,
true, rpcm);
}
EXPORT_SYMBOL(snd_pcm_new_internal);
static void free_chmap(struct snd_pcm_str *pstr)
{
if (pstr->chmap_kctl) {
struct snd_card *card = pstr->pcm->card;
down_write(&card->controls_rwsem);
snd_ctl_remove(card, pstr->chmap_kctl);
up_write(&card->controls_rwsem);
pstr->chmap_kctl = NULL;
}
}
static void snd_pcm_free_stream(struct snd_pcm_str * pstr)
{
struct snd_pcm_substream *substream, *substream_next;
#if IS_ENABLED(CONFIG_SND_PCM_OSS)
struct snd_pcm_oss_setup *setup, *setupn;
#endif
/* free all proc files under the stream */
snd_pcm_stream_proc_done(pstr);
substream = pstr->substream;
while (substream) {
substream_next = substream->next;
snd_pcm_timer_done(substream);
kfree(substream);
substream = substream_next;
}
#if IS_ENABLED(CONFIG_SND_PCM_OSS)
for (setup = pstr->oss.setup_list; setup; setup = setupn) {
setupn = setup->next;
kfree(setup->task_name);
kfree(setup);
}
#endif
free_chmap(pstr);
if (pstr->substream_count)
put_device(&pstr->dev);
}
#if IS_ENABLED(CONFIG_SND_PCM_OSS)
#define pcm_call_notify(pcm, call) \
do { \
struct snd_pcm_notify *_notify; \
list_for_each_entry(_notify, &snd_pcm_notify_list, list) \
_notify->call(pcm); \
} while (0)
#else
#define pcm_call_notify(pcm, call) do {} while (0)
#endif
static int snd_pcm_free(struct snd_pcm *pcm)
{
if (!pcm)
return 0;
if (!pcm->internal)
pcm_call_notify(pcm, n_unregister);
if (pcm->private_free)
pcm->private_free(pcm);
snd_pcm_lib_preallocate_free_for_all(pcm);
snd_pcm_free_stream(&pcm->streams[SNDRV_PCM_STREAM_PLAYBACK]);
snd_pcm_free_stream(&pcm->streams[SNDRV_PCM_STREAM_CAPTURE]);
kfree(pcm);
return 0;
}
static int snd_pcm_dev_free(struct snd_device *device)
{
struct snd_pcm *pcm = device->device_data;
return snd_pcm_free(pcm);
}
int snd_pcm_attach_substream(struct snd_pcm *pcm, int stream,
struct file *file,
struct snd_pcm_substream **rsubstream)
{
struct snd_pcm_str * pstr;
struct snd_pcm_substream *substream;
struct snd_pcm_runtime *runtime;
struct snd_card *card;
int prefer_subdevice;
size_t size;
if (snd_BUG_ON(!pcm || !rsubstream))
return -ENXIO;
if (snd_BUG_ON(stream != SNDRV_PCM_STREAM_PLAYBACK &&
stream != SNDRV_PCM_STREAM_CAPTURE))
return -EINVAL;
*rsubstream = NULL;
pstr = &pcm->streams[stream];
if (pstr->substream == NULL || pstr->substream_count == 0)
return -ENODEV;
card = pcm->card;
prefer_subdevice = snd_ctl_get_preferred_subdevice(card, SND_CTL_SUBDEV_PCM);
if (pcm->info_flags & SNDRV_PCM_INFO_HALF_DUPLEX) {
int opposite = !stream;
for (substream = pcm->streams[opposite].substream; substream;
substream = substream->next) {
if (SUBSTREAM_BUSY(substream))
return -EAGAIN;
}
}
if (file->f_flags & O_APPEND) {
if (prefer_subdevice < 0) {
if (pstr->substream_count > 1)
return -EINVAL; /* must be unique */
substream = pstr->substream;
} else {
for (substream = pstr->substream; substream;
substream = substream->next)
if (substream->number == prefer_subdevice)
break;
}
if (! substream)
return -ENODEV;
if (! SUBSTREAM_BUSY(substream))
return -EBADFD;
substream->ref_count++;
*rsubstream = substream;
return 0;
}
for (substream = pstr->substream; substream; substream = substream->next) {
if (!SUBSTREAM_BUSY(substream) &&
(prefer_subdevice == -1 ||
substream->number == prefer_subdevice))
break;
}
if (substream == NULL)
return -EAGAIN;
runtime = kzalloc(sizeof(*runtime), GFP_KERNEL);
if (runtime == NULL)
return -ENOMEM;
size = PAGE_ALIGN(sizeof(struct snd_pcm_mmap_status));
runtime->status = alloc_pages_exact(size, GFP_KERNEL);
if (runtime->status == NULL) {
kfree(runtime);
return -ENOMEM;
}
memset(runtime->status, 0, size);
size = PAGE_ALIGN(sizeof(struct snd_pcm_mmap_control));
runtime->control = alloc_pages_exact(size, GFP_KERNEL);
if (runtime->control == NULL) {
free_pages_exact(runtime->status,
PAGE_ALIGN(sizeof(struct snd_pcm_mmap_status)));
kfree(runtime);
return -ENOMEM;
}
memset(runtime->control, 0, size);
init_waitqueue_head(&runtime->sleep);
init_waitqueue_head(&runtime->tsleep);
__snd_pcm_set_state(runtime, SNDRV_PCM_STATE_OPEN);
mutex_init(&runtime->buffer_mutex);
ALSA: pcm: Fix potential AB/BA lock with buffer_mutex and mmap_lock syzbot caught a potential deadlock between the PCM runtime->buffer_mutex and the mm->mmap_lock. It was brought by the recent fix to cover the racy read/write and other ioctls, and in that commit, I overlooked a (hopefully only) corner case that may take the revert lock, namely, the OSS mmap. The OSS mmap operation exceptionally allows to re-configure the parameters inside the OSS mmap syscall, where mm->mmap_mutex is already held. Meanwhile, the copy_from/to_user calls at read/write operations also take the mm->mmap_lock internally, hence it may lead to a AB/BA deadlock. A similar problem was already seen in the past and we fixed it with a refcount (in commit b248371628aa). The former fix covered only the call paths with OSS read/write and OSS ioctls, while we need to cover the concurrent access via both ALSA and OSS APIs now. This patch addresses the problem above by replacing the buffer_mutex lock in the read/write operations with a refcount similar as we've used for OSS. The new field, runtime->buffer_accessing, keeps the number of concurrent read/write operations. Unlike the former buffer_mutex protection, this protects only around the copy_from/to_user() calls; the other codes are basically protected by the PCM stream lock. The refcount can be a negative, meaning blocked by the ioctls. If a negative value is seen, the read/write aborts with -EBUSY. In the ioctl side, OTOH, they check this refcount, too, and set to a negative value for blocking unless it's already being accessed. Reported-by: syzbot+6e5c88838328e99c7e1c@syzkaller.appspotmail.com Fixes: dca947d4d26d ("ALSA: pcm: Fix races among concurrent read/write and buffer changes") Cc: <stable@vger.kernel.org> Link: https://lore.kernel.org/r/000000000000381a0d05db622a81@google.com Link: https://lore.kernel.org/r/20220330120903.4738-1-tiwai@suse.de Signed-off-by: Takashi Iwai <tiwai@suse.de>
2022-03-30 15:09:03 +03:00
atomic_set(&runtime->buffer_accessing, 0);
substream->runtime = runtime;
substream->private_data = pcm->private_data;
substream->ref_count = 1;
substream->f_flags = file->f_flags;
substream->pid = get_pid(task_pid(current));
pstr->substream_opened++;
*rsubstream = substream;
return 0;
}
void snd_pcm_detach_substream(struct snd_pcm_substream *substream)
{
struct snd_pcm_runtime *runtime;
if (PCM_RUNTIME_CHECK(substream))
return;
runtime = substream->runtime;
if (runtime->private_free != NULL)
runtime->private_free(runtime);
free_pages_exact(runtime->status,
PAGE_ALIGN(sizeof(struct snd_pcm_mmap_status)));
free_pages_exact(runtime->control,
PAGE_ALIGN(sizeof(struct snd_pcm_mmap_control)));
kfree(runtime->hw_constraints.rules);
/* Avoid concurrent access to runtime via PCM timer interface */
if (substream->timer) {
spin_lock_irq(&substream->timer->lock);
substream->runtime = NULL;
spin_unlock_irq(&substream->timer->lock);
} else {
substream->runtime = NULL;
}
mutex_destroy(&runtime->buffer_mutex);
snd_fasync_free(runtime->fasync);
kfree(runtime);
put_pid(substream->pid);
substream->pid = NULL;
substream->pstr->substream_opened--;
}
static ssize_t pcm_class_show(struct device *dev,
struct device_attribute *attr, char *buf)
{
struct snd_pcm_str *pstr = container_of(dev, struct snd_pcm_str, dev);
struct snd_pcm *pcm = pstr->pcm;
const char *str;
static const char *strs[SNDRV_PCM_CLASS_LAST + 1] = {
[SNDRV_PCM_CLASS_GENERIC] = "generic",
[SNDRV_PCM_CLASS_MULTI] = "multi",
[SNDRV_PCM_CLASS_MODEM] = "modem",
[SNDRV_PCM_CLASS_DIGITIZER] = "digitizer",
};
if (pcm->dev_class > SNDRV_PCM_CLASS_LAST)
str = "none";
else
str = strs[pcm->dev_class];
return sysfs_emit(buf, "%s\n", str);
}
static DEVICE_ATTR_RO(pcm_class);
static struct attribute *pcm_dev_attrs[] = {
&dev_attr_pcm_class.attr,
NULL
};
static const struct attribute_group pcm_dev_attr_group = {
.attrs = pcm_dev_attrs,
};
static const struct attribute_group *pcm_dev_attr_groups[] = {
&pcm_dev_attr_group,
NULL
};
static int snd_pcm_dev_register(struct snd_device *device)
{
int cidx, err;
struct snd_pcm_substream *substream;
struct snd_pcm *pcm;
if (snd_BUG_ON(!device || !device->device_data))
return -ENXIO;
pcm = device->device_data;
mutex_lock(&register_mutex);
err = snd_pcm_add(pcm);
if (err)
goto unlock;
for (cidx = 0; cidx < 2; cidx++) {
int devtype = -1;
if (pcm->streams[cidx].substream == NULL)
continue;
switch (cidx) {
case SNDRV_PCM_STREAM_PLAYBACK:
devtype = SNDRV_DEVICE_TYPE_PCM_PLAYBACK;
break;
case SNDRV_PCM_STREAM_CAPTURE:
devtype = SNDRV_DEVICE_TYPE_PCM_CAPTURE;
break;
}
/* register pcm */
err = snd_register_device(devtype, pcm->card, pcm->device,
&snd_pcm_f_ops[cidx], pcm,
&pcm->streams[cidx].dev);
if (err < 0) {
list_del_init(&pcm->list);
goto unlock;
}
for (substream = pcm->streams[cidx].substream; substream; substream = substream->next)
snd_pcm_timer_init(substream);
}
pcm_call_notify(pcm, n_register);
unlock:
mutex_unlock(&register_mutex);
return err;
}
static int snd_pcm_dev_disconnect(struct snd_device *device)
{
struct snd_pcm *pcm = device->device_data;
struct snd_pcm_substream *substream;
int cidx;
mutex_lock(&register_mutex);
mutex_lock(&pcm->open_mutex);
wake_up(&pcm->open_wait);
list_del_init(&pcm->list);
for_each_pcm_substream(pcm, cidx, substream) {
snd_pcm_stream_lock_irq(substream);
if (substream->runtime) {
if (snd_pcm_running(substream))
snd_pcm_stop(substream, SNDRV_PCM_STATE_DISCONNECTED);
/* to be sure, set the state unconditionally */
__snd_pcm_set_state(substream->runtime,
SNDRV_PCM_STATE_DISCONNECTED);
wake_up(&substream->runtime->sleep);
wake_up(&substream->runtime->tsleep);
}
snd_pcm_stream_unlock_irq(substream);
}
for_each_pcm_substream(pcm, cidx, substream)
snd_pcm_sync_stop(substream, false);
pcm_call_notify(pcm, n_disconnect);
for (cidx = 0; cidx < 2; cidx++) {
snd_unregister_device(&pcm->streams[cidx].dev);
free_chmap(&pcm->streams[cidx]);
}
mutex_unlock(&pcm->open_mutex);
mutex_unlock(&register_mutex);
return 0;
}
#if IS_ENABLED(CONFIG_SND_PCM_OSS)
/**
* snd_pcm_notify - Add/remove the notify list
* @notify: PCM notify list
* @nfree: 0 = register, 1 = unregister
*
* This adds the given notifier to the global list so that the callback is
* called for each registered PCM devices. This exists only for PCM OSS
* emulation, so far.
*
* Return: zero if successful, or a negative error code
*/
int snd_pcm_notify(struct snd_pcm_notify *notify, int nfree)
{
struct snd_pcm *pcm;
if (snd_BUG_ON(!notify ||
!notify->n_register ||
!notify->n_unregister ||
!notify->n_disconnect))
return -EINVAL;
mutex_lock(&register_mutex);
if (nfree) {
list_del(&notify->list);
list_for_each_entry(pcm, &snd_pcm_devices, list)
notify->n_unregister(pcm);
} else {
list_add_tail(&notify->list, &snd_pcm_notify_list);
list_for_each_entry(pcm, &snd_pcm_devices, list)
notify->n_register(pcm);
}
mutex_unlock(&register_mutex);
return 0;
}
EXPORT_SYMBOL(snd_pcm_notify);
#endif /* CONFIG_SND_PCM_OSS */
#ifdef CONFIG_SND_PROC_FS
/*
* Info interface
*/
static void snd_pcm_proc_read(struct snd_info_entry *entry,
struct snd_info_buffer *buffer)
{
struct snd_pcm *pcm;
mutex_lock(&register_mutex);
list_for_each_entry(pcm, &snd_pcm_devices, list) {
snd_iprintf(buffer, "%02i-%02i: %s : %s",
pcm->card->number, pcm->device, pcm->id, pcm->name);
if (pcm->streams[SNDRV_PCM_STREAM_PLAYBACK].substream)
snd_iprintf(buffer, " : playback %i",
pcm->streams[SNDRV_PCM_STREAM_PLAYBACK].substream_count);
if (pcm->streams[SNDRV_PCM_STREAM_CAPTURE].substream)
snd_iprintf(buffer, " : capture %i",
pcm->streams[SNDRV_PCM_STREAM_CAPTURE].substream_count);
snd_iprintf(buffer, "\n");
}
mutex_unlock(&register_mutex);
}
static struct snd_info_entry *snd_pcm_proc_entry;
static void snd_pcm_proc_init(void)
{
struct snd_info_entry *entry;
entry = snd_info_create_module_entry(THIS_MODULE, "pcm", NULL);
if (entry) {
snd_info_set_text_ops(entry, NULL, snd_pcm_proc_read);
if (snd_info_register(entry) < 0) {
snd_info_free_entry(entry);
entry = NULL;
}
}
snd_pcm_proc_entry = entry;
}
static void snd_pcm_proc_done(void)
{
snd_info_free_entry(snd_pcm_proc_entry);
}
#else /* !CONFIG_SND_PROC_FS */
#define snd_pcm_proc_init()
#define snd_pcm_proc_done()
#endif /* CONFIG_SND_PROC_FS */
/*
* ENTRY functions
*/
static int __init alsa_pcm_init(void)
{
snd_ctl_register_ioctl(snd_pcm_control_ioctl);
snd_ctl_register_ioctl_compat(snd_pcm_control_ioctl);
snd_pcm_proc_init();
return 0;
}
static void __exit alsa_pcm_exit(void)
{
snd_ctl_unregister_ioctl(snd_pcm_control_ioctl);
snd_ctl_unregister_ioctl_compat(snd_pcm_control_ioctl);
snd_pcm_proc_done();
}
module_init(alsa_pcm_init)
module_exit(alsa_pcm_exit)