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control.c
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// SPDX-License-Identifier: GPL-2.0-or-later
/*
* Routines for driver control interface
* Copyright (c) by Jaroslav Kysela <perex@perex.cz>
*/
#include <linux/threads.h>
#include <linux/interrupt.h>
#include <linux/module.h>
#include <linux/moduleparam.h>
#include <linux/slab.h>
#include <linux/vmalloc.h>
#include <linux/time.h>
#include <linux/mm.h>
#include <linux/math64.h>
#include <linux/sched/signal.h>
#include <sound/core.h>
#include <sound/minors.h>
#include <sound/info.h>
#include <sound/control.h>
// Max allocation size for user controls.
static int max_user_ctl_alloc_size = 8 * 1024 * 1024;
module_param_named(max_user_ctl_alloc_size, max_user_ctl_alloc_size, int, 0444);
MODULE_PARM_DESC(max_user_ctl_alloc_size, "Max allocation size for user controls");
#define MAX_CONTROL_COUNT 1028
struct snd_kctl_ioctl {
struct list_head list; /* list of all ioctls */
snd_kctl_ioctl_func_t fioctl;
};
static DECLARE_RWSEM(snd_ioctl_rwsem);
static DECLARE_RWSEM(snd_ctl_layer_rwsem);
static LIST_HEAD(snd_control_ioctls);
#ifdef CONFIG_COMPAT
static LIST_HEAD(snd_control_compat_ioctls);
#endif
static struct snd_ctl_layer_ops *snd_ctl_layer;
static int snd_ctl_remove_locked(struct snd_card *card,
struct snd_kcontrol *kcontrol);
static int snd_ctl_open(struct inode *inode, struct file *file)
{
struct snd_card *card;
struct snd_ctl_file *ctl;
int i, err;
err = stream_open(inode, file);
if (err < 0)
return err;
card = snd_lookup_minor_data(iminor(inode), SNDRV_DEVICE_TYPE_CONTROL);
if (!card) {
err = -ENODEV;
goto __error1;
}
err = snd_card_file_add(card, file);
if (err < 0) {
err = -ENODEV;
goto __error1;
}
if (!try_module_get(card->module)) {
err = -EFAULT;
goto __error2;
}
ctl = kzalloc(sizeof(*ctl), GFP_KERNEL);
if (ctl == NULL) {
err = -ENOMEM;
goto __error;
}
INIT_LIST_HEAD(&ctl->events);
init_waitqueue_head(&ctl->change_sleep);
spin_lock_init(&ctl->read_lock);
ctl->card = card;
for (i = 0; i < SND_CTL_SUBDEV_ITEMS; i++)
ctl->preferred_subdevice[i] = -1;
ctl->pid = get_pid(task_pid(current));
file->private_data = ctl;
scoped_guard(write_lock_irqsave, &card->ctl_files_rwlock)
list_add_tail(&ctl->list, &card->ctl_files);
snd_card_unref(card);
return 0;
__error:
module_put(card->module);
__error2:
snd_card_file_remove(card, file);
__error1:
if (card)
snd_card_unref(card);
return err;
}
static void snd_ctl_empty_read_queue(struct snd_ctl_file * ctl)
{
struct snd_kctl_event *cread;
guard(spinlock_irqsave)(&ctl->read_lock);
while (!list_empty(&ctl->events)) {
cread = snd_kctl_event(ctl->events.next);
list_del(&cread->list);
kfree(cread);
}
}
static int snd_ctl_release(struct inode *inode, struct file *file)
{
struct snd_card *card;
struct snd_ctl_file *ctl;
struct snd_kcontrol *control;
unsigned int idx;
ctl = file->private_data;
file->private_data = NULL;
card = ctl->card;
scoped_guard(write_lock_irqsave, &card->ctl_files_rwlock)
list_del(&ctl->list);
scoped_guard(rwsem_write, &card->controls_rwsem) {
list_for_each_entry(control, &card->controls, list)
for (idx = 0; idx < control->count; idx++)
if (control->vd[idx].owner == ctl)
control->vd[idx].owner = NULL;
}
snd_fasync_free(ctl->fasync);
snd_ctl_empty_read_queue(ctl);
put_pid(ctl->pid);
kfree(ctl);
module_put(card->module);
snd_card_file_remove(card, file);
return 0;
}
/**
* snd_ctl_notify - Send notification to user-space for a control change
* @card: the card to send notification
* @mask: the event mask, SNDRV_CTL_EVENT_*
* @id: the ctl element id to send notification
*
* This function adds an event record with the given id and mask, appends
* to the list and wakes up the user-space for notification. This can be
* called in the atomic context.
*/
void snd_ctl_notify(struct snd_card *card, unsigned int mask,
struct snd_ctl_elem_id *id)
{
struct snd_ctl_file *ctl;
struct snd_kctl_event *ev;
if (snd_BUG_ON(!card || !id))
return;
if (card->shutdown)
return;
guard(read_lock_irqsave)(&card->ctl_files_rwlock);
#if IS_ENABLED(CONFIG_SND_MIXER_OSS)
card->mixer_oss_change_count++;
#endif
list_for_each_entry(ctl, &card->ctl_files, list) {
if (!ctl->subscribed)
continue;
scoped_guard(spinlock, &ctl->read_lock) {
list_for_each_entry(ev, &ctl->events, list) {
if (ev->id.numid == id->numid) {
ev->mask |= mask;
goto _found;
}
}
ev = kzalloc(sizeof(*ev), GFP_ATOMIC);
if (ev) {
ev->id = *id;
ev->mask = mask;
list_add_tail(&ev->list, &ctl->events);
} else {
dev_err(card->dev, "No memory available to allocate event\n");
}
_found:
wake_up(&ctl->change_sleep);
}
snd_kill_fasync(ctl->fasync, SIGIO, POLL_IN);
}
}
EXPORT_SYMBOL(snd_ctl_notify);
/**
* snd_ctl_notify_one - Send notification to user-space for a control change
* @card: the card to send notification
* @mask: the event mask, SNDRV_CTL_EVENT_*
* @kctl: the pointer with the control instance
* @ioff: the additional offset to the control index
*
* This function calls snd_ctl_notify() and does additional jobs
* like LED state changes.
*/
void snd_ctl_notify_one(struct snd_card *card, unsigned int mask,
struct snd_kcontrol *kctl, unsigned int ioff)
{
struct snd_ctl_elem_id id = kctl->id;
struct snd_ctl_layer_ops *lops;
id.index += ioff;
id.numid += ioff;
snd_ctl_notify(card, mask, &id);
guard(rwsem_read)(&snd_ctl_layer_rwsem);
for (lops = snd_ctl_layer; lops; lops = lops->next)
lops->lnotify(card, mask, kctl, ioff);
}
EXPORT_SYMBOL(snd_ctl_notify_one);
/**
* snd_ctl_new - create a new control instance with some elements
* @kctl: the pointer to store new control instance
* @count: the number of elements in this control
* @access: the default access flags for elements in this control
* @file: given when locking these elements
*
* Allocates a memory object for a new control instance. The instance has
* elements as many as the given number (@count). Each element has given
* access permissions (@access). Each element is locked when @file is given.
*
* Return: 0 on success, error code on failure
*/
static int snd_ctl_new(struct snd_kcontrol **kctl, unsigned int count,
unsigned int access, struct snd_ctl_file *file)
{
unsigned int idx;
if (count == 0 || count > MAX_CONTROL_COUNT)
return -EINVAL;
*kctl = kzalloc(struct_size(*kctl, vd, count), GFP_KERNEL);
if (!*kctl)
return -ENOMEM;
for (idx = 0; idx < count; idx++) {
(*kctl)->vd[idx].access = access;
(*kctl)->vd[idx].owner = file;
}
(*kctl)->count = count;
return 0;
}
/**
* snd_ctl_new1 - create a control instance from the template
* @ncontrol: the initialization record
* @private_data: the private data to set
*
* Allocates a new struct snd_kcontrol instance and initialize from the given
* template. When the access field of ncontrol is 0, it's assumed as
* READWRITE access. When the count field is 0, it's assumes as one.
*
* Return: The pointer of the newly generated instance, or %NULL on failure.
*/
struct snd_kcontrol *snd_ctl_new1(const struct snd_kcontrol_new *ncontrol,
void *private_data)
{
struct snd_kcontrol *kctl;
unsigned int count;
unsigned int access;
int err;
if (snd_BUG_ON(!ncontrol || !ncontrol->info))
return NULL;
count = ncontrol->count;
if (count == 0)
count = 1;
access = ncontrol->access;
if (access == 0)
access = SNDRV_CTL_ELEM_ACCESS_READWRITE;
access &= (SNDRV_CTL_ELEM_ACCESS_READWRITE |
SNDRV_CTL_ELEM_ACCESS_VOLATILE |
SNDRV_CTL_ELEM_ACCESS_INACTIVE |
SNDRV_CTL_ELEM_ACCESS_TLV_READWRITE |
SNDRV_CTL_ELEM_ACCESS_TLV_COMMAND |
SNDRV_CTL_ELEM_ACCESS_TLV_CALLBACK |
SNDRV_CTL_ELEM_ACCESS_LED_MASK |
SNDRV_CTL_ELEM_ACCESS_SKIP_CHECK);
err = snd_ctl_new(&kctl, count, access, NULL);
if (err < 0)
return NULL;
/* The 'numid' member is decided when calling snd_ctl_add(). */
kctl->id.iface = ncontrol->iface;
kctl->id.device = ncontrol->device;
kctl->id.subdevice = ncontrol->subdevice;
if (ncontrol->name) {
strscpy(kctl->id.name, ncontrol->name, sizeof(kctl->id.name));
if (strcmp(ncontrol->name, kctl->id.name) != 0)
pr_warn("ALSA: Control name '%s' truncated to '%s'\n",
ncontrol->name, kctl->id.name);
}
kctl->id.index = ncontrol->index;
kctl->info = ncontrol->info;
kctl->get = ncontrol->get;
kctl->put = ncontrol->put;
kctl->tlv.p = ncontrol->tlv.p;
kctl->private_value = ncontrol->private_value;
kctl->private_data = private_data;
return kctl;
}
EXPORT_SYMBOL(snd_ctl_new1);
/**
* snd_ctl_free_one - release the control instance
* @kcontrol: the control instance
*
* Releases the control instance created via snd_ctl_new()
* or snd_ctl_new1().
* Don't call this after the control was added to the card.
*/
void snd_ctl_free_one(struct snd_kcontrol *kcontrol)
{
if (kcontrol) {
if (kcontrol->private_free)
kcontrol->private_free(kcontrol);
kfree(kcontrol);
}
}
EXPORT_SYMBOL(snd_ctl_free_one);
static bool snd_ctl_remove_numid_conflict(struct snd_card *card,
unsigned int count)
{
struct snd_kcontrol *kctl;
/* Make sure that the ids assigned to the control do not wrap around */
if (card->last_numid >= UINT_MAX - count)
card->last_numid = 0;
list_for_each_entry(kctl, &card->controls, list) {
if (kctl->id.numid < card->last_numid + 1 + count &&
kctl->id.numid + kctl->count > card->last_numid + 1) {
card->last_numid = kctl->id.numid + kctl->count - 1;
return true;
}
}
return false;
}
static int snd_ctl_find_hole(struct snd_card *card, unsigned int count)
{
unsigned int iter = 100000;
while (snd_ctl_remove_numid_conflict(card, count)) {
if (--iter == 0) {
/* this situation is very unlikely */
dev_err(card->dev, "unable to allocate new control numid\n");
return -ENOMEM;
}
}
return 0;
}
/* check whether the given id is contained in the given kctl */
static bool elem_id_matches(const struct snd_kcontrol *kctl,
const struct snd_ctl_elem_id *id)
{
return kctl->id.iface == id->iface &&
kctl->id.device == id->device &&
kctl->id.subdevice == id->subdevice &&
!strncmp(kctl->id.name, id->name, sizeof(kctl->id.name)) &&
kctl->id.index <= id->index &&
kctl->id.index + kctl->count > id->index;
}
#ifdef CONFIG_SND_CTL_FAST_LOOKUP
/* Compute a hash key for the corresponding ctl id
* It's for the name lookup, hence the numid is excluded.
* The hash key is bound in LONG_MAX to be used for Xarray key.
*/
#define MULTIPLIER 37
static unsigned long get_ctl_id_hash(const struct snd_ctl_elem_id *id)
{
int i;
unsigned long h;
h = id->iface;
h = MULTIPLIER * h + id->device;
h = MULTIPLIER * h + id->subdevice;
for (i = 0; i < SNDRV_CTL_ELEM_ID_NAME_MAXLEN && id->name[i]; i++)
h = MULTIPLIER * h + id->name[i];
h = MULTIPLIER * h + id->index;
h &= LONG_MAX;
return h;
}
/* add hash entries to numid and ctl xarray tables */
static void add_hash_entries(struct snd_card *card,
struct snd_kcontrol *kcontrol)
{
struct snd_ctl_elem_id id = kcontrol->id;
int i;
xa_store_range(&card->ctl_numids, kcontrol->id.numid,
kcontrol->id.numid + kcontrol->count - 1,
kcontrol, GFP_KERNEL);
for (i = 0; i < kcontrol->count; i++) {
id.index = kcontrol->id.index + i;
if (xa_insert(&card->ctl_hash, get_ctl_id_hash(&id),
kcontrol, GFP_KERNEL)) {
/* skip hash for this entry, noting we had collision */
card->ctl_hash_collision = true;
dev_dbg(card->dev, "ctl_hash collision %d:%s:%d\n",
id.iface, id.name, id.index);
}
}
}
/* remove hash entries that have been added */
static void remove_hash_entries(struct snd_card *card,
struct snd_kcontrol *kcontrol)
{
struct snd_ctl_elem_id id = kcontrol->id;
struct snd_kcontrol *matched;
unsigned long h;
int i;
for (i = 0; i < kcontrol->count; i++) {
xa_erase(&card->ctl_numids, id.numid);
h = get_ctl_id_hash(&id);
matched = xa_load(&card->ctl_hash, h);
if (matched && (matched == kcontrol ||
elem_id_matches(matched, &id)))
xa_erase(&card->ctl_hash, h);
id.index++;
id.numid++;
}
}
#else /* CONFIG_SND_CTL_FAST_LOOKUP */
static inline void add_hash_entries(struct snd_card *card,
struct snd_kcontrol *kcontrol)
{
}
static inline void remove_hash_entries(struct snd_card *card,
struct snd_kcontrol *kcontrol)
{
}
#endif /* CONFIG_SND_CTL_FAST_LOOKUP */
enum snd_ctl_add_mode {
CTL_ADD_EXCLUSIVE, CTL_REPLACE, CTL_ADD_ON_REPLACE,
};
/* add/replace a new kcontrol object; call with card->controls_rwsem locked */
static int __snd_ctl_add_replace(struct snd_card *card,
struct snd_kcontrol *kcontrol,
enum snd_ctl_add_mode mode)
{
struct snd_ctl_elem_id id;
unsigned int idx;
struct snd_kcontrol *old;
int err;
lockdep_assert_held_write(&card->controls_rwsem);
id = kcontrol->id;
if (id.index > UINT_MAX - kcontrol->count)
return -EINVAL;
old = snd_ctl_find_id_locked(card, &id);
if (!old) {
if (mode == CTL_REPLACE)
return -EINVAL;
} else {
if (mode == CTL_ADD_EXCLUSIVE) {
dev_err(card->dev,
"control %i:%i:%i:%s:%i is already present\n",
id.iface, id.device, id.subdevice, id.name,
id.index);
return -EBUSY;
}
err = snd_ctl_remove_locked(card, old);
if (err < 0)
return err;
}
if (snd_ctl_find_hole(card, kcontrol->count) < 0)
return -ENOMEM;
list_add_tail(&kcontrol->list, &card->controls);
card->controls_count += kcontrol->count;
kcontrol->id.numid = card->last_numid + 1;
card->last_numid += kcontrol->count;
add_hash_entries(card, kcontrol);
for (idx = 0; idx < kcontrol->count; idx++)
snd_ctl_notify_one(card, SNDRV_CTL_EVENT_MASK_ADD, kcontrol, idx);
return 0;
}
static int snd_ctl_add_replace(struct snd_card *card,
struct snd_kcontrol *kcontrol,
enum snd_ctl_add_mode mode)
{
int err = -EINVAL;
if (! kcontrol)
return err;
if (snd_BUG_ON(!card || !kcontrol->info))
goto error;
scoped_guard(rwsem_write, &card->controls_rwsem)
err = __snd_ctl_add_replace(card, kcontrol, mode);
if (err < 0)
goto error;
return 0;
error:
snd_ctl_free_one(kcontrol);
return err;
}
/**
* snd_ctl_add - add the control instance to the card
* @card: the card instance
* @kcontrol: the control instance to add
*
* Adds the control instance created via snd_ctl_new() or
* snd_ctl_new1() to the given card. Assigns also an unique
* numid used for fast search.
*
* It frees automatically the control which cannot be added.
*
* Return: Zero if successful, or a negative error code on failure.
*
*/
int snd_ctl_add(struct snd_card *card, struct snd_kcontrol *kcontrol)
{
return snd_ctl_add_replace(card, kcontrol, CTL_ADD_EXCLUSIVE);
}
EXPORT_SYMBOL(snd_ctl_add);
/**
* snd_ctl_replace - replace the control instance of the card
* @card: the card instance
* @kcontrol: the control instance to replace
* @add_on_replace: add the control if not already added
*
* Replaces the given control. If the given control does not exist
* and the add_on_replace flag is set, the control is added. If the
* control exists, it is destroyed first.
*
* It frees automatically the control which cannot be added or replaced.
*
* Return: Zero if successful, or a negative error code on failure.
*/
int snd_ctl_replace(struct snd_card *card, struct snd_kcontrol *kcontrol,
bool add_on_replace)
{
return snd_ctl_add_replace(card, kcontrol,
add_on_replace ? CTL_ADD_ON_REPLACE : CTL_REPLACE);
}
EXPORT_SYMBOL(snd_ctl_replace);
static int __snd_ctl_remove(struct snd_card *card,
struct snd_kcontrol *kcontrol,
bool remove_hash)
{
unsigned int idx;
lockdep_assert_held_write(&card->controls_rwsem);
if (snd_BUG_ON(!card || !kcontrol))
return -EINVAL;
list_del(&kcontrol->list);
if (remove_hash)
remove_hash_entries(card, kcontrol);
card->controls_count -= kcontrol->count;
for (idx = 0; idx < kcontrol->count; idx++)
snd_ctl_notify_one(card, SNDRV_CTL_EVENT_MASK_REMOVE, kcontrol, idx);
snd_ctl_free_one(kcontrol);
return 0;
}
static inline int snd_ctl_remove_locked(struct snd_card *card,
struct snd_kcontrol *kcontrol)
{
return __snd_ctl_remove(card, kcontrol, true);
}
/**
* snd_ctl_remove - remove the control from the card and release it
* @card: the card instance
* @kcontrol: the control instance to remove
*
* Removes the control from the card and then releases the instance.
* You don't need to call snd_ctl_free_one().
* Passing NULL to @kcontrol argument is allowed as noop.
*
* Return: 0 if successful, or a negative error code on failure.
*
* Note that this function takes card->controls_rwsem lock internally.
*/
int snd_ctl_remove(struct snd_card *card, struct snd_kcontrol *kcontrol)
{
if (!kcontrol)
return 0;
guard(rwsem_write)(&card->controls_rwsem);
return snd_ctl_remove_locked(card, kcontrol);
}
EXPORT_SYMBOL(snd_ctl_remove);
/**
* snd_ctl_remove_id - remove the control of the given id and release it
* @card: the card instance
* @id: the control id to remove
*
* Finds the control instance with the given id, removes it from the
* card list and releases it.
*
* Return: 0 if successful, or a negative error code on failure.
*/
int snd_ctl_remove_id(struct snd_card *card, struct snd_ctl_elem_id *id)
{
struct snd_kcontrol *kctl;
guard(rwsem_write)(&card->controls_rwsem);
kctl = snd_ctl_find_id_locked(card, id);
if (kctl == NULL)
return -ENOENT;
return snd_ctl_remove_locked(card, kctl);
}
EXPORT_SYMBOL(snd_ctl_remove_id);
/**
* snd_ctl_remove_user_ctl - remove and release the unlocked user control
* @file: active control handle
* @id: the control id to remove
*
* Finds the control instance with the given id, removes it from the
* card list and releases it.
*
* Return: 0 if successful, or a negative error code on failure.
*/
static int snd_ctl_remove_user_ctl(struct snd_ctl_file * file,
struct snd_ctl_elem_id *id)
{
struct snd_card *card = file->card;
struct snd_kcontrol *kctl;
int idx;
guard(rwsem_write)(&card->controls_rwsem);
kctl = snd_ctl_find_id_locked(card, id);
if (kctl == NULL)
return -ENOENT;
if (!(kctl->vd[0].access & SNDRV_CTL_ELEM_ACCESS_USER))
return -EINVAL;
for (idx = 0; idx < kctl->count; idx++)
if (kctl->vd[idx].owner != NULL && kctl->vd[idx].owner != file)
return -EBUSY;
return snd_ctl_remove_locked(card, kctl);
}
/**
* snd_ctl_activate_id - activate/inactivate the control of the given id
* @card: the card instance
* @id: the control id to activate/inactivate
* @active: non-zero to activate
*
* Finds the control instance with the given id, and activate or
* inactivate the control together with notification, if changed.
* The given ID data is filled with full information.
*
* Return: 0 if unchanged, 1 if changed, or a negative error code on failure.
*/
int snd_ctl_activate_id(struct snd_card *card, struct snd_ctl_elem_id *id,
int active)
{
struct snd_kcontrol *kctl;
struct snd_kcontrol_volatile *vd;
unsigned int index_offset;
int ret;
down_write(&card->controls_rwsem);
kctl = snd_ctl_find_id_locked(card, id);
if (kctl == NULL) {
ret = -ENOENT;
goto unlock;
}
index_offset = snd_ctl_get_ioff(kctl, id);
vd = &kctl->vd[index_offset];
ret = 0;
if (active) {
if (!(vd->access & SNDRV_CTL_ELEM_ACCESS_INACTIVE))
goto unlock;
vd->access &= ~SNDRV_CTL_ELEM_ACCESS_INACTIVE;
} else {
if (vd->access & SNDRV_CTL_ELEM_ACCESS_INACTIVE)
goto unlock;
vd->access |= SNDRV_CTL_ELEM_ACCESS_INACTIVE;
}
snd_ctl_build_ioff(id, kctl, index_offset);
downgrade_write(&card->controls_rwsem);
snd_ctl_notify_one(card, SNDRV_CTL_EVENT_MASK_INFO, kctl, index_offset);
up_read(&card->controls_rwsem);
return 1;
unlock:
up_write(&card->controls_rwsem);
return ret;
}
EXPORT_SYMBOL_GPL(snd_ctl_activate_id);
/**
* snd_ctl_rename_id - replace the id of a control on the card
* @card: the card instance
* @src_id: the old id
* @dst_id: the new id
*
* Finds the control with the old id from the card, and replaces the
* id with the new one.
*
* The function tries to keep the already assigned numid while replacing
* the rest.
*
* Note that this function should be used only in the card initialization
* phase. Calling after the card instantiation may cause issues with
* user-space expecting persistent numids.
*
* Return: Zero if successful, or a negative error code on failure.
*/
int snd_ctl_rename_id(struct snd_card *card, struct snd_ctl_elem_id *src_id,
struct snd_ctl_elem_id *dst_id)
{
struct snd_kcontrol *kctl;
int saved_numid;
guard(rwsem_write)(&card->controls_rwsem);
kctl = snd_ctl_find_id_locked(card, src_id);
if (kctl == NULL)
return -ENOENT;
saved_numid = kctl->id.numid;
remove_hash_entries(card, kctl);
kctl->id = *dst_id;
kctl->id.numid = saved_numid;
add_hash_entries(card, kctl);
return 0;
}
EXPORT_SYMBOL(snd_ctl_rename_id);
/**
* snd_ctl_rename - rename the control on the card
* @card: the card instance
* @kctl: the control to rename
* @name: the new name
*
* Renames the specified control on the card to the new name.
*
* Note that this function takes card->controls_rwsem lock internally.
*/
void snd_ctl_rename(struct snd_card *card, struct snd_kcontrol *kctl,
const char *name)
{
guard(rwsem_write)(&card->controls_rwsem);
remove_hash_entries(card, kctl);
if (strscpy(kctl->id.name, name, sizeof(kctl->id.name)) < 0)
pr_warn("ALSA: Renamed control new name '%s' truncated to '%s'\n",
name, kctl->id.name);
add_hash_entries(card, kctl);
}
EXPORT_SYMBOL(snd_ctl_rename);
#ifndef CONFIG_SND_CTL_FAST_LOOKUP
static struct snd_kcontrol *
snd_ctl_find_numid_slow(struct snd_card *card, unsigned int numid)
{
struct snd_kcontrol *kctl;
list_for_each_entry(kctl, &card->controls, list) {
if (kctl->id.numid <= numid && kctl->id.numid + kctl->count > numid)
return kctl;
}
return NULL;
}
#endif /* !CONFIG_SND_CTL_FAST_LOOKUP */
/**
* snd_ctl_find_numid_locked - find the control instance with the given number-id
* @card: the card instance
* @numid: the number-id to search
*
* Finds the control instance with the given number-id from the card.
*
* The caller must down card->controls_rwsem before calling this function
* (if the race condition can happen).
*
* Return: The pointer of the instance if found, or %NULL if not.
*/
struct snd_kcontrol *
snd_ctl_find_numid_locked(struct snd_card *card, unsigned int numid)
{
if (snd_BUG_ON(!card || !numid))
return NULL;
lockdep_assert_held(&card->controls_rwsem);
#ifdef CONFIG_SND_CTL_FAST_LOOKUP
return xa_load(&card->ctl_numids, numid);
#else
return snd_ctl_find_numid_slow(card, numid);
#endif
}
EXPORT_SYMBOL(snd_ctl_find_numid_locked);
/**
* snd_ctl_find_numid - find the control instance with the given number-id
* @card: the card instance
* @numid: the number-id to search
*
* Finds the control instance with the given number-id from the card.
*
* Return: The pointer of the instance if found, or %NULL if not.
*
* Note that this function takes card->controls_rwsem lock internally.
*/
struct snd_kcontrol *snd_ctl_find_numid(struct snd_card *card,
unsigned int numid)
{
guard(rwsem_read)(&card->controls_rwsem);
return snd_ctl_find_numid_locked(card, numid);
}
EXPORT_SYMBOL(snd_ctl_find_numid);
/**
* snd_ctl_find_id_locked - find the control instance with the given id
* @card: the card instance
* @id: the id to search
*
* Finds the control instance with the given id from the card.
*
* The caller must down card->controls_rwsem before calling this function
* (if the race condition can happen).
*
* Return: The pointer of the instance if found, or %NULL if not.
*/
struct snd_kcontrol *snd_ctl_find_id_locked(struct snd_card *card,
const struct snd_ctl_elem_id *id)
{
struct snd_kcontrol *kctl;
if (snd_BUG_ON(!card || !id))
return NULL;
lockdep_assert_held(&card->controls_rwsem);
if (id->numid != 0)
return snd_ctl_find_numid_locked(card, id->numid);
#ifdef CONFIG_SND_CTL_FAST_LOOKUP
kctl = xa_load(&card->ctl_hash, get_ctl_id_hash(id));
if (kctl && elem_id_matches(kctl, id))
return kctl;
if (!card->ctl_hash_collision)
return NULL; /* we can rely on only hash table */
#endif
/* no matching in hash table - try all as the last resort */
list_for_each_entry(kctl, &card->controls, list)
if (elem_id_matches(kctl, id))
return kctl;
return NULL;
}
EXPORT_SYMBOL(snd_ctl_find_id_locked);
/**
* snd_ctl_find_id - find the control instance with the given id
* @card: the card instance
* @id: the id to search
*
* Finds the control instance with the given id from the card.
*
* Return: The pointer of the instance if found, or %NULL if not.
*
* Note that this function takes card->controls_rwsem lock internally.
*/
struct snd_kcontrol *snd_ctl_find_id(struct snd_card *card,
const struct snd_ctl_elem_id *id)
{
guard(rwsem_read)(&card->controls_rwsem);
return snd_ctl_find_id_locked(card, id);
}
EXPORT_SYMBOL(snd_ctl_find_id);
static int snd_ctl_card_info(struct snd_card *card, struct snd_ctl_file * ctl,
unsigned int cmd, void __user *arg)
{
struct snd_ctl_card_info *info __free(kfree) = NULL;
info = kzalloc(sizeof(*info), GFP_KERNEL);
if (! info)
return -ENOMEM;
scoped_guard(rwsem_read, &snd_ioctl_rwsem) {
info->card = card->number;
strscpy(info->id, card->id, sizeof(info->id));
strscpy(info->driver, card->driver, sizeof(info->driver));
strscpy(info->name, card->shortname, sizeof(info->name));
strscpy(info->longname, card->longname, sizeof(info->longname));
strscpy(info->mixername, card->mixername, sizeof(info->mixername));
strscpy(info->components, card->components, sizeof(info->components));
}
if (copy_to_user(arg, info, sizeof(struct snd_ctl_card_info)))
return -EFAULT;
return 0;
}
static int snd_ctl_elem_list(struct snd_card *card,
struct snd_ctl_elem_list *list)
{
struct snd_kcontrol *kctl;
struct snd_ctl_elem_id id;
unsigned int offset, space, jidx;
offset = list->offset;
space = list->space;
guard(rwsem_read)(&card->controls_rwsem);
list->count = card->controls_count;
list->used = 0;
if (!space)
return 0;
list_for_each_entry(kctl, &card->controls, list) {
if (offset >= kctl->count) {
offset -= kctl->count;
continue;
}
for (jidx = offset; jidx < kctl->count; jidx++) {
snd_ctl_build_ioff(&id, kctl, jidx);
if (copy_to_user(list->pids + list->used, &id, sizeof(id)))
return -EFAULT;
list->used++;
if (!--space)
return 0;
}
offset = 0;
}
return 0;
}
static int snd_ctl_elem_list_user(struct snd_card *card,
struct snd_ctl_elem_list __user *_list)
{
struct snd_ctl_elem_list list;
int err;
if (copy_from_user(&list, _list, sizeof(list)))
return -EFAULT;
err = snd_ctl_elem_list(card, &list);
if (err)
return err;
if (copy_to_user(_list, &list, sizeof(list)))
return -EFAULT;
return 0;
}
/* Check whether the given kctl info is valid */
static int snd_ctl_check_elem_info(struct snd_card *card,
const struct snd_ctl_elem_info *info)
{
static const unsigned int max_value_counts[] = {
[SNDRV_CTL_ELEM_TYPE_BOOLEAN] = 128,
[SNDRV_CTL_ELEM_TYPE_INTEGER] = 128,
[SNDRV_CTL_ELEM_TYPE_ENUMERATED] = 128,
[SNDRV_CTL_ELEM_TYPE_BYTES] = 512,
[SNDRV_CTL_ELEM_TYPE_IEC958] = 1,
[SNDRV_CTL_ELEM_TYPE_INTEGER64] = 64,
};
if (info->type < SNDRV_CTL_ELEM_TYPE_BOOLEAN ||
info->type > SNDRV_CTL_ELEM_TYPE_INTEGER64) {
if (card)
dev_err(card->dev,
"control %i:%i:%i:%s:%i: invalid type %d\n",
info->id.iface, info->id.device,
info->id.subdevice, info->id.name,
info->id.index, info->type);
return -EINVAL;
}
if (info->type == SNDRV_CTL_ELEM_TYPE_ENUMERATED &&
info->value.enumerated.items == 0) {
if (card)
dev_err(card->dev,
"control %i:%i:%i:%s:%i: zero enum items\n",
info->id.iface, info->id.device,