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Commit 2225e79b authored by Takashi Sakamoto's avatar Takashi Sakamoto Committed by Takashi Iwai
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ALSA: core: reduce stack usage related to snd_ctl_new() 



The callers of snd_ctl_new() need to have 'struct snd_kcontrol' data,
and pass the data as template. Then, the function allocates the structure
data again and copy from the template. This is a waste of resources.
Especially, the callers use large stack for the template.

This commit removes a need of template for the function, thus, changes
the prototype of snd_ctl_new(). Furthermore, this commit changes
the code of callers, snd_ctl_new1() and snd_ctl_elem_add() for better
shape.

Signed-off-by: default avatarTakashi Sakamoto <o-takashi@sakamocchi.jp>
Signed-off-by: default avatarTakashi Iwai <tiwai@suse.de>
parent 4ed56666

sound/core/control.c

+130 −83
Original line number Diff line number Diff line
@@ -192,36 +192,43 @@ void snd_ctl_notify(struct snd_card *card, unsigned int mask, 
EXPORT_SYMBOL(snd_ctl_notify);



/**

 * snd_ctl_new - create a control instance from the template

 * @control: the control template

 * @access: the default control access

 * 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 new struct snd_kcontrol instance and copies the given template 

 * to the new instance. It does not copy volatile data (access).

 * 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: The pointer of the new instance, or %NULL on failure.

 * Return: 0 on success, error code on failure

 */

static struct snd_kcontrol *snd_ctl_new(struct snd_kcontrol *control,

					unsigned int access)

static int snd_ctl_new(struct snd_kcontrol **kctl, unsigned int count,

		       unsigned int access, struct snd_ctl_file *file)

{

	struct snd_kcontrol *kctl;

	unsigned int size;

	unsigned int idx;

	

	if (snd_BUG_ON(!control || !control->count))

		return NULL;

	if (count == 0 || count > MAX_CONTROL_COUNT)

		return -EINVAL;



	if (control->count > MAX_CONTROL_COUNT)

		return NULL;

	size  = sizeof(struct snd_kcontrol);

	size += sizeof(struct snd_kcontrol_volatile) * count;



	kctl = kzalloc(sizeof(*kctl) + sizeof(struct snd_kcontrol_volatile) * control->count, GFP_KERNEL);

	if (kctl == NULL) {

	*kctl = kzalloc(size, GFP_KERNEL);

	if (*kctl == NULL) {

		pr_err("ALSA: Cannot allocate control instance\n");

		return NULL;

		return -ENOMEM;

	}

	*kctl = *control;

	for (idx = 0; idx < kctl->count; idx++)

		kctl->vd[idx].access = access;

	return kctl;



	for (idx = 0; idx < count; idx++) {

		(*kctl)->vd[idx].access = access;

		(*kctl)->vd[idx].owner = file;

	}

	(*kctl)->count = count;



	return 0;

}



/**
@@ -238,37 +245,53 @@ static struct snd_kcontrol *snd_ctl_new(struct snd_kcontrol *control, 
struct snd_kcontrol *snd_ctl_new1(const struct snd_kcontrol_new *ncontrol,

				  void *private_data)

{

	struct snd_kcontrol kctl;

	struct snd_kcontrol *kctl;

	unsigned int count;

	unsigned int access;

	int err;

	

	if (snd_BUG_ON(!ncontrol || !ncontrol->info))

		return NULL;

	memset(&kctl, 0, sizeof(kctl));

	kctl.id.iface = ncontrol->iface;

	kctl.id.device = ncontrol->device;

	kctl.id.subdevice = ncontrol->subdevice;

	if (ncontrol->name) {

		strlcpy(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.count = ncontrol->count ? ncontrol->count : 1;

	access = ncontrol->access == 0 ? SNDRV_CTL_ELEM_ACCESS_READWRITE :

		 (ncontrol->access & (SNDRV_CTL_ELEM_ACCESS_READWRITE|



	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));

	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 snd_ctl_new(&kctl, access);

		   SNDRV_CTL_ELEM_ACCESS_TLV_CALLBACK);



	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) {

		strlcpy(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);
@@ -1179,44 +1202,48 @@ static int snd_ctl_elem_add(struct snd_ctl_file *file, 
		[SNDRV_CTL_ELEM_TYPE_INTEGER64] = 64,

	};

	struct snd_card *card = file->card;

	struct snd_kcontrol kctl, *_kctl;

	struct snd_kcontrol *kctl;

	unsigned int count;

	unsigned int access;

	long private_size;

	struct user_element *ue;

	int idx, err;



	access = info->access == 0 ? SNDRV_CTL_ELEM_ACCESS_READWRITE :

		(info->access & (SNDRV_CTL_ELEM_ACCESS_READWRITE|

				 SNDRV_CTL_ELEM_ACCESS_INACTIVE|

				 SNDRV_CTL_ELEM_ACCESS_TLV_READWRITE));

	info->id.numid = 0;

	memset(&kctl, 0, sizeof(kctl));

	int err;



	/* Delete a control to replace them if needed. */

	if (replace) {

		info->id.numid = 0;

		err = snd_ctl_remove_user_ctl(file, &info->id);

		if (err)

			return err;

	}



	if (card->user_ctl_count >= MAX_USER_CONTROLS)

	/*

	 * The number of userspace controls are counted control by control,

	 * not element by element.

	 */

	if (card->user_ctl_count + 1 > MAX_USER_CONTROLS)

		return -ENOMEM;



	memcpy(&kctl.id, &info->id, sizeof(info->id));

	kctl.count = info->owner ? info->owner : 1;

	access |= SNDRV_CTL_ELEM_ACCESS_USER;

	if (info->type == SNDRV_CTL_ELEM_TYPE_ENUMERATED)

		kctl.info = snd_ctl_elem_user_enum_info;

	else

		kctl.info = snd_ctl_elem_user_info;

	if (access & SNDRV_CTL_ELEM_ACCESS_READ)

		kctl.get = snd_ctl_elem_user_get;

	if (access & SNDRV_CTL_ELEM_ACCESS_WRITE)

		kctl.put = snd_ctl_elem_user_put;

	if (access & SNDRV_CTL_ELEM_ACCESS_TLV_READWRITE) {

		kctl.tlv.c = snd_ctl_elem_user_tlv;

	/* Check the number of elements for this userspace control. */

	count = info->owner;

	if (count == 0)

		count = 1;



	/* Arrange access permissions if needed. */

	access = info->access;

	if (access == 0)

		access = SNDRV_CTL_ELEM_ACCESS_READWRITE;

	access &= (SNDRV_CTL_ELEM_ACCESS_READWRITE |

		   SNDRV_CTL_ELEM_ACCESS_INACTIVE |

		   SNDRV_CTL_ELEM_ACCESS_TLV_READWRITE);

	if (access & SNDRV_CTL_ELEM_ACCESS_TLV_READWRITE)

		access |= SNDRV_CTL_ELEM_ACCESS_TLV_CALLBACK;

	}

	access |= SNDRV_CTL_ELEM_ACCESS_USER;



	/*

	 * Check information and calculate the size of data specific to

	 * this userspace control.

	 */

	if (info->type < SNDRV_CTL_ELEM_TYPE_BOOLEAN ||

	    info->type > SNDRV_CTL_ELEM_TYPE_INTEGER64)

		return -EINVAL;
@@ -1226,11 +1253,27 @@ static int snd_ctl_elem_add(struct snd_ctl_file *file, 
	if (info->count < 1 ||

	    info->count > max_value_counts[info->type])

		return -EINVAL;



	private_size = value_sizes[info->type] * info->count;

	ue = kzalloc(sizeof(struct user_element) + private_size, GFP_KERNEL);

	if (ue == NULL)



	/*

	 * Keep memory object for this userspace control. After passing this

	 * code block, the instance should be freed by snd_ctl_free_one().

	 *

	 * Note that these elements in this control are locked.

	 */

	err = snd_ctl_new(&kctl, count, access, file);

	if (err < 0)

		return err;

	kctl->private_data = kzalloc(sizeof(struct user_element) + private_size,

				     GFP_KERNEL);

	if (kctl->private_data == NULL) {

		kfree(kctl);

		return -ENOMEM;

	}

	kctl->private_free = snd_ctl_elem_user_free;



	/* Set private data for this userspace control. */

	ue = (struct user_element *)kctl->private_data;

	ue->card = card;

	ue->info = *info;

	ue->info.access = 0;
@@ -1239,21 +1282,25 @@ static int snd_ctl_elem_add(struct snd_ctl_file *file, 
	if (ue->info.type == SNDRV_CTL_ELEM_TYPE_ENUMERATED) {

		err = snd_ctl_elem_init_enum_names(ue);

		if (err < 0) {

			kfree(ue);

			snd_ctl_free_one(kctl);

			return err;

		}

	}

	kctl.private_free = snd_ctl_elem_user_free;

	_kctl = snd_ctl_new(&kctl, access);

	if (_kctl == NULL) {

		kfree(ue->priv_data);

		kfree(ue);

		return -ENOMEM;

	}

	_kctl->private_data = ue;

	for (idx = 0; idx < _kctl->count; idx++)

		_kctl->vd[idx].owner = file;

	err = snd_ctl_add(card, _kctl);



	/* Set callback functions. */

	if (info->type == SNDRV_CTL_ELEM_TYPE_ENUMERATED)

		kctl->info = snd_ctl_elem_user_enum_info;

	else

		kctl->info = snd_ctl_elem_user_info;

	if (access & SNDRV_CTL_ELEM_ACCESS_READ)

		kctl->get = snd_ctl_elem_user_get;

	if (access & SNDRV_CTL_ELEM_ACCESS_WRITE)

		kctl->put = snd_ctl_elem_user_put;

	if (access & SNDRV_CTL_ELEM_ACCESS_TLV_READWRITE)

		kctl->tlv.c = snd_ctl_elem_user_tlv;



	/* This function manage to free the instance on failure. */

	err = snd_ctl_add(card, kctl);

	if (err < 0)

		return err;