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Commit 450296f3 authored by Takashi Sakamoto's avatar Takashi Sakamoto Committed by Takashi Iwai
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ALSA: control: code refactoring TLV ioctl handler 



In a design of ALSA control core, execution path bifurcates depending on
target element. When a set with the target element has a handler, it's
called. Else, registered buffer is copied to user space. These two
operations are apparently different.  In current implementation, they're
on the same function with a condition statement. This makes it a bit hard
to understand conditions of each case.

This commit splits codes for these two cases.

Signed-off-by: default avatarTakashi Sakamoto <o-takashi@sakamocchi.jp>
Signed-off-by: default avatarTakashi Iwai <tiwai@suse.de>
parent 30d8340b

sound/core/control.c

+91 −41
Original line number Diff line number Diff line
@@ -1394,67 +1394,117 @@ static int snd_ctl_subscribe_events(struct snd_ctl_file *file, int __user *ptr) 
	return 0;

}



static int snd_ctl_tlv_ioctl(struct snd_ctl_file *file,

                             struct snd_ctl_tlv __user *_tlv,

                             int op_flag)

static int call_tlv_handler(struct snd_ctl_file *file, int op_flag,

			    struct snd_kcontrol *kctl,

			    struct snd_ctl_elem_id *id,

			    unsigned int __user *buf, unsigned int size)

{

	struct snd_card *card = file->card;

	struct snd_ctl_tlv tlv;

	struct snd_kcontrol *kctl;

	struct snd_kcontrol_volatile *vd;

	unsigned int len;



	if (copy_from_user(&tlv, _tlv, sizeof(tlv)))

		return -EFAULT;

	if (tlv.length < sizeof(unsigned int) * 2)

		return -EINVAL;

	if (!tlv.numid)

		return -EINVAL;



	kctl = snd_ctl_find_numid(card, tlv.numid);

	if (kctl == NULL)

		return -ENOENT;

	static const struct {

		int op;

		int perm;

	} pairs[] = {

		{SNDRV_CTL_TLV_OP_READ,  SNDRV_CTL_ELEM_ACCESS_TLV_READ},

		{SNDRV_CTL_TLV_OP_WRITE, SNDRV_CTL_ELEM_ACCESS_TLV_WRITE},

		{SNDRV_CTL_TLV_OP_CMD,   SNDRV_CTL_ELEM_ACCESS_TLV_COMMAND},

	};

	struct snd_kcontrol_volatile *vd = &kctl->vd[snd_ctl_get_ioff(kctl, id)];

	int i;

	int err;



	if (kctl->tlv.p == NULL)

	/* Check support of the request for this element. */

	for (i = 0; i < ARRAY_SIZE(pairs); ++i) {

		if (op_flag == pairs[i].op && (vd->access & pairs[i].perm))

			break;

	}

	if (i == ARRAY_SIZE(pairs))

		return -ENXIO;



	vd = &kctl->vd[tlv.numid - kctl->id.numid];

	if ((op_flag == SNDRV_CTL_TLV_OP_READ &&

	     (vd->access & SNDRV_CTL_ELEM_ACCESS_TLV_READ) == 0) ||

	    (op_flag == SNDRV_CTL_TLV_OP_WRITE &&

	     (vd->access & SNDRV_CTL_ELEM_ACCESS_TLV_WRITE) == 0) ||

	    (op_flag == SNDRV_CTL_TLV_OP_CMD &&

	     (vd->access & SNDRV_CTL_ELEM_ACCESS_TLV_COMMAND) == 0))

	if (kctl->tlv.c == NULL)

		return -ENXIO;



	if (vd->access & SNDRV_CTL_ELEM_ACCESS_TLV_CALLBACK) {

		int err;



	/* When locked, this is unavailable. */

	if (vd->owner != NULL && vd->owner != file)

		return -EPERM;



		err = kctl->tlv.c(kctl, op_flag, tlv.length, _tlv->tlv);

	err = kctl->tlv.c(kctl, op_flag, size, buf);

	if (err < 0)

		return err;

		if (err > 0) {

			struct snd_ctl_elem_id id = kctl->id;

			snd_ctl_notify(card, SNDRV_CTL_EVENT_MASK_TLV, &id);



	if (err > 0)

		snd_ctl_notify(file->card, SNDRV_CTL_EVENT_MASK_TLV, id);



	return 0;

}

	} else {

		if (op_flag != SNDRV_CTL_TLV_OP_READ)



static int read_tlv_buf(struct snd_kcontrol *kctl, struct snd_ctl_elem_id *id,

			unsigned int __user *buf, unsigned int size)

{

	struct snd_kcontrol_volatile *vd = &kctl->vd[snd_ctl_get_ioff(kctl, id)];

	unsigned int len;



	if (!(vd->access & SNDRV_CTL_ELEM_ACCESS_TLV_READ))

		return -ENXIO;



		len = kctl->tlv.p[1] + 2 * sizeof(unsigned int);

		if (tlv.length < len)

	if (kctl->tlv.p == NULL)

		return -ENXIO;



	len = sizeof(unsigned int) * 2 + kctl->tlv.p[1];

	if (size < len)

		return -ENOMEM;



		if (copy_to_user(_tlv->tlv, kctl->tlv.p, len))

	if (copy_to_user(buf, kctl->tlv.p, len))

		return -EFAULT;

	}



	return 0;

}



static int snd_ctl_tlv_ioctl(struct snd_ctl_file *file,

			     struct snd_ctl_tlv __user *buf,

                             int op_flag)

{

	struct snd_ctl_tlv header;

	unsigned int *container;

	unsigned int container_size;

	struct snd_kcontrol *kctl;

	struct snd_ctl_elem_id id;

	struct snd_kcontrol_volatile *vd;



	if (copy_from_user(&header, buf, sizeof(header)))

		return -EFAULT;



	/* In design of control core, numerical ID starts at 1. */

	if (header.numid == 0)

		return -EINVAL;



	/* At least, container should include type and length fields.  */

	if (header.length < sizeof(unsigned int) * 2)

		return -EINVAL;

	container_size = header.length;

	container = buf->tlv;



	kctl = snd_ctl_find_numid(file->card, header.numid);

	if (kctl == NULL)

		return -ENOENT;



	/* Calculate index of the element in this set. */

	id = kctl->id;

	snd_ctl_build_ioff(&id, kctl, header.numid - id.numid);

	vd = &kctl->vd[snd_ctl_get_ioff(kctl, &id)];



	if (vd->access & SNDRV_CTL_ELEM_ACCESS_TLV_CALLBACK) {

		return call_tlv_handler(file, op_flag, kctl, &id, container,

					container_size);

	} else {

		if (op_flag == SNDRV_CTL_TLV_OP_READ) {

			return read_tlv_buf(kctl, &id, container,

					    container_size);

		}

	}



	/* Not supported. */

	return -ENXIO;

}



static long snd_ctl_ioctl(struct file *file, unsigned int cmd, unsigned long arg)

{

	struct snd_ctl_file *ctl;