Commit 332682b1 authored by Clemens Ladisch's avatar Clemens Ladisch Committed by Jaroslav Kysela
Browse files

[ALSA] dynamic minors (4/6): dynamic minor number allocation 



Modules: ALSA Core,ALSA Minor Numbers

Add an option to allocate device file minor numbers dynamically.

Signed-off-by: default avatarClemens Ladisch <clemens@ladisch.de>
parent f87135f5

include/sound/minors.h

+25 −4
Original line number Original line Diff line number Diff line
@@ -26,18 +26,20 @@ 
#define SNDRV_MINOR_DEVICE(minor)	((minor) & 0x001f)

#define SNDRV_MINOR_DEVICE(minor)	((minor) & 0x001f)

#define SNDRV_MINOR(card, dev)		(((card) << 5) | (dev))

#define SNDRV_MINOR(card, dev)		(((card) << 5) | (dev))





#define SNDRV_MINOR_CONTROL		0	/* 0 - 0 */

/* these minors can still be used for autoloading devices (/dev/aload*) */

#define SNDRV_MINOR_CONTROL		0	/* 0 */

#define SNDRV_MINOR_GLOBAL		1	/* 1 */

#define SNDRV_MINOR_GLOBAL		1	/* 1 */

#define SNDRV_MINOR_SEQUENCER		(SNDRV_MINOR_GLOBAL + 0 * 32)

#define SNDRV_MINOR_SEQUENCER		(SNDRV_MINOR_GLOBAL + 0 * 32)

#define SNDRV_MINOR_TIMER		(SNDRV_MINOR_GLOBAL + 1 * 32)

#define SNDRV_MINOR_TIMER		(SNDRV_MINOR_GLOBAL + 1 * 32)



#ifndef CONFIG_SND_DYNAMIC_MINORS

						/* 2 - 3 (reserved) */

#define SNDRV_MINOR_HWDEP		4	/* 4 - 7 */

#define SNDRV_MINOR_HWDEP		4	/* 4 - 7 */

#define SNDRV_MINOR_HWDEPS		4

#define SNDRV_MINOR_RAWMIDI		8	/* 8 - 15 */

#define SNDRV_MINOR_RAWMIDI		8	/* 8 - 15 */

#define SNDRV_MINOR_RAWMIDIS		8

#define SNDRV_MINOR_PCM_PLAYBACK	16	/* 16 - 23 */

#define SNDRV_MINOR_PCM_PLAYBACK	16	/* 16 - 23 */

#define SNDRV_MINOR_PCM_CAPTURE		24	/* 24 - 31 */

#define SNDRV_MINOR_PCM_CAPTURE		24	/* 24 - 31 */

#define SNDRV_MINOR_PCMS		8





/* same as first respective minor number to make minor allocation easier */

#define SNDRV_DEVICE_TYPE_CONTROL	SNDRV_MINOR_CONTROL

#define SNDRV_DEVICE_TYPE_CONTROL	SNDRV_MINOR_CONTROL

#define SNDRV_DEVICE_TYPE_HWDEP		SNDRV_MINOR_HWDEP

#define SNDRV_DEVICE_TYPE_HWDEP		SNDRV_MINOR_HWDEP

#define SNDRV_DEVICE_TYPE_RAWMIDI	SNDRV_MINOR_RAWMIDI

#define SNDRV_DEVICE_TYPE_RAWMIDI	SNDRV_MINOR_RAWMIDI
@@ -46,6 +48,25 @@ 
#define SNDRV_DEVICE_TYPE_SEQUENCER	SNDRV_MINOR_SEQUENCER

#define SNDRV_DEVICE_TYPE_SEQUENCER	SNDRV_MINOR_SEQUENCER

#define SNDRV_DEVICE_TYPE_TIMER		SNDRV_MINOR_TIMER

#define SNDRV_DEVICE_TYPE_TIMER		SNDRV_MINOR_TIMER





#else /* CONFIG_SND_DYNAMIC_MINORS */



enum {

	SNDRV_DEVICE_TYPE_CONTROL,

	SNDRV_DEVICE_TYPE_SEQUENCER,

	SNDRV_DEVICE_TYPE_TIMER,

	SNDRV_DEVICE_TYPE_HWDEP,

	SNDRV_DEVICE_TYPE_RAWMIDI,

	SNDRV_DEVICE_TYPE_PCM_PLAYBACK,

	SNDRV_DEVICE_TYPE_PCM_CAPTURE,

};



#endif /* CONFIG_SND_DYNAMIC_MINORS */



#define SNDRV_MINOR_HWDEPS		4

#define SNDRV_MINOR_RAWMIDIS		8

#define SNDRV_MINOR_PCMS		8





#ifdef CONFIG_SND_OSSEMUL

#ifdef CONFIG_SND_OSSEMUL





#define SNDRV_MINOR_OSS_DEVICES		16

#define SNDRV_MINOR_OSS_DEVICES		16

sound/core/Kconfig

+11 −0
Original line number Original line Diff line number Diff line
@@ -111,6 +111,17 @@ config SND_SEQ_RTCTIMER_DEFAULT 




	  If in doubt, say Y.

	  If in doubt, say Y.





config SND_DYNAMIC_MINORS

	bool "Dynamic device file minor numbers (EXPERIMENTAL)"

	depends on SND && EXPERIMENTAL

	help

	  If you say Y here, the minor numbers of ALSA device files in

	  /dev/snd/ are allocated dynamically.  This allows you to have

	  more than 8 sound cards, but requires a dynamic device file

	  system like udev.



	  If you are unsure about this, say N here.



config SND_VERBOSE_PRINTK

config SND_VERBOSE_PRINTK

	bool "Verbose printk"

	bool "Verbose printk"

	depends on SND

	depends on SND

sound/core/sound.c

+46 −19
Original line number Original line Diff line number Diff line
@@ -133,29 +133,34 @@ void *snd_lookup_minor_data(unsigned int minor, int type) 




static int snd_open(struct inode *inode, struct file *file)

static int snd_open(struct inode *inode, struct file *file)

{

{

	int minor = iminor(inode);

	unsigned int minor = iminor(inode);

	int card = SNDRV_MINOR_CARD(minor);

	int dev = SNDRV_MINOR_DEVICE(minor);

	struct snd_minor *mptr = NULL;

	struct snd_minor *mptr = NULL;

	struct file_operations *old_fops;

	struct file_operations *old_fops;

	int err = 0;

	int err = 0;





	if (dev != SNDRV_MINOR_GLOBAL) {

	if (minor > ARRAY_SIZE(snd_minors))

		if (snd_cards[card] == NULL) {

#ifdef CONFIG_KMOD

			snd_request_card(card);

			if (snd_cards[card] == NULL)

#endif

		return -ENODEV;

		return -ENODEV;

		}

	mptr = snd_minors[minor];

	} else {

	if (mptr == NULL) {

#ifdef CONFIG_KMOD

#ifdef CONFIG_KMOD

		if ((mptr = snd_minors[minor]) == NULL)

		int dev = SNDRV_MINOR_DEVICE(minor);

		if (dev == SNDRV_MINOR_CONTROL) {

			/* /dev/aloadC? */

			int card = SNDRV_MINOR_CARD(minor);

			if (snd_cards[card] == NULL)

				snd_request_card(card);

		} else if (dev == SNDRV_MINOR_GLOBAL) {

			/* /dev/aloadSEQ */

			snd_request_other(minor);

			snd_request_other(minor);

#endif

		}

		}

	if (mptr == NULL && (mptr = snd_minors[minor]) == NULL)

#ifndef CONFIG_SND_DYNAMIC_MINORS

		/* /dev/snd/{controlC?,seq} */

		mptr = snd_minors[minor];

		if (mptr == NULL)

#endif

#endif

			return -ENODEV;

			return -ENODEV;

	}

	old_fops = file->f_op;

	old_fops = file->f_op;

	file->f_op = fops_get(mptr->f_ops);

	file->f_op = fops_get(mptr->f_ops);

	if (file->f_op->open)

	if (file->f_op->open)
@@ -174,6 +179,22 @@ static struct file_operations snd_fops = 
	.open =		snd_open

	.open =		snd_open

};

};





#ifdef CONFIG_SND_DYNAMIC_MINORS

static int snd_find_free_minor(void)

{

	int minor;



	for (minor = 0; minor < ARRAY_SIZE(snd_minors); ++minor) {

		/* skip minors still used statically for autoloading devices */

		if (SNDRV_MINOR_DEVICE(minor) == SNDRV_MINOR_CONTROL ||

		    minor == SNDRV_MINOR_SEQUENCER)

			continue;

		if (!snd_minors[minor])

			return minor;

	}

	return -EBUSY;

}

#else

static int snd_kernel_minor(int type, struct snd_card *card, int dev)

static int snd_kernel_minor(int type, struct snd_card *card, int dev)

{

{

	int minor;

	int minor;
@@ -200,6 +221,7 @@ static int snd_kernel_minor(int type, struct snd_card *card, int dev) 
	snd_assert(minor >= 0 && minor < SNDRV_OS_MINORS, return -EINVAL);

	snd_assert(minor >= 0 && minor < SNDRV_OS_MINORS, return -EINVAL);

	return minor;

	return minor;

}

}

#endif





/**

/**

 * snd_register_device - Register the ALSA device file for the card

 * snd_register_device - Register the ALSA device file for the card
@@ -219,12 +241,10 @@ int snd_register_device(int type, struct snd_card *card, int dev, 
			struct file_operations *f_ops, void *private_data,

			struct file_operations *f_ops, void *private_data,

			const char *name)

			const char *name)

{

{

	int minor = snd_kernel_minor(type, card, dev);

	int minor;

	struct snd_minor *preg;

	struct snd_minor *preg;

	struct device *device = NULL;

	struct device *device = NULL;





	if (minor < 0)

		return minor;

	snd_assert(name, return -EINVAL);

	snd_assert(name, return -EINVAL);

	preg = kmalloc(sizeof(struct snd_minor) + strlen(name) + 1, GFP_KERNEL);

	preg = kmalloc(sizeof(struct snd_minor) + strlen(name) + 1, GFP_KERNEL);

	if (preg == NULL)

	if (preg == NULL)
@@ -236,10 +256,17 @@ int snd_register_device(int type, struct snd_card *card, int dev, 
	preg->private_data = private_data;

	preg->private_data = private_data;

	strcpy(preg->name, name);

	strcpy(preg->name, name);

	down(&sound_mutex);

	down(&sound_mutex);

	if (snd_minors[minor]) {

#ifdef CONFIG_SND_DYNAMIC_MINORS

	minor = snd_find_free_minor();

#else

	minor = snd_kernel_minor(type, card, dev);

	if (minor >= 0 && snd_minors[minor])

		minor = -EBUSY;

#endif

	if (minor < 0) {

		up(&sound_mutex);

		up(&sound_mutex);

		kfree(preg);

		kfree(preg);

		return -EBUSY;

		return minor;

	}

	}

	snd_minors[minor] = preg;

	snd_minors[minor] = preg;

	if (type != SNDRV_DEVICE_TYPE_CONTROL || preg->card >= cards_limit)

	if (type != SNDRV_DEVICE_TYPE_CONTROL || preg->card >= cards_limit)