[ALSA] dynamic minors (4/6): dynamic minor number allocation (332682b1) · Commits · 戴 / test

include/sound/minors.h

+25 −4

Original line number	Diff line number	Diff line
		@@ -26,18 +26,20 @@
		#define SNDRV_MINOR_DEVICE(minor) ((minor) & 0x001f)
		#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_SEQUENCER (SNDRV_MINOR_GLOBAL + 0 * 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_HWDEPS 4
		#define SNDRV_MINOR_RAWMIDI 8 /* 8 - 15 */
		#define SNDRV_MINOR_RAWMIDIS 8
		#define SNDRV_MINOR_PCM_PLAYBACK 16 /* 16 - 23 */
		#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_HWDEP SNDRV_MINOR_HWDEP
		#define SNDRV_DEVICE_TYPE_RAWMIDI SNDRV_MINOR_RAWMIDI
		@@ -46,6 +48,25 @@
		#define SNDRV_DEVICE_TYPE_SEQUENCER SNDRV_MINOR_SEQUENCER
		#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

		#define SNDRV_MINOR_OSS_DEVICES 16

sound/core/Kconfig

+11 −0

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

		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
		bool "Verbose printk"
		depends on SND

sound/core/sound.c

+46 −19

Original line number	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)
		{
		int minor = iminor(inode);
		int card = SNDRV_MINOR_CARD(minor);
		int dev = SNDRV_MINOR_DEVICE(minor);
		unsigned int minor = iminor(inode);
		struct snd_minor *mptr = NULL;
		struct file_operations *old_fops;
		int err = 0;

		if (dev != SNDRV_MINOR_GLOBAL) {
		if (snd_cards[card] == NULL) {
		#ifdef CONFIG_KMOD
		snd_request_card(card);
		if (snd_cards[card] == NULL)
		#endif
		if (minor > ARRAY_SIZE(snd_minors))
		return -ENODEV;
		}
		} else {
		mptr = snd_minors[minor];
		if (mptr == NULL) {
		#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);
		#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;
		}
		old_fops = file->f_op;
		file->f_op = fops_get(mptr->f_ops);
		if (file->f_op->open)
		@@ -174,6 +179,22 @@ static struct file_operations snd_fops =
		.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)
		{
		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);
		return minor;
		}
		#endif

		/**
		* 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,
		const char *name)
		{
		int minor = snd_kernel_minor(type, card, dev);
		int minor;
		struct snd_minor *preg;
		struct device *device = NULL;

		if (minor < 0)
		return minor;
		snd_assert(name, return -EINVAL);
		preg = kmalloc(sizeof(struct snd_minor) + strlen(name) + 1, GFP_KERNEL);
		if (preg == NULL)
		@@ -236,10 +256,17 @@ int snd_register_device(int type, struct snd_card *card, int dev,
		preg->private_data = private_data;
		strcpy(preg->name, name);
		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);
		kfree(preg);
		return -EBUSY;
		return minor;
		}
		snd_minors[minor] = preg;
		if (type != SNDRV_DEVICE_TYPE_CONTROL \|\| preg->card >= cards_limit)

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