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[ALSA] dynamic minors (3/6): store device-specific object pointers dynamically

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Instead of storing the pointers to the device-specific structures in an
array, put them into the struct snd_minor, and look them up dynamically.

This makes the device type modules independent of the minor number
encoding.

Signed-off-by: Clemens Ladisch <clemens@ladisch.de>
This commit is contained in:
Clemens Ladisch
2005-11-20 14:06:59 +01:00
committed by Jaroslav Kysela
parent 6983b7240c
commit f87135f56c
17 changed files with 278 additions and 197 deletions
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46
sound/core/sound.c
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@@ -60,7 +60,6 @@ MODULE_ALIAS_CHARDEV_MAJOR(CONFIG_SND_MAJOR);
int snd_ecards_limit;
static struct snd_minor *snd_minors[SNDRV_OS_MINORS];
static DECLARE_MUTEX(sound_mutex);
extern struct class *sound_class;
@@ -107,6 +106,31 @@ static void snd_request_other(int minor)
#endif /* request_module support */
/**
* snd_lookup_minor_data - get user data of a registered device
* @minor: the minor number
* @type: device type (SNDRV_DEVICE_TYPE_XXX)
*
* Checks that a minor device with the specified type is registered, and returns
* its user data pointer.
*/
void *snd_lookup_minor_data(unsigned int minor, int type)
{
struct snd_minor *mreg;
void *private_data;
if (minor > ARRAY_SIZE(snd_minors))
return NULL;
down(&sound_mutex);
mreg = snd_minors[minor];
if (mreg && mreg->type == type)
private_data = mreg->private_data;
else
private_data = NULL;
up(&sound_mutex);
return private_data;
}
static int snd_open(struct inode *inode, struct file *file)
{
int minor = iminor(inode);
@@ -183,6 +207,7 @@ static int snd_kernel_minor(int type, struct snd_card *card, int dev)
* @card: the card instance
* @dev: the device index
* @f_ops: the file operations
* @private_data: user pointer for f_ops->open()
* @name: the device file name
*
* Registers an ALSA device file for the given card.
@@ -191,7 +216,8 @@ static int snd_kernel_minor(int type, struct snd_card *card, int dev)
* Retrurns zero if successful, or a negative error code on failure.
*/
int snd_register_device(int type, struct snd_card *card, int dev,
struct file_operations *f_ops, const char *name)
struct file_operations *f_ops, void *private_data,
const char *name)
{
int minor = snd_kernel_minor(type, card, dev);
struct snd_minor *preg;
@@ -207,6 +233,7 @@ int snd_register_device(int type, struct snd_card *card, int dev,
preg->card = card ? card->number : -1;
preg->device = dev;
preg->f_ops = f_ops;
preg->private_data = private_data;
strcpy(preg->name, name);
down(&sound_mutex);
if (snd_minors[minor]) {
@@ -238,13 +265,18 @@ int snd_register_device(int type, struct snd_card *card, int dev,
*/
int snd_unregister_device(int type, struct snd_card *card, int dev)
{
int minor = snd_kernel_minor(type, card, dev);
int cardnum, minor;
struct snd_minor *mptr;
if (minor < 0)
return minor;
cardnum = card ? card->number : -1;
down(&sound_mutex);
if ((mptr = snd_minors[minor]) == NULL) {
for (minor = 0; minor < ARRAY_SIZE(snd_minors); ++minor)
if ((mptr = snd_minors[minor]) != NULL &&
mptr->type == type &&
mptr->card == cardnum &&
mptr->device == dev)
break;
if (minor == ARRAY_SIZE(snd_minors)) {
up(&sound_mutex);
return -EINVAL;
}
@@ -392,9 +424,11 @@ EXPORT_SYMBOL(snd_request_card);
#endif
EXPORT_SYMBOL(snd_register_device);
EXPORT_SYMBOL(snd_unregister_device);
EXPORT_SYMBOL(snd_lookup_minor_data);
#if defined(CONFIG_SND_OSSEMUL)
EXPORT_SYMBOL(snd_register_oss_device);
EXPORT_SYMBOL(snd_unregister_oss_device);
EXPORT_SYMBOL(snd_lookup_oss_minor_data);
#endif
/* memory.c */
EXPORT_SYMBOL(copy_to_user_fromio);