[ALSA] dynamic minors (3/6): store device-specific object pointers dynamically
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>
diff --git a/sound/core/sound.c b/sound/core/sound.c
index a509f49..1e5eca5 100644
--- a/sound/core/sound.c
+++ b/sound/core/sound.c
@@ -60,7 +60,6 @@
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 @@
#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 @@
* @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 @@
* 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 @@
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_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 @@
#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);