[ALSA] dynamic minors (2/6): simplify storage of snd_minor structures

Modules: ALSA Core

Store the snd_minor structure pointers in one array instead of using a
separate list for each card.  This simplifies the mapping from device
files to minor struct by removing the need to know about the encoding
of the card number in the minor number.
Signed-off-by: NClemens Ladisch <clemens@ladisch.de>

include/sound/core.h

@@ -183,9 +183,8 @@ static inline int snd_power_wait(struct snd_card *card, unsigned int state, stru
 #endif /* CONFIG_PM */
 
 struct snd_minor {
-	struct list_head list;		/* list of all minors per card */
-	int number;			/* minor number */
 	int type;			/* SNDRV_DEVICE_TYPE_XXX */
+	int card;			/* card number */
 	int device;			/* device number */
 	struct file_operations *f_ops;	/* file operations */
 	char name[0];			/* device name (keep at the end of
@@ -217,11 +216,9 @@ int snd_minor_info_done(void);
 #ifdef CONFIG_SND_OSSEMUL
 int snd_minor_info_oss_init(void);
 int snd_minor_info_oss_done(void);
-int snd_oss_init_module(void);
 #else
 #define snd_minor_info_oss_init() /*NOP*/
 #define snd_minor_info_oss_done() /*NOP*/
-#define snd_oss_init_module() 0
 #endif
 
 /* memory.c */

sound/core/sound.c

@@ -59,7 +59,7 @@ MODULE_ALIAS_CHARDEV_MAJOR(CONFIG_SND_MAJOR);
  */
 int snd_ecards_limit;
 
-static struct list_head snd_minors_hash[SNDRV_CARDS];
+static struct snd_minor *snd_minors[SNDRV_OS_MINORS];
 
 static DECLARE_MUTEX(sound_mutex);
 
@@ -107,19 +107,6 @@ static void snd_request_other(int minor)
 
 #endif				/* request_module support */
 
-static struct snd_minor *snd_minor_search(int minor)
-{
-	struct list_head *list;
-	struct snd_minor *mptr;
-
-	list_for_each(list, &snd_minors_hash[SNDRV_MINOR_CARD(minor)]) {
-		mptr = list_entry(list, struct snd_minor, list);
-		if (mptr->number == minor)
-			return mptr;
-	}
-	return NULL;
-}
-
 static int snd_open(struct inode *inode, struct file *file)
 {
 	int minor = iminor(inode);
@@ -139,11 +126,11 @@ static int snd_open(struct inode *inode, struct file *file)
 		}
 	} else {
 #ifdef CONFIG_KMOD
-		if ((mptr = snd_minor_search(minor)) == NULL)
+		if ((mptr = snd_minors[minor]) == NULL)
 			snd_request_other(minor);
 #endif
 	}
-	if (mptr == NULL && (mptr = snd_minor_search(minor)) == NULL)
+	if (mptr == NULL && (mptr = snd_minors[minor]) == NULL)
 		return -ENODEV;
 	old_fops = file->f_op;
 	file->f_op = fops_get(mptr->f_ops);
@@ -213,22 +200,22 @@ int snd_register_device(int type, struct snd_card *card, int dev,
 	if (minor < 0)
 		return minor;
 	snd_assert(name, return -EINVAL);
-	preg = kzalloc(sizeof(struct snd_minor) + strlen(name) + 1, GFP_KERNEL);
+	preg = kmalloc(sizeof(struct snd_minor) + strlen(name) + 1, GFP_KERNEL);
 	if (preg == NULL)
 		return -ENOMEM;
-	preg->number = minor;
 	preg->type = type;
+	preg->card = card ? card->number : -1;
 	preg->device = dev;
 	preg->f_ops = f_ops;
 	strcpy(preg->name, name);
 	down(&sound_mutex);
-	if (snd_minor_search(minor)) {
+	if (snd_minors[minor]) {
 		up(&sound_mutex);
 		kfree(preg);
 		return -EBUSY;
 	}
-	list_add_tail(&preg->list, &snd_minors_hash[SNDRV_MINOR_CARD(minor)]);
-	if (strncmp(name, "controlC", 8) || card->number >= cards_limit)
+	snd_minors[minor] = preg;
+	if (type != SNDRV_DEVICE_TYPE_CONTROL || preg->card >= cards_limit)
 		devfs_mk_cdev(MKDEV(major, minor), S_IFCHR | device_mode, "snd/%s", name);
 	if (card)
 		device = card->dev;
@@ -257,16 +244,17 @@ int snd_unregister_device(int type, struct snd_card *card, int dev)
 	if (minor < 0)
 		return minor;
 	down(&sound_mutex);
-	if ((mptr = snd_minor_search(minor)) == NULL) {
+	if ((mptr = snd_minors[minor]) == NULL) {
 		up(&sound_mutex);
 		return -EINVAL;
 	}
 
-	if (strncmp(mptr->name, "controlC", 8) || card->number >= cards_limit) /* created in sound.c */
+	if (mptr->type != SNDRV_DEVICE_TYPE_CONTROL ||
+	    mptr->card >= cards_limit)			/* created in sound.c */
 		devfs_remove("snd/%s", mptr->name);
 	class_device_destroy(sound_class, MKDEV(major, minor));
 
-	list_del(&mptr->list);
+	snd_minors[minor] = NULL;
 	up(&sound_mutex);
 	kfree(mptr);
 	return 0;
@@ -302,23 +290,25 @@ static const char *snd_device_type_name(int type)
 
 static void snd_minor_info_read(struct snd_info_entry *entry, struct snd_info_buffer *buffer)
 {
-	int card, device;
-	struct list_head *list;
+	int minor;
 	struct snd_minor *mptr;
 
 	down(&sound_mutex);
-	for (card = 0; card < SNDRV_CARDS; card++) {
-		list_for_each(list, &snd_minors_hash[card]) {
-			mptr = list_entry(list, struct snd_minor, list);
-			if (SNDRV_MINOR_DEVICE(mptr->number) != SNDRV_MINOR_GLOBAL) {
-				if ((device = mptr->device) >= 0)
-					snd_iprintf(buffer, "%3i: [%i-%2i]: %s\n", mptr->number, card, device, snd_device_type_name(mptr->type));
+	for (minor = 0; minor < SNDRV_OS_MINORS; ++minor) {
+		if (!(mptr = snd_minors[minor]))
+			continue;
+		if (mptr->card >= 0) {
+			if (mptr->device >= 0)
+				snd_iprintf(buffer, "%3i: [%i-%2i]: %s\n",
+					    minor, mptr->card, mptr->device,
+					    snd_device_type_name(mptr->type));
 			else
-					snd_iprintf(buffer, "%3i: [%i]   : %s\n", mptr->number, card, snd_device_type_name(mptr->type));
-			} else {
-				snd_iprintf(buffer, "%3i:       : %s\n", mptr->number, snd_device_type_name(mptr->type));
-			}
-		}
+				snd_iprintf(buffer, "%3i: [%i]   : %s\n",
+					    minor, mptr->card,
+					    snd_device_type_name(mptr->type));
+		} else
+			snd_iprintf(buffer, "%3i:       : %s\n", minor,
+				    snd_device_type_name(mptr->type));
 	}
 	up(&sound_mutex);
 }
@@ -354,15 +344,9 @@ int __exit snd_minor_info_done(void)
 static int __init alsa_sound_init(void)
 {
 	short controlnum;
-	int err;
-	int card;
 
 	snd_major = major;
 	snd_ecards_limit = cards_limit;
-	for (card = 0; card < SNDRV_CARDS; card++)
-		INIT_LIST_HEAD(&snd_minors_hash[card]);
-	if ((err = snd_oss_init_module()) < 0)
-		return err;
 	devfs_mk_dir("snd");
 	if (register_chrdev(major, "alsa", &snd_fops)) {
 		snd_printk(KERN_ERR "unable to register native major device number %d\n", major);

sound/core/sound_oss.c

@@ -35,25 +35,12 @@
 #include <sound/info.h>
 #include <linux/sound.h>
 
-#define SNDRV_OS_MINORS		256
+#define SNDRV_OSS_MINORS 128
 
-static struct list_head snd_oss_minors_hash[SNDRV_CARDS];
+static struct snd_minor *snd_oss_minors[SNDRV_OSS_MINORS];
 
 static DECLARE_MUTEX(sound_oss_mutex);
 
-static struct snd_minor *snd_oss_minor_search(int minor)
-{
-	struct list_head *list;
-	struct snd_minor *mptr;
-
-	list_for_each(list, &snd_oss_minors_hash[SNDRV_MINOR_OSS_CARD(minor)]) {
-		mptr = list_entry(list, struct snd_minor, list);
-		if (mptr->number == minor)
-			return mptr;
-	}
-	return NULL;
-}
-
 static int snd_oss_kernel_minor(int type, struct snd_card *card, int dev)
 {
 	int minor;
@@ -86,7 +73,7 @@ static int snd_oss_kernel_minor(int type, struct snd_card *card, int dev)
 	default:
 		return -EINVAL;
 	}
-	snd_assert(minor >= 0 && minor < SNDRV_OS_MINORS, return -EINVAL);
+	snd_assert(minor >= 0 && minor < SNDRV_OSS_MINORS, return -EINVAL);
 	return minor;
 }
 
@@ -103,15 +90,15 @@ int snd_register_oss_device(int type, struct snd_card *card, int dev,
 
 	if (minor < 0)
 		return minor;
-	preg = kzalloc(sizeof(struct snd_minor), GFP_KERNEL);
+	preg = kmalloc(sizeof(struct snd_minor), GFP_KERNEL);
 	if (preg == NULL)
 		return -ENOMEM;
-	preg->number = minor;
 	preg->type = type;
+	preg->card = card ? card->number : -1;
 	preg->device = dev;
 	preg->f_ops = f_ops;
 	down(&sound_oss_mutex);
-	list_add_tail(&preg->list, &snd_oss_minors_hash[cidx]);
+	snd_oss_minors[minor] = preg;
 	minor_unit = SNDRV_MINOR_OSS_DEVICE(minor);
 	switch (minor_unit) {
 	case SNDRV_MINOR_OSS_PCM:
@@ -143,7 +130,7 @@ int snd_register_oss_device(int type, struct snd_card *card, int dev,
       		unregister_sound_special(register2);
       	if (register1 >= 0)
       		unregister_sound_special(register1);
-      	list_del(&preg->list);
+	snd_oss_minors[minor] = NULL;
 	up(&sound_oss_mutex);
 	kfree(preg);
       	return -EBUSY;
@@ -159,7 +146,7 @@ int snd_unregister_oss_device(int type, struct snd_card *card, int dev)
 	if (minor < 0)
 		return minor;
 	down(&sound_oss_mutex);
-	mptr = snd_oss_minor_search(minor);
+	mptr = snd_oss_minors[minor];
 	if (mptr == NULL) {
 		up(&sound_oss_mutex);
 		return -ENOENT;
@@ -178,7 +165,7 @@ int snd_unregister_oss_device(int type, struct snd_card *card, int dev)
 	}
 	if (track2 >= 0)
 		unregister_sound_special(track2);
-	list_del(&mptr->list);
+	snd_oss_minors[minor] = NULL;
 	up(&sound_oss_mutex);
 	kfree(mptr);
 	return 0;
@@ -214,22 +201,20 @@ static const char *snd_oss_device_type_name(int type)
 static void snd_minor_info_oss_read(struct snd_info_entry *entry,
 				    struct snd_info_buffer *buffer)
 {
-	int card, dev;
-	struct list_head *list;
+	int minor;
 	struct snd_minor *mptr;
 
 	down(&sound_oss_mutex);
-	for (card = 0; card < SNDRV_CARDS; card++) {
-		list_for_each(list, &snd_oss_minors_hash[card]) {
-			mptr = list_entry(list, struct snd_minor, list);
-			dev = SNDRV_MINOR_OSS_DEVICE(mptr->number);
-		        if (dev != SNDRV_MINOR_OSS_SNDSTAT &&
-			    dev != SNDRV_MINOR_OSS_SEQUENCER &&
-			    dev != SNDRV_MINOR_OSS_MUSIC)
-				snd_iprintf(buffer, "%3i: [%i-%2i]: %s\n", mptr->number, card, dev, snd_oss_device_type_name(mptr->type));
+	for (minor = 0; minor < SNDRV_OSS_MINORS; ++minor) {
+		if (!(mptr = snd_oss_minors[minor]))
+			continue;
+		if (mptr->card >= 0)
+			snd_iprintf(buffer, "%3i: [%i-%2i]: %s\n", minor,
+				    mptr->card, mptr->device,
+				    snd_oss_device_type_name(mptr->type));
 		else
-				snd_iprintf(buffer, "%3i:       : %s\n", mptr->number, snd_oss_device_type_name(mptr->type));
-		}
+			snd_iprintf(buffer, "%3i:       : %s\n", minor,
+				    snd_oss_device_type_name(mptr->type));
 	}
 	up(&sound_oss_mutex);
 }
@@ -264,13 +249,4 @@ int __exit snd_minor_info_oss_done(void)
 	return 0;
 }
 
-int __init snd_oss_init_module(void)
-{
-	int card;
-	
-	for (card = 0; card < SNDRV_CARDS; card++)
-		INIT_LIST_HEAD(&snd_oss_minors_hash[card]);
-	return 0;
-}
-
 #endif /* CONFIG_SND_OSSEMUL */