[PATCH 19/20] ALSA: Use priority list for managing device list

[Takashi Iwai <tiwai@suse.de>]

Basically, the device type specifies the priority of the device to be
registered / freed, too.  However, the priority value isn't well
utilized but only it's checked as a group.  This results in
inconsistent register and free order (where each of them should be in
reversed direction).

This patch simplifies the device list management code by simply
inserting a list entry at creation time in an incremental order for
the priority value.  Since we can just follow the link for register,
disconnect and free calls, we don't have to specify the group; so the
whole enum definitions are also simplified as well.

The visible change to outside is that now the SNDRV_DEV_CARD object is
registered before others (control, PCM, etc) and, in return, released
after others.  The priority of some components
(e.g. SNDRV_DEV_COMPRESS) are also adjusted as well.

Also, the unused SNDRV_DEV_TOPLEVEL, SNDRV_DEV_LOWLEVEL_PRE and
SNDRV_DEV_LOWLEVEL_NORMAL are removed as a cleanup.

Signed-off-by: Takashi Iwai <tiwai@suse.de>
---
 include/sound/core.h | 28 ++++++++--------------
 sound/core/device.c  | 66 +++++++++++++++++++++++++++++-----------------------
 sound/core/init.c    | 14 +++--------
 3 files changed, 50 insertions(+), 58 deletions(-)

diff --git a/include/sound/core.h b/include/sound/core.h
index 127b908a2422..07a7ab9a49bf 100644
--- a/include/sound/core.h
+++ b/include/sound/core.h
@@ -46,25 +46,23 @@ struct device_attribute;
 
 /* device allocation stuff */
 
-#define SNDRV_DEV_TYPE_RANGE_SIZE		0x1000
-
+/* type of the object used in snd_device_*()
+ * this also defines the calling order
+ */
 enum snd_device_type {
-	SNDRV_DEV_TOPLEVEL	= 0,
-	SNDRV_DEV_CONTROL	= 1,
-	SNDRV_DEV_LOWLEVEL_PRE	= 2,
-	SNDRV_DEV_LOWLEVEL_NORMAL = 0x1000,
+	SNDRV_DEV_CARD,
+	SNDRV_DEV_BUS,
+	SNDRV_DEV_CODEC,
+	SNDRV_DEV_CONTROL,
 	SNDRV_DEV_PCM,
+	SNDRV_DEV_COMPRESS,
 	SNDRV_DEV_RAWMIDI,
 	SNDRV_DEV_TIMER,
 	SNDRV_DEV_SEQUENCER,
 	SNDRV_DEV_HWDEP,
 	SNDRV_DEV_INFO,
-	SNDRV_DEV_BUS,
-	SNDRV_DEV_CODEC,
 	SNDRV_DEV_JACK,
-	SNDRV_DEV_COMPRESS,
-	SNDRV_DEV_LOWLEVEL	= 0x2000,
-	SNDRV_DEV_CARD = SNDRV_DEV_LOWLEVEL,
+	SNDRV_DEV_LOWLEVEL,
 };
 
 enum snd_device_state {
@@ -73,12 +71,6 @@ enum snd_device_state {
 	SNDRV_DEV_DISCONNECTED,
 };
 
-enum snd_device_cmd {
-	SNDRV_DEV_CMD_PRE,
-	SNDRV_DEV_CMD_NORMAL,
-	SNDRV_DEV_CMD_POST,
-};
-
 struct snd_device;
 
 struct snd_device_ops {
@@ -321,7 +313,7 @@ int snd_device_register_all(struct snd_card *card);
 int snd_device_disconnect(struct snd_card *card, void *device_data);
 int snd_device_disconnect_all(struct snd_card *card);
 int snd_device_free(struct snd_card *card, void *device_data);
-int snd_device_free_all(struct snd_card *card, enum snd_device_cmd cmd);
+int snd_device_free_all(struct snd_card *card);
 
 /* isadma.c */
 
diff --git a/sound/core/device.c b/sound/core/device.c
index 6f734fe50296..b6f9d6702c69 100644
--- a/sound/core/device.c
+++ b/sound/core/device.c
@@ -45,6 +45,7 @@ int snd_device_new(struct snd_card *card, enum snd_device_type type,
 		   void *device_data, struct snd_device_ops *ops)
 {
 	struct snd_device *dev;
+	struct list_head *p;
 
 	if (snd_BUG_ON(!card || !device_data || !ops))
 		return -ENXIO;
@@ -53,17 +54,36 @@ int snd_device_new(struct snd_card *card, enum snd_device_type type,
 		snd_printk(KERN_ERR "Cannot allocate device\n");
 		return -ENOMEM;
 	}
+	INIT_LIST_HEAD(&dev->list);
 	dev->card = card;
 	dev->type = type;
 	dev->state = SNDRV_DEV_BUILD;
 	dev->device_data = device_data;
 	dev->ops = ops;
-	list_add(&dev->list, &card->devices);	/* add to the head of list */
+
+	/* insert the entry in an incrementally sorted list */
+	list_for_each_prev(p, &card->devices) {
+		struct snd_device *pdev = list_entry(p, struct snd_device, list);
+		if ((unsigned int)pdev->type <= (unsigned int)type)
+			break;
+	}
+
+	list_add(&dev->list, p);
 	return 0;
 }
-
 EXPORT_SYMBOL(snd_device_new);
 
+static struct snd_device *look_for_dev(struct snd_card *card, void *device_data)
+{
+	struct snd_device *dev;
+
+	list_for_each_entry(dev, &card->devices, list)
+		if (dev->device_data == device_data)
+			return dev;
+
+	return NULL;
+}
+
 /**
  * snd_device_free - release the device from the card
  * @card: the card instance
@@ -82,9 +102,8 @@ int snd_device_free(struct snd_card *card, void *device_data)
 	
 	if (snd_BUG_ON(!card || !device_data))
 		return -ENXIO;
-	list_for_each_entry(dev, &card->devices, list) {
-		if (dev->device_data != device_data)
-			continue;
+	dev = look_for_dev(card, device_data);
+	if (dev) {
 		/* unlink */
 		list_del(&dev->list);
 		if (dev->state == SNDRV_DEV_REGISTERED &&
@@ -103,7 +122,6 @@ int snd_device_free(struct snd_card *card, void *device_data)
 		   __builtin_return_address(0));
 	return -ENXIO;
 }
-
 EXPORT_SYMBOL(snd_device_free);
 
 /**
@@ -125,9 +143,8 @@ int snd_device_disconnect(struct snd_card *card, void *device_data)
 
 	if (snd_BUG_ON(!card || !device_data))
 		return -ENXIO;
-	list_for_each_entry(dev, &card->devices, list) {
-		if (dev->device_data != device_data)
-			continue;
+	dev = look_for_dev(card, device_data);
+	if (dev) {
 		if (dev->state == SNDRV_DEV_REGISTERED &&
 		    dev->ops->dev_disconnect) {
 			if (dev->ops->dev_disconnect(dev))
@@ -161,9 +178,8 @@ int snd_device_register(struct snd_card *card, void *device_data)
 
 	if (snd_BUG_ON(!card || !device_data))
 		return -ENXIO;
-	list_for_each_entry(dev, &card->devices, list) {
-		if (dev->device_data != device_data)
-			continue;
+	dev = look_for_dev(card, device_data);
+	if (dev) {
 		if (dev->state == SNDRV_DEV_BUILD && dev->ops->dev_register) {
 			if ((err = dev->ops->dev_register(dev)) < 0)
 				return err;
@@ -176,7 +192,6 @@ int snd_device_register(struct snd_card *card, void *device_data)
 	snd_BUG();
 	return -ENXIO;
 }
-
 EXPORT_SYMBOL(snd_device_register);
 
 /*
@@ -211,7 +226,7 @@ int snd_device_disconnect_all(struct snd_card *card)
 
 	if (snd_BUG_ON(!card))
 		return -ENXIO;
-	list_for_each_entry(dev, &card->devices, list) {
+	list_for_each_entry_reverse(dev, &card->devices, list) {
 		if (snd_device_disconnect(card, dev->device_data) < 0)
 			err = -ENXIO;
 	}
@@ -222,24 +237,17 @@ int snd_device_disconnect_all(struct snd_card *card)
  * release all the devices on the card.
  * called from init.c
  */
-int snd_device_free_all(struct snd_card *card, enum snd_device_cmd cmd)
+int snd_device_free_all(struct snd_card *card)
 {
-	struct snd_device *dev;
-	int err;
-	unsigned int range_low, range_high, type;
+	struct snd_device *dev, *next;
+	int ret = 0;
 
 	if (snd_BUG_ON(!card))
 		return -ENXIO;
-	range_low = (unsigned int)cmd * SNDRV_DEV_TYPE_RANGE_SIZE;
-	range_high = range_low + SNDRV_DEV_TYPE_RANGE_SIZE - 1;
-      __again:
-	list_for_each_entry(dev, &card->devices, list) {
-		type = (unsigned int)dev->type;
-		if (type >= range_low && type <= range_high) {
-			if ((err = snd_device_free(card, dev->device_data)) < 0)
-				return err;
-			goto __again;
-		}
+	list_for_each_entry_safe_reverse(dev, next, &card->devices, list) {
+		int err = snd_device_free(card, dev->device_data);
+		if (err < 0)
+			ret = err;
 	}
-	return 0;
+	return ret;
 }
diff --git a/sound/core/init.c b/sound/core/init.c
index f4d3ac633ff8..0115034914c9 100644
--- a/sound/core/init.c
+++ b/sound/core/init.c
@@ -248,7 +248,7 @@ int snd_card_new(struct device *parent, int idx, const char *xid,
 	return 0;
 
       __error_ctl:
-	snd_device_free_all(card, SNDRV_DEV_CMD_PRE);
+	snd_device_free_all(card);
       __error:
 	kfree(card);
   	return err;
@@ -436,16 +436,8 @@ static int snd_card_do_free(struct snd_card *card)
 	if (snd_mixer_oss_notify_callback)
 		snd_mixer_oss_notify_callback(card, SND_MIXER_OSS_NOTIFY_FREE);
 #endif
-	if (snd_device_free_all(card, SNDRV_DEV_CMD_PRE) < 0) {
-		snd_printk(KERN_ERR "unable to free all devices (pre)\n");
-		/* Fatal, but this situation should never occur */
-	}
-	if (snd_device_free_all(card, SNDRV_DEV_CMD_NORMAL) < 0) {
-		snd_printk(KERN_ERR "unable to free all devices (normal)\n");
-		/* Fatal, but this situation should never occur */
-	}
-	if (snd_device_free_all(card, SNDRV_DEV_CMD_POST) < 0) {
-		snd_printk(KERN_ERR "unable to free all devices (post)\n");
+	if (snd_device_free_all(card) < 0) {
+		snd_printk(KERN_ERR "unable to free all devices\n");
 		/* Fatal, but this situation should never occur */
 	}
 	if (card->private_free)
-- 
1.8.5.2