[alsa-devel] [PATCH 2/2] ALSA: control: Consolidate helpers for adding and replacing ctl elements

[Takashi Iwai]

Both snd_ctl_add() and snd_ctl_replace() process the things in a
fairly similar way, and indeed the most of the codes can be unified.

This patch is a refactoring to consolidate the both functions to call
a single helper with an extra "mode" argument.  There should be no
functional difference, except for one additional sanity check applied
now to snd_ctl_replace() (which was rather overlooking, IMO), too.

Signed-off-by: Takashi Iwai <tiwai at suse.de>
---
 sound/core/control.c | 123 ++++++++++++++++++-------------------------
 1 file changed, 52 insertions(+), 71 deletions(-)

diff --git a/sound/core/control.c b/sound/core/control.c
index 649d3217590e..fad7db402443 100644
--- a/sound/core/control.c
+++ b/sound/core/control.c
@@ -348,22 +348,41 @@ static int snd_ctl_find_hole(struct snd_card *card, unsigned int count)
 	return 0;
 }
 
-/* add a new kcontrol object; call with card->controls_rwsem locked */
-static int __snd_ctl_add(struct snd_card *card, struct snd_kcontrol *kcontrol)
+enum snd_ctl_add_mode {
+	CTL_ADD_EXCLUSIVE, CTL_REPLACE, CTL_ADD_ON_REPLACE,
+};
+
+/* add/replace a new kcontrol object; call with card->controls_rwsem locked */
+static int __snd_ctl_add_replace(struct snd_card *card,
+				 struct snd_kcontrol *kcontrol,
+				 enum snd_ctl_add_mode mode)
 {
 	struct snd_ctl_elem_id id;
 	unsigned int idx;
 	unsigned int count;
+	struct snd_kcontrol *old;
+	int err;
 
 	id = kcontrol->id;
 	if (id.index > UINT_MAX - kcontrol->count)
 		return -EINVAL;
 
-	if (snd_ctl_find_id(card, &id)) {
-		dev_err(card->dev,
-			"control %i:%i:%i:%s:%i is already present\n",
-			id.iface, id.device, id.subdevice, id.name, id.index);
-		return -EBUSY;
+	old = snd_ctl_find_id(card, &id);
+	if (!old) {
+		if (mode == CTL_REPLACE)
+			return -EINVAL;
+	} else {
+		if (mode == CTL_ADD_EXCLUSIVE) {
+			dev_err(card->dev,
+				"control %i:%i:%i:%s:%i is already present\n",
+				id.iface, id.device, id.subdevice, id.name,
+				id.index);
+			return -EBUSY;
+		}
+
+		err = snd_ctl_remove(card, old);
+		if (err < 0)
+			return err;
 	}
 
 	if (snd_ctl_find_hole(card, kcontrol->count) < 0)
@@ -382,21 +401,9 @@ static int __snd_ctl_add(struct snd_card *card, struct snd_kcontrol *kcontrol)
 	return 0;
 }
 
-/**
- * snd_ctl_add - add the control instance to the card
- * @card: the card instance
- * @kcontrol: the control instance to add
- *
- * Adds the control instance created via snd_ctl_new() or
- * snd_ctl_new1() to the given card. Assigns also an unique
- * numid used for fast search.
- *
- * It frees automatically the control which cannot be added.
- *
- * Return: Zero if successful, or a negative error code on failure.
- *
- */
-int snd_ctl_add(struct snd_card *card, struct snd_kcontrol *kcontrol)
+static int snd_ctl_add_replace(struct snd_card *card,
+			       struct snd_kcontrol *kcontrol,
+			       enum snd_ctl_add_mode mode)
 {
 	int err = -EINVAL;
 
@@ -406,7 +413,7 @@ int snd_ctl_add(struct snd_card *card, struct snd_kcontrol *kcontrol)
 		goto error;
 
 	down_write(&card->controls_rwsem);
-	err = __snd_ctl_add(card, kcontrol);
+	err = __snd_ctl_add_replace(card, kcontrol, mode);
 	up_write(&card->controls_rwsem);
 	if (err < 0)
 		goto error;
@@ -416,6 +423,25 @@ int snd_ctl_add(struct snd_card *card, struct snd_kcontrol *kcontrol)
 	snd_ctl_free_one(kcontrol);
 	return err;
 }
+
+/**
+ * snd_ctl_add - add the control instance to the card
+ * @card: the card instance
+ * @kcontrol: the control instance to add
+ *
+ * Adds the control instance created via snd_ctl_new() or
+ * snd_ctl_new1() to the given card. Assigns also an unique
+ * numid used for fast search.
+ *
+ * It frees automatically the control which cannot be added.
+ *
+ * Return: Zero if successful, or a negative error code on failure.
+ *
+ */
+int snd_ctl_add(struct snd_card *card, struct snd_kcontrol *kcontrol)
+{
+	return snd_ctl_add_replace(card, kcontrol, CTL_ADD_EXCLUSIVE);
+}
 EXPORT_SYMBOL(snd_ctl_add);
 
 /**
@@ -435,53 +461,8 @@ EXPORT_SYMBOL(snd_ctl_add);
 int snd_ctl_replace(struct snd_card *card, struct snd_kcontrol *kcontrol,
 		    bool add_on_replace)
 {
-	struct snd_ctl_elem_id id;
-	unsigned int count;
-	unsigned int idx;
-	struct snd_kcontrol *old;
-	int ret;
-
-	if (!kcontrol)
-		return -EINVAL;
-	if (snd_BUG_ON(!card || !kcontrol->info)) {
-		ret = -EINVAL;
-		goto error;
-	}
-	id = kcontrol->id;
-	down_write(&card->controls_rwsem);
-	old = snd_ctl_find_id(card, &id);
-	if (!old) {
-		if (add_on_replace)
-			goto add;
-		up_write(&card->controls_rwsem);
-		ret = -EINVAL;
-		goto error;
-	}
-	ret = snd_ctl_remove(card, old);
-	if (ret < 0) {
-		up_write(&card->controls_rwsem);
-		goto error;
-	}
-add:
-	if (snd_ctl_find_hole(card, kcontrol->count) < 0) {
-		up_write(&card->controls_rwsem);
-		ret = -ENOMEM;
-		goto error;
-	}
-	list_add_tail(&kcontrol->list, &card->controls);
-	card->controls_count += kcontrol->count;
-	kcontrol->id.numid = card->last_numid + 1;
-	card->last_numid += kcontrol->count;
-	id = kcontrol->id;
-	count = kcontrol->count;
-	up_write(&card->controls_rwsem);
-	for (idx = 0; idx < count; idx++, id.index++, id.numid++)
-		snd_ctl_notify(card, SNDRV_CTL_EVENT_MASK_ADD, &id);
-	return 0;
-
-error:
-	snd_ctl_free_one(kcontrol);
-	return ret;
+	return snd_ctl_add_replace(card, kcontrol,
+				   add_on_replace ? CTL_ADD_ON_REPLACE : CTL_REPLACE);
 }
 EXPORT_SYMBOL(snd_ctl_replace);
 
@@ -1369,7 +1350,7 @@ static int snd_ctl_elem_add(struct snd_ctl_file *file,
 
 	/* This function manage to free the instance on failure. */
 	down_write(&card->controls_rwsem);
-	err = __snd_ctl_add(card, kctl);
+	err = __snd_ctl_add_replace(card, kctl, CTL_ADD_EXCLUSIVE);
 	if (err < 0) {
 		snd_ctl_free_one(kctl);
 		goto unlock;
-- 
2.19.1