ALSA: core: Fix possible memory leaks at error path in info.c

Currently, snd_info_init() just returns an error without releasing the
previously assigned resources at error path.  The assigned proc and
info entries have to be released properly.  This patch covers it.

While we are at it, refactor the code a bit, too.

Acked-by: Jaroslav Kysela <perex@perex.cz>
Signed-off-by: Takashi Iwai <tiwai@suse.de>

sound/core/info.c

@@ -446,6 +446,22 @@ static const struct file_operations snd_info_text_entry_ops =
 	.read =			seq_read,
 };
 
+static struct snd_info_entry *create_subdir(struct module *mod,
+					    const char *name)
+{
+	struct snd_info_entry *entry;
+
+	entry = snd_info_create_module_entry(mod, name, NULL);
+	if (!entry)
+		return NULL;
+	entry->mode = S_IFDIR | S_IRUGO | S_IXUGO;
+	if (snd_info_register(entry) < 0) {
+		snd_info_free_entry(entry);
+		return NULL;
+	}
+	return entry;
+}
+
 int __init snd_info_init(void)
 {
 	struct proc_dir_entry *p;
@@ -455,36 +471,27 @@ int __init snd_info_init(void)
 		return -ENOMEM;
 	snd_proc_root = p;
 #ifdef CONFIG_SND_OSSEMUL
-	{
-		struct snd_info_entry *entry;
-		if ((entry = snd_info_create_module_entry(THIS_MODULE, "oss", NULL)) == NULL)
-			return -ENOMEM;
-		entry->mode = S_IFDIR | S_IRUGO | S_IXUGO;
-		if (snd_info_register(entry) < 0) {
-			snd_info_free_entry(entry);
-			return -ENOMEM;
-		}
-		snd_oss_root = entry;
-	}
+	snd_oss_root = create_subdir(THIS_MODULE, "oss");
+	if (!snd_oss_root)
+		goto error;
 #endif
 #if IS_ENABLED(CONFIG_SND_SEQUENCER)
-	{
-		struct snd_info_entry *entry;
-		if ((entry = snd_info_create_module_entry(THIS_MODULE, "seq", NULL)) == NULL)
-			return -ENOMEM;
-		entry->mode = S_IFDIR | S_IRUGO | S_IXUGO;
-		if (snd_info_register(entry) < 0) {
-			snd_info_free_entry(entry);
-			return -ENOMEM;
-		}
-		snd_seq_root = entry;
-	}
+	snd_seq_root = create_subdir(THIS_MODULE, "seq");
+	if (!snd_seq_root)
+		goto error;
 #endif
 	snd_info_version_init();
 	snd_minor_info_init();
 	snd_minor_info_oss_init();
 	snd_card_info_init();
 	return 0;
+
+ error:
+#ifdef CONFIG_SND_OSSEMUL
+	snd_info_free_entry(snd_oss_root);
+#endif
+	proc_remove(snd_proc_root);
+	return -ENOMEM;
 }
 
 int __exit snd_info_done(void)
@@ -523,13 +530,9 @@ int snd_info_card_create(struct snd_card *card)
 		return -ENXIO;
 
 	sprintf(str, "card%i", card->number);
-	if ((entry = snd_info_create_module_entry(card->module, str, NULL)) == NULL)
-		return -ENOMEM;
-	entry->mode = S_IFDIR | S_IRUGO | S_IXUGO;
-	if (snd_info_register(entry) < 0) {
-		snd_info_free_entry(entry);
+	entry = create_subdir(card->module, str);
+	if (!entry)
 		return -ENOMEM;
-	}
 	card->proc_root = entry;
 	return 0;
 }
@@ -758,7 +761,6 @@ EXPORT_SYMBOL(snd_info_create_card_entry);
 static void snd_info_disconnect(struct snd_info_entry *entry)
 {
 	struct list_head *p, *n;
-	struct proc_dir_entry *root;
 
 	list_for_each_safe(p, n, &entry->children) {
 		snd_info_disconnect(list_entry(p, struct snd_info_entry, list));
@@ -767,8 +769,6 @@ static void snd_info_disconnect(struct snd_info_entry *entry)
 	if (! entry->p)
 		return;
 	list_del_init(&entry->list);
-	root = entry->parent == NULL ? snd_proc_root : entry->parent->p;
-	snd_BUG_ON(!root);
 	proc_remove(entry->p);
 	entry->p = NULL;
 }