[RFC][PATCH v4 2/4] alsa: jack: adjust jack_kctl debugfs folder's name

[Hui Wang <hui.wang@canonical.com>]

We used jack_kctl->kctl.id as the folder's name, but there are some
characters which are not suitable for foler's name, for example, a
HDMI/DP audio jack id contains '/', ',', '=' and ' ', this patch will
remove them from folder's name.

Before applying patch, the folders look like:
'HDMI!DP,pcm=3 Jack'  'Headphone Jack'  'Mic Jack'

After applying the patch, the folders look like:
HDMIDPpcm3Jack  HeadphoneJack  MicJack

Signed-off-by: Hui Wang <hui.wang@canonical.com>
---
 sound/core/jack.c | 26 ++++++++++++++++++++++----
 1 file changed, 22 insertions(+), 4 deletions(-)

diff --git a/sound/core/jack.c b/sound/core/jack.c
index 0092cb6b5b79..e1d1b26f3a5e 100644
--- a/sound/core/jack.c
+++ b/sound/core/jack.c
@@ -243,18 +243,36 @@ static const struct file_operations jackin_inject_fops = {
 	.llseek = default_llseek,
 };
 
+/* The substrings in the jack's name but not suitable for folder's name */
+static const char * const dropped_chars[] = {
+	"/", "=", ",", " ",
+};
+
+static char *strremove(char *s, const char *c)
+{
+	char *p;
+
+	while ((p = strstr(s, c))) {
+		*p = '\0';
+		strcat(s, p+strlen(c));
+	}
+
+	return s;
+}
+
 static int snd_jack_debugfs_add_inject_node(struct snd_jack *jack,
 					    struct snd_jack_kctl *jack_kctl)
 {
 	char *tname;
+	int i;
 
-	/* the folder's name can't contains '/', need to replace it with '!'
-	 * as lib/kobject.c does
-	 */
 	tname = kstrdup(jack_kctl->kctl->id.name, GFP_KERNEL);
 	if (!tname)
 		return -ENOMEM;
-	strreplace(tname, '/', '!');
+
+	for (i = 0; i < ARRAY_SIZE(dropped_chars); i++)
+		tname = strremove(tname, dropped_chars[i]);
+
 	jack_kctl->jack_debugfs_root = debugfs_create_dir(tname, jack->card->debugfs_root);
 	kfree(tname);
 
-- 
2.25.1