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

[Takashi Iwai <tiwai@suse.de>]

On Mon, 11 Jan 2021 14:05:55 +0100,
Hui Wang wrote:
> 
> 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);

We can take a simpler approach, e.g. just replace the chars that are
!isalnum() to '_'.


Takashi