linux-kernel - Re: [PATCH 01/13] tty: simplify tty_dev_name_to

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Message-ID: <5bafde51-abaf-d367-eb9a-220c1339daca@linux.intel.com>
Date: Mon, 5 Aug 2024 17:25:06 +0300 (EEST)
From: Ilpo Järvinen <ilpo.jarvinen@...ux.intel.com>
To: "Jiri Slaby (SUSE)" <jirislaby@...nel.org>
cc: gregkh@...uxfoundation.org, linux-serial@...r.kernel.org, 
    linux-kernel@...r.kernel.org
Subject: Re: [PATCH 01/13] tty: simplify tty_dev_name_to_number() using
 guard(mutex)

On Mon, 5 Aug 2024, Jiri Slaby (SUSE) wrote:

> In tty_dev_name_to_number(), a guard can help to make the code easier to
> follow. Especially how 0 is returned in the successful case. So use a
> guard there.
> 
> Signed-off-by: Jiri Slaby (SUSE) <jirislaby@...nel.org>
> ---
>  drivers/tty/tty_io.c | 11 ++++-------
>  1 file changed, 4 insertions(+), 7 deletions(-)
> 
> diff --git a/drivers/tty/tty_io.c b/drivers/tty/tty_io.c
> index bc9aebcb873f..267682bcfea0 100644
> --- a/drivers/tty/tty_io.c
> +++ b/drivers/tty/tty_io.c
> @@ -350,22 +350,19 @@ int tty_dev_name_to_number(const char *name, dev_t *number)
>  		return ret;
>  
>  	prefix_length = str - name;
> -	mutex_lock(&tty_mutex);
> +
> +	guard(mutex)(&tty_mutex);
>  
>  	list_for_each_entry(p, &tty_drivers, tty_drivers)
>  		if (prefix_length == strlen(p->name) && strncmp(name,
>  					p->name, prefix_length) == 0) {
>  			if (index < p->num) {
>  				*number = MKDEV(p->major, p->minor_start + index);
> -				goto out;
> +				return 0;
>  			}
>  		}
>  
> -	/* if here then driver wasn't found */
> -	ret = -ENODEV;
> -out:
> -	mutex_unlock(&tty_mutex);
> -	return ret;
> +	return -ENODEV;
>  }
>  EXPORT_SYMBOL_GPL(tty_dev_name_to_number);

Should add also #include <linux/cleanup.h>. With that fixed:

Reviewed-by: Ilpo Järvinen <ilpo.jarvinen@...ux.intel.com>

-- 
 i.