linux-kernel - Re: [PATCH v3 2/5] console: Drop double check for console

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Date:   Wed, 29 Jan 2020 14:24:27 +0100
From:   Petr Mladek <pmladek@...e.com>
To:     Andy Shevchenko <andriy.shevchenko@...ux.intel.com>
Cc:     Sergey Senozhatsky <sergey.senozhatsky@...il.com>,
        Steven Rostedt <rostedt@...dmis.org>,
        linux-kernel@...r.kernel.org
Subject: Re: [PATCH v3 2/5] console: Drop double check for console_drivers
 being non-NULL

On Mon 2020-01-27 13:47:16, Andy Shevchenko wrote:
> There is no need to explicitly check for console_drivers to be non-NULL
> since for_each_console() does this.
> 
> Signed-off-by: Andy Shevchenko <andriy.shevchenko@...ux.intel.com>

Nice catch.

Reviewed-by: Petr Mladek <pmladek@...e.com>

There is a candidate for another patch, see the note below.

> ---
> v3: no changes
>  kernel/printk/printk.c | 16 ++++++----------
>  1 file changed, 6 insertions(+), 10 deletions(-)
> 
> diff --git a/kernel/printk/printk.c b/kernel/printk/printk.c
> index fada22dc4ab6..51337ed426e0 100644
> --- a/kernel/printk/printk.c
> +++ b/kernel/printk/printk.c
> @@ -2653,18 +2650,17 @@ void register_console(struct console *newcon)
>  	struct console_cmdline *c;
>  	static bool has_preferred;
>  
> -	if (console_drivers)
> -		for_each_console(bcon)
> -			if (WARN(bcon == newcon,
> -					"console '%s%d' already registered\n",
> -					bcon->name, bcon->index))
> -				return;
> +	for_each_console(bcon) {
> +		if (WARN(bcon == newcon, "console '%s%d' already registered\n",
> +					 bcon->name, bcon->index))
> +			return;
> +	}
>  
>  	/*
>  	 * before we register a new CON_BOOT console, make sure we don't
>  	 * already have a valid console
>  	 */
> -	if (console_drivers && newcon->flags & CON_BOOT) {
> +	if (newcon->flags & CON_BOOT) {
>  		/* find the last or real console */

Note: This comment is misleading. I would just remove it.

>  		for_each_console(bcon) {
>  			if (!(bcon->flags & CON_BOOT)) {

Best Regards,
Petr