linux-kernel - Re: [PATCH 7/7] printk: Don't check for CON_ENABLED on console

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Message-ID: <aFAkD2i0ceH6qYQz@pathway.suse.cz>
Date: Mon, 16 Jun 2025 16:02:55 +0200
From: Petr Mladek <pmladek@...e.com>
To: Marcos Paulo de Souza <mpdesouza@...e.com>
Cc: Steven Rostedt <rostedt@...dmis.org>,
	John Ogness <john.ogness@...utronix.de>,
	Sergey Senozhatsky <senozhatsky@...omium.org>,
	Greg Kroah-Hartman <gregkh@...uxfoundation.org>,
	Jiri Slaby <jirislaby@...nel.org>,
	Jason Wessel <jason.wessel@...driver.com>,
	Daniel Thompson <danielt@...nel.org>,
	Douglas Anderson <dianders@...omium.org>,
	Richard Weinberger <richard@....at>,
	Anton Ivanov <anton.ivanov@...bridgegreys.com>,
	Johannes Berg <johannes@...solutions.net>,
	linux-kernel@...r.kernel.org, linux-serial@...r.kernel.org,
	kgdb-bugreport@...ts.sourceforge.net, linux-um@...ts.infradead.org
Subject: Re: [PATCH 7/7] printk: Don't check for CON_ENABLED on
 console_unblank

On Fri 2025-06-06 23:53:49, Marcos Paulo de Souza wrote:
> All consoles found on for_each_console_srcu are registered, meaning that all of
> them are already CON_ENABLEDed.
> 
> Signed-off-by: Marcos Paulo de Souza <mpdesouza@...e.com>
> ---
>  kernel/printk/printk.c | 4 ++--
>  1 file changed, 2 insertions(+), 2 deletions(-)
> 
> diff --git a/kernel/printk/printk.c b/kernel/printk/printk.c
> index 658acf92aa3d2a3d1e294b7e17e5ee96d8169afe..8074a0f73691cfc5f637361048097ace1545c7c0 100644
> --- a/kernel/printk/printk.c
> +++ b/kernel/printk/printk.c
> @@ -3360,7 +3360,7 @@ void console_unblank(void)
>  		if (flags & CON_SUSPENDED)
>  			continue;
>  
> -		if ((flags & CON_ENABLED) && c->unblank) {
> +		if (c->unblank) {

It might actually make sense to check is_console_usable() here.
The reason is similar as for the 5th and 6th patch, see
https://lore.kernel.org/r/aFAdGas9yGB4zhqc@pathway.suse.cz
https://lore.kernel.org/r/aFAiq3IEic8DuATR@pathway.suse.cz


>  			found_unblank = true;
>  			break;
>  		}
> @@ -3402,7 +3402,7 @@ void console_unblank(void)
>  		if (flags & CON_SUSPENDED)
>  			continue;
>  
> -		if ((flags & CON_ENABLED) && c->unblank)
> +		if (c->unblank)
>  			c->unblank();

Same here.

>  	}
>  	console_srcu_read_unlock(cookie);
> 
> -- 
> 2.49.0