Re: [PATCH printk v2 15/26] printk: Track registered boot consoles
From: Petr Mladek
Date: Fri Feb 23 2024 - 10:57:20 EST
On Sun 2024-02-18 20:03:15, John Ogness wrote:
> Unfortunately it is not known if a boot console and a regular
> (legacy or nbcon) console use the same hardware. For this reason
> they must not be allowed to print simultaneously.
>
> For legacy consoles this is not an issue because they are
> already synchronized with the boot consoles using the console
> lock. However nbcon consoles can be triggered separately.
>
> Add a global flag @have_boot_console to identify if any boot
> consoles are registered. This will be used in follow-up commits
> to ensure that boot consoles and nbcon consoles cannot print
> simultaneously.
>
> Signed-off-by: John Ogness <john.ogness@xxxxxxxxxxxxx>
Reviewed-by: Petr Mladek <pmladek@xxxxxxxx>
Just a nit below.
> --- a/kernel/printk/printk.c
> +++ b/kernel/printk/printk.c
> @@ -3598,6 +3611,17 @@ static int unregister_console_locked(struct console *console)
> if (console->exit)
> res = console->exit(console);
>
> + /*
> + * With this console gone, the global flags tracking registered
> + * console types may have changed. Update them.
> + */
> + for_each_console(c) {
> + if (c->flags & CON_BOOT)
> + found_boot_con = true;
> + }
> + if (!found_boot_con)
> + have_boot_console = false;
I would use:
have_boot_console = found_boot_console;
But I do not have strong opinion. Maybe, you wanted to make
it obvious that the function only clears the flag.
Best Regards,
Petr