linux-kernel - Re: [PATCH v2 1/5] console: Don't perform test for CON

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Date:   Mon, 27 Jan 2020 11:44:04 +0200
From:   Andy Shevchenko <andriy.shevchenko@...ux.intel.com>
To:     Sergey Senozhatsky <sergey.senozhatsky.work@...il.com>
Cc:     Petr Mladek <pmladek@...e.com>,
        Sergey Senozhatsky <sergey.senozhatsky@...il.com>,
        Steven Rostedt <rostedt@...dmis.org>,
        linux-kernel@...r.kernel.org
Subject: Re: [PATCH v2 1/5] console: Don't perform test for CON_BRL flag twice

On Mon, Jan 27, 2020 at 11:41:14AM +0900, Sergey Senozhatsky wrote:
> On (20/01/24 17:57), Andy Shevchenko wrote:
> [..]
> > +++ b/drivers/accessibility/braille/braille_console.c
> > @@ -369,10 +369,10 @@ int braille_register_console(struct console *console, int index,
> >  
> >  int braille_unregister_console(struct console *console)
> >  {
> > -	if (braille_co != console)
> > -		return -EINVAL;
> >  	if (!(console->flags & CON_BRL))
> >  		return 0;
> > +	if (braille_co != console)
> > +		return -EINVAL;
> >  	unregister_keyboard_notifier(&keyboard_notifier_block);
> >  	unregister_vt_notifier(&vt_notifier_block);
> >  	braille_co = NULL;
> > diff --git a/kernel/printk/braille.c b/kernel/printk/braille.c
> > index 17a9591e54ff..2ec42173890f 100644
> > --- a/kernel/printk/braille.c
> > +++ b/kernel/printk/braille.c
> > @@ -51,8 +51,5 @@ _braille_register_console(struct console *console, struct console_cmdline *c)
> >  int
> >  _braille_unregister_console(struct console *console)
> >  {
> > -	if (console->flags & CON_BRL)
> > -		return braille_unregister_console(console);
> > -
> > -	return 0;
> > +	return braille_unregister_console(console);
> >  }
> 
> Hmm, I don't know. This moves sort of important code from common upper
> layer down to particular driver implementation. Should there be another
> driver/super-braille.c it must test CON_BRL flag as well.
> Because printk invokes _braille_unregister_console() unconditionally,
> and _braille_unregister_console() unconditionally calls into the driver.
> 
> I guess we can remove CON_BRL from braille_unregister_console() instead,
> because printk tests it.

Let me do that way, thanks!

-- 
With Best Regards,
Andy Shevchenko