linux-kernel - Re: [PATCH v3 5/5] console: Introduce ->exit() callback

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Message-ID: <20200130131427.GZ32742@smile.fi.intel.com>
Date:   Thu, 30 Jan 2020 15:14:27 +0200
From:   Andy Shevchenko <andriy.shevchenko@...ux.intel.com>
To:     Sergey Senozhatsky <sergey.senozhatsky@...il.com>
Cc:     Sergey Senozhatsky <sergey.senozhatsky.work@...il.com>,
        Petr Mladek <pmladek@...e.com>,
        Steven Rostedt <rostedt@...dmis.org>,
        linux-kernel@...r.kernel.org
Subject: Re: [PATCH v3 5/5] console: Introduce ->exit() callback

On Thu, Jan 30, 2020 at 01:50:53AM +0900, Sergey Senozhatsky wrote:
> On (20/01/30 00:12), Sergey Senozhatsky wrote:
> > On (20/01/29 16:25), Andy Shevchenko wrote:
> > > I understand. Seems the ->setup() has to be idempotent. We can tell the same
> > > for ->exit() in some comment.
> > > 
> > > Can you describe, btw, struct console in kernel doc format?
> > > It will be very helpful!
> > 
> > We probably need some documentation.
> > 
> > > > > In both cases we will get the console to have CON_ENABLED flag set.
> > > > 
> > > > And there are sneaky consoles that have CON_ENABLED before we even
> > > > register them.
> > > 
> > > So, taking into consideration my comment to the previous patch, what would be
> > > suggested guard here?
> > > 
> > > For a starter something like this?
> > > 
> > >   if ((console->flags & CON_ENABLED) && console->exit)
> > > 	console->exit(console);
> > 
> > This will work if we also add something like this
> 
> No, wait... This will not work, console can be suspended, yet
> still registered. I think the only criteria is "the console is
> on the list".

Okay, I guess we need to drop CON_ENABLE bits from this patch and
rely on the res value instead.

-- 
With Best Regards,
Andy Shevchenko