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From: Sergey Senozhatsky <sergey.senozhatsky.work@gmail.com>
To: Petr Mladek <pmladek@suse.com>
Cc: Benjamin Herrenschmidt <benh@kernel.crashing.org>,
	linux-kernel@vger.kernel.org,
	Sergey Senozhatsky <sergey.senozhatsky@gmail.com>,
	Steven Rostedt <rostedt@goodmis.org>,
	Linus Torvalds <torvalds@linux-foundation.org>
Subject: Re: [PATCH v2] printk: Fix preferred console selection with multiple matches
Date: Mon, 6 Jan 2020 14:15:08 +0900	[thread overview]
Message-ID: <20200106051508.GA17351@google.com> (raw)
In-Reply-To: <20191220091131.4uifcbudwppjspf4@pathway.suse.cz>

On (19/12/20 10:11), Petr Mladek wrote:
[..]
> > > > +enum con_match {
> > > > +	con_matched,
> > > > +	con_matched_preferred,
> > > > +	con_braille,
> > > > +	con_failed,
> > > > +	con_no_match,
> > > > +};
> > > 
> > > Please, replace this with int, where:
> > > 
> > >    + con_matched -> 0
> > >    + con_matched_preferred -> 0 and make "has_preferred" global variable
> > >    + con_braile -> 0		later check for CON_BRL flag
> > >    + con_failed -> -EFAULT
> > >    + con_no_match -> -ENOENT
> > 
> > Not fan of using -EFAULT here, it's a detail since it's rather kernel
> > internal, but I'd rather use -ENXIO for no match and -EIO for failed
> > (or pass the original error code up if any). That said it's really bike
> > shed painting at this point :-)
> 
> Sigh, either variant is somehow confusing.
> 
> I think that -ENOENT is a bit better than -EIO. It is abbreviation of
> "No entry or No entity" which quite fits here. Also the device might
> exist but it is not used when not requested.

Can we please keep the enum? Enum is super self-descriptive, can't
get any better. Any other alternative - be it -EFAULT or -EIO or
-ENOENT - would force one to always look at what is actually going
on in try_match_new_console() and what particular errno means. None
of those errnos fit, they make things cryptic. IMHO.

	-ss

  reply	other threads:[~2020-01-06  5:15 UTC|newest]

Thread overview: 9+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2019-12-16  1:08 [PATCH v2] printk: Fix preferred console selection with multiple matches Benjamin Herrenschmidt
2019-12-17  5:45 ` Sergey Senozhatsky
2019-12-19 13:50 ` Petr Mladek
2019-12-19 21:48   ` Benjamin Herrenschmidt
2019-12-20  9:11     ` Petr Mladek
2020-01-06  5:15       ` Sergey Senozhatsky [this message]
2020-01-06 10:25         ` Petr Mladek
2020-01-07  0:50           ` Benjamin Herrenschmidt
2020-01-07  5:19           ` Sergey Senozhatsky

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