linux-kernel - Re: [PATCH 05/15] drivers: input: Drop unlikely before IS_ERR(_OR

lists.openwall.net		lists / announce owl-users owl-dev john-users john-dev passwdqc-users yescrypt popa3d-users / oss-security kernel-hardening musl sabotage tlsify passwords / crypt-dev xvendor / Bugtraq Full-Disclosure linux-kernel linux-netdev linux-ext4 linux-hardening linux-cve-announce PHC
Open Source and information security mailing list archives

Hash Suite: Windows password security audit tool. GUI, reports in PDF.

[<prev] [next>] [<thread-prev] [thread-next>] [day] [month] [year] [list]

Date:	Sun, 2 Aug 2015 17:59:39 +0200
From:	Pali Rohár <pali.rohar@...il.com>
To:	Pavel Machek <pavel@....cz>
Cc:	Viresh Kumar <viresh.kumar@...aro.org>,
	Dmitry Torokhov <dmitry.torokhov@...il.com>,
	akpm@...ux-foundation.org, linaro-kernel@...ts.linaro.org,
	linux-kernel@...r.kernel.org, Hans de Goede <hdegoede@...hat.com>,
	"open list:INPUT (KEYBOARD, MOUSE, JOYSTICK, TOUCHSCREEN)..." 
	<linux-input@...r.kernel.org>, Masaki Ota <masaki.ota@...alps.com>
Subject: Re: [PATCH 05/15] drivers: input: Drop unlikely before IS_ERR(_OR_NULL)

On Sunday 02 August 2015 17:43:52 Pavel Machek wrote:
> On Sat 2015-08-01 13:44:59, Pali Rohár wrote:
> > On Saturday 01 August 2015 13:22:51 Viresh Kumar wrote:
> > > On 31-07-15, 09:58, Dmitry Torokhov wrote:
> > > > On Fri, Jul 31, 2015 at 02:08:25PM +0530, Viresh Kumar wrote:
> > > > > IS_ERR(_OR_NULL) already contain an 'unlikely' compiler flag
> > > > > and there is no need to do that again from its callers. Drop
> > > > > it.
> > > > 
> > > > I'd rather keep it as it documents the expected behavior and
> > > > double unlikely should work just fine.
> > > 
> > > TBH, I don't really agree that it is there for documentation. The
> > > only purpose of such compiler flags is to try make code more
> > > efficient.
> > > 
> > > Anyway, I got to this series as someone asked me to fix this for
> > > one of my patches which used unlikely(IS_ERR_OR_NULL()). And so
> > > I thought about fixing all sites that are doing double unlikely
> > > (that shouldn't hurt for sure).
> > > 
> > > I will leave it to you.
> > 
> > I think that unlikely() macro here make code more readable. Yes, it
> > is also for compiler optimization, but also for me it looks like
> > Clean Code pattern <https://de.wikipedia.org/wiki/Clean_Code> --
> > is not it?
> 
> People know that errors are unlikely, no need to tell them. I'd
> remove it.
> 									Pavel

Errors and bugs are always unlikely ;-)

-- 
Pali Rohár
pali.rohar@...il.com

Download attachment "signature.asc " of type "application/pgp-signature" (199 bytes)