linux-kernel - Re: [PATCH 4/5] kconfig: Introduce "showif" to factor out conditions on visibility

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]

Message-ID: <1432825060.8508.57.camel@x220>
Date:	Thu, 28 May 2015 16:57:40 +0200
From:	Paul Bolle <pebolle@...cali.nl>
To:	josh@...htriplett.org
Cc:	Ingo Molnar <mingo@...nel.org>,
	Andrew Morton <akpm@...ux-foundation.org>,
	"Paul E. McKenney" <paulmck@...ux.vnet.ibm.com>,
	Michal Hocko <mhocko@...e.cz>,
	Vladimir Davydov <vdavydov@...allels.com>,
	Johannes Weiner <hannes@...xchg.org>,
	Geert Uytterhoeven <geert@...ux-m68k.org>,
	Andy Lutomirski <luto@...capital.net>,
	Bertrand Jacquin <beber@...eeweb.net>,
	"Luis R. Rodriguez" <mcgrof@...e.com>,
	Iulia Manda <iulia.manda21@...il.com>,
	Pranith Kumar <bobby.prani@...il.com>,
	Clark Williams <clark.williams@...il.com>,
	Mel Gorman <mgorman@...e.de>,
	Randy Dunlap <rdunlap@...radead.org>,
	Michal Marek <mmarek@...e.cz>, linux-kbuild@...r.kernel.org,
	linux-kernel@...r.kernel.org
Subject: Re: [PATCH 4/5] kconfig: Introduce "showif" to factor out
 conditions on visibility

On Wed, 2015-05-20 at 11:30 -0700, josh@...htriplett.org wrote:
> In net/rfkill/Kconfig, RFKILL_REGULATOR oddly has
> "depends on RFKILL || !RFKILL".  WIMAX does the same thing.

That's only tristate logic. It's a common idiom, but it looks very odd
compared to boolean logic. It ensures RFKILL_REGULATOR will not be 'y'
if RFKILL is 'm'. Because:
    RFKILL = 'n' => RFKILL_REGULATOR = 'n' || 'm' || 'y'
    RFKILL = 'm' => RFKILL_REGULATOR = 'n' || 'm'
    RFKILL = 'y' => RFKILL_REGULATOR = 'n' || 'm' || 'y'

Hope this helps,


Paul Bolle

--
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majordomo@...r.kernel.org
More majordomo info at  http://vger.kernel.org/majordomo-info.html
Please read the FAQ at  http://www.tux.org/lkml/