linux-kernel - Re: [PATCH -v4 1/8] locking/drm: Kill mutex trickery

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: <57F81AA3.1080905@hpe.com>
Date:   Fri, 7 Oct 2016 17:58:59 -0400
From:   Waiman Long <waiman.long@....com>
To:     Peter Zijlstra <peterz@...radead.org>
CC:     Linus Torvalds <torvalds@...ux-foundation.org>,
        Jason Low <jason.low2@....com>,
        Ding Tianhong <dingtianhong@...wei.com>,
        Thomas Gleixner <tglx@...utronix.de>,
        Will Deacon <Will.Deacon@....com>,
        Ingo Molnar <mingo@...hat.com>,
        Imre Deak <imre.deak@...el.com>,
        Linux Kernel Mailing List <linux-kernel@...r.kernel.org>,
        Davidlohr Bueso <dave@...olabs.net>,
        Tim Chen <tim.c.chen@...ux.intel.com>,
        Terry Rudd <terry.rudd@....com>,
        "Paul E. McKenney" <paulmck@...ibm.com>,
        Chris Wilson <chris@...is-wilson.co.uk>,
        Daniel Vetter <daniel.vetter@...ll.ch>,
        Rob Clark <robdclark@...il.com>
Subject: Re: [PATCH -v4 1/8] locking/drm: Kill mutex trickery

On 10/07/2016 12:13 PM, Peter Zijlstra wrote:
> On Fri, Oct 07, 2016 at 08:58:43AM -0700, Linus Torvalds wrote:
>> The other choice would be to just make the choices be negative (==
>> recursive), zero (== failed) or positive (== got lock), which allows
>> for the same value re-use for the non-recursive case, and you could
>> avoid the enum entirely.
> I thought about that, but liked the enum better for having to then spell
> it out.
>
> I'll go make the enum shout and add comment as you suggest.

I like the idea of having a tri-state returned value (<0, 0, >0). I 
don't mind having the enum, but just making mutex_trylock_recursive 
equal to -1 will be great.

Cheers,
Longman