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

[Waiman Long]

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