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Date:   Thu, 15 Mar 2018 10:39:59 -0700
From:   Ram Pai <linuxram@us.ibm.com>
To:     Dave Hansen <dave.hansen@intel.com>
Cc:     Thomas Gleixner <tglx@linutronix.de>, mingo@redhat.com,
        mpe@ellerman.id.au, linuxppc-dev@lists.ozlabs.org,
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        Ulrich.Weigand@de.ibm.com
Subject: Re: [PATCH v3] x86: treat pkey-0 special
Reply-To: Ram Pai <linuxram@us.ibm.com>
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On Thu, Mar 15, 2018 at 10:31:51AM -0700, Dave Hansen wrote:
> On 03/15/2018 10:21 AM, Ram Pai wrote:
> > On Thu, Mar 15, 2018 at 08:55:31AM -0700, Dave Hansen wrote:
> >> On 03/15/2018 02:46 AM, Thomas Gleixner wrote:
> >>>> +	if (!pkey || !mm_pkey_is_allocated(mm, pkey))
> >>> Why this extra check? mm_pkey_is_allocated(mm, 0) should not return true
> >>> ever. If it does, then this wants to be fixed.
> >> I was thinking that we _do_ actually want it to seem allocated.  It just
> >> get "allocated" implicitly when an mm is created.  I think that will
> >> simplify the code if we avoid treating it specially in as many places as
> >> possible.
> > I think, the logic that makes pkey-0 special must to go
> > in arch-neutral code.   How about checking for pkey-0 in sys_pkey_free()
> > itself?
> 
> This is for protection against shooting yourself in the foot?  Yes, that
> can go in sys_pkey_free().
> 
> Does this need manpage and/or selftests updates?

Yes. it needs selftest, manpage and documentation updates too.

Unfortunately I am not getting enough reviewed-by for my selftests
and documentation changes. :-(  Need help!


-- 
Ram Pai