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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, linux-mm@kvack.org,
	x86@kernel.org, linux-arch@vger.kernel.org,
	linux-kernel@vger.kernel.org, akpm@linux-foundation.org,
	benh@kernel.crashing.org, paulus@samba.org,
	khandual@linux.vnet.ibm.com, aneesh.kumar@linux.vnet.ibm.com,
	bsingharora@gmail.com, hbabu@us.ibm.com, mhocko@kernel.org,
	bauerman@linux.vnet.ibm.com, ebiederm@xmission.com,
	corbet@lwn.net, arnd@arndb.de, fweimer@redhat.com,
	msuchanek@suse.com, Ulrich.Weigand@de.ibm.com
Subject: Re: [PATCH v3] x86: treat pkey-0 special
Date: Thu, 15 Mar 2018 10:21:29 -0700	[thread overview]
Message-ID: <20180315172129.GD1060@ram.oc3035372033.ibm.com> (raw)
In-Reply-To: <f5ef79ef-122a-e0a3-9b8e-d49c33f4a417@intel.com>

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?

RP

  parent reply	other threads:[~2018-03-15 17:21 UTC|newest]

Thread overview: 7+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2018-03-14 21:00 [PATCH v3] x86: treat pkey-0 special Ram Pai
2018-03-15  9:46 ` Thomas Gleixner
2018-03-15 15:55   ` Dave Hansen
2018-03-15 16:13     ` Thomas Gleixner
2018-03-15 17:21     ` Ram Pai [this message]
2018-03-15 17:31       ` Dave Hansen
2018-03-15 17:39         ` Ram Pai

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