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From: Jarkko Sakkinen <jarkko.sakkinen@linux.intel.com>
To: Jason Gunthorpe <jgunthorpe@obsidianresearch.com>
Cc: tpmdd-devel@lists.sourceforge.net,
	linux-security-module@vger.kernel.org,
	Peter Huewe <peterhuewe@gmx.de>,
	Marcel Selhorst <tpmdd@selhorst.net>,
	Christophe Ricard <christophe.ricard@gmail.com>,
	open list <linux-kernel@vger.kernel.org>
Subject: Re: [PATCH] tpm: drop chip->is_open and chip->duration_adjusted
Date: Mon, 14 Nov 2016 21:11:54 -0800	[thread overview]
Message-ID: <20161115051106.u2xoduwf2kpcznv3@intel.com> (raw)
In-Reply-To: <20161115043001.GA22482@obsidianresearch.com>

On Mon, Nov 14, 2016 at 09:30:01PM -0700, Jason Gunthorpe wrote:
> On Mon, Nov 14, 2016 at 03:44:58PM -0800, Jarkko Sakkinen wrote:
> > Use atomic bitops for chip->flags so that we do not need chip->is_open
> > and chip->duration_adjusted anymore.
> 
> I don't know if it s a really great idea to use atomic bit ops for
> things that do not need to be atomic.. It makes the locking scheme
> less clear. is open is genuinely different since it relies on the
> atomic for correctness.

The way I see it is one of the status flags bound to chip among the
others. I do not see this cause too much harm for clarity. It eases
debugging the driver a bit because you get more state out of 'flags'.

It also makes code little a bit more robust as flags is independent of
locks.

How strong is your opposition here? I do not see any exceptional damage
done but see some subtle but still significant benefits.

> Merging is_duration makes lots of sense though

Also timeout_adjusted should be merged (for some reason missed it).

> Jason

/Jarkko

WARNING: multiple messages have this Message-ID (diff)
From: Jarkko Sakkinen <jarkko.sakkinen-VuQAYsv1563Yd54FQh9/CA@public.gmane.org>
To: Jason Gunthorpe
	<jgunthorpe-ePGOBjL8dl3ta4EC/59zMFaTQe2KTcn/@public.gmane.org>
Cc: Christophe Ricard
	<christophe.ricard-Re5JQEeQqe8AvxtiuMwx3w@public.gmane.org>,
	open list <linux-kernel-u79uwXL29TY76Z2rM5mHXA@public.gmane.org>,
	linux-security-module-u79uwXL29TY76Z2rM5mHXA@public.gmane.org,
	tpmdd-devel-5NWGOfrQmneRv+LV9MX5uipxlwaOVQ5f@public.gmane.org
Subject: Re: [PATCH] tpm: drop chip->is_open and chip->duration_adjusted
Date: Mon, 14 Nov 2016 21:11:54 -0800	[thread overview]
Message-ID: <20161115051106.u2xoduwf2kpcznv3@intel.com> (raw)
In-Reply-To: <20161115043001.GA22482-ePGOBjL8dl3ta4EC/59zMFaTQe2KTcn/@public.gmane.org>

On Mon, Nov 14, 2016 at 09:30:01PM -0700, Jason Gunthorpe wrote:
> On Mon, Nov 14, 2016 at 03:44:58PM -0800, Jarkko Sakkinen wrote:
> > Use atomic bitops for chip->flags so that we do not need chip->is_open
> > and chip->duration_adjusted anymore.
> 
> I don't know if it s a really great idea to use atomic bit ops for
> things that do not need to be atomic.. It makes the locking scheme
> less clear. is open is genuinely different since it relies on the
> atomic for correctness.

The way I see it is one of the status flags bound to chip among the
others. I do not see this cause too much harm for clarity. It eases
debugging the driver a bit because you get more state out of 'flags'.

It also makes code little a bit more robust as flags is independent of
locks.

How strong is your opposition here? I do not see any exceptional damage
done but see some subtle but still significant benefits.

> Merging is_duration makes lots of sense though

Also timeout_adjusted should be merged (for some reason missed it).

> Jason

/Jarkko

------------------------------------------------------------------------------

  reply	other threads:[~2016-11-15  5:12 UTC|newest]

Thread overview: 11+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2016-11-14 23:44 [PATCH] tpm: drop chip->is_open and chip->duration_adjusted Jarkko Sakkinen
2016-11-14 23:44 ` Jarkko Sakkinen
2016-11-15  4:30 ` Jason Gunthorpe
2016-11-15  5:11   ` Jarkko Sakkinen [this message]
2016-11-15  5:11     ` Jarkko Sakkinen
2016-11-16  5:28     ` Jason Gunthorpe
2016-11-16 22:54       ` Jarkko Sakkinen
2016-11-17 10:40 ` [tpmdd-devel] " Nayna
2016-11-17 10:40   ` Nayna
2016-11-17 17:36   ` [tpmdd-devel] " Jarkko Sakkinen
2016-11-17 17:36     ` Jarkko Sakkinen

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