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Date: Wed, 15 Apr 2015 17:17:10 +1000
From: David Gibson <david@gibson.dropbear.id.au>
To: Alexey Kardashevskiy <aik@ozlabs.ru>
Subject: Re: [PATCH kernel v8 09/31] powerpc/powernv: Do not set "read" flag
 if direction==DMA_NONE
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On Fri, Apr 10, 2015 at 04:30:51PM +1000, Alexey Kardashevskiy wrote:
> Normally a bitmap from the iommu_table is used to track what TCE entry
> is in use. Since we are going to use iommu_table without its locks and
> do xchg() instead, it becomes essential not to put bits which are not
> implied in the direction flag.

It's not clear to me from this why lack of locking implies the need to
not put extra bits in.

> This adds iommu_direction_to_tce_perm() (its counterpart is there already)
> and uses it for powernv's pnv_tce_build().
>=20
> Signed-off-by: Alexey Kardashevskiy <aik@ozlabs.ru>

I have no objection to the patch though, so

Reviewed-by: David Gibson <david@gibson.dropbear.id.au>

--=20
David Gibson			| I'll have my music baroque, and my code
david AT gibson.dropbear.id.au	| minimalist, thank you.  NOT _the_ _other_
				| _way_ _around_!
http://www.ozlabs.org/~dgibson

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