| Date | Wed, 15 Apr 2015 17:17:10 +1000 | From | David Gibson <> | 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(). > > 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>
-- 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 [unhandled content-type:application/pgp-signature] |