Re: [PATCH kernel v8 09/31] powerpc/powernv: Do not set "read" flag if direction==DMA_NONE

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 <redacted>

I have no objection to the patch though, so

Reviewed-by: David Gibson <redacted>

-- 
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