Re: [PATCH v2] iommu/dma: Map scatterlists more parsimoniously

[Yong Wu <yong.wu-NuS5LvNUpcJWk0Htik3J/w@public.gmane.org>]

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On Fri, 2015-11-20 at 10:57 +0000, Robin Murphy wrote:

> Whilst blindly assuming the worst case for segment boundaries and
> aligning every segment individually is safe from the point of view
> of respecting the device's parameters, it is also undeniably a waste
> of IOVA space. Futhermore, the knock-on effects of more pages than
> necessary being exposed to device access, additional overhead in page
> table updates and TLB invalidations, etc., are even more undesirable.
> 
> Improve matters by taking the actual boundary mask into account to
> actively detect the cases in which we really do need to adjust a
> segment, and avoid wasting space in the remainder.
> 
> Tested-by: Yong Wu <yong.wu-NuS5LvNUpcJWk0Htik3J/w@public.gmane.org>
> Signed-off-by: Robin Murphy <robin.murphy-5wv7dgnIgG8@public.gmane.org>


Hi Robin,
    What's the status of this patch? Could we know whether it will be
merged into v4.5?
 

> ---
> 
> Minor change: removed the now-redundant null check on prev, since we no
> longer dereference it unconditionally and pad_len is guaranteed to be
> zero the first time around.
> 
>  drivers/iommu/dma-iommu.c | 16 ++++++++--------
>  1 file changed, 8 insertions(+), 8 deletions(-)
> 

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