Re: [PATCH v2 0/2] iommu: Remove iommu_sva_ops::mm_exit()

[Jean-Philippe Brucker <jean-philippe@linaro.org>]

Hi Joerg,

I was wondering if you could take these two patches for v5.8. The API
change is a precursor for the SVA support in SMMUv3, and the VT-d
implementation of the SVA API (queued for 5.8) doesn't implement
iommu_sva_ops.

Thanks,
Jean

On Thu, Apr 23, 2020 at 02:53:27PM +0200, Jean-Philippe Brucker wrote:
> The IOMMU SVA API currently requires device drivers to implement an
> mm_exit() callback, which stops device jobs that do DMA. This function
> is called in the release() MMU notifier, when an address space that is
> shared with a device exits.
> 
> It has been noted several time during discussions about SVA that
> cancelling DMA jobs can be slow and complex, and doing it in the
> release() notifier might cause synchronization issues. Device drivers
> must in any case call unbind() to remove their bond, after stopping DMA
> from a more favorable context (release of a file descriptor).
> 
> Patch 1 removes the mm_exit() callback from the uacce module, and patch
> 2 removes it from the IOMMU API. Since v1 [1] I fixed the uacce unbind
> reported by Zhangfei and added details in the commit message of patch 2.

[1] https://lore.kernel.org/linux-iommu/20200408140427.212807-1-jean-philippe@linaro.org/

> Jean-Philippe Brucker (2):
>   uacce: Remove mm_exit() op
>   iommu: Remove iommu_sva_ops::mm_exit()
> 
>  include/linux/iommu.h      |  30 -------
>  include/linux/uacce.h      |  34 ++------
>  drivers/iommu/iommu.c      |  11 ---
>  drivers/misc/uacce/uacce.c | 172 +++++++++----------------------------
>  4 files changed, 51 insertions(+), 196 deletions(-)
> 
> -- 
> 2.26.0
> 
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