Re: [PATCH v3] iommufd: Only enforce cache coherency in iommufd_hw_pagetable_alloc

[Jason Gunthorpe]

On Mon, Oct 23, 2023 at 11:57:00AM -0700, Nicolin Chen wrote:
> According to the conversion in the following link:
> https://lore.kernel.org/linux-iommu/20231020135501.GG3952@xxxxxxxxxx/
> 
> The enforce_cache_coherency should be set/enforced in the hwpt allocation
> routine. The iommu driver in its attach_dev() op should decide whether to
> reject or not a device that doesn't match with the configuration of cache
> coherency. Drop the enforce_cache_coherency piece in the attach/replace()
> and move the remaining "num_devices" piece closer to the refcount that is
> using it.
> 
> Accordingly drop its function prototype in the header and mark it static.
> Also add some extra comments to clarify the expected behaviors.
> 
> Suggested-by: Kevin Tian <kevin.tian@xxxxxxxxx>
> Reviewed-by: Lu Baolu <baolu.lu@xxxxxxxxxxxxxxx>
> Signed-off-by: Nicolin Chen <nicolinc@xxxxxxxxxx>
> ---
> Changelog
> v3:
>  * Reworked the first line of the added commets.
> v2: https://lore.kernel.org/all/20231023035733.27378-1-nicolinc@xxxxxxxxxx/
>  * Dropped "fixes" tags and merged two patches into one (Jason)
>  * Added comments to the remaining enforce_cache_coherency call (Jason)
>    [Please feel free to rephrase, or let me know what to change.]
>  * Replace "num_devices++" with list_for_each_entry (Baolu)
> v1: https://lore.kernel.org/all/cover.1697848510.git.nicolinc@xxxxxxxxxx/
> 
>  drivers/iommu/iommufd/device.c          | 20 ++------------------
>  drivers/iommu/iommufd/hw_pagetable.c    |  9 ++++++++-
>  drivers/iommu/iommufd/iommufd_private.h |  1 -
>  3 files changed, 10 insertions(+), 20 deletions(-)

This looks OK to me, Kevin is it what you think it should be now?

Thanks,
Jason