Re: [PATCH 2/2] iommu: Undo pasid attachment only for the devices that have succeeded

[Jason Gunthorpe <jgg@nvidia.com>]

On Wed, Mar 27, 2024 at 05:54:33AM -0700, Yi Liu wrote:
> There is no error handling now in __iommu_set_group_pasid(), it relies on
> its caller to loop all the devices to undo the pasid attachment. This is
> not self-contained and has unnecessary remove_dev_pasid() calls on the
> devices that have not changed in the __iommu_set_group_pasid() call. this
> results in unnecessary warnings by the underlying iommu drivers. Like the
> Intel iommu driver, it would warn when there is no pasid attachment to
> destroy in the remove_dev_pasid() callback.
> 
> The ideal way is to handle the error within __iommu_set_group_pasid(). This
> not only makes __iommu_set_group_pasid() self-contained, but also avoids
> unnecessary warnings.
> 
> Fixes: 16603704559c7a68 ("iommu: Add attach/detach_dev_pasid iommu interfaces")
> Suggested-by: Jason Gunthorpe <jgg@nvidia.com>
> Signed-off-by: Yi Liu <yi.l.liu@intel.com>
> ---
>  drivers/iommu/iommu.c | 20 ++++++++++++++------
>  1 file changed, 14 insertions(+), 6 deletions(-)

Reviewed-by: Jason Gunthorpe <jgg@nvidia.com>

This will need revising when we get to PASID replace, but good enough
for now

Thanks,
Jason