Re: [PATCH v5 1/7] iommu: Factor out some helpers

[Jason Gunthorpe <jgg@nvidia.com>]

On Wed, Oct 11, 2023 at 07:14:48PM +0100, Robin Murphy wrote:
> The pattern for picking the first device out of the group list is
> repeated a few times now, so it's clearly worth factoring out, which
> also helps hide the iommu_group_dev detail from places that don't need
> to know. Similarly, the safety check for dev_iommu_ops() at certain
> public interfaces starts looking a bit repetitive, and might not be
> completely obvious at first glance, so let's factor that out for clarity
> as well, in preparation for more uses of both.
> 
> Reviewed-by: Lu Baolu <baolu.lu@linux.intel.com>
> Signed-off-by: Robin Murphy <robin.murphy@arm.com>
> 
> ---
> 
> v3: Rename dev_iommu_ops_valid() to reflect what it's actually checking,
>     rather than an implied consequence.
> v4: Rebase, also catch the sneaky one in iommu_get_group_resv_regions()
>     which wasn't the full pattern (but really should be since it guards
>     the dev_iommu_ops() invocation in iommu_get_resv_regions()).
> ---
>  drivers/iommu/iommu.c | 56 ++++++++++++++++++++-----------------------
>  1 file changed, 26 insertions(+), 30 deletions(-)

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

Jason