[PATCH v9 06/11] ACPI/IORT: Add support to retrieve IORT RMR reserved regions

[Christoph Hellwig]

On Tue, Apr 19, 2022 at 08:31:55AM +0000, Shameerali Kolothum Thodi via iommu wrote:
> Sorry for the delayed response(was on holidays). So if we move the
> iommu_dma_put_resv_region() call to generic_iommu_put_resv_regions() ,
> will that address the concerns here?
> 
> I think it will resolve the issue in 05/11 as well pointed out by Christoph
> where we end up not releasing reserved regions when
> CONFIG_IOMMU_DMA is not set.

As Robin pointed out we might not really deduct that ACPI means RMR.

I suspect the best would be to just attach a free callback to the
regions.  Either by adding it directly to struct iommu_resv_region
if we thing there are few enough regions to not be worried about
the memory use, or other by adding a container struct for the list_head
that contains the free callback.