Re: [PATCH 05/10] PCI/P2PDMA: Export pci_p2pdma_map_type() function

[Logan Gunthorpe]

On 2025-07-24 02:13, Leon Romanovsky wrote:
> On Thu, Jul 24, 2025 at 10:03:13AM +0200, Christoph Hellwig wrote:
>> On Wed, Jul 23, 2025 at 04:00:06PM +0300, Leon Romanovsky wrote:
>>> From: Leon Romanovsky <leo...@nvidia.com>
>>>
>>> Export the pci_p2pdma_map_type() function to allow external modules
>>> and subsystems to determine the appropriate mapping type for P2PDMA
>>> transfers between a provider and target device.
>>
>> External modules have no business doing this.
> 
> VFIO PCI code is built as module. There is no way to access PCI p2p code
> without exporting functions in it.

The solution that would make more sense to me would be for either
dma_iova_try_alloc() or another helper in dma-iommu.c to handle the
P2PDMA case. dma-iommu.c already uses those same interfaces and thus
there would be no need to export the low level helpers from the p2pdma code.

Logan