[PATCH v1 0/3] udmabuf: Add support for page migration out of movable zone or CMA

[Jason Gunthorpe]

On Wed, Aug 16, 2023 at 11:49:31PM -0700, Vivek Kasireddy wrote:
> This patch series adds support for migrating pages associated with
> a udmabuf out of the movable zone or CMA to avoid breaking features
> such as memory hotunplug.
> 
> The first patch exports check_and_migrate_movable_pages() function
> out of GUP so that the udmabuf driver can leverage it for page
> migration that is done as part of the second patch. The last patch
> adds two new udmabuf selftests to verify data coherency after
> page migration.

Please don't do this. If you want to do what GUP does then call
GUP. udmabuf is not so special that it needs to open code its own
weird version of it.

Jason