[PATCH] mm/migrate_device: Return number of migrating pages in args->cpages

[Ralph Campbell]

On 11/10/22 16:51, Alistair Popple wrote:
> migrate_vma->cpages originally contained a count of the number of
> pages migrating including non-present pages which can be poluated

"populated"

> directly on the target.
>
> Commit 241f68859656 ("mm/migrate_device.c: refactor migrate_vma and
> migrate_deivce_coherent_page()") inadvertantly changed this to contain
> just the number of pages that were unmapped. Usage of
> migrate_vma->cpages isn't documented, but most drivers use it to see
> if all the requested addresses can be migrated so restore the original
> behaviour.
>
> Fixes: 241f68859656 ("mm/migrate_device.c: refactor migrate_vma and migrate_deivce_coherent_page()")
> Signed-off-by: Alistair Popple <apopple at nvidia.com>
> Reported-by: Ralph Campbell <rcampbell at nvidia.com>

You can add
Reviewed-by: Ralph Campbell <rcampbell at nvidia.com>

Thanks!