[PATCH 13/27] mm: move the migrate_vma_* device migration code into it's own file

[Christoph Hellwig]

On Thu, Feb 10, 2022 at 09:35:10PM +1100, Alistair Popple wrote:
> I got the following build error:
> 
> /data/source/linux/mm/migrate_device.c: In function ‘migrate_vma_collect_pmd’:
> /data/source/linux/mm/migrate_device.c:242:3: error: implicit declaration of function ‘flush_tlb_range’; did you mean ‘flush_pmd_tlb_range’? [-Werror=implicit-function-declaration]
>   242 |   flush_tlb_range(walk->vma, start, end);
>       |   ^~~~~~~~~~~~~~~
>       |   flush_pmd_tlb_range
> 
> Including asm/tlbflush.h in migrate_device.c fixed it for me.

Yes, the buildbot also complained about this, but somehow in my test
configfs it got pulled in implicitly.