Re: [PATCH 0/2] KVM: do not assume PTE is writable after follow_pfn

[Joao Martins]

On 2/9/21 8:19 AM, Christoph Hellwig wrote:
> On Mon, Feb 08, 2021 at 07:26:25PM -0400, Jason Gunthorpe wrote:
>>>> page_mkclean() has some technique to make the notifier have the right
>>>> size without becoming entangled in the PTL locks..
>>>
>>> Right.  I guess it's because dax doesn't have "struct page*" on the
>>> back, so it
>>
>> It doesn't? I thought DAX cases did?
> 
> File system DAX has a struct page, device DAX does not.  Which means
> everything using iomap should have a page available, but i'm adding
> Dan as he should know the details :)
> 
Both fsdax and device-dax have struct page. It's the pmem block device
that doesn't.