Re: [PATCH 2/2] mm: set PG_dma_pinned on get_user_pages*()

[John Hubbard]

On 06/18/2018 01:12 AM, Christoph Hellwig wrote:
> On Sun, Jun 17, 2018 at 01:28:18PM -0700, John Hubbard wrote:
>> Yes. However, my thinking was: get_user_pages() can become a way to indicate that 
>> these pages are going to be treated specially. In particular, the caller
>> does not really want or need to support certain file operations, while the
>> page is flagged this way.
>>
>> If necessary, we could add a new API call.
> 
> That API call is called get_user_pages_longterm.

OK...I had the impression that this was just semi-temporary API for dax, but
given that it's an exported symbol, I guess it really is here to stay.

Anyway, are you thinking that we could set the new page flag here? Or just pointing
out that the other get_user_pages* variants are the wrong place?