Re: [PATCH 1/3] drivers/gpu/drm/via: convert put_page() to put_user_page*()

[Matthew Wilcox]

On Mon, Jul 22, 2019 at 11:53:54AM -0700, John Hubbard wrote:
> On 7/22/19 2:33 AM, Christoph Hellwig wrote:
> > On Sun, Jul 21, 2019 at 09:30:10PM -0700, john.hubbard@xxxxxxxxx wrote:
> >>  		for (i = 0; i < vsg->num_pages; ++i) {
> >>  			if (NULL != (page = vsg->pages[i])) {
> >>  				if (!PageReserved(page) && (DMA_FROM_DEVICE == vsg->direction))
> >> -					SetPageDirty(page);
> >> -				put_page(page);
> >> +					put_user_pages_dirty(&page, 1);
> >> +				else
> >> +					put_user_page(page);
> >>  			}
> > 
> > Can't just pass a dirty argument to put_user_pages?  Also do we really
> 
> Yes, and in fact that would help a lot more than the single page case,
> which is really just cosmetic after all.
> 
> > need a separate put_user_page for the single page case?
> > put_user_pages_dirty?
> 
> Not really. I'm still zeroing in on the ideal API for all these call sites,
> and I agree that the approach below is cleaner.

so enum { CLEAN = 0, DIRTY = 1, LOCK = 2, DIRTY_LOCK = 3 };
?