On 7/22/19 2:33 AM, Christoph Hellwig wrote:
> On Sun, Jul 21, 2019 at 09:30:10PM -0700, john.hubb...@gmail.com 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.

> 
> Also the PageReserved check looks bogus, as I can't see how a reserved
> page can end up here.  So IMHO the above snippled should really look
> something like this:
> 
>       put_user_pages(vsg->pages[i], vsg->num_pages,
>                       vsg->direction == DMA_FROM_DEVICE);
> 
> in the end.
> 

Agreed.

thanks,
-- 
John Hubbard
NVIDIA

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