Re: [PATCH v8 02/10] iov_iter: Add a function to extract a page list from an iterator

[David Howells]

David Hildenbrand <david@xxxxxxxxxx> wrote:

> > +#define iov_iter_extract_mode(iter) (user_backed_iter(iter) ? FOLL_PIN : 0)
> > +
> 
> Does it make sense to move that to the patch where it is needed? (do we need
> it at all anymore?)

Yes, we need something.  Granted, there are now only two alternatives, not
three: either the pages are going to be pinned or they're not going to be
pinned, but I would rather have a specific function that tells you than just
use, say, user_backed_iter() to make it easier to adjust it later if we need
to - and easier to find the places where we need to adjust.

But if it's preferred we could require people to use user_backed_iter()
instead.

David