Re: [PATCH 3/6] iov_iter: new iov_iter_pin_pages*() routines

[Al Viro]

On Sat, Aug 27, 2022 at 01:36:04AM -0700, John Hubbard wrote:
> Provide two new wrapper routines that are intended for user space pages
> only:
> 
>     iov_iter_pin_pages()
>     iov_iter_pin_pages_alloc()
> 
> Internally, these routines call pin_user_pages_fast(), instead of
> get_user_pages_fast().
> 
> As always, callers must use unpin_user_pages() or a suitable FOLL_PIN
> variant, to release the pages, if they actually were acquired via
> pin_user_pages_fast().
> 
> This is a prerequisite to converting bio/block layers over to use
> pin_user_pages_fast().

You do realize that O_DIRECT on ITER_BVEC is possible, right?