Re: [PATCH v7 18/19] iov_iter: Introduce nofault flag to disable page faults

[Al Viro]

On Fri, Aug 27, 2021 at 06:49:25PM +0200, Andreas Gruenbacher wrote:
> Introduce a new nofault flag to indicate to get_user_pages to use the
> FOLL_NOFAULT flag.  This will cause get_user_pages to fail when it
> would otherwise fault in a page.
> 
> Currently, the noio flag is only checked in iov_iter_get_pages and
> iov_iter_get_pages_alloc.  This is enough for iomaop_dio_rw, but it
> may make sense to check in other contexts as well.

I can live with that, but
	* direct assignments (as in the next patch) are fucking hard to
grep for.  Is it intended to be "we set it for duration of primitive",
or...?
	* it would be nice to have a description of intended semantics
for that thing.  This "may make sense to check in other contexts" really
needs to be elaborated (and agreed) upon.  Details, please.