Re: [PATCH v1 00/15] Keep track of GUPed pages in fs and block

Jerome Glisse
2019-04-17T21:19:57Z

On Tue, Apr 16, 2019 at 10:03:45PM -0400, Jerome Glisse wrote:
> On Wed, Apr 17, 2019 at 04:11:03AM +0300, Boaz Harrosh wrote:
> > On 17/04/19 02:16, Jerome Glisse wrote:
> > > On Wed, Apr 17, 2019 at 01:09:22AM +0300, Boaz Harrosh wrote:
> > >> On 16/04/19 22:57, Jerome Glisse wrote:

[...]

> > >>
> > >> BTW: Are you aware of the users of iov_iter_get_pages_alloc() Do they need fixing too?
> > >
> > > Yeah and that patchset should address those already, i do not think
> > > i missed any.
> > >
> >
> > I could not find a patch for nfs/direct.c where a put_page is called
> > to balance the iov_iter_get_pages_alloc(). Which takes care of for example of
> > the blocklayout.c pages state
> >
> > So I think the deep Audit needs to be for iov_iter_get_pages and get_user_pages
> > and the balancing of that. And the all of bio_alloc and bio_add_page should stay
> > agnostic to any pege-refs taking/putting
>
> Will try to get started on that and see if i hit any roadblock. I will
> report once i get my feet wet, or at least before i drown ;)

So far it does not look too bad:

https://cgit.freedesktop.org/~glisse/linux/log/?h=gup-bio-v2

they are few things that will be harder to fit in like splice
and pipe that are populated from GUP.

Cheers,
Jérôme