Re: [RESEND 5/7] IB/hfi1: Use the new FOLL_LONGTERM flag to get_user_pages_fast()

Ira Weiny
2019-03-25T08:43:59Z

On Fri, Mar 22, 2019 at 03:14:26PM -0700, Dan Williams wrote:
> On Sun, Mar 17, 2019 at 7:36 PM <ira.weiny@intel.com> wrote:
> >
> > From: Ira Weiny <ira.weiny@intel.com>
> >
> > Use the new FOLL_LONGTERM to get_user_pages_fast() to protect against
> > FS DAX pages being mapped.
> >
> > Signed-off-by: Ira Weiny <ira.weiny@intel.com>
> > ---
> > drivers/infiniband/hw/hfi1/user_pages.c | 6 ++++--
> > 1 file changed, 4 insertions(+), 2 deletions(-)
> >
> > diff --git a/drivers/infiniband/hw/hfi1/user_pages.c b/drivers/infiniband/hw/hfi1/user_pages.c
> > index 78ccacaf97d0..6a7f9cd5a94e 100644
> > --- a/drivers/infiniband/hw/hfi1/user_pages.c
> > +++ b/drivers/infiniband/hw/hfi1/user_pages.c
> > @@ -104,9 +104,11 @@ int hfi1_acquire_user_pages(struct mm_struct *mm, unsigned long vaddr, size_t np
> > bool writable, struct page **pages)
> > {
> > int ret;
> > + unsigned int gup_flags = writable ? FOLL_WRITE : 0;
>
> Maybe:
>
> unsigned int gup_flags = FOLL_LONGTERM | (writable ? FOLL_WRITE : 0);
>
> ?

Sure looks good.

Ira

>
> >
> > - ret = get_user_pages_fast(vaddr, npages, writable ? FOLL_WRITE : 0,
> > - pages);
> > + gup_flags |= FOLL_LONGTERM;
> > +
> > + ret = get_user_pages_fast(vaddr, npages, gup_flags, pages);
> > if (ret < 0)
> > return ret;
> >
> > --
> > 2.20.1
> >
>