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

Dan Williams
2019-03-22T22:14:26Z

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);

?

>
> - 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
>