linux-kernel - Re: [RESEND 5/7] IB/hfi1: Use the new FOLL_LONGTERM flag to get_user_pages

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Message-ID: <CAA9_cmdQjMekSFU09gLc87-PVx2iHeeh2jC6KeFY1UeadpPh4A@mail.gmail.com>
Date:   Fri, 22 Mar 2019 15:14:26 -0700
From:   Dan Williams <dan.j.williams@...el.com>
To:     ira.weiny@...el.com
Cc:     Andrew Morton <akpm@...ux-foundation.org>,
        John Hubbard <jhubbard@...dia.com>,
        Michal Hocko <mhocko@...e.com>,
        "Kirill A. Shutemov" <kirill.shutemov@...ux.intel.com>,
        Peter Zijlstra <peterz@...radead.org>,
        Jason Gunthorpe <jgg@...pe.ca>,
        Benjamin Herrenschmidt <benh@...nel.crashing.org>,
        Paul Mackerras <paulus@...ba.org>,
        "David S. Miller" <davem@...emloft.net>,
        Martin Schwidefsky <schwidefsky@...ibm.com>,
        Heiko Carstens <heiko.carstens@...ibm.com>,
        Rich Felker <dalias@...c.org>,
        Yoshinori Sato <ysato@...rs.sourceforge.jp>,
        Thomas Gleixner <tglx@...utronix.de>,
        Ingo Molnar <mingo@...hat.com>, Borislav Petkov <bp@...en8.de>,
        Ralf Baechle <ralf@...ux-mips.org>,
        James Hogan <jhogan@...nel.org>, linux-mm <linux-mm@...ck.org>,
        Linux Kernel Mailing List <linux-kernel@...r.kernel.org>,
        linux-mips@...r.kernel.org,
        linuxppc-dev <linuxppc-dev@...ts.ozlabs.org>,
        linux-s390 <linux-s390@...r.kernel.org>,
        Linux-sh <linux-sh@...r.kernel.org>, sparclinux@...r.kernel.org,
        linux-rdma@...r.kernel.org,
        "netdev@...r.kernel.org" <netdev@...r.kernel.org>
Subject: Re: [RESEND 5/7] IB/hfi1: Use the new FOLL_LONGTERM flag to get_user_pages_fast()

On Sun, Mar 17, 2019 at 7:36 PM <ira.weiny@...el.com> wrote:
>
> From: Ira Weiny <ira.weiny@...el.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@...el.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
>