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From:   Oded Gabbay <ogabbay@kernel.org>
Date:   Mon, 7 Nov 2022 23:25:35 +0200
Message-ID: <CAFCwf12AtZ3jqJf8fTmq+bK5Z109N_k4WG1nuDmMXoBNA3KMmA@mail.gmail.com>
Subject: Re: [PATCH RFC 19/19] habanalabs: remove FOLL_FORCE usage
To:     David Hildenbrand <david@redhat.com>
Cc:     linux-kernel@vger.kernel.org, linux-mm@kvack.org,
        etnaviv@lists.freedesktop.org, dri-devel@lists.freedesktop.org,
        linux-arm-kernel@lists.infradead.org,
        linux-samsung-soc@vger.kernel.org, linux-rdma@vger.kernel.org,
        linux-media@vger.kernel.org, linux-kselftest@vger.kernel.org,
        Linus Torvalds <torvalds@linux-foundation.org>,
        Andrew Morton <akpm@linux-foundation.org>,
        Jason Gunthorpe <jgg@ziepe.ca>,
        John Hubbard <jhubbard@nvidia.com>,
        Peter Xu <peterx@redhat.com>,
        Greg Kroah-Hartman <gregkh@linuxfoundation.org>,
        Andrea Arcangeli <aarcange@redhat.com>,
        Hugh Dickins <hughd@google.com>, Nadav Amit <namit@vmware.com>,
        Vlastimil Babka <vbabka@suse.cz>,
        Matthew Wilcox <willy@infradead.org>,
        Mike Kravetz <mike.kravetz@oracle.com>,
        Muchun Song <songmuchun@bytedance.com>,
        Lucas Stach <l.stach@pengutronix.de>,
        David Airlie <airlied@gmail.com>, Arnd Bergmann <arnd@arndb.de>
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On Mon, Nov 7, 2022 at 6:19 PM David Hildenbrand <david@redhat.com> wrote:
>
> FOLL_FORCE is really only for debugger access. As we unpin the pinned pages
> using unpin_user_pages_dirty_lock(true), the assumption is that all these
> pages are writable.
>
> FOLL_FORCE in this case seems to be due to copy-and-past from other
> drivers. Let's just remove it.
>
> Cc: Oded Gabbay <ogabbay@kernel.org>
> Cc: Arnd Bergmann <arnd@arndb.de>
> Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
> Signed-off-by: David Hildenbrand <david@redhat.com>
> ---
>  drivers/misc/habanalabs/common/memory.c | 3 +--
>  1 file changed, 1 insertion(+), 2 deletions(-)
>
> diff --git a/drivers/misc/habanalabs/common/memory.c b/drivers/misc/habanalabs/common/memory.c
> index ef28f3b37b93..e35cca96bbef 100644
> --- a/drivers/misc/habanalabs/common/memory.c
> +++ b/drivers/misc/habanalabs/common/memory.c
> @@ -2312,8 +2312,7 @@ static int get_user_memory(struct hl_device *hdev, u64 addr, u64 size,
>         if (!userptr->pages)
>                 return -ENOMEM;
>
> -       rc = pin_user_pages_fast(start, npages,
> -                                FOLL_FORCE | FOLL_WRITE | FOLL_LONGTERM,
> +       rc = pin_user_pages_fast(start, npages, FOLL_WRITE | FOLL_LONGTERM,
>                                  userptr->pages);
>
>         if (rc != npages) {
> --
> 2.38.1
>
>
Acked-by: Oded Gabbay <ogabbay@kernel.org>
Thanks,
Oded