On Mon, Jul 18, 2022 at 04:47:44AM -0700, Nadav Amit wrote:
> From: Nadav Amit <namit@xxxxxxxxxx>
>
> As the next patches are going to introduce more information that needs
> to be propagated regarding handled user requests, introduce uffd_flags
> that would be used to propagate this information.
>
> Remove the unused UFFD_FLAGS_SET to avoid confusion in the constant
> names.
>
> Introducing uffd flags also allows to avoid mm/userfaultfd from being
> using uapi (e.g., UFFDIO_COPY_MODE_WP).
>
> Cc: Mike Kravetz <mike.kravetz@xxxxxxxxxx>
> Cc: Hugh Dickins <hughd@xxxxxxxxxx>
> Cc: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx>
> Cc: Axel Rasmussen <axelrasmussen@xxxxxxxxxx>
> Cc: Peter Xu <peterx@xxxxxxxxxx>
> Cc: Mike Rapoport <rppt@xxxxxxxxxxxxx>
> Acked-by: David Hildenbrand <david@xxxxxxxxxx>
> Signed-off-by: Nadav Amit <namit@xxxxxxxxxx>
> ---
> fs/userfaultfd.c | 22 +++++++++++---
> include/linux/hugetlb.h | 4 +--
> include/linux/shmem_fs.h | 8 +++--
> include/linux/userfaultfd_k.h | 24 +++++++++------
> mm/hugetlb.c | 3 +-
> mm/shmem.c | 6 ++--
> mm/userfaultfd.c | 57 ++++++++++++++++++-----------------
> 7 files changed, 73 insertions(+), 51 deletions(-)
>
> diff --git a/fs/userfaultfd.c b/fs/userfaultfd.c
> index e943370107d0..2ae24327beec 100644
> --- a/fs/userfaultfd.c
> +++ b/fs/userfaultfd.c
> @@ -1682,6 +1682,8 @@ static int userfaultfd_copy(struct userfaultfd_ctx *ctx,
> struct uffdio_copy uffdio_copy;
> struct uffdio_copy __user *user_uffdio_copy;
> struct userfaultfd_wake_range range;
> + bool mode_wp;
> + uffd_flags_t uffd_flags;
>
> user_uffdio_copy = (struct uffdio_copy __user *) arg;
>
> @@ -1708,10 +1710,15 @@ static int userfaultfd_copy(struct userfaultfd_ctx *ctx,
> goto out;
> if (uffdio_copy.mode & ~(UFFDIO_COPY_MODE_DONTWAKE|UFFDIO_COPY_MODE_WP))
> goto out;
> +
> + mode_wp = uffdio_copy.mode & UFFDIO_COPY_MODE_WP;
This seems to be the only place where mode_wp is used in this function.
I'd just drop it, and set uffd_flags directly from uffdio_copy.mode. E.g.
something like
uffd_flags_t uffd_flags = UFFD_FLAGS_NONE;
...
if (uffdio_copy.mode & UFFDIO_COPY_MODE_WP)
uffd_flags = UFFD_FLAGS_WP;
Otherwise
Acked-by: Mike Rapoport <rppt@xxxxxxxxxxxxx>
> +
> + uffd_flags = mode_wp ? UFFD_FLAGS_WP : UFFD_FLAGS_NONE;
> +
> if (mmget_not_zero(ctx->mm)) {
> ret = mcopy_atomic(ctx->mm, uffdio_copy.dst, uffdio_copy.src,
> uffdio_copy.len, &ctx->mmap_changing,
> - uffdio_copy.mode);
> + uffd_flags);
> mmput(ctx->mm);
> } else {
> return -ESRCH;
--
Sincerely yours,
Mike.
