Re: [PATCH v4 2/4] io_uring/rsrc: store folio shift and mask into imu

[Anuj gupta <anuj1072538@gmail.com>]

On Tue, May 14, 2024 at 1:25 PM Chenliang Li <cliang01.li@samsung.com> wrote:
>
> Store the folio shift and folio mask into imu struct and use it in
> iov_iter adjust, as we will have non PAGE_SIZE'd chunks if a
> multi-hugepage buffer get coalesced.
>
> Signed-off-by: Chenliang Li <cliang01.li@samsung.com>
> ---
>  io_uring/rsrc.c | 6 ++++--
>  io_uring/rsrc.h | 2 ++
>  2 files changed, 6 insertions(+), 2 deletions(-)
>
> diff --git a/io_uring/rsrc.c b/io_uring/rsrc.c
> index d08224c0c5b0..578d382ca9bc 100644
> --- a/io_uring/rsrc.c
> +++ b/io_uring/rsrc.c
> @@ -1015,6 +1015,8 @@ static int io_sqe_buffer_register(struct io_ring_ctx *ctx, struct iovec *iov,
>         imu->ubuf = (unsigned long) iov->iov_base;
>         imu->ubuf_end = imu->ubuf + iov->iov_len;
>         imu->nr_bvecs = nr_pages;
> +       imu->folio_shift = PAGE_SHIFT;
> +       imu->folio_mask = PAGE_MASK;
>         *pimu = imu;
>         ret = 0;
>
> @@ -1153,12 +1155,12 @@ int io_import_fixed(int ddir, struct iov_iter *iter,
>
>                         /* skip first vec */
>                         offset -= bvec->bv_len;
> -                       seg_skip = 1 + (offset >> PAGE_SHIFT);
> +                       seg_skip = 1 + (offset >> imu->folio_shift);
>
>                         iter->bvec = bvec + seg_skip;
>                         iter->nr_segs -= seg_skip;
>                         iter->count -= bvec->bv_len + offset;
> -                       iter->iov_offset = offset & ~PAGE_MASK;
> +                       iter->iov_offset = offset & ~imu->folio_mask;
>                 }
>         }
>
> diff --git a/io_uring/rsrc.h b/io_uring/rsrc.h
> index b2a9d66b76dd..93da02e652bc 100644
> --- a/io_uring/rsrc.h
> +++ b/io_uring/rsrc.h
> @@ -46,7 +46,9 @@ struct io_mapped_ubuf {
>         u64             ubuf;
>         u64             ubuf_end;
>         unsigned int    nr_bvecs;
> +       unsigned int    folio_shift;
>         unsigned long   acct_pages;
> +       unsigned long   folio_mask;
>         struct bio_vec  bvec[] __counted_by(nr_bvecs);
>  };
>
> --
> 2.34.1
>
>
Looks good.
Reviewed-by: Anuj Gupta <anuj20.g@samsung.com>
--
Anuj Gupta