On Mon, Jan 05, 2026 at 05:57:37PM -0700, Caleb Sander Mateos wrote:
> Factor a helper function ublk_copy_user_bvec() out of
> ublk_copy_user_pages(). It will be used for copying integrity data too.
>
> Signed-off-by: Caleb Sander Mateos <csander@purestorage.com>
> ---
> drivers/block/ublk_drv.c | 52 +++++++++++++++++++++++-----------------
> 1 file changed, 30 insertions(+), 22 deletions(-)
>
> diff --git a/drivers/block/ublk_drv.c b/drivers/block/ublk_drv.c
> index 2b0a9720921d..2ce9afdecc15 100644
> --- a/drivers/block/ublk_drv.c
> +++ b/drivers/block/ublk_drv.c
> @@ -1000,10 +1000,39 @@ static const struct block_device_operations ub_fops = {
> .open = ublk_open,
> .free_disk = ublk_free_disk,
> .report_zones = ublk_report_zones,
> };
>
> +static bool ublk_copy_user_bvec(const struct bio_vec *bv, unsigned *offset,
> + struct iov_iter *uiter, int dir, size_t *done)
> +{
> + unsigned len;
> + void *bv_buf;
> + size_t copied;
> +
> + if (*offset >= bv->bv_len) {
> + *offset -= bv->bv_len;
> + return true;
> + }
> +
> + len = bv->bv_len - *offset;
> + bv_buf = kmap_local_page(bv->bv_page) + bv->bv_offset + *offset;
> + if (dir == ITER_DEST)
> + copied = copy_to_iter(bv_buf, len, uiter);
> + else
> + copied = copy_from_iter(bv_buf, len, uiter);
> +
> + kunmap_local(bv_buf);
> +
> + *done += copied;
> + if (copied < len)
> + return false;
> +
> + *offset = 0;
> + return true;
> +}
> +
> /*
> * Copy data between request pages and io_iter, and 'offset'
> * is the start point of linear offset of request.
> */
> static size_t ublk_copy_user_pages(const struct request *req,
> @@ -1012,33 +1041,12 @@ static size_t ublk_copy_user_pages(const struct request *req,
> struct req_iterator iter;
> struct bio_vec bv;
> size_t done = 0;
>
> rq_for_each_segment(bv, req, iter) {
> - unsigned len;
> - void *bv_buf;
> - size_t copied;
> -
> - if (offset >= bv.bv_len) {
> - offset -= bv.bv_len;
> - continue;
> - }
> -
> - len = bv.bv_len - offset;
> - bv_buf = kmap_local_page(bv.bv_page) + bv.bv_offset + offset;
> - if (dir == ITER_DEST)
> - copied = copy_to_iter(bv_buf, len, uiter);
> - else
> - copied = copy_from_iter(bv_buf, len, uiter);
> -
> - kunmap_local(bv_buf);
> -
> - done += copied;
> - if (copied < len)
> + if (!ublk_copy_user_bvec(&bv, &offset, uiter, dir, &done))
> break;
> -
> - offset = 0;
> }
> return done;
> }
Reviewed-by: Ming Lei <ming.lei@redhat.com>
Thanks,
Ming