Re: [PATCH 12/20] ublk: implement integrity user copy

Ming Lei
2025-12-26T02:38:26Z

On Tue, Dec 16, 2025 at 10:34:46PM -0700, Caleb Sander Mateos wrote:
> From: Stanley Zhang <stazhang@purestorage.com>
>
> Add a function ublk_copy_user_integrity() to copy integrity information
> between a request and a user iov_iter. This mirrors the existing
> ublk_copy_user_pages() but operates on request integrity data instead of
> regular data. Check UBLKSRV_IO_INTEGRITY_FLAG in iocb->ki_pos in
> ublk_user_copy() to choose between copying data or integrity data.
>
> Signed-off-by: Stanley Zhang <stazhang@purestorage.com>
> [csander: change offset units from data bytes to integrity data bytes,
> test UBLKSRV_IO_INTEGRITY_FLAG after subtracting UBLKSRV_IO_BUF_OFFSET,
> fix CONFIG_BLK_DEV_INTEGRITY=n build,
> rebase on ublk user copy refactor]
> Signed-off-by: Caleb Sander Mateos <csander@purestorage.com>
> ---
> drivers/block/ublk_drv.c | 43 ++++++++++++++++++++++++++++++++++++++--
> 1 file changed, 41 insertions(+), 2 deletions(-)
>
> diff --git a/drivers/block/ublk_drv.c b/drivers/block/ublk_drv.c
> index 7fa0a9f0bfae..042df4de9253 100644
> --- a/drivers/block/ublk_drv.c
> +++ b/drivers/block/ublk_drv.c
> @@ -606,10 +606,15 @@ static inline unsigned ublk_pos_to_tag(loff_t pos)
> {
> return ((pos - UBLKSRV_IO_BUF_OFFSET) >> UBLK_TAG_OFF) &
> UBLK_TAG_BITS_MASK;
> }
>
> +static inline bool ublk_pos_is_integrity(loff_t pos)
> +{
> + return !!((pos - UBLKSRV_IO_BUF_OFFSET) & UBLKSRV_IO_INTEGRITY_FLAG);
> +}
> +
> static void ublk_dev_param_basic_apply(struct ublk_device *ub)
> {
> const struct ublk_param_basic *p = &ub->params.basic;
>
> if (p->attrs & UBLK_ATTR_READ_ONLY)
> @@ -1034,10 +1039,31 @@ static size_t ublk_copy_user_pages(const struct request *req,
> break;
> }
> return done;
> }
>
> +static size_t ublk_copy_user_integrity(const struct request *req,
> + unsigned offset, struct iov_iter *uiter, int dir)
> +{
> + size_t done = 0;
> +#ifdef CONFIG_BLK_DEV_INTEGRITY
> + struct bio *bio = req->bio;
> + struct bvec_iter iter;
> + struct bio_vec iv;
> +
> + if (!blk_integrity_rq(req))
> + return 0;
> +
> + bio_for_each_integrity_vec(iv, bio, iter) {
> + if (!ublk_copy_user_bvec(iv, &offset, uiter, dir, &done))
> + break;
> + }
> +#endif
> +
> + return done;
> +}

The usual way is to define the whole helper conditionally:

#ifdef CONFIG_BLK_DEV_INTEGRITY
static size_t ublk_copy_user_integrity(const struct request *req,
unsigned offset, struct iov_iter *uiter, int dir)
{
...
}
#else
static inline size_t ublk_copy_user_integrity(const struct request *req,
unsigned offset, struct iov_iter *uiter, int dir)
{
return 0;
}
#endif

Otherwise, this patch looks fine.

Thanks,
Ming