On Mon, Jan 05, 2026 at 05:57:41PM -0700, Caleb Sander Mateos wrote:
> From: Stanley Zhang <[email protected]>
>
> 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 <[email protected]>
> [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 <[email protected]>
> ---
> drivers/block/ublk_drv.c | 52 +++++++++++++++++++++++++++++++++--
> include/uapi/linux/ublk_cmd.h | 4 +++
> 2 files changed, 53 insertions(+), 3 deletions(-)
>
> diff --git a/drivers/block/ublk_drv.c b/drivers/block/ublk_drv.c
> index e44ab9981ef4..9694a4c1caa7 100644
> --- a/drivers/block/ublk_drv.c
> +++ b/drivers/block/ublk_drv.c
> @@ -621,10 +621,15 @@ 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);
> +}
> +
It could be more readable to check UBLKSRV_IO_INTEGRITY_FLAG only.
> 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)
> @@ -1047,10 +1052,37 @@ static size_t ublk_copy_user_pages(const struct
> request *req,
> break;
> }
> return done;
> }
>
> +#ifdef CONFIG_BLK_DEV_INTEGRITY
> +static size_t ublk_copy_user_integrity(const struct request *req,
> + unsigned offset, struct iov_iter *uiter, int dir)
> +{
> + size_t done = 0;
> + 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;
> + }
> +
> + return done;
> +}
> +#else /* #ifdef CONFIG_BLK_DEV_INTEGRITY */
> +static size_t ublk_copy_user_integrity(const struct request *req,
> + unsigned offset, struct iov_iter *uiter, int dir)
> +{
> + return 0;
> +}
> +#endif /* #ifdef CONFIG_BLK_DEV_INTEGRITY */
> +
> static inline bool ublk_need_map_req(const struct request *req)
> {
> return ublk_rq_has_data(req) && req_op(req) == REQ_OP_WRITE;
> }
>
> @@ -2654,10 +2686,12 @@ ublk_user_copy(struct kiocb *iocb, struct iov_iter
> *iter, int dir)
> {
> struct ublk_device *ub = iocb->ki_filp->private_data;
> struct ublk_queue *ubq;
> struct request *req;
> struct ublk_io *io;
> + unsigned data_len;
> + bool is_integrity;
> size_t buf_off;
> u16 tag, q_id;
> ssize_t ret;
>
> if (!user_backed_iter(iter))
> @@ -2667,10 +2701,11 @@ ublk_user_copy(struct kiocb *iocb, struct iov_iter
> *iter, int dir)
> return -EACCES;
>
> tag = ublk_pos_to_tag(iocb->ki_pos);
> q_id = ublk_pos_to_hwq(iocb->ki_pos);
> buf_off = ublk_pos_to_buf_off(iocb->ki_pos);
> + is_integrity = ublk_pos_is_integrity(iocb->ki_pos);
UBLKSRV_IO_INTEGRITY_FLAG can be set for device without UBLK_F_INTEGRITY,
so UBLK_F_INTEGRITY need to be checked in case of `is_integrity`.
>
> if (q_id >= ub->dev_info.nr_hw_queues)
> return -EINVAL;
>
> ubq = ublk_get_queue(ub, q_id);
> @@ -2683,21 +2718,31 @@ ublk_user_copy(struct kiocb *iocb, struct iov_iter
> *iter, int dir)
> io = &ubq->ios[tag];
> req = __ublk_check_and_get_req(ub, q_id, tag, io);
> if (!req)
> return -EINVAL;
>
> - if (buf_off > blk_rq_bytes(req)) {
> + if (is_integrity) {
> + struct blk_integrity *bi = &req->q->limits.integrity;
> +
> + data_len = bio_integrity_bytes(bi, blk_rq_sectors(req));
> + } else {
> + data_len = blk_rq_bytes(req);
> + }
> + if (buf_off > data_len) {
> ret = -EINVAL;
> goto out;
> }
>
> if (!ublk_check_ubuf_dir(req, dir)) {
> ret = -EACCES;
> goto out;
> }
>
> - ret = ublk_copy_user_pages(req, buf_off, iter, dir);
> + if (is_integrity)
> + ret = ublk_copy_user_integrity(req, buf_off, iter, dir);
> + else
> + ret = ublk_copy_user_pages(req, buf_off, iter, dir);
>
> out:
> ublk_put_req_ref(io, req);
> return ret;
> }
> @@ -3931,11 +3976,12 @@ static struct miscdevice ublk_misc = {
> static int __init ublk_init(void)
> {
> int ret;
>
> BUILD_BUG_ON((u64)UBLKSRV_IO_BUF_OFFSET +
> - UBLKSRV_IO_BUF_TOTAL_SIZE < UBLKSRV_IO_BUF_OFFSET);
> + UBLKSRV_IO_BUF_TOTAL_SIZE +
> + UBLKSRV_IO_INTEGRITY_FLAG < UBLKSRV_IO_BUF_OFFSET);
Maybe it can be simplified as:
BUILD_BUG_ON(UBLK_INTEGRITY_FLAG_OFF >= 63); /* Must fit in loff_t */
> BUILD_BUG_ON(sizeof(struct ublk_auto_buf_reg) != 8);
>
> init_waitqueue_head(&ublk_idr_wq);
>
> ret = misc_register(&ublk_misc);
> diff --git a/include/uapi/linux/ublk_cmd.h b/include/uapi/linux/ublk_cmd.h
> index c1103ad5925b..3af7e3684834 100644
> --- a/include/uapi/linux/ublk_cmd.h
> +++ b/include/uapi/linux/ublk_cmd.h
> @@ -132,10 +132,14 @@
> #define UBLK_MAX_NR_QUEUES (1U << UBLK_QID_BITS)
>
> #define UBLKSRV_IO_BUF_TOTAL_BITS (UBLK_QID_OFF + UBLK_QID_BITS)
> #define UBLKSRV_IO_BUF_TOTAL_SIZE (1ULL << UBLKSRV_IO_BUF_TOTAL_BITS)
>
> +/* Copy to/from request integrity buffer instead of data buffer */
> +#define UBLK_INTEGRITY_FLAG_OFF UBLKSRV_IO_BUF_TOTAL_BITS
> +#define UBLKSRV_IO_INTEGRITY_FLAG (1ULL << UBLK_INTEGRITY_FLAG_OFF)
> +
> /*
> * ublk server can register data buffers for incoming I/O requests with a
> sparse
> * io_uring buffer table. The request buffer can then be used as the data
> buffer
> * for io_uring operations via the fixed buffer index.
> * Note that the ublk server can never directly access the request data
> memory.
> --
> 2.45.2
>
Thanks,
Ming
