Re: [PATCH 06/20] ublk: support UBLK_PARAM_TYPE_INTEGRITY in device creation

Ming Lei
2025-12-22T14:47:28Z

On Tue, Dec 16, 2025 at 10:34:40PM -0700, Caleb Sander Mateos wrote:
> From: Stanley Zhang <stazhang@purestorage.com>
>
> If the UBLK_PARAM_TYPE_INTEGRITY flag is set, validate the integrity
> parameters and apply them to the blk_integrity limits.
> UBLK_PARAM_TYPE_INTEGRITY requires CONFIG_BLK_DEV_INTEGRITY=y,
> UBLK_F_USER_COPY, and metadata_size > 0. Reuse the block metadata ioctl
> LBMD_PI_CAP_* and LBMD_PI_CSUM_* constants from the linux/fs.h UAPI
> header for the flags and csum_type field values.
> The struct ublk_param_integrity validations are based on the checks in
> blk_validate_integrity_limits(). Any invalid parameters should be
> rejected before being applied to struct blk_integrity.
>
> Signed-off-by: Stanley Zhang <stazhang@purestorage.com>
> [csander: add param validation]
> Signed-off-by: Caleb Sander Mateos <csander@purestorage.com>
> ---
> drivers/block/ublk_drv.c | 92 +++++++++++++++++++++++++++++++++++++++-
> 1 file changed, 91 insertions(+), 1 deletion(-)
>
> diff --git a/drivers/block/ublk_drv.c b/drivers/block/ublk_drv.c
> index 4da5d8ff1e1d..2893a9172220 100644
> --- a/drivers/block/ublk_drv.c
> +++ b/drivers/block/ublk_drv.c
> @@ -42,10 +42,12 @@
> #include <linux/mm.h>
> #include <asm/page.h>
> #include <linux/task_work.h>
> #include <linux/namei.h>
> #include <linux/kref.h>
> +#include <linux/blk-integrity.h>
> +#include <uapi/linux/fs.h>
> #include <uapi/linux/ublk_cmd.h>
>
> #define UBLK_MINORS (1U << MINORBITS)
>
> #define UBLK_INVALID_BUF_IDX ((u16)-1)
> @@ -81,11 +83,12 @@
>
> /* All UBLK_PARAM_TYPE_* should be included here */
> #define UBLK_PARAM_TYPE_ALL \
> (UBLK_PARAM_TYPE_BASIC | UBLK_PARAM_TYPE_DISCARD | \
> UBLK_PARAM_TYPE_DEVT | UBLK_PARAM_TYPE_ZONED | \
> - UBLK_PARAM_TYPE_DMA_ALIGN | UBLK_PARAM_TYPE_SEGMENT)
> + UBLK_PARAM_TYPE_DMA_ALIGN | UBLK_PARAM_TYPE_SEGMENT | \
> + UBLK_PARAM_TYPE_INTEGRITY)
>
> struct ublk_uring_cmd_pdu {
> /*
> * Store requests in same batch temporarily for queuing them to
> * daemon context.
> @@ -613,10 +616,57 @@ static void ublk_dev_param_basic_apply(struct ublk_device *ub)
> set_disk_ro(ub->ub_disk, true);
>
> set_capacity(ub->ub_disk, p->dev_sectors);
> }
>
> +static int ublk_integrity_flags(u32 flags)
> +{
> + int ret_flags = 0;
> +
> + if (flags & LBMD_PI_CAP_INTEGRITY) {
> + flags &= ~LBMD_PI_CAP_INTEGRITY;
> + ret_flags |= BLK_INTEGRITY_DEVICE_CAPABLE;
> + }
> + if (flags & LBMD_PI_CAP_REFTAG) {
> + flags &= ~LBMD_PI_CAP_REFTAG;
> + ret_flags |= BLK_INTEGRITY_REF_TAG;
> + }
> + return flags ? -EINVAL : ret_flags;
> +}
> +
> +static int ublk_integrity_pi_tuple_size(u8 csum_type)
> +{
> + switch (csum_type) {
> + case LBMD_PI_CSUM_NONE:
> + return 0;
> + case LBMD_PI_CSUM_IP:
> + case LBMD_PI_CSUM_CRC16_T10DIF:
> + return 8;
> + case LBMD_PI_CSUM_CRC64_NVME:
> + return 16;
> + default:
> + return -EINVAL;
> + }
> +}
> +
> +static enum blk_integrity_checksum ublk_integrity_csum_type(u8 csum_type)
> +{
> + switch (csum_type) {
> + case LBMD_PI_CSUM_NONE:
> + return BLK_INTEGRITY_CSUM_NONE;
> + case LBMD_PI_CSUM_IP:
> + return BLK_INTEGRITY_CSUM_IP;
> + case LBMD_PI_CSUM_CRC16_T10DIF:
> + return BLK_INTEGRITY_CSUM_CRC;
> + case LBMD_PI_CSUM_CRC64_NVME:
> + return BLK_INTEGRITY_CSUM_CRC64;
> + default:
> + WARN_ON_ONCE(1);
> + return BLK_INTEGRITY_CSUM_NONE;
> + }
> +}
> +
> static int ublk_validate_params(const struct ublk_device *ub)
> {
> /* basic param is the only one which must be set */
> if (ub->params.types & UBLK_PARAM_TYPE_BASIC) {
> const struct ublk_param_basic *p = &ub->params.basic;
> @@ -675,10 +725,35 @@ static int ublk_validate_params(const struct ublk_device *ub)
> return -EINVAL;
> if (p->max_segment_size < UBLK_MIN_SEGMENT_SIZE)
> return -EINVAL;
> }
>
> + if (ub->params.types & UBLK_PARAM_TYPE_INTEGRITY) {
> + const struct ublk_param_integrity *p = &ub->params.integrity;
> + int pi_tuple_size = ublk_integrity_pi_tuple_size(p->csum_type);
> + int flags = ublk_integrity_flags(p->flags);
> +
> + if (!IS_ENABLED(CONFIG_BLK_DEV_INTEGRITY))
> + return -EINVAL;
> + if (!ublk_dev_support_user_copy(ub))
> + return -EINVAL;

UBLK_IO_F_INTEGRITY should be checked here, and ublk_dev_support_user_copy() can be
validated with UBLK_IO_F_INTEGRITY together in ublk_ctrl_add_dev(), so
mis-matched features can be failed earlier.

Same for IS_ENABLED(CONFIG_BLK_DEV_INTEGRITY).

> + if (flags < 0)
> + return flags;
> + if (pi_tuple_size < 0)
> + return pi_tuple_size;
> + if (!p->metadata_size)
> + return -EINVAL;

blk_validate_integrity_limits() allows zero p->metadata_size with
LBMD_PI_CSUM_NONE, maybe document ublk's support for zero metadata_size & LBMD_PI_CSUM_NONE?

Thanks,
Ming