Re: [PATCH v3 03/19] ublk: support UBLK_PARAM_TYPE_INTEGRITY in device creation

On Mon, Jan 05, 2026 at 05:57:35PM -0700, Caleb Sander Mateos wrote:

From: Stanley Zhang stazhang@purestorage.com

Add a feature flag UBLK_F_INTEGRITY for a ublk server to request integrity/metadata support when creating a ublk device. The ublk server can also check for the feature flag on the created device or the result of UBLK_U_CMD_GET_FEATURES to tell if the ublk driver supports it. UBLK_F_INTEGRITY requires UBLK_F_USER_COPY, as user copy is the only data copy mode initially supported for integrity data. Add UBLK_PARAM_TYPE_INTEGRITY and struct ublk_param_integrity to struct ublk_params to specify the integrity params of a ublk device. UBLK_PARAM_TYPE_INTEGRITY requires UBLK_F_INTEGRITY and a nonzero metadata_size. The LBMD_PI_CAP_* and LBMD_PI_CSUM_* values from the linux/fs.h UAPI header are used for the flags and csum_type fields. If the UBLK_PARAM_TYPE_INTEGRITY flag is set, validate the integrity parameters and apply them to the blk_integrity limits. 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: drop redundant pi_tuple_size field, use block metadata UAPI constants, add param validation] Signed-off-by: Caleb Sander Mateos csander@purestorage.com

---

drivers/block/ublk_drv.c | 94 ++++++++++++++++++++++++++++++++++- include/uapi/linux/ublk_cmd.h | 18 +++++++ 2 files changed, 111 insertions(+), 1 deletion(-)

diff --git a/drivers/block/ublk_drv.c b/drivers/block/ublk_drv.c index 8e3da9b2b93a..066c6ae062a0 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. @@ -628,10 +631,57 @@ 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; @@ -690,10 +740,33 @@ 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 (!(ub->dev_info.flags & UBLK_F_INTEGRITY))
  

• 	return -EINVAL;
  

• if (flags < 0)
  

• 	return flags;
  

• if (pi_tuple_size < 0)
  

• 	return pi_tuple_size;
  

• if (!p->metadata_size)
  

• 	return -EINVAL;
  

• if (p->csum_type == LBMD_PI_CSUM_NONE &&
  

•     p->flags & LBMD_PI_CAP_REFTAG)
  

• 	return -EINVAL;
  

• if (p->pi_offset + pi_tuple_size > p->metadata_size)
  

• 	return -EINVAL;
  

• if (p->interval_exp < SECTOR_SHIFT ||
  

•     p->interval_exp > ub->params.basic.logical_bs_shift)
  

• 	return -EINVAL;
  

• }
• return 0;

} static void ublk_apply_params(struct ublk_device *ub) { @@ -2941,10 +3014,25 @@ static int ublk_ctrl_start_dev(struct ublk_device *ub, lim.seg_boundary_mask = ub->params.seg.seg_boundary_mask; lim.max_segment_size = ub->params.seg.max_segment_size; lim.max_segments = ub->params.seg.max_segments; }

• 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);
  

• lim.integrity = (struct blk_integrity) {
  

• 	.flags = ublk_integrity_flags(p->flags),
  

• 	.csum_type = ublk_integrity_csum_type(p->csum_type),
  

• 	.metadata_size = p->metadata_size,
  

• 	.pi_offset = p->pi_offset,
  

• 	.interval_exp = p->interval_exp,
  

• 	.tag_size = p->tag_size,
  

• 	.pi_tuple_size = pi_tuple_size,
  

• };
  

• }
• if (wait_for_completion_interruptible(&ub->completion) != 0) return -EINTR;

if (ub->ublksrv_tgid != ublksrv_pid) return -EINVAL; @@ -3131,10 +3219,14 @@ static int ublk_ctrl_add_dev(const struct ublksrv_ctrl_cmd *header) if (info.flags & (UBLK_F_USER_COPY | UBLK_F_SUPPORT_ZERO_COPY | UBLK_F_AUTO_BUF_REG)) return -EINVAL; }

• /* User copy is required to access integrity buffer */
• if (info.flags & UBLK_F_INTEGRITY && !(info.flags & UBLK_F_USER_COPY))

• return -EINVAL;
  

• /* the created device is always owned by current user */ ublk_store_owner_uid_gid(&info.owner_uid, &info.owner_gid);

if (header->dev_id != info.dev_id) { pr_warn("%s: dev id not match %u %u\n", diff --git a/include/uapi/linux/ublk_cmd.h b/include/uapi/linux/ublk_cmd.h index ec77dabba45b..a54c47832fa2 100644 --- a/include/uapi/linux/ublk_cmd.h +++ b/include/uapi/linux/ublk_cmd.h @@ -309,10 +309,16 @@

• the I/O's daemon task. The q_id and tag of the registered buffer are required
• in UBLK_U_IO_UNREGISTER_IO_BUF's ublksrv_io_cmd.

*/ #define UBLK_F_BUF_REG_OFF_DAEMON (1ULL << 14) +/*

• • ublk device supports requests with integrity/metadata buffer.
• • Requires UBLK_F_USER_COPY.
• */

+#define UBLK_F_INTEGRITY (1ULL << 16)

/* device state */ #define UBLK_S_DEV_DEAD 0 #define UBLK_S_DEV_LIVE 1 #define UBLK_S_DEV_QUIESCED 2 #define UBLK_S_DEV_FAIL_IO 3 @@ -598,10 +604,20 @@ struct ublk_param_segment { __u32 max_segment_size; __u16 max_segments; __u8 pad[2]; }; +struct ublk_param_integrity {

• __u32 flags; /* LBMD_PI_CAP_* from linux/fs.h */
• __u8 interval_exp;
• __u8 metadata_size; /* UBLK_PARAM_TYPE_INTEGRITY requires nonzero */
• __u8 pi_offset;
• __u8 csum_type; /* LBMD_PI_CSUM_* from linux/fs.h */
• __u8 tag_size;
• __u8 pad[7];

+};

Looks max_integrity_segments is missed, otherwise this patch is fine for me.

Thanks, Ming