[PATCH 04/20] ublk: add integrity UAPI

Caleb Sander Mateos
2025-12-17T05:35:12Z

From: Stanley Zhang <stazhang@purestorage.com>

Add UAPI definitions for metadata/integrity support in ublk.
UBLK_PARAM_TYPE_INTEGRITY and struct ublk_param_integrity allow a ublk
server to specify the integrity params of a ublk device.
The ublk driver will set UBLK_IO_F_INTEGRITY in the op_flags field of
struct ublksrv_io_desc for requests with integrity data.
The ublk server uses user copy with UBLKSRV_IO_INTEGRITY_FLAG set in the
offset parameter to access a request's integrity buffer.

Signed-off-by: Stanley Zhang <stazhang@purestorage.com>
[csander: drop feature flag and redundant pi_tuple_size field,
add io_desc flag, use block metadata UAPI constants]
Signed-off-by: Caleb Sander Mateos <csander@purestorage.com>
---
include/uapi/linux/ublk_cmd.h | 20 +++++++++++++++++++-
1 file changed, 19 insertions(+), 1 deletion(-)

diff --git a/include/uapi/linux/ublk_cmd.h b/include/uapi/linux/ublk_cmd.h
index ec77dabba45b..5bfb9a0521c3 100644
--- a/include/uapi/linux/ublk_cmd.h
+++ b/include/uapi/linux/ublk_cmd.h
@@ -129,11 +129,15 @@
#define UBLK_QID_BITS 12
#define UBLK_QID_BITS_MASK ((1ULL << UBLK_QID_BITS) - 1)

#define UBLK_MAX_NR_QUEUES (1U << UBLK_QID_BITS)

-#define UBLKSRV_IO_BUF_TOTAL_BITS (UBLK_QID_OFF + UBLK_QID_BITS)
+/* Copy to/from request integrity buffer instead of data buffer */
+#define UBLK_INTEGRITY_FLAG_OFF (UBLK_QID_OFF + UBLK_QID_BITS)
+#define UBLKSRV_IO_INTEGRITY_FLAG (1ULL << UBLK_INTEGRITY_FLAG_OFF)
+
+#define UBLKSRV_IO_BUF_TOTAL_BITS (UBLK_INTEGRITY_FLAG_OFF + 1)
#define UBLKSRV_IO_BUF_TOTAL_SIZE (1ULL << UBLKSRV_IO_BUF_TOTAL_BITS)

/*
* 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
@@ -406,10 +410,12 @@ struct ublksrv_ctrl_dev_info {
*
* ublk server has to check this flag if UBLK_AUTO_BUF_REG_FALLBACK is
* passed in.
*/
#define UBLK_IO_F_NEED_REG_BUF (1U << 17)
+/* Request has an integrity data buffer */
+#define UBLK_IO_F_INTEGRITY (1U << 18)

/*
* io cmd is described by this structure, and stored in share memory, indexed
* by request tag.
*
@@ -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;
+ __u8 pi_offset;
+ __u8 csum_type; /* LBMD_PI_CSUM_* from linux/fs.h */
+ __u8 tag_size;
+ __u8 pad[7];
+};
+
struct ublk_params {
/*
* Total length of parameters, userspace has to set 'len' for both
* SET_PARAMS and GET_PARAMS command, and driver may update len
* if two sides use different version of 'ublk_params', same with
@@ -612,16 +628,18 @@ struct ublk_params {
#define UBLK_PARAM_TYPE_DISCARD (1 << 1)
#define UBLK_PARAM_TYPE_DEVT (1 << 2)
#define UBLK_PARAM_TYPE_ZONED (1 << 3)
#define UBLK_PARAM_TYPE_DMA_ALIGN (1 << 4)
#define UBLK_PARAM_TYPE_SEGMENT (1 << 5)
+#define UBLK_PARAM_TYPE_INTEGRITY (1 << 6)
__u32 types; /* types of parameter included */

struct ublk_param_basic basic;
struct ublk_param_discard discard;
struct ublk_param_devt devt;
struct ublk_param_zoned zoned;
struct ublk_param_dma_align dma;
struct ublk_param_segment seg;
+ struct ublk_param_integrity integrity;
};

#endif
--
2.45.2