[PATCH 04/20] ublk: add integrity UAPI

[Caleb Sander Mateos <csander@purestorage.com>]

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