ublk: add new batch command UBLK_U_IO_PREP_IO_CMDS & UBLK_U_IO_COMMIT_IO_CMDS

Add new command UBLK_U_IO_PREP_IO_CMDS, which is the batch version of
UBLK_IO_FETCH_REQ.

Add new command UBLK_U_IO_COMMIT_IO_CMDS, which is for committing io command
result only, still the batch version.

The new command header type is `struct ublk_batch_io`.

This patch doesn't actually implement these commands yet, just validates the
SQE fields.

Reviewed-by: Caleb Sander Mateos <csander@purestorage.com>
Signed-off-by: Ming Lei <ming.lei@redhat.com>
Signed-off-by: Jens Axboe <axboe@kernel.dk>

1 files changed, 49 insertions, 0 deletions

diff --git a/include/uapi/linux/ublk_cmd.h b/include/uapi/linux/ublk_cmd.h
index 90f47da4f435..0cc58e19d401 100644
--- a/include/uapi/linux/ublk_cmd.h
+++ b/include/uapi/linux/ublk_cmd.h
@@ -103,6 +103,10 @@
 	_IOWR('u', 0x23, struct ublksrv_io_cmd)
 #define	UBLK_U_IO_UNREGISTER_IO_BUF	\
 	_IOWR('u', 0x24, struct ublksrv_io_cmd)
+#define	UBLK_U_IO_PREP_IO_CMDS	\
+	_IOWR('u', 0x25, struct ublk_batch_io)
+#define	UBLK_U_IO_COMMIT_IO_CMDS	\
+	_IOWR('u', 0x26, struct ublk_batch_io)
 
 /* only ABORT means that no re-fetch */
 #define UBLK_IO_RES_OK			0
@@ -544,6 +548,51 @@ struct ublksrv_io_cmd {
 	};
 };
 
+struct ublk_elem_header {
+	__u16 tag;	/* IO tag */
+
+	/*
+	 * Buffer index for incoming io command, only valid iff
+	 * UBLK_F_AUTO_BUF_REG is set
+	 */
+	__u16 buf_index;
+	__s32 result;	/* I/O completion result (commit only) */
+};
+
+/*
+ * uring_cmd buffer structure for batch commands
+ *
+ * buffer includes multiple elements, which number is specified by
+ * `nr_elem`. Each element buffer is organized in the following order:
+ *
+ * struct ublk_elem_buffer {
+ * 	// Mandatory fields (8 bytes)
+ * 	struct ublk_elem_header header;
+ *
+ * 	// Optional fields (8 bytes each, included based on flags)
+ *
+ * 	// Buffer address (if UBLK_BATCH_F_HAS_BUF_ADDR) for copying data
+ * 	// between ublk request and ublk server buffer
+ * 	__u64 buf_addr;
+ *
+ * 	// returned Zone append LBA (if UBLK_BATCH_F_HAS_ZONE_LBA)
+ * 	__u64 zone_lba;
+ * }
+ *
+ * Used for `UBLK_U_IO_PREP_IO_CMDS` and `UBLK_U_IO_COMMIT_IO_CMDS`
+ */
+struct ublk_batch_io {
+	__u16  q_id;
+#define UBLK_BATCH_F_HAS_ZONE_LBA	(1 << 0)
+#define UBLK_BATCH_F_HAS_BUF_ADDR 	(1 << 1)
+#define UBLK_BATCH_F_AUTO_BUF_REG_FALLBACK	(1 << 2)
+	__u16	flags;
+	__u16	nr_elem;
+	__u8	elem_bytes;
+	__u8	reserved;
+	__u64   reserved2;
+};
+
 struct ublk_param_basic {
 #define UBLK_ATTR_READ_ONLY            (1 << 0)
 #define UBLK_ATTR_ROTATIONAL           (1 << 1)