[RFC PATCH 6/8] io_uring: add BUILD_BUG_SQE_HDR_COMMON() macro

[Stefan Metzmacher <metze@samba.org>]

This will be used in the next commits in order to
check common fields of opcode specific struct io_uring_sqe
union arms.

Signed-off-by: Stefan Metzmacher <metze@samba.org>
---
 io_uring/io_uring.c | 14 ++++++++++++++
 1 file changed, 14 insertions(+)

diff --git a/io_uring/io_uring.c b/io_uring/io_uring.c
index f82173bde393..8e1a8800b252 100644
--- a/io_uring/io_uring.c
+++ b/io_uring/io_uring.c
@@ -3916,6 +3916,20 @@ static int __init io_uring_init(void)
 #define BUILD_BUG_SQE_LEGACY_ALIAS(eoffset, etype, ename, lname) \
 	__BUILD_BUG_VERIFY_ALIAS(struct io_uring_sqe, eoffset, sizeof(etype), ename, legacy.lname)
 
+#define BUILD_BUG_SQE_HDR_COMMON(subtype, subname) do { \
+	BUILD_BUG_ON(sizeof(subtype) != 64); \
+	BUILD_BUG_SQE_ELEM(0,  subtype, subname); \
+	BUILD_BUG_SQE_ELEM(0,  struct io_uring_sqe_hdr, subname.hdr); \
+	BUILD_BUG_SQE_ALIAS(0,  __u8,   subname.hdr.opcode, hdr.opcode); \
+	BUILD_BUG_SQE_ALIAS(1,  __u8,   subname.hdr.flags, hdr.flags); \
+	BUILD_BUG_SQE_ALIAS(2,  __u16,  subname.hdr.ioprio, hdr.ioprio); \
+	BUILD_BUG_SQE_ALIAS(4,  __s32,  subname.hdr.fd, hdr.fd); \
+	BUILD_BUG_SQE_ELEM(32, struct io_uring_sqe_common, subname.common); \
+	BUILD_BUG_SQE_ALIAS(32, __u64,  subname.common.user_data, common.user_data); \
+	BUILD_BUG_SQE_ALIAS(40, __u16,  subname.common.buf_info, common.buf_info); \
+	BUILD_BUG_SQE_ALIAS(42, __u16,  subname.common.personality, common.personality); \
+} while (0)
+
 	BUILD_BUG_ON(sizeof(struct io_uring_sqe_hdr) != 8);
 	BUILD_BUG_SQE_HDR_ELEM(0,  __u8,   opcode);
 	BUILD_BUG_SQE_HDR_ELEM(1,  __u8,   flags);
-- 
2.34.1