[PATCH v2 3/3] io_uring: Remove unnecessary BUILD_BUG_ON

Breno Leitao
2023-04-21T11:47:13Z

In the io_uring_cmd_prep_async() there is a unnecessary compilation time
check to check if cmd is correctly placed at field 48 of the SQE.

This is uncessary, since this check is already in place at
io_uring_init():

BUILD_BUG_SQE_ELEM(48, __u64, addr3);

Remove it and the uring_cmd_pdu_size() function, which is not used
anymore.

Keith started a discussion about this topic in the following thread:
https://lore.kernel.org/lkml/ZDBmQOhbyU0iLhMw@kbusch-mbp.dhcp.thefacebook.com/

Signed-off-by: Breno Leitao <leitao@debian.org>
---
io_uring/uring_cmd.c | 3 ---
io_uring/uring_cmd.h | 8 --------
2 files changed, 11 deletions(-)

diff --git a/io_uring/uring_cmd.c b/io_uring/uring_cmd.c
index a1be746cd009..743d1496431b 100644
--- a/io_uring/uring_cmd.c
+++ b/io_uring/uring_cmd.c
@@ -71,9 +71,6 @@ int io_uring_cmd_prep_async(struct io_kiocb *req)
struct io_uring_cmd *ioucmd = io_kiocb_to_cmd(req, struct io_uring_cmd);
size_t size = uring_sqe_size(req->ctx);

- BUILD_BUG_ON(uring_cmd_pdu_size(0) != 16);
- BUILD_BUG_ON(uring_cmd_pdu_size(1) != 80);
-
memcpy(req->async_data, ioucmd->sqe, size);
ioucmd->sqe = req->async_data;
return 0;
diff --git a/io_uring/uring_cmd.h b/io_uring/uring_cmd.h
index 7c6697d13cb2..8117684ec3ca 100644
--- a/io_uring/uring_cmd.h
+++ b/io_uring/uring_cmd.h
@@ -3,11 +3,3 @@
int io_uring_cmd(struct io_kiocb *req, unsigned int issue_flags);
int io_uring_cmd_prep(struct io_kiocb *req, const struct io_uring_sqe *sqe);
int io_uring_cmd_prep_async(struct io_kiocb *req);
-
-/*
- * The URING_CMD payload starts at 'cmd' in the first sqe, and continues into
- * the following sqe if SQE128 is used.
- */
-#define uring_cmd_pdu_size(is_sqe128) \
- ((1 + !!(is_sqe128)) * sizeof(struct io_uring_sqe) - \
- offsetof(struct io_uring_sqe, cmd))
--
2.34.1