On 11/11/25 20:56, Leon Romanovsky wrote:
On Tue, Nov 11, 2025 at 12:35:02PM +0900, Gustavo A. R. Silva wrote:
-Wflex-array-member-not-at-end was introduced in GCC-14, and we are
getting ready to enable it, globally.
Use the new TRAILING_OVERLAP() helper to fix the following warning:
21 drivers/infiniband/sw/rxe/rxe_verbs.h:271:33: warning: structure containing
a flexible array member is not at the end of another structure
[-Wflex-array-member-not-at-end]
This helper creates a union between a flexible-array member (FAM) and a
set of MEMBERS that would otherwise follow it.
This overlays the trailing MEMBER struct ib_sge sge[RXE_MAX_SGE]; onto
the FAM struct rxe_recv_wqe::dma.sge, while keeping the FAM and the
start of MEMBER aligned.
The static_assert() ensures this alignment remains, and it's
intentionally placed inmediately after the related structure --no
blank line in between.
Lastly, move the conflicting declaration struct rxe_resp_info resp;
to the end of the corresponding structure.
Signed-off-by: Gustavo A. R. Silva <[email protected]>
---
drivers/infiniband/sw/rxe/rxe_verbs.h | 18 +++++++++++-------
1 file changed, 11 insertions(+), 7 deletions(-)
diff --git a/drivers/infiniband/sw/rxe/rxe_verbs.h
b/drivers/infiniband/sw/rxe/rxe_verbs.h
index fd48075810dd..6498d61e8956 100644
--- a/drivers/infiniband/sw/rxe/rxe_verbs.h
+++ b/drivers/infiniband/sw/rxe/rxe_verbs.h
@@ -219,12 +219,6 @@ struct rxe_resp_info {
u32 rkey;
u32 length;
- /* SRQ only */
- struct {
- struct rxe_recv_wqe wqe;
- struct ib_sge sge[RXE_MAX_SGE];
- } srq_wqe;
-
/* Responder resources. It's a circular list where the oldest
* resource is dropped first.
*/
@@ -232,7 +226,15 @@ struct rxe_resp_info {
unsigned int res_head;
unsigned int res_tail;
struct resp_res *res;
+
+ /* SRQ only */
+ /* Must be last as it ends in a flexible-array member. */
+ TRAILING_OVERLAP(struct rxe_recv_wqe, wqe, dma.sge,
+ struct ib_sge sge[RXE_MAX_SGE];
+ ) srq_wqe;
Will this change be enough?
diff --git a/drivers/infiniband/sw/rxe/rxe_verbs.h
b/drivers/infiniband/sw/rxe/rxe_verbs.h
index fd48075810dd..9ab11421a585 100644
--- a/drivers/infiniband/sw/rxe/rxe_verbs.h
+++ b/drivers/infiniband/sw/rxe/rxe_verbs.h
@@ -219,12 +219,6 @@ struct rxe_resp_info {
u32 rkey;
u32 length;
- /* SRQ only */
- struct {
- struct rxe_recv_wqe wqe;
- struct ib_sge sge[RXE_MAX_SGE];
- } srq_wqe;
-
/* Responder resources. It's a circular list where the oldest
* resource is dropped first.
*/
@@ -232,6 +226,12 @@ struct rxe_resp_info {
unsigned int res_head;
unsigned int res_tail;
struct resp_res *res;
+
+ /* SRQ only */
+ struct {
+ struct ib_sge sge[RXE_MAX_SGE];
+ struct rxe_recv_wqe wqe;
+ } srq_wqe;
};
The question is if this is really what you want?
sge[RXE_MAX_SGE] is of the following type:
struct ib_sge {
u64 addr;
u32 length;
u32 lkey;
};
and struct rxe_recv_wqe::dma.sge[] is of type:
struct rxe_sge {
__aligned_u64 addr;
__u32 length;
__u32 lkey;
};
Both types are basically the same, and the original code looks
pretty much like what people do when they want to pre-allocate
a number of elements (of the same element type as the flex array)
for a flexible-array member.
Based on the above, the change you suggest seems a bit suspicious,
and I'm not sure that's actually what you want?
Thanks
-Gustavo
