Re: [PATCH v3 1/1] RDMA/rxe: Avoid -Wflex-array-member-not-at-end warnings
From: Zhu Yanjun
Date: Tue Dec 23 2025 - 00:10:34 EST
在 2025/12/22 21:03, Gustavo A. R. Silva 写道:
On 12/23/25 13:41, Zhu Yanjun wrote:
From: "Gustavo A. R. Silva" <gustavoars@xxxxxxxxxx>
-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.
Reviewed-by: Zhu Yanjun <yanjun.zhu@xxxxxxxxx>
Signed-off-by: Gustavo A. R. Silva <gustavoars@xxxxxxxxxx>
---
V2->V3: Replace struct ib_sge with struct rxe_sge
What are you doing?
Because struct rxe_sge differs from struct ib_sge, I aligned it to use the same structure.
Yanjun.Zhu
--
You're making a mess of this whole thing. Please, don't make changes
to my patches on your own.
-Gustavo
---
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..3ffd7be8e7b1 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 rxe_sge sge[RXE_MAX_SGE];
+ ) srq_wqe;
};
+static_assert(offsetof(struct rxe_resp_info, srq_wqe.wqe.dma.sge) ==
+ offsetof(struct rxe_resp_info, srq_wqe.sge));
struct rxe_qp {
struct ib_qp ibqp;
@@ -269,7 +271,6 @@ struct rxe_qp {
struct rxe_req_info req;
struct rxe_comp_info comp;
- struct rxe_resp_info resp;
atomic_t ssn;
atomic_t skb_out;
@@ -289,6 +290,9 @@ struct rxe_qp {
spinlock_t state_lock; /* guard requester and completer */
struct execute_work cleanup_work;
+
+ /* Must be last as it ends in a flexible-array member. */
+ struct rxe_resp_info resp;
};
enum {
Best Regards,
Yanjun.Zhu