Re: [PATCH][next] RDMA/rxe: Avoid -Wflex-array-member-not-at-end warnings

[Zhu Yanjun]

在 2025/12/2 10:13, Jason Gunthorpe 写道:

On Tue, Nov 11, 2025 at 12:35:02PM +0900, Gustavo A. R. Silva wrote:

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;

I think this existing is just a mess, can we fix it properly?

What this code wants to do is to have rxe_resp_info allocate a
rxe_recv_wqe and have a maximum size of its flex array pre-allocated.

Probably like this, though maybe we need a FLEX version of the
INIT_RDMA_OBJ_SIZE macro to make it safer.

Zhu, this seems like a good thing for you to look at?

Thanks. I’ll take a closer look at this.

I’ll provide my comments over the weekend.

Zhu Yanjun

diff --git a/drivers/infiniband/sw/rxe/rxe_verbs.c 
b/drivers/infiniband/sw/rxe/rxe_verbs.c
index 38d8c408320f11..189eaa59a5fb14 100644
--- a/drivers/infiniband/sw/rxe/rxe_verbs.c
+++ b/drivers/infiniband/sw/rxe/rxe_verbs.c
@@ -1524,7 +1524,8 @@ static const struct ib_device_ops rxe_dev_ops = {
        INIT_RDMA_OBJ_SIZE(ib_ah, rxe_ah, ibah),
        INIT_RDMA_OBJ_SIZE(ib_cq, rxe_cq, ibcq),
        INIT_RDMA_OBJ_SIZE(ib_pd, rxe_pd, ibpd),
-       INIT_RDMA_OBJ_SIZE(ib_qp, rxe_qp, ibqp),
+       /* For resp.srq_wqe.dma.sge */
+       INIT_RDMA_OBJ_SIZE(ib_qp, rxe_qp, ibqp) + RXE_MAX_SGE*sizeof(struct 
ib_sge),
        INIT_RDMA_OBJ_SIZE(ib_srq, rxe_srq, ibsrq),
        INIT_RDMA_OBJ_SIZE(ib_ucontext, rxe_ucontext, ibuc),
        INIT_RDMA_OBJ_SIZE(ib_mw, rxe_mw, ibmw),
diff --git a/drivers/infiniband/sw/rxe/rxe_verbs.h 
b/drivers/infiniband/sw/rxe/rxe_verbs.h
index fd48075810dd10..dda741ec3ac701 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 +226,9 @@ struct rxe_resp_info {
        unsigned int            res_head;
        unsigned int            res_tail;
        struct resp_res         *res;
+
+       /* SRQ only. srq_wqe.dma.sge is a flex array */
+       struct rxe_recv_wqe srq_wqe;
  };

struct rxe_qp {

@@ -269,7 +266,6 @@ 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 +285,7 @@ struct rxe_qp {
        spinlock_t              state_lock; /* guard requester and completer */

struct execute_work cleanup_work;

+       struct rxe_resp_info    resp;
  };

enum {