rdma: (fix) memory leak: don't alloc recv_conn_resp_req on EAGAIN

Move call to `prepare_recv_conn_resp_req` before entry point of
`COMM_SEND_CONN` stage.

This resolves a potential memory leak where `prepare_recv_conn_resp_req`
is called multiple times on EAGAIN.

Also fixup a similar case in `accept`, although there was no memory
allocation there so no leak.

Signed-off-by: Eric Raut <[email protected]>
(cherry picked from commit 398b853)

src/nccl_ofi_rdma.c

@@ -3790,10 +3790,6 @@ static int accept(nccl_net_ofi_listen_comm_t *listen_comm,
 		/* Reset request state for connect response message */
 		prepare_send_conn_resp_req(l_comm);
 
-		l_comm->stage = COMM_SEND_CONN;
-
-	case COMM_SEND_CONN:
-
 		/* Initialize connect response message */
 		ret = prepare_conn_resp(ep, l_comm, dev_id);
 		if (ret != 0) {
@@ -3806,6 +3802,10 @@ static int accept(nccl_net_ofi_listen_comm_t *listen_comm,
 		/* Send r_comm's remote comm ID */
 		conn_msg->remote_comm_id = r_comm->remote_comm_id;
 
+		l_comm->stage = COMM_SEND_CONN;
+
+	case COMM_SEND_CONN:
+
 		/* COMM_SEND_CONN: Send connect response message to remote */
 		ret = post_send_conn_resp(r_comm, conn_msg, device, ep, req);
 		if (ret == -FI_EAGAIN) {
@@ -5159,17 +5159,17 @@ static int connect(nccl_net_ofi_ep_t *base_ep,
 		}
 		comm_state->req = &req->base;
 
-		comm_state->stage = COMM_SEND_CONN;
-
-	case COMM_SEND_CONN:
-
 		/* Prepare request to receive connect response message */
 		s_comm->conn_resp_req = prepare_recv_conn_resp_req(s_comm);
 		if (OFI_UNLIKELY(s_comm->conn_resp_req == NULL)) {
 			send_close(s_comm);
 			return -EINVAL;
 		}
 
+		comm_state->stage = COMM_SEND_CONN;
+
+	case COMM_SEND_CONN:
+
 		/* COMM_SEND_CONN: Post a connect message to send peer connections */
 		ret = post_send_conn(s_comm, device, ep, req);
 		if (ret == -FI_EAGAIN) {