xprtrdma: Move recv_wr to struct rpcrdma_rep

Clean up: The fields in the recv_wr do not vary. There is no need to
initialize them before each ib_post_recv(). This removes a large-ish
data structure from the stack.
Signed-off-by: Chuck Lever <chuck.lever@oracle.com>
Signed-off-by: Anna Schumaker <Anna.Schumaker@Netapp.com>

net/sunrpc/xprtrdma/verbs.c

@@ -880,6 +880,10 @@ rpcrdma_create_rep(struct rpcrdma_xprt *r_xprt)
 	rep->rr_cqe.done = rpcrdma_receive_wc;
 	rep->rr_rxprt = r_xprt;
 	INIT_WORK(&rep->rr_work, rpcrdma_receive_worker);
+	rep->rr_recv_wr.next = NULL;
+	rep->rr_recv_wr.wr_cqe = &rep->rr_cqe;
+	rep->rr_recv_wr.sg_list = &rep->rr_rdmabuf->rg_iov;
+	rep->rr_recv_wr.num_sge = 1;
 	return rep;
 
 out_free:
@@ -1302,17 +1306,12 @@ int
 rpcrdma_ep_post_recv(struct rpcrdma_ia *ia,
 		     struct rpcrdma_rep *rep)
 {
-	struct ib_recv_wr recv_wr, *recv_wr_fail;
+	struct ib_recv_wr *recv_wr_fail;
 	int rc;
 
-	recv_wr.next = NULL;
-	recv_wr.wr_cqe = &rep->rr_cqe;
-	recv_wr.sg_list = &rep->rr_rdmabuf->rg_iov;
-	recv_wr.num_sge = 1;
-
 	if (!rpcrdma_dma_map_regbuf(ia, rep->rr_rdmabuf))
 		goto out_map;
-	rc = ib_post_recv(ia->ri_id->qp, &recv_wr, &recv_wr_fail);
+	rc = ib_post_recv(ia->ri_id->qp, &rep->rr_recv_wr, &recv_wr_fail);
 	if (rc)
 		goto out_postrecv;
 	return 0;

net/sunrpc/xprtrdma/xprt_rdma.h

@@ -189,6 +189,7 @@ struct rpcrdma_rep {
 	struct rpcrdma_xprt	*rr_rxprt;
 	struct work_struct	rr_work;
 	struct list_head	rr_list;
+	struct ib_recv_wr	rr_recv_wr;
 	struct rpcrdma_regbuf	*rr_rdmabuf;
 };