IB/core: postpone WR initialization during queue drain

No need to initialize completion and WR in case we fail
during QP modification.

Signed-off-by: Max Gurtovoy <maxg@mellanox.com>
Acked-by: Sagi Grimberg <sagi@grimberg.me>
Signed-off-by: Doug Ledford <dledford@redhat.com>

drivers/infiniband/core/verbs.c

@@ -2191,16 +2191,16 @@ static void __ib_drain_sq(struct ib_qp *qp)
 	struct ib_send_wr swr = {}, *bad_swr;
 	int ret;
 
-	swr.wr_cqe = &sdrain.cqe;
-	sdrain.cqe.done = ib_drain_qp_done;
-	init_completion(&sdrain.done);
-
 	ret = ib_modify_qp(qp, &attr, IB_QP_STATE);
 	if (ret) {
 		WARN_ONCE(ret, "failed to drain send queue: %d\n", ret);
 		return;
 	}
 
+	swr.wr_cqe = &sdrain.cqe;
+	sdrain.cqe.done = ib_drain_qp_done;
+	init_completion(&sdrain.done);
+
 	ret = ib_post_send(qp, &swr, &bad_swr);
 	if (ret) {
 		WARN_ONCE(ret, "failed to drain send queue: %d\n", ret);
@@ -2225,16 +2225,16 @@ static void __ib_drain_rq(struct ib_qp *qp)
 	struct ib_recv_wr rwr = {}, *bad_rwr;
 	int ret;
 
-	rwr.wr_cqe = &rdrain.cqe;
-	rdrain.cqe.done = ib_drain_qp_done;
-	init_completion(&rdrain.done);
-
 	ret = ib_modify_qp(qp, &attr, IB_QP_STATE);
 	if (ret) {
 		WARN_ONCE(ret, "failed to drain recv queue: %d\n", ret);
 		return;
 	}
 
+	rwr.wr_cqe = &rdrain.cqe;
+	rdrain.cqe.done = ib_drain_qp_done;
+	init_completion(&rdrain.done);
+
 	ret = ib_post_recv(qp, &rwr, &bad_rwr);
 	if (ret) {
 		WARN_ONCE(ret, "failed to drain recv queue: %d\n", ret);