xprtrdma: Do not wait if ib_post_send() fails

If ib_post_send() in ro_unmap_sync() fails, the WRs have not been
posted, no completions will fire, and wait_for_completion() will
wait forever. Skip the wait in that case.

To ensure the MRs are invalid, disconnect.
Signed-off-by: Chuck Lever <chuck.lever@oracle.com>
Signed-off-by: Anna Schumaker <Anna.Schumaker@Netapp.com>

net/sunrpc/xprtrdma/frwr_ops.c

@@ -520,14 +520,18 @@ frwr_op_unmap_sync(struct rpcrdma_xprt *r_xprt, struct rpcrdma_req *req)
 	 * unless ri_id->qp is a valid pointer.
 	 */
 	rc = ib_post_send(ia->ri_id->qp, invalidate_wrs, &bad_wr);
-	if (rc)
+	if (rc) {
 		pr_warn("%s: ib_post_send failed %i\n", __func__, rc);
+		rdma_disconnect(ia->ri_id);
+		goto unmap;
+	}
 
 	wait_for_completion(&f->fr_linv_done);
 
 	/* ORDER: Now DMA unmap all of the req's MRs, and return
 	 * them to the free MW list.
 	 */
+unmap:
 	for (i = 0, nchunks = req->rl_nchunks; nchunks; nchunks--) {
 		seg = &req->rl_segments[i];