SUNRPC: Handle low memory situations in call_status()

We need to handle ENFILE, ENOBUFS, and ENOMEM, because
xprt_wake_pending_tasks() can be called with any one of these due to
socket creation failures.

Fixes: b61d59fffd ("SUNRPC: xs_tcp_connect_worker{4,6}: merge common code")
Signed-off-by: Trond Myklebust <trond.myklebust@hammerspace.com>

net/sunrpc/clnt.c

@@ -2367,6 +2367,11 @@ call_status(struct rpc_task *task)
 	case -EPIPE:
 	case -EAGAIN:
 		break;
+	case -ENFILE:
+	case -ENOBUFS:
+	case -ENOMEM:
+		rpc_delay(task, HZ>>2);
+		break;
 	case -EIO:
 		/* shutdown or soft timeout */
 		goto out_exit;