From patchwork Mon Oct 24 15:08:16 2016 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Jan Beulich X-Patchwork-Id: 685933 X-Patchwork-Delegate: davem@davemloft.net Return-Path: X-Original-To: patchwork-incoming@ozlabs.org Delivered-To: patchwork-incoming@ozlabs.org Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by ozlabs.org (Postfix) with ESMTP id 3t2fmp5t6yz9t0P for ; Tue, 25 Oct 2016 02:08:26 +1100 (AEDT) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S965100AbcJXPIW convert rfc822-to-8bit (ORCPT ); Mon, 24 Oct 2016 11:08:22 -0400 Received: from prv-mh.provo.novell.com ([137.65.248.74]:54864 "EHLO prv-mh.provo.novell.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S939720AbcJXPIU (ORCPT ); Mon, 24 Oct 2016 11:08:20 -0400 Received: from INET-PRV-MTA by prv-mh.provo.novell.com with Novell_GroupWise; Mon, 24 Oct 2016 09:08:19 -0600 Message-Id: <580E40000200007800119234@prv-mh.provo.novell.com> X-Mailer: Novell GroupWise Internet Agent 14.2.1 Date: Mon, 24 Oct 2016 09:08:16 -0600 From: "Jan Beulich" To: "Paul Durrant" , "Wei Liu" Cc: , , , "Juergen Gross" , Subject: [PATCH v2 RESEND] xen-netback: prefer xenbus_scanf() over xenbus_gather() Mime-Version: 1.0 Content-Disposition: inline Sender: netdev-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: netdev@vger.kernel.org For single items being collected this should be preferred as being more typesafe (as the compiler can check format string and to-be-written-to variable match) and more efficient (requiring one less parameter to be passed). Signed-off-by: Jan Beulich --- v2: Avoid commit message to continue from subject. --- drivers/net/xen-netback/xenbus.c | 14 +++++++------- 1 file changed, 7 insertions(+), 7 deletions(-) --- 4.9-rc2/drivers/net/xen-netback/xenbus.c +++ 4.9-rc2-xen-netback-prefer-xenbus_scanf/drivers/net/xen-netback/xenbus.c @@ -889,16 +889,16 @@ static int connect_ctrl_ring(struct back unsigned int evtchn; int err; - err = xenbus_gather(XBT_NIL, dev->otherend, - "ctrl-ring-ref", "%u", &val, NULL); - if (err) + err = xenbus_scanf(XBT_NIL, dev->otherend, + "ctrl-ring-ref", "%u", &val); + if (err <= 0) goto done; /* The frontend does not have a control ring */ ring_ref = val; - err = xenbus_gather(XBT_NIL, dev->otherend, - "event-channel-ctrl", "%u", &val, NULL); - if (err) { + err = xenbus_scanf(XBT_NIL, dev->otherend, + "event-channel-ctrl", "%u", &val); + if (err <= 0) { xenbus_dev_fatal(dev, err, "reading %s/event-channel-ctrl", dev->otherend); @@ -919,7 +919,7 @@ done: return 0; fail: - return err; + return err ?: -ENODATA; } static void connect(struct backend_info *be)