From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-2.8 required=3.0 tests=HEADER_FROM_DIFFERENT_DOMAINS, MAILING_LIST_MULTI,SPF_PASS,URIBL_BLOCKED,USER_AGENT_NEOMUTT autolearn=ham autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id 1EC87C433F5 for ; Thu, 6 Sep 2018 13:00:22 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id D63C9204EC for ; Thu, 6 Sep 2018 13:00:21 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org D63C9204EC Authentication-Results: mail.kernel.org; dmarc=none (p=none dis=none) header.from=citrix.com Authentication-Results: mail.kernel.org; spf=none smtp.mailfrom=linux-kernel-owner@vger.kernel.org Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1728787AbeIFRfm (ORCPT ); Thu, 6 Sep 2018 13:35:42 -0400 Received: from smtp03.citrix.com ([162.221.156.55]:61880 "EHLO SMTP03.CITRIX.COM" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1727700AbeIFRfm (ORCPT ); Thu, 6 Sep 2018 13:35:42 -0400 X-IronPort-AV: E=Sophos;i="5.53,338,1531785600"; d="scan'208";a="64591337" Date: Thu, 6 Sep 2018 14:00:16 +0100 From: Wei Liu To: Vitaly Kuznetsov CC: , , Boris Ostrovsky , Juergen Gross , Wei Liu Subject: Re: [PATCH] xen/manage: don't complain about an empty value in control/sysrq node Message-ID: <20180906130016.3nu6zvitjci7x5ge@zion.uk.xensource.com> References: <20180906112608.4221-1-vkuznets@redhat.com> MIME-Version: 1.0 Content-Type: text/plain; charset="us-ascii" Content-Disposition: inline In-Reply-To: <20180906112608.4221-1-vkuznets@redhat.com> User-Agent: NeoMutt/20170113 (1.7.2) Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Thu, Sep 06, 2018 at 01:26:08PM +0200, Vitaly Kuznetsov wrote: > When guest receives a sysrq request from the host it acknowledges it by > writing '\0' to control/sysrq xenstore node. This, however, make xenstore > watch fire again but xenbus_scanf() fails to parse empty value with "%c" > format string: > > sysrq: SysRq : Emergency Sync > Emergency Sync complete > xen:manage: Error -34 reading sysrq code in control/sysrq > > Ignore -ERANGE the same way we already ignore -ENOENT, empty value in > control/sysrq is totally legal. > > Signed-off-by: Vitaly Kuznetsov Reviewed-by: Wei Liu