From mboxrd@z Thu Jan 1 00:00:00 1970 From: David Vrabel Subject: Re: [PATCH net-next 2/2] xen-netback: handle frontends that fail to transition through Closing Date: Fri, 20 Sep 2013 14:38:46 +0100 Message-ID: <523C4FE6.30309@citrix.com> References: <1379681791-21842-1-git-send-email-paul.durrant@citrix.com> <1379681791-21842-3-git-send-email-paul.durrant@citrix.com> <20130920133448.GC457@zion.uk.xensource.com> Mime-Version: 1.0 Content-Type: text/plain; charset="ISO-8859-1" Content-Transfer-Encoding: 7bit Cc: Paul Durrant , , , Ian Campbell To: Wei Liu Return-path: Received: from smtp.citrix.com ([66.165.176.89]:43441 "EHLO SMTP.CITRIX.COM" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1754590Ab3ITNit (ORCPT ); Fri, 20 Sep 2013 09:38:49 -0400 In-Reply-To: <20130920133448.GC457@zion.uk.xensource.com> Sender: netdev-owner@vger.kernel.org List-ID: On 20/09/13 14:34, Wei Liu wrote: > On Fri, Sep 20, 2013 at 01:56:31PM +0100, Paul Durrant wrote: >> Some old Windows frontends fail to transition through the xenbus Closing >> state and move directly from Connected to Closed. Handle this case properly. >> >> --- a/drivers/net/xen-netback/xenbus.c >> +++ b/drivers/net/xen-netback/xenbus.c >> @@ -265,6 +265,8 @@ static void frontend_changed(struct xenbus_device *dev, >> break; >> >> case XenbusStateClosed: >> + if (dev->state == XenbusStateConnected) >> + disconnect_backend(dev); > > Could you please add a comment above this change stating that this is a > workaround for some old frontend that we cannot fix / upgrade. Handling frontend CONNECTED -> CLOSED is a sensible thing for a backend to do regardless of whether there are old frontends that do this or not. > We would still like to later frontend goes through the normal connected > -> closing -> closed path. This should be documented as a full description of the two state machines in public/io/netif.h in Xen. Not scattered about in comments in a particular backend implementation. David