From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1752357AbcD3VEj (ORCPT ); Sat, 30 Apr 2016 17:04:39 -0400 Received: from mail.linuxfoundation.org ([140.211.169.12]:55327 "EHLO mail.linuxfoundation.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751403AbcD3VEh (ORCPT ); Sat, 30 Apr 2016 17:04:37 -0400 Date: Sat, 30 Apr 2016 14:04:36 -0700 From: Greg KH To: "K. Y. Srinivasan" Cc: linux-kernel@vger.kernel.org, devel@linuxdriverproject.org, olaf@aepfle.de, apw@canonical.com, vkuznets@redhat.com, jasowang@redhat.com Subject: Re: [PATCH 1/8] Drivers: hv: kvp: fix IP Failover Message-ID: <20160430210436.GA31172@kroah.com> References: <1459900641-20328-1-git-send-email-kys@microsoft.com> <1459900667-20367-1-git-send-email-kys@microsoft.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <1459900667-20367-1-git-send-email-kys@microsoft.com> User-Agent: Mutt/1.6.0 (2016-04-01) Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Tue, Apr 05, 2016 at 04:57:40PM -0700, K. Y. Srinivasan wrote: > From: Vitaly Kuznetsov > > Hyper-V VMs can be replicated to another hosts and there is a feature to > set different IP for replicas, it is called 'Failover TCP/IP'. When > such guest starts Hyper-V host sends it KVP_OP_SET_IP_INFO message as soon > as we finish negotiation procedure. The problem is that it can happen (and > it actually happens) before userspace daemon connects and we reply with > HV_E_FAIL to the message. As there are no repetitions we fail to set the > requested IP. > > Solve the issue by postponing our reply to the negotiation message till > userspace daemon is connected. We can't wait too long as there is a > host-side timeout (cca. 75 seconds) and if we fail to reply in this time > frame the whole KVP service will become inactive. The solution is not > ideal - if it takes userspace daemon more than 60 seconds to connect > IP Failover will still fail but I don't see a solution with our current > separation between kernel and userspace parts. > > Other two modules (VSS and FCOPY) don't require such delay, leave them > untouched. > > Signed-off-by: Vitaly Kuznetsov > Signed-off-by: K. Y. Srinivasan > --- > drivers/hv/hv_kvp.c | 31 +++++++++++++++++++++++++++++++ > drivers/hv/hyperv_vmbus.h | 5 +++++ > 2 files changed, 36 insertions(+), 0 deletions(-) This series doesn't apply to my tree :(