From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Date: Wed, 17 Oct 2018 16:47:25 +0200 From: Greg Kroah-Hartman To: Sasha Levin Cc: Haiyang Zhang , "linux-kernel@vger.kernel.org" , "stable@vger.kernel.org" , Stephen Hemminger , "David S. Miller" , Sasha Levin Subject: Re: [PATCH 4.18 101/135] hv_netvsc: pair VF based on serial number Message-ID: <20181017144725.GB3094@kroah.com> References: <20181016170515.447235311@linuxfoundation.org> <20181016170522.303317746@linuxfoundation.org> <20181017074629.GD25537@kroah.com> <20181017131717.GA10130@kroah.com> <20181017142621.GB366@kroah.com> <20181017144034.GB135013@sasha-vm> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20181017144034.GB135013@sasha-vm> List-ID: On Wed, Oct 17, 2018 at 10:40:34AM -0400, Sasha Levin wrote: > On Wed, Oct 17, 2018 at 04:26:21PM +0200, Greg Kroah-Hartman wrote: > > On Wed, Oct 17, 2018 at 02:15:30PM +0000, Haiyang Zhang wrote: > > > The VF NIC needs to be paired with synthetic NIC on HyperV -- to do that we > > > use MAC address matching before the patch #A. But a non VF NIC can also > > > have the same MAC, which shouldn't be paired with synthetic NIC. So a better > > > method is implemented by #A to use VF serial number for matching. > > > > > > But, #A has a bug, which causes matching to fail. Patch #B fixed it by extracting > > > the VF serial number correctly from slot info. > > > > My question is, "what bug is patch #A fixing"? Somehow things have been > > working just fine for people without this, right? Remember, new > > features should not be backported to stable kernels if at all possible. > > The current mechanism works fine most of the time, the problem is that > once in a while we'd see collisions between the synthetic device MAC > address and a different network device such as a bond device or just a > regular non-VF network device. > > So while in most cases assuming that MAC is unique and looking up > devices based on it works, there's no guarantee that it's unique so > this assumption isn't true and things break. > > This is why it (usually) works now, but still has a bug that needs > fixing. > > If that makes sense, I'll requeue it when the fixes have soaked upstream > for a few weeks. That does, thanks, it should have been in the first patch's original changelog comments :) So when both are upstream, feel free to resend. thanks, greg k-h