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Date: Tue, 5 Mar 2013 10:53:35 -0500 From: Konrad Rzeszutek Wilk <konrad.wilk@...cle.com> To: David Vrabel <david.vrabel@...rix.com> Cc: Wei Liu <wei.liu2@...rix.com>, "netdev@...r.kernel.org" <netdev@...r.kernel.org>, "annie.li@...cle.com" <annie.li@...cle.com>, Ian Campbell <Ian.Campbell@...rix.com>, "xen-devel@...ts.xen.org" <xen-devel@...ts.xen.org> Subject: Re: [Xen-devel] [PATCH 3/8] netback: get/put module along with vif connect/disconnect On Tue, Mar 05, 2013 at 02:07:42PM +0000, David Vrabel wrote: > On 05/03/13 13:30, Wei Liu wrote: > > On Tue, 2013-03-05 at 10:02 +0000, David Vrabel wrote: > >> On 15/02/13 16:00, Wei Liu wrote: > >>> If there is vif running and user unloads netback, guest's network interface > >>> just mysteriously stops working. So we need to prevent unloading netback > >>> module if there is vif running. > >> > >> It's not mysterious -- it is cleanly disconnected, and will reconnect > >> when the module is reinserted. > >> > > > > From a guest's POV, it just stops without any sign. This should be > > prevented IMHO. > > This is a bug in the frontend or a bug in the backend failing to > disconnect correctly. > > I posted a series of "xen-foofront: handle backend CLOSED without > CLOSING" patches that may help here. (I didn't get applied to netfront > for some reason.) Hm, could you resent it please and make sure that the networking maintainer is on the To list? > > Disabling module unload doesn't prevent this from happening away. You > can always manually unbind the backend device from the xen-netback > driver which has the same effect as unloading the module. > > > Netback / netfront lose all states when netback is unloaded. And > > netfront doesn't support reconfiguration at the moment. My guess is that > > this is the reason why netback doesn't even have unload function at > > first. > > If netfront cannot handle reconnect then that's a bug in the frontend or > a bug in the backend xenbus code not setting up the reconnect correctly. > > >> Being able to unload modules while they are in use is standard so I > >> don't think this should be applied. > > > > I don't think this is true from a module dependency point of view - just > > try to unload any in use module, rmmod / modprobe will give you a fatal > > error. > > Try it with any other network interface driver and it will unload just fine. > > David > > _______________________________________________ > Xen-devel mailing list > Xen-devel@...ts.xen.org > http://lists.xen.org/xen-devel > -- To unsubscribe from this list: send the line "unsubscribe netdev" in the body of a message to majordomo@...r.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html
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