From mboxrd@z Thu Jan 1 00:00:00 1970 From: Jiri Pirko Subject: Re: [PATCH net-next 0/4] net: switchdev: Avoid sleep in atomic with DSA Date: Tue, 10 Jan 2017 13:08:46 +0100 Message-ID: <20170110120846.GC1827@nanopsycho> References: <20170109194503.10713-1-f.fainelli@gmail.com> <20170109204849.GA28310@splinter> <20170109211436.GB28310@splinter> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Cc: Florian Fainelli , netdev@vger.kernel.org, davem@davemloft.net, vivien.didelot@savoirfairelinux.com, andrew@lunn.ch To: Ido Schimmel Return-path: Received: from mail-wm0-f67.google.com ([74.125.82.67]:33837 "EHLO mail-wm0-f67.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1031537AbdAJMIu (ORCPT ); Tue, 10 Jan 2017 07:08:50 -0500 Received: by mail-wm0-f67.google.com with SMTP id c85so29041002wmi.1 for ; Tue, 10 Jan 2017 04:08:49 -0800 (PST) Content-Disposition: inline In-Reply-To: <20170109211436.GB28310@splinter> Sender: netdev-owner@vger.kernel.org List-ID: Mon, Jan 09, 2017 at 10:14:36PM CET, idosch@idosch.org wrote: >On Mon, Jan 09, 2017 at 12:56:48PM -0800, Florian Fainelli wrote: >> On 01/09/2017 12:48 PM, Ido Schimmel wrote: >> > Hi Florian, >> > >> > On Mon, Jan 09, 2017 at 11:44:59AM -0800, Florian Fainelli wrote: >> >> Hi all, >> >> >> >> This patch series is to resolve a sleeping function called in atomic context >> >> debug splat that we observe with DSA. >> >> >> >> Let me know what you think, I was also wondering if we should just always >> >> make switchdev_port_vlan_fill() set SWITCHDEV_F_DEFER, but was afraid this >> >> could cause invalid contexts to be used for rocker, mlxsw, i40e etc. >> > >> > Isn't this a bit of overkill? All the drivers you mention fill the VLAN >> > dump from their cache and don't require sleeping. Even b53 that you >> > mention in the last patch does that, but reads the PVID from the device, >> > which entails taking a mutex. >> >> Correct. >> >> > >> > Can't you just cache the PVID as well? I think this will solve your >> > problem. Didn't look too much into the b53 code, so maybe I'm missing >> > something. Seems that mv88e6xxx has a similar problem. >> >> I suppose we could indeed cache the PVID for b53, but for mv88e6xxx it >> seems like we need to perform a bunch of VTU operations, and those >> access HW registers, Andrew, Vivien, how do you want to solve that, do >> we want to introduce a general VLAN cache somewhere in switchdev/DSA/driver? > >Truth be told, I don't quite understand why switchdev infra even tries >to dump the VLANs from the device. Like, in which situations is this >going to be different from what the software bridge reports? Sure, you >can set the VLAN filters with SELF and skip the software bridge, but how >does that make sense in a model where you want to reflect the software >datapath? But the vlans added by rtnl_bridge_setlink & SELF are not tracked by the bridge and therefore driver needs to dump them. You would have to pass some flag down to driver when adding SWITCHDEV_OBJ_ID_PORT_VLAN indicating the need to track the vlan and dump it. Right?