From mboxrd@z Thu Jan 1 00:00:00 1970 From: Roopa Prabhu Subject: Re: [RFC 0/3] Adding config get/set to devlink Date: Thu, 12 Oct 2017 09:05:22 -0700 Message-ID: References: <1507815262-33294-1-git-send-email-steven.lin1@broadcom.com> <20171012144032.GG14672@nanopsycho> <20171012150419.GI14672@nanopsycho> <24E5DE7C-A401-48BF-BF80-673ACC38FBBE@gmail.com> Mime-Version: 1.0 Content-Type: text/plain; charset="UTF-8" Content-Transfer-Encoding: quoted-printable Cc: Jiri Pirko , Steve Lin , "netdev@vger.kernel.org" , Jiri Pirko , "davem@davemloft.net" , Michael Chan , linux-pci@vger.kernel.org, "John W. Linville" , Andy Gospodarek To: Florian Fainelli Return-path: In-Reply-To: <24E5DE7C-A401-48BF-BF80-673ACC38FBBE@gmail.com> Sender: linux-pci-owner@vger.kernel.org List-Id: netdev.vger.kernel.org On Thu, Oct 12, 2017 at 8:43 AM, Florian Fainelli wr= ote: > On October 12, 2017 8:04:19 AM PDT, Jiri Pirko wrote: >>Thu, Oct 12, 2017 at 04:46:24PM CEST, roopa@cumulusnetworks.com wrote: >>>On Thu, Oct 12, 2017 at 7:40 AM, Jiri Pirko wrote: >>>> Thu, Oct 12, 2017 at 04:35:10PM CEST, roopa@cumulusnetworks.com >>wrote: >>>>>On Thu, Oct 12, 2017 at 6:34 AM, Steve Lin >> wrote: >>>>>> Adds a devlink command for getting & setting device configuration >>>>>> parameters, and enumerates a bunch of those parameters as devlink >>>>>> attributes. Also introduces an attribute that can be set by a >>>>>> driver to indicate that the config change doesn't take effect >>>>>> until the next restart (as in the case of the bnxt driver changes >>>>>> in this patchset, for which all the configuration changes affect >>NVM >>>>>> only, and aren't loaded until the next restart.) >>>>>> >>>>>> bnxt driver patches make use of these new devlink cmds/attributes. >>>>>> >>>>>> Steve Lin (3): >>>>>> devlink: Add config parameter get/set operations >>>>>> bnxt: Move generic devlink code to new file >>>>>> bnxt: Add devlink support for config get/set >>>>>> >>>>> >>>>>Is the goal here to move all ethtool operations to devlink (I saw >>some >>>>>attrs related to speed etc). ?. >>>>>We do need to move ethtool attrs to netlink and devlink is a good >>>>>place (and of-course leave the current ethtool api around for >>backward >>>>>compatibility). >>>> >>>> We need to make sure we are not moving things to devlink which don't >>>> belong there. All options that use "netdev" as a handle should go >>into >>>> rtnetlink instead. >>>> >>> >>>Any reason you want to keep that restriction ?. >>>FWIS, devlink is a driver api just like ethtool is. >>>and ethtool needs to move to netlink soon...and It would be better to >>>not put the rtnl_lock burden on ethtool driver operations. Instead of >>>adding yet another driver api, extending devlink seems like a great >>>fit to me. >> >>Hmm, the original purpose of devlink was to obtain iface for things >>that >>could not use "netdev" as a handle. I try to stick with it as we >>already >>have iface for things that could use "netdev" as a handle - rtnetlink. >> >>Not sure we want to go this way and add "netdev"-handle things into >>devlink. Thoughts? > > In the current situation where we have ethtool and devlink operating sepa= rately on different objects as entry points to the kernel, I agree with tha= t design. > > Once we move ethtool (or however we name its successor) over to netlink t= here is an opportunity for accessing objects that do and do not have a netd= evice representor today (e.g: management ports on switches) with the same i= nterface, and devlink could be used for that. > > In terms of compatibility though we should have a pseudo generic layer th= at can take ethtool ioctl() and transform that into a netlink message and t= hen call back down to drivers with the existing ethtool_ops that are implem= ented. It is reasonably simple to use coccinelle to update these ethtool_op= s with possibly updated signatures to support netlink attributes and whatno= t, ack, that sounds like a good approach. > but forcing drivers to quit doing ethtool_ops entitely and implement new = sets of "ethtool over netlink" ops is a non starter IMHO. correct, nobody disagrees with that point.