From mboxrd@z Thu Jan 1 00:00:00 1970 From: Florian Fainelli Subject: Re: [RFC 07/20] net: dsa: list ports in switch\\ Date: Thu, 28 Apr 2016 11:29:32 -0700 Message-ID: <5722568C.8000003@gmail.com> References: <1461796217-18893-1-git-send-email-vivien.didelot@savoirfairelinux.com> <1461796217-18893-8-git-send-email-vivien.didelot@savoirfairelinux.com> <20160427231537.GJ29024@lunn.ch> <572241BB.1070304@gmail.com> <871t5pr3zm.fsf@ketchup.mtl.sfl> Mime-Version: 1.0 Content-Type: text/plain; charset=utf-8 Content-Transfer-Encoding: 7bit Cc: netdev@vger.kernel.org, linux-kernel@vger.kernel.org, kernel@savoirfairelinux.com, "David S. Miller" , Jiri Pirko To: Vivien Didelot , Andrew Lunn Return-path: Received: from mail-pf0-f169.google.com ([209.85.192.169]:33587 "EHLO mail-pf0-f169.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751824AbcD1Sbw (ORCPT ); Thu, 28 Apr 2016 14:31:52 -0400 In-Reply-To: <871t5pr3zm.fsf@ketchup.mtl.sfl> Sender: netdev-owner@vger.kernel.org List-ID: On 28/04/16 11:18, Vivien Didelot wrote: > Florian Fainelli writes: > >> On 27/04/16 16:15, Andrew Lunn wrote: >>> On Wed, Apr 27, 2016 at 06:30:04PM -0400, Vivien Didelot wrote: >>>> List DSA port structures in their switch structure, so that drivers can >>>> iterate on them to retrieve information such as their ports membership. >>> >>> And this would be so much easier using a plan array. >> >> Agreed, I do not see much value in doing this at the moment. Even if you >> have unused ports in a switch, allocating an array is a small price to >> pay compared to directly indexing by port number. >> >> NAK from me unless there is a compelling reason for doing so. > > The point of having a list is 1) get rid of the DSA_MAX_PORTS and have > variable number of ports 2) lists make iteration easier with variable > number of switchs/ports, e.g.: You could get rid of the DSA_MAX_PORTS by asking switch drivers how many ports they support and allocate that dynamically. > > dsa_tree_for_each_switch(dst, ds) > dsa_switch_for_each_port(ds, dp) > /* do something with the port */; This is not more compact or efficient than an array walk, but at this point this becoming preference over anything. > > Anyway, I'm writing a proposal for a new design of DSA, in order to > support the D in DSA. That way, we'll avoid reviewing details of the > implementation and have a big picture of the necessary API changes. Quite frankly, I think your set of changes are submitted at a terrible time, I would very much prefer to allow Andrew to complete his work on re-designing the DSA layer to allow different kinds of switches, thus allowing other people to support more HW in a blink of an eye, and therefore allowing us all to get a clearer picture of what these little switches are capable, rather than some patches that produce a lot of churn with little documented benefits outside of the cross-chip operations. Don't get me wrong, I think we should get to the point where you want us to go, and work in that area is very much appreciated! Thanks -- Florian