From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-5.3 required=3.0 tests=BAYES_00,DKIMWL_WL_HIGH, DKIM_SIGNED,DKIM_VALID,HEADER_FROM_DIFFERENT_DOMAINS,MAILING_LIST_MULTI, SPF_HELO_NONE,SPF_PASS autolearn=no autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id CEB43C43469 for ; Sun, 20 Sep 2020 08:47:09 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 91ADA20EDD for ; Sun, 20 Sep 2020 08:47:09 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1600591629; bh=eVe8YinMtI2dMDa4O8XZdud/EOS2AHiSaBq4i3l/pXs=; h=Date:From:To:Cc:Subject:References:In-Reply-To:List-ID:From; b=oehdRDxrT2AO9GD4J7VBkEm8JCPhghtMhOEWvggP/oFo2B27WC8tUtac4Sv3ztJOO g+BewpVqP5VW1YIkf6JQ1w/QaxVbOKcVmBL4tXR9axaaDw6ixLq/sBaQwO0x7J0lLO wtT/5kkBS35OefINiYZCC0QRL9lgfHT5E2Mgonnc= Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1726316AbgITIrH (ORCPT ); Sun, 20 Sep 2020 04:47:07 -0400 Received: from mail.kernel.org ([198.145.29.99]:49212 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1726247AbgITIrH (ORCPT ); Sun, 20 Sep 2020 04:47:07 -0400 Received: from localhost (83-86-74-64.cable.dynamic.v4.ziggo.nl [83.86.74.64]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by mail.kernel.org (Postfix) with ESMTPSA id 3322A20897; Sun, 20 Sep 2020 08:47:05 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1600591626; bh=eVe8YinMtI2dMDa4O8XZdud/EOS2AHiSaBq4i3l/pXs=; h=Date:From:To:Cc:Subject:References:In-Reply-To:From; b=l5mpg2LA4Q9ZBmfrhUxMWUlwfkd3S3KMiyqm4UWBAF7WVSFIk1msArDvr2idO300A VrV4V+AxUXRqkEj6dsdgII5+WR1ij7nK28FQew9TvNqH2IN6FpnmYBRi7lRYXZkKuc FsSbbPTHzERTbXB/fkgtCVX2WMDi3e1ElSgWn58A= Date: Sun, 20 Sep 2020 10:47:02 +0200 From: Greg Kroah-Hartman To: Jason Gunthorpe Cc: Oded Gabbay , Leon Romanovsky , Gal Pressman , Jakub Kicinski , "Linux-Kernel@Vger. Kernel. Org" , netdev@vger.kernel.org, SW_Drivers , "David S. Miller" , Andrew Lunn , Florian Fainelli , linux-rdma@vger.kernel.org Subject: Re: [PATCH v3 00/14] Adding GAUDI NIC code to habanalabs driver Message-ID: <20200920084702.GA533114@kroah.com> References: <20200918120340.GT869610@unreal> <20200918121905.GU869610@unreal> <20200919064020.GC439518@kroah.com> <20200919082003.GW869610@unreal> <20200919083012.GA465680@kroah.com> <20200919172730.GC2733595@kroah.com> <20200919192235.GB8409@ziepe.ca> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20200919192235.GB8409@ziepe.ca> Precedence: bulk List-ID: X-Mailing-List: netdev@vger.kernel.org On Sat, Sep 19, 2020 at 04:22:35PM -0300, Jason Gunthorpe wrote: > On Sat, Sep 19, 2020 at 07:27:30PM +0200, Greg Kroah-Hartman wrote: > > > It's probably heresy, but why do I need to integrate into the RDMA subsystem ? > > > I understand your reasoning about networking (Ethernet) as the driver > > > connects to the kernel networking stack (netdev), but with RDMA the > > > driver doesn't use or connect to anything in that stack. If I were to > > > support IBverbs and declare that I support it, then of course I would > > > need to integrate to the RDMA subsystem and add my backend to > > > rdma-core. > > > > IBverbs are horrid and I would not wish them on anyone. Seriously. > > I'm curious what drives this opinion? Did you have it since you > reviewed the initial submission all those years ago? As I learned more about that interface, yes, I like it less and less :) But that's the userspace api you all are stuck with, for various reasons, my opinion doesn't matter here. > > I think the general rdma apis are the key here, not the userspace api. > > Are you proposing that habana should have uAPI in drivers/misc and > present a standard rdma-core userspace for it? This is the only > userspace programming interface for RoCE HW. I think that would be > much more work. > > If not, what open source userspace are you going to ask them to > present to merge the kernel side into misc? I don't think that they have a userspace api to their rdma feature from what I understand, but I could be totally wrong as I do not know their hardware at all, so I'll let them answer this question. > > Note, I do not know exactly what they are, but no, IBverbs are not ok. > > Should we stop merging new drivers and abandon the RDMA subsystem? Is > there something you'd like to see fixed? > > Don't really understand your position, sorry. For anything that _has_ to have a userspace RMDA interface, sure ibverbs are the one we are stuck with, but I didn't think that was the issue here at all, which is why I wrote the above comments. thanks, greg k-h