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=-5.8 required=3.0 tests=BAYES_00,DKIMWL_WL_HIGH, DKIM_SIGNED,DKIM_VALID,DKIM_VALID_AU,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 577E4C433DB for ; Wed, 24 Feb 2021 08:09:56 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id ED48764EDB for ; Wed, 24 Feb 2021 08:09:55 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S230001AbhBXIJy (ORCPT ); Wed, 24 Feb 2021 03:09:54 -0500 Received: from mail.kernel.org ([198.145.29.99]:59596 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S231439AbhBXIJx (ORCPT ); Wed, 24 Feb 2021 03:09:53 -0500 Received: by mail.kernel.org (Postfix) with ESMTPSA id 5092864EC9; Wed, 24 Feb 2021 08:09:11 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=linuxfoundation.org; s=korg; t=1614154152; bh=RETsMJK2CkuQGmJyX4ZtY1lIevb1XJyyBhbQe9+7WBM=; h=Date:From:To:Cc:Subject:References:In-Reply-To:From; b=MlPeznh1EgFmavD9KZTNj1a/dQRwLCMXrbTpGNcgqHyatMTTzttIMjKpASUSN8o5w TZVmYg7rvAVQ2eX+/QH316884GM/vhfr9lyPr+r1m5FxR8Cj8VOUoUy/qyjZcr4wMS Z8360HGPCLnuHoSYU74FF26nH0TLnw2/SyU60MyU= Date: Wed, 24 Feb 2021 09:09:09 +0100 From: Greg Kroah-Hartman To: Bjorn Helgaas Cc: Leon Romanovsky , Bjorn Helgaas , Saeed Mahameed , Jason Gunthorpe , Alexander Duyck , Jakub Kicinski , linux-pci@vger.kernel.org, linux-rdma@vger.kernel.org, netdev@vger.kernel.org, Don Dutile , Alex Williamson , "David S . Miller" , Krzysztof =?utf-8?Q?Wilczy=C5=84ski?= Subject: Re: [PATCH mlx5-next v6 1/4] PCI: Add sysfs callback to allow MSI-X table size change of SR-IOV VFs Message-ID: References: <20210223210743.GA1475710@bjorn-Precision-5520> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20210223210743.GA1475710@bjorn-Precision-5520> Precedence: bulk List-ID: X-Mailing-List: linux-pci@vger.kernel.org On Tue, Feb 23, 2021 at 03:07:43PM -0600, Bjorn Helgaas wrote: > On Sun, Feb 21, 2021 at 08:59:18AM +0200, Leon Romanovsky wrote: > > On Sat, Feb 20, 2021 at 01:06:00PM -0600, Bjorn Helgaas wrote: > > > On Fri, Feb 19, 2021 at 09:20:18AM +0100, Greg Kroah-Hartman wrote: > > > > > > > Ok, can you step back and try to explain what problem you are trying to > > > > solve first, before getting bogged down in odd details? I find it > > > > highly unlikely that this is something "unique", but I could be wrong as > > > > I do not understand what you are wanting to do here at all. > > > > > > We want to add two new sysfs files: > > > > > > sriov_vf_total_msix, for PF devices > > > sriov_vf_msix_count, for VF devices associated with the PF > > > > > > AFAICT it is *acceptable* if they are both present always. But it > > > would be *ideal* if they were only present when a driver that > > > implements the ->sriov_get_vf_total_msix() callback is bound to the > > > PF. > > > > BTW, we already have all possible combinations: static, static with > > folder, with and without "sriov_" prefix, dynamic with and without > > folders on VFs. > > > > I need to know on which version I'll get Acked-by and that version I > > will resubmit. > > I propose that you make static attributes for both files, so > "sriov_vf_total_msix" is visible for *every* PF in the system and > "sriov_vf_msix_count" is visible for *every* VF in the system. > > The PF "sriov_vf_total_msix" show function can return zero if there's > no PF driver or it doesn't support ->sriov_get_vf_total_msix(). > (Incidentally, I think the documentation should mention that when it > *is* supported, the contents of this file are *constant*, i.e., it > does not decrease as vectors are assigned to VFs.) > > The "sriov_vf_msix_count" set function can ignore writes if there's no > PF driver or it doesn't support ->sriov_get_vf_total_msix(), or if a > VF driver is bound. > > Any userspace software must be able to deal with those scenarios > anyway, so I don't think the mere presence or absence of the files is > a meaningful signal to that software. Hopefully, good luck with that! > If we figure out a way to make the files visible only when the > appropriate driver is bound, that might be nice and could always be > done later. But I don't think it's essential. That seems reasonable, feel free to cc: me on the next patch series and I'll try to review it, which should make more sense to me than this email thread :) thanks, greg k-h