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 Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by smtp.lore.kernel.org (Postfix) with ESMTP id 7832BC001DE for ; Thu, 10 Aug 2023 07:48:57 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S233493AbjHJHs4 (ORCPT ); Thu, 10 Aug 2023 03:48:56 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:55958 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S233927AbjHJHs4 (ORCPT ); Thu, 10 Aug 2023 03:48:56 -0400 Received: from dfw.source.kernel.org (dfw.source.kernel.org [IPv6:2604:1380:4641:c500::1]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 8CA15211E; Thu, 10 Aug 2023 00:48:54 -0700 (PDT) Received: from smtp.kernel.org (relay.kernel.org [52.25.139.140]) (using TLSv1.3 with cipher TLS_AES_256_GCM_SHA384 (256/256 bits) key-exchange X25519 server-signature RSA-PSS (2048 bits)) (No client certificate requested) by dfw.source.kernel.org (Postfix) with ESMTPS id 22E29651D6; Thu, 10 Aug 2023 07:48:54 +0000 (UTC) Received: by smtp.kernel.org (Postfix) with ESMTPSA id 2E0EEC433C8; Thu, 10 Aug 2023 07:48:53 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=linuxfoundation.org; s=korg; t=1691653733; bh=Tm3hXQwoDjfq1lJqS0uY3AYuTtyBzJD+EkwzV99FVaU=; h=Date:From:To:Cc:Subject:References:In-Reply-To:From; b=XveL0le9szv1D4Vty0V1Ks2eJJ8IiK8v/awhvRgoaJhdK2HpRjCtxKHJeMR028QJQ Fr+pv/2PGMCxqQbYKYKvLx76V7RC4oZ7IP5fqmZHdGmsWYckheki8Kf/FE/VPjkZUK VSKuZ5yKX6h2s5YVwwpX6poeeGQiBLsBttVVeQ6M= Date: Thu, 10 Aug 2023 09:48:50 +0200 From: Greg KH To: Lukas Wunner Cc: Alistair Francis , bhelgaas@google.com, linux-pci@vger.kernel.org, Jonathan.Cameron@huawei.com, alex.williamson@redhat.com, christian.koenig@amd.com, kch@nvidia.com, logang@deltatee.com, linux-kernel@vger.kernel.org, Alistair Francis Subject: Re: [PATCH v3] PCI/DOE: Expose the DOE protocols via sysfs Message-ID: <2023081019-nuclei-drone-32de@gregkh> References: <20230809232851.1004023-1-alistair.francis@wdc.com> <2023081005-ground-muster-63c8@gregkh> <20230810074444.GA11861@wunner.de> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20230810074444.GA11861@wunner.de> Precedence: bulk List-ID: X-Mailing-List: linux-pci@vger.kernel.org On Thu, Aug 10, 2023 at 09:44:44AM +0200, Lukas Wunner wrote: > On Thu, Aug 10, 2023 at 07:05:12AM +0200, Greg KH wrote: > > On Wed, Aug 09, 2023 at 07:28:51PM -0400, Alistair Francis wrote: > > > v3: > > > - Expose each DOE feature as a separate file > > > > But you don't actually have anything in the sysfs files, why not? > > He wants to expose a list of supported protocols. > > He first exposed the list in a single attribute, separated by newlines. > Which made sense because it allows users to grep for a specific protocol. > > You told him not to expose multiple values in a single attribute. > So he's exposing the available protocols each in an empty file. > The file name contains the protocol. > > You got what you asked for. ;) But that's not what was documented, it should say "empty file", otherwise this is going to be very odd when people try to read a file that is marked as readable, but yet returns an error :( > > > --- a/drivers/pci/doe.c > > > +++ b/drivers/pci/doe.c > > > @@ -56,6 +56,10 @@ struct pci_doe_mb { > > > wait_queue_head_t wq; > > > struct workqueue_struct *work_queue; > > > unsigned long flags; > > > + > > > +#ifdef CONFIG_SYSFS > > > + struct device_attribute *sysfs_attrs; > > > +#endif > > > > Please don't put #ifdefs in .c files if you can prevent it. I think > > this will work just fine if you don't have the #ifdef. And who would be > > using pci without sysfs? > > People with space-constrained devices such as routers. So the extra pointer here is a real problem for them? And how much memory are you saving? > It is perfectly legal to compile a kernel with CONFIG_PCI=y and > CONFIG_SYSFS=n. Sure, just not common. > And it is reasonable not to include code in the kernel which has > specifically been deselected in the kernel config. Sure, but not at the expense of a zillion #ifdef lines :) thanks, greg k-h