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=-5.5 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,URIBL_BLOCKED,USER_AGENT_SANE_1 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 356ECC433DB for ; Tue, 16 Mar 2021 07:58:41 +0000 (UTC) Received: from desiato.infradead.org (desiato.infradead.org [90.155.92.199]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by mail.kernel.org (Postfix) with ESMTPS id B340864F4D for ; Tue, 16 Mar 2021 07:58:40 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org B340864F4D Authentication-Results: mail.kernel.org; dmarc=none (p=none dis=none) header.from=lst.de Authentication-Results: mail.kernel.org; spf=none smtp.mailfrom=linux-nvme-bounces+linux-nvme=archiver.kernel.org@lists.infradead.org DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=lists.infradead.org; s=desiato.20200630; h=Sender:Content-Transfer-Encoding :Content-Type:List-Subscribe:List-Help:List-Post:List-Archive: List-Unsubscribe:List-Id:In-Reply-To:MIME-Version:References:Message-ID: Subject:Cc:To:From:Date:Reply-To:Content-ID:Content-Description:Resent-Date: Resent-From:Resent-Sender:Resent-To:Resent-Cc:Resent-Message-ID:List-Owner; bh=QZ49UZzYN1Uwm8cjyTVGeC75I3Y6NKtHibuNOlqS6uE=; b=ffbbxNApMj2yXyYOLQEGUA7lZ TN/ZcMNoP6Y2ROmf4UcxHYcp3M7dsfSqDyUa6ZUycjJhdNgScqJ/TbaT5mPPh1thYWcF8bvBPzdgB J/cotUMlNyX6p+AhFwyMf4mUfFqdv4+k3i11ioUaFsh8T245sOBi4ugtQNvMtLPbJM/ZOxyTY023a rKDlklZAi00ePshbtYbl7xfW99swUdNMCua9RHdyTzjhfgCaBiOwB6EWSrKpUDg6wbQCFi990BZFX faJ/pxd0MfFY3Wc0PnhcXd5oxEaVWQK11tWDogoeAoZq4u7yK8blAXmxdpPNKDNTOXt/1T24Ob6T5 slEZWucAg==; Received: from localhost ([::1] helo=desiato.infradead.org) by desiato.infradead.org with esmtp (Exim 4.94 #2 (Red Hat Linux)) id 1lM4ax-0002wB-CG; Tue, 16 Mar 2021 07:58:27 +0000 Received: from verein.lst.de ([213.95.11.211]) by desiato.infradead.org with esmtps (Exim 4.94 #2 (Red Hat Linux)) id 1lM4at-0002uo-Gt for linux-nvme@lists.infradead.org; Tue, 16 Mar 2021 07:58:25 +0000 Received: by verein.lst.de (Postfix, from userid 2407) id 677A768C65; Tue, 16 Mar 2021 08:58:22 +0100 (CET) Date: Tue, 16 Mar 2021 08:58:21 +0100 From: Christoph Hellwig To: Logan Gunthorpe Cc: Robin Murphy , linux-kernel@vger.kernel.org, linux-nvme@lists.infradead.org, linux-block@vger.kernel.org, linux-pci@vger.kernel.org, linux-mm@kvack.org, iommu@lists.linux-foundation.org, Minturn Dave B , John Hubbard , Dave Hansen , Matthew Wilcox , Christian =?iso-8859-1?Q?K=F6nig?= , Jason Gunthorpe , Jason Ekstrand , Daniel Vetter , Dan Williams , Stephen Bates , Jakowski Andrzej , Christoph Hellwig , Xiong Jianxin Subject: Re: [RFC PATCH v2 06/11] dma-direct: Support PCI P2PDMA pages in dma-direct map_sg Message-ID: <20210316075821.GB15949@lst.de> References: <20210311233142.7900-1-logang@deltatee.com> <20210311233142.7900-7-logang@deltatee.com> <215e1472-5294-d20a-a43a-ff6dfe8cd66e@arm.com> <367fa81e-588d-5734-c69c-8cdc800dcb7e@deltatee.com> MIME-Version: 1.0 Content-Disposition: inline In-Reply-To: <367fa81e-588d-5734-c69c-8cdc800dcb7e@deltatee.com> User-Agent: Mutt/1.5.17 (2007-11-01) X-CRM114-Version: 20100106-BlameMichelson ( TRE 0.8.0 (BSD) ) MR-646709E3 X-CRM114-CacheID: sfid-20210316_075823_735498_EF832A2E X-CRM114-Status: GOOD ( 12.05 ) X-BeenThere: linux-nvme@lists.infradead.org X-Mailman-Version: 2.1.34 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit Sender: "Linux-nvme" Errors-To: linux-nvme-bounces+linux-nvme=archiver.kernel.org@lists.infradead.org On Fri, Mar 12, 2021 at 11:27:46AM -0700, Logan Gunthorpe wrote: > So then we reject the patches that make that change. Seems like an odd > argument to say that we can't do something that won't cause problems > because someone might use it as an example and do something that will > cause problems. Reject the change that causes the problem. No, the problem is a mess of calling conventions. A calling convention returning 0 for error, positive values for success is fine. One returning a negative errno for error and positive values for success is fine a well. One returning 0 for the usual errors and negativ errnos for an unusual corner case is just a complete mess. _______________________________________________ Linux-nvme mailing list Linux-nvme@lists.infradead.org http://lists.infradead.org/mailman/listinfo/linux-nvme