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 bombadil.infradead.org (bombadil.infradead.org [198.137.202.133]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.lore.kernel.org (Postfix) with ESMTPS id A4FDEC4332F for ; Tue, 29 Nov 2022 08:43:18 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=lists.infradead.org; s=bombadil.20210309; h=Sender:List-Subscribe:List-Help :List-Post:List-Archive:List-Unsubscribe:List-Id:In-Reply-To:Content-Type: MIME-Version:References:Message-ID:Subject:Cc:To:From:Date:Reply-To: Content-Transfer-Encoding:Content-ID:Content-Description:Resent-Date: Resent-From:Resent-Sender:Resent-To:Resent-Cc:Resent-Message-ID:List-Owner; bh=ll8adlbd4mpMCn/XqEsw7DfOyBPlh9xblMPx9JQ88lA=; b=xGzNAxPnK70jJ7MYmUFjRfV2qI Brh7Mxht6WQIcTm1lDlFQDwaXpiUpDfyg9dcnYv3sZKX88utRb0X+nf8DsnoGVkz04Bjo8VnM2JkN AnLuUT0or0VDiQcnnIkabmyXi8h6UYxsFqQfE5MJAIs35qOMPYdgQPR3aUG5eB9YdLv+wictfic0T UMtBt0s0t0YRkx6e+m0sR49//3hD/01XpcaHoETjNy6Pkl5h58in2epUxEyytaoiet7TFQQOBvQn0 MWP+dvvK7eTLDtIoFoUpA56ABYk2geYQ/Q1sQf3F6OR4H+OpXIga6PdUp/csS2eXmRSnEoCf3Esir PTIVE3QQ==; Received: from localhost ([::1] helo=bombadil.infradead.org) by bombadil.infradead.org with esmtp (Exim 4.94.2 #2 (Red Hat Linux)) id 1ozwCy-007TCI-2U; Tue, 29 Nov 2022 08:43:16 +0000 Received: from verein.lst.de ([213.95.11.211]) by bombadil.infradead.org with esmtps (Exim 4.94.2 #2 (Red Hat Linux)) id 1ozwCv-007T9y-4R for linux-nvme@lists.infradead.org; Tue, 29 Nov 2022 08:43:14 +0000 Received: by verein.lst.de (Postfix, from userid 2407) id 6238D68AFE; Tue, 29 Nov 2022 09:43:10 +0100 (CET) Date: Tue, 29 Nov 2022 09:43:10 +0100 From: "hch@lst.de" To: "Rao, Lei" Cc: Chaitanya Kulkarni , "kbusch@kernel.org" , "axboe@fb.com" , "hch@lst.de" , "sagi@grimberg.me" , "linux-nvme@lists.infradead.org" , "linux-kernel@vger.kernel.org" Subject: Re: [PATCH] nvme: clear the prp2 field of the nvme command. Message-ID: <20221129084310.GB25609@lst.de> References: <20221129014711.91305-1-lei.rao@intel.com> <15de4902-03e7-0d2c-4b4c-45d713d0f1fd@nvidia.com> <4cee0097-4f08-1990-112f-6e39229f59ef@intel.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <4cee0097-4f08-1990-112f-6e39229f59ef@intel.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-20221129_004313_336468_4CEA1FFB X-CRM114-Status: GOOD ( 13.38 ) 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: , Sender: "Linux-nvme" Errors-To: linux-nvme-bounces+linux-nvme=archiver.kernel.org@lists.infradead.org On Tue, Nov 29, 2022 at 12:50:57PM +0800, Rao, Lei wrote: > stricter checks, and if prp2 is not used but has a value, some warnings will be > printed. According to the NVMe spec, it seems to write a reserved field produces > an undefined result, so maybe clearing it is better. NVMe is a little weird about reserved fields settable by the host. I don't think your controllers warnings are correct, but given that the cost of clearing is very low I think we should clear it in Linux. Please resend a patch with the clearing in the right place as suggested in my previous mail.