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=-2.2 required=3.0 tests=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 2C03AC433E0 for ; Tue, 7 Jul 2020 08:47:08 +0000 (UTC) Received: from merlin.infradead.org (merlin.infradead.org [205.233.59.134]) (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 ECB6A2064B for ; Tue, 7 Jul 2020 08:47:07 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (2048-bit key) header.d=lists.infradead.org header.i=@lists.infradead.org header.b="JvaKsgw3" DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org ECB6A2064B 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=merlin.20170209; h=Sender:Content-Transfer-Encoding: Content-Type:Cc:List-Subscribe:List-Help:List-Post:List-Archive: List-Unsubscribe:List-Id:In-Reply-To:MIME-Version:References:Message-ID: Subject: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=cpBB/v2FwC0dBseLzQx7ETL54K2Ke8Maad781Wlz8rc=; b=JvaKsgw3Wgl8CiTkiilcn/ZW/ MlekVdSgnz+6bKi2I3Zh0t2flL+31QLNWL7rrxc9iRhhtqG9iqBQBBrIYvZ86W3hWaxuiw2XY82PN grv6QiUThZmIHy9XyIP7SPHeMuKjiKDnqKtMXQFcCXlG0ceq80NulIQY9nJAoA03I5iFQ9p/UL0q3 dxTgfoULiqRp5xuiXmd6CjM+5NZSNmfkiodiK5vMbfUxEZ3KGYb7PqcnZuHHmAQ/5VsiYeFcwGq5B JELlDXeXmqeLl/7gwqvGo24eNSwpBgIHdZvH6N3KHKo/r3RY8Bt5z0dmguN7vC4LzntKYFZ70taEE QlYvtV6Sg==; Received: from localhost ([::1] helo=merlin.infradead.org) by merlin.infradead.org with esmtp (Exim 4.92.3 #3 (Red Hat Linux)) id 1jsjFo-0003es-St; Tue, 07 Jul 2020 08:47:04 +0000 Received: from verein.lst.de ([213.95.11.211]) by merlin.infradead.org with esmtps (Exim 4.92.3 #3 (Red Hat Linux)) id 1jsjFm-0003eE-PF for linux-nvme@lists.infradead.org; Tue, 07 Jul 2020 08:47:03 +0000 Received: by verein.lst.de (Postfix, from userid 2407) id 2A4D568AFE; Tue, 7 Jul 2020 10:47:00 +0200 (CEST) Date: Tue, 7 Jul 2020 10:46:59 +0200 From: Christoph Hellwig To: Chaitanya Kulkarni Subject: Re: [PATCH RFC] nvme-pci: remove the unsed code in alloc_size Message-ID: <20200707084659.GA26962@lst.de> References: <20200706225305.14892-1-chaitanya.kulkarni@wdc.com> MIME-Version: 1.0 Content-Disposition: inline In-Reply-To: <20200706225305.14892-1-chaitanya.kulkarni@wdc.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-20200707_044702_954072_AD7A600B X-CRM114-Status: GOOD ( 12.32 ) X-BeenThere: linux-nvme@lists.infradead.org X-Mailman-Version: 2.1.29 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Cc: kbusch@kernel.org, hch@lst.de, linux-nvme@lists.infradead.org, sagi@grimberg.me 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 Mon, Jul 06, 2020 at 03:53:05PM -0700, Chaitanya Kulkarni wrote: > >From the initial implementation of NVMe SGL kernel support > commit a7a7cbe353a5 ("nvme-pci: add SGL support") with addition of the > commit 943e942e6266 ("nvme-pci: limit max IO size and segments to avoid > high order allocations") now there is only caller left for > nvme_pci_iod_alloc_size() which statically passes true for last > parameter that calculates allocation size based on SGL since we need > size of biggest command supported for mempool allocation. > > This patch removes the helper functions nvme_pci_iod_alloc_size() and > nvme_npages() used for allocation size calculation and open codes it > into nvme_probe(). This is an obviously correct transformation, but I think the existing code is a land mine. I think we should change it to use the maximum of either the PRP or SGL case to gurantee that we are on the safe side. Can you do that instead? _______________________________________________ Linux-nvme mailing list Linux-nvme@lists.infradead.org http://lists.infradead.org/mailman/listinfo/linux-nvme