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 0C62ACED61D for ; Wed, 9 Oct 2024 07:58:02 +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-Transfer-Encoding:Content-Type: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=E8n2+txT6iMc4vPU2nhfohToAa6JBx/GfkMaNr88468=; b=dHsA2GCi7iLFvhxK+7A2wjcA0Y aG6I0KhFclhDt/KtjqHHBGg1FlMCCYj1fM9R7jtsvOfErlvHp4ySYunLB3hrxuXE0KsRyxG7JThNY Sw0HCQm8WDk/vOfMpp+uJPfi72XYcFgmOL6DlyNTPV1sscXU6k9b0vA4cKqoBurmPLVSyaVoG5QYN +dveBtEZjas2JzsmnK3lLdJtGdrczhz17EWMZF2hNshsdcmJ5Q0iA5RoN95HpLxaBbGEta428fRQn XEkMK8XszNPVgxxroO8afMIUjZZzILniC6pHhh5xcapy/U5thxyJKBzm8zmELnxepEAF6vRfoTh3X bq6LlLzA==; Received: from localhost ([::1] helo=bombadil.infradead.org) by bombadil.infradead.org with esmtp (Exim 4.98 #2 (Red Hat Linux)) id 1syRa4-00000008L4D-0ZJY; Wed, 09 Oct 2024 07:58:00 +0000 Received: from verein.lst.de ([213.95.11.211]) by bombadil.infradead.org with esmtps (Exim 4.98 #2 (Red Hat Linux)) id 1syRQY-00000008J6m-30PW for linux-nvme@lists.infradead.org; Wed, 09 Oct 2024 07:48:11 +0000 Received: by verein.lst.de (Postfix, from userid 2407) id 3C8AC227A8E; Wed, 9 Oct 2024 09:48:06 +0200 (CEST) Date: Wed, 9 Oct 2024 09:48:05 +0200 From: Christoph Hellwig To: Matias =?iso-8859-1?Q?Bj=F8rling?= Cc: kbusch@kernel.org, hch@lst.de, dlemoal@kernel.org, cassel@kernel.org, linux-nvme@lists.infradead.org, linux-block@vger.kernel.org, linux-kernel@vger.kernel.org, Matias =?iso-8859-1?Q?Bj=F8rling?= Subject: Re: [PATCH 2/2] nvme: add rotational support Message-ID: <20241009074805.GC16181@lst.de> References: <20241008145503.987195-1-m@bjorling.me> <20241008145503.987195-3-m@bjorling.me> MIME-Version: 1.0 Content-Type: text/plain; charset=iso-8859-1 Content-Disposition: inline Content-Transfer-Encoding: 8bit In-Reply-To: <20241008145503.987195-3-m@bjorling.me> 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-20241009_004810_916882_8D1C8E69 X-CRM114-Status: GOOD ( 10.48 ) 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, Oct 08, 2024 at 04:55:03PM +0200, Matias Bjørling wrote: > + if (info->is_rotational) > + lim.features |= BLK_FEAT_ROTATIONAL | BLK_FEAT_ADD_RANDOM; Entropy from block devices is pretty useless. The only reason we still keep it for SCSI is because of retro-computing platforms without a proper platform hardware RNG. NVMe HDDs reall should not show up in those kinds of environments. Also without a add_disk_randomness in the nvme I/O completion handler this won't actually do anything.