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 DC776E77188 for ; Mon, 6 Jan 2025 08:29:10 +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=5OSSHtlh5FPTXeoNeKBaq2mv0nToARhEzErQPPIDk0E=; b=aOo8TqWNub+4gSc4q92dZJ4mSp 0fcyMZPvDMnN/2KJ5UxTGix2QQQO4FthJ/tg3CCNPeJC5FoevIjMisW/GvAm544OlHHGkRqK+2Ios P6AvaLxuw9lNe1H3YvRWQqsixYzraFk6Nn5m5Fmfg8gcaRO1EyjGMeqk5bnRflTX1EoAE3kpkpWNZ RccK8csbMsyqljPp7NZ6jWmu/HoISxK6T6e83Uv2IR2CeN/s4+diSAnU8Arh79p7IrcqwaoENZHM6 x26t/uqjG+4GuSdv8z5XZhLNJDNVJNsEBIuToZ0UCVh2GkmcU/Bajz5FeiQfVJoUviFUfYKxNvM6m QIMmo1/g==; Received: from localhost ([::1] helo=bombadil.infradead.org) by bombadil.infradead.org with esmtp (Exim 4.98 #2 (Red Hat Linux)) id 1tUiU1-00000000Ve5-28zs; Mon, 06 Jan 2025 08:29:09 +0000 Received: from verein.lst.de ([213.95.11.211]) by bombadil.infradead.org with esmtps (Exim 4.98 #2 (Red Hat Linux)) id 1tUiTy-00000000Vci-44jg for linux-nvme@lists.infradead.org; Mon, 06 Jan 2025 08:29:08 +0000 Received: by verein.lst.de (Postfix, from userid 2407) id CE4A668BFE; Mon, 6 Jan 2025 09:29:02 +0100 (CET) Date: Mon, 6 Jan 2025 09:29:02 +0100 From: Christoph Hellwig To: Ming Lei Cc: Damien Le Moal , Jens Axboe , linux-block@vger.kernel.org, linux-nvme@lists.infradead.org, Christoph Hellwig , Keith Busch , Sagi Grimberg , Nilay Shroff Subject: Re: [PATCH 1/3] block: Fix sysfs queue freeze and limits lock order Message-ID: <20250106082902.GC18408@lst.de> References: <20250104132522.247376-1-dlemoal@kernel.org> <20250104132522.247376-2-dlemoal@kernel.org> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: 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-20250106_002907_148997_DE6DDCBB X-CRM114-Status: GOOD ( 15.75 ) 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 Mon, Jan 06, 2025 at 11:31:43AM +0800, Ming Lei wrote: > As I mentioned in another thread, freezing queue may not be needed in > ->store(), so let's discuss and confirm if it is needed here first. > > https://lore.kernel.org/linux-block/Z3tHozKiUqWr7gjO@fedora/ We do need the freezing. What you're proposing is playing fast and loose which is going to get us in trouble. While most (all?) limits are simple scalars, you often can't update just one without the others without having coherent state. Having coherent state was the entire point of the atomic queue limit updates.