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 9684DC433F5 for ; Thu, 12 May 2022 08:09:48 +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=jeTIHt3wgzCIsOFoN76KPV7b2vGbO12U/TrCtgb+ew4=; b=fLjfaf7LnekYwMKWRY4XI0WGQp /XClLIs6ahAYQ8MxpE7wtHbl6hwGx3PJ81Bh4JVHgCrtOO9sl3rxOMwde2Be83M8xjVrcNNbvg37E HzoSLz4e4dW4bNeIya3GB9MUyGAvFlS2NnC4ZI8WFUaPILYQ6hhHMyKaKk0Bu8BECV5Z9sdTjAuwo i2fttdJmVQGcp/ukVKuCu6BsygWFNwB/CIQsCC1wODQmRjxXHRXuNP8e8j4nu3GH28uOgNsnO770g 3I9LYVpS65XcHhIqxL/o31ii6Aequbwe5OK8vJPLALljbJe+CMAqkzD32kALbE/DHOAl2dBYFhtKG D+KFCDiQ==; Received: from localhost ([::1] helo=bombadil.infradead.org) by bombadil.infradead.org with esmtp (Exim 4.94.2 #2 (Red Hat Linux)) id 1np3tE-00AsV6-PL; Thu, 12 May 2022 08:09:40 +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 1np3sy-00AsSN-NK for linux-nvme@lists.infradead.org; Thu, 12 May 2022 08:09:27 +0000 Received: by verein.lst.de (Postfix, from userid 2407) id CC0A668BEB; Thu, 12 May 2022 10:09:12 +0200 (CEST) Date: Thu, 12 May 2022 10:09:12 +0200 From: Christoph Hellwig To: Ming Lei Cc: Kanchan Joshi , axboe@kernel.dk, hch@lst.de, io-uring@vger.kernel.org, linux-nvme@lists.infradead.org, asml.silence@gmail.com, mcgrof@kernel.org, shr@fb.com, joshiiitr@gmail.com, anuj20.g@samsung.com, gost.dev@samsung.com Subject: Re: [PATCH v5 2/6] block: wire-up support for passthrough plugging Message-ID: <20220512080912.GA26882@lst.de> References: <20220511054750.20432-1-joshi.k@samsung.com> <20220511054750.20432-3-joshi.k@samsung.com> 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-20220512_010924_936804_1A7B8715 X-CRM114-Status: GOOD ( 12.31 ) 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 Thu, May 12, 2022 at 01:25:24PM +0800, Ming Lei wrote: > This way may cause nested plugging, and breaks xfstests generic/131. > Also may cause io hang since request can't be polled before flushing > plug in blk_execute_rq(). Looking at this again, yes blk_mq_request_bypass_insert is probably the wrong place. > I'd suggest to apply the plug in blk_execute_rq_nowait(), such as: Do we really need the use_plug parameter and the extra helper? If someone holds a plug over passthrough command submission I think we can assume they actually do want to use it. Otherwise this does indeed look like the better plan.