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 vger.kernel.org (vger.kernel.org [23.128.96.18]) by smtp.lore.kernel.org (Postfix) with ESMTP id DF454C433EF for ; Thu, 12 May 2022 08:09:18 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S240801AbiELIJS (ORCPT ); Thu, 12 May 2022 04:09:18 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:47202 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S230017AbiELIJR (ORCPT ); Thu, 12 May 2022 04:09:17 -0400 Received: from verein.lst.de (verein.lst.de [213.95.11.211]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id C75FE6B086 for ; Thu, 12 May 2022 01:09:16 -0700 (PDT) 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) Precedence: bulk List-ID: X-Mailing-List: io-uring@vger.kernel.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.