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 C1A27C4332F for ; Wed, 19 Oct 2022 07:30:43 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S229658AbiJSHam (ORCPT ); Wed, 19 Oct 2022 03:30:42 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:40588 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S229717AbiJSHaj (ORCPT ); Wed, 19 Oct 2022 03:30:39 -0400 Received: from verein.lst.de (verein.lst.de [213.95.11.211]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 128075F204 for ; Wed, 19 Oct 2022 00:30:39 -0700 (PDT) Received: by verein.lst.de (Postfix, from userid 2407) id 72A9F68C4E; Wed, 19 Oct 2022 09:30:35 +0200 (CEST) Date: Wed, 19 Oct 2022 09:30:35 +0200 From: Christoph Hellwig To: axboe@kernel.dk, ming.lei@redhat.com Cc: linux-block@vger.kernel.org Subject: blk_mq_quiesce_queue in del_gendisk Message-ID: <20221019073035.GB11606@lst.de> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline User-Agent: Mutt/1.5.17 (2007-11-01) Precedence: bulk List-ID: X-Mailing-List: linux-block@vger.kernel.org Based on the per-tagset srcu for quiesce discusion I've been wondering why we need the queue quiesce around elevator_exit and rq_qos_exit in del_gendisk. At the point where we call it, we've stopped new fs I/O submissions, and the queue is frozen. What does the quiesce still protect against, and if anything can we come up with a cheaper way to do that?