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 X-Spam-Level: X-Spam-Status: No, score=-2.5 required=3.0 tests=MAILING_LIST_MULTI, SPF_HELO_NONE,SPF_PASS,USER_AGENT_SANE_1 autolearn=no autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id 78E01C2BA2B for ; Tue, 14 Apr 2020 03:38:09 +0000 (UTC) Received: from kanga.kvack.org (kanga.kvack.org [205.233.56.17]) by mail.kernel.org (Postfix) with ESMTP id 35959206C0 for ; Tue, 14 Apr 2020 03:38:09 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org 35959206C0 Authentication-Results: mail.kernel.org; dmarc=fail (p=none dis=none) header.from=kernel.org Authentication-Results: mail.kernel.org; spf=pass smtp.mailfrom=owner-linux-mm@kvack.org Received: by kanga.kvack.org (Postfix) id D10D68E0003; Mon, 13 Apr 2020 23:38:08 -0400 (EDT) Received: by kanga.kvack.org (Postfix, from userid 40) id CBF768E0001; Mon, 13 Apr 2020 23:38:08 -0400 (EDT) X-Delivered-To: int-list-linux-mm@kvack.org Received: by kanga.kvack.org (Postfix, from userid 63042) id BD47C8E0003; Mon, 13 Apr 2020 23:38:08 -0400 (EDT) X-Delivered-To: linux-mm@kvack.org Received: from forelay.hostedemail.com (smtprelay0181.hostedemail.com [216.40.44.181]) by kanga.kvack.org (Postfix) with ESMTP id A460A8E0001 for ; Mon, 13 Apr 2020 23:38:08 -0400 (EDT) Received: from smtpin17.hostedemail.com (10.5.19.251.rfc1918.com [10.5.19.251]) by forelay01.hostedemail.com (Postfix) with ESMTP id 6A21D180AD806 for ; Tue, 14 Apr 2020 03:38:08 +0000 (UTC) X-FDA: 76705052256.17.test76_4708ba5b3ae5f X-HE-Tag: test76_4708ba5b3ae5f X-Filterd-Recvd-Size: 4643 Received: from mail-pf1-f196.google.com (mail-pf1-f196.google.com [209.85.210.196]) by imf01.hostedemail.com (Postfix) with ESMTP for ; Tue, 14 Apr 2020 03:38:08 +0000 (UTC) Received: by mail-pf1-f196.google.com with SMTP id m21so1641677pff.13 for ; Mon, 13 Apr 2020 20:38:07 -0700 (PDT) X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20161025; h=x-gm-message-state:date:from:to:cc:subject:message-id:references :mime-version:content-disposition:in-reply-to:user-agent; bh=h/r5aOsQUftJul1WcNyBZHlZU1sP9juTahr+5gdxxlg=; b=jzFfhDqaw8/7i02HT9xhGa2iUBm56FY6SRmnJCqckb4tTUxKyVSsOfdlkiiVyMawm+ FkUjozSKDnOJUsYA6pkoDSXCoYWv8WWhxmlza/sNszaQKhkBUJOH47VHRLh+rVVmFNnx 5EpFg3PGfaQxAYLhhNKyVWlf80wIZgRNKS7DXcWkpT0KeT/9LW+NDXzIZ69QJ3078e/H zk44YP/p+vlZLJR90UEjUtaNMFZbxNkQgh9Eqb9jo6zkJbStn7fppa3clCcvwxObfbjY CP7cepxIWeBrN9u5jEB8NwrT+xkyyy4tafSEOkwr8Nh1uIW5aTZTEm6sKp5NyyBxFkk7 dzsA== X-Gm-Message-State: AGi0PubDMtexsyjU08JtX3EVH00NgmNJk6YWrum8wO6sQknUpOV3yg3W FT3LDnNR9zUeoq9sp5ET4IU= X-Google-Smtp-Source: APiQypLbMnY7RmOhI54DEIQDHmqf9p5b+ywolxB5Vv3/JhisfnuzWeRXYY9C/ZyBC+MSinBn4WxhUg== X-Received: by 2002:a63:da47:: with SMTP id l7mr21029707pgj.315.1586835487193; Mon, 13 Apr 2020 20:38:07 -0700 (PDT) Received: from 42.do-not-panic.com (42.do-not-panic.com. [157.230.128.187]) by smtp.gmail.com with ESMTPSA id x71sm9855165pfd.129.2020.04.13.20.38.05 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Mon, 13 Apr 2020 20:38:05 -0700 (PDT) Received: by 42.do-not-panic.com (Postfix, from userid 1000) id EF98140277; Tue, 14 Apr 2020 03:38:04 +0000 (UTC) Date: Tue, 14 Apr 2020 03:38:04 +0000 From: Luis Chamberlain To: Bart Van Assche Cc: Jens Axboe , Al Viro , Greg Kroah-Hartman , Steven Rostedt , Ingo Molnar , Jan Kara , Ming Lei , Nicolai Stange , Andrew Morton , Michal Hocko , yu kuai , linux-block@vger.kernel.org, Linux FS Devel , linux-mm , "linux-kernel@vger.kernel.org" , Omar Sandoval , Hannes Reinecke , Michal Hocko Subject: Re: [RFC v2 5/5] block: revert back to synchronous request_queue removal Message-ID: <20200414033804.GO11244@42.do-not-panic.com> References: <20200409214530.2413-1-mcgrof@kernel.org> <20200409214530.2413-6-mcgrof@kernel.org> <161e938d-929b-1fdb-ba77-56b839c14b5b@acm.org> <20200410143412.GK11244@42.do-not-panic.com> <64c9212d-aaa3-d172-0ab9-0fc0e25a019a@acm.org> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <64c9212d-aaa3-d172-0ab9-0fc0e25a019a@acm.org> User-Agent: Mutt/1.10.1 (2018-07-13) X-Bogosity: Ham, tests=bogofilter, spamicity=0.000000, version=1.2.4 Sender: owner-linux-mm@kvack.org Precedence: bulk X-Loop: owner-majordomo@kvack.org List-ID: On Sat, Apr 11, 2020 at 04:21:17PM -0700, Bart Van Assche wrote: > On 2020-04-10 14:27, Luis Chamberlain wrote: > > On Fri, Apr 10, 2020 at 2:50 PM Luis Chamberlain wrote: > >> > >> On Fri, Apr 10, 2020 at 8:34 AM Luis Chamberlain wrote: > >>> On Thu, Apr 09, 2020 at 08:12:21PM -0700, Bart Van Assche wrote: > >>>> Please add a might_sleep() call in blk_put_queue() since with this patch > >>>> applied it is no longer allowed to call blk_put_queue() from atomic context. > >>> > >>> Sure thing. > >> > >> On second though, I don't think blk_put_queue() would be the right > >> place for might_sleep(), given we really only care about the *last* > >> refcount decrement to 0. So I'll move it to blk_release_queue(). > >> Granted, at that point we are too late, and we'd get a splat about > >> this issue *iff* we really sleep. So yeah, I do suppose that forcing > >> this check there still makes sense. > > > > I'll add might_sleep() to both blk_release_queue() *and* blk_cleanup_queue(). > > Since there is already an unconditional mutex_lock() call in > blk_cleanup_queue(), do we really need to add a might_sleep() call in > blk_cleanup_queue()? You are right, mutex_lock() already has a might_sleep() sprinkled on it. Luis