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=-6.9 required=3.0 tests=DKIMWL_WL_HIGH,DKIM_SIGNED, DKIM_VALID,DKIM_VALID_AU,HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_PATCH, MAILING_LIST_MULTI,SIGNED_OFF_BY,SPF_HELO_NONE,SPF_PASS autolearn=unavailable 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 D33CCC83004 for ; Wed, 29 Apr 2020 14:05:38 +0000 (UTC) Received: from kanga.kvack.org (kanga.kvack.org [205.233.56.17]) by mail.kernel.org (Postfix) with ESMTP id 8E4F52082E for ; Wed, 29 Apr 2020 14:05:38 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (1024-bit key) header.d=redhat.com header.i=@redhat.com header.b="UhtTEWO1" DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org 8E4F52082E Authentication-Results: mail.kernel.org; dmarc=fail (p=none dis=none) header.from=redhat.com Authentication-Results: mail.kernel.org; spf=pass smtp.mailfrom=owner-linux-mm@kvack.org Received: by kanga.kvack.org (Postfix) id 41B208E0027; Wed, 29 Apr 2020 10:05:38 -0400 (EDT) Received: by kanga.kvack.org (Postfix, from userid 40) id 3A2BD8E0005; Wed, 29 Apr 2020 10:05:38 -0400 (EDT) X-Delivered-To: int-list-linux-mm@kvack.org Received: by kanga.kvack.org (Postfix, from userid 63042) id 26B8C8E0027; Wed, 29 Apr 2020 10:05:38 -0400 (EDT) X-Delivered-To: linux-mm@kvack.org Received: from forelay.hostedemail.com (smtprelay0015.hostedemail.com [216.40.44.15]) by kanga.kvack.org (Postfix) with ESMTP id 059328E0005 for ; Wed, 29 Apr 2020 10:05:38 -0400 (EDT) Received: from smtpin09.hostedemail.com (10.5.19.251.rfc1918.com [10.5.19.251]) by forelay03.hostedemail.com (Postfix) with ESMTP id C37A0824805A for ; Wed, 29 Apr 2020 14:05:37 +0000 (UTC) X-FDA: 76761065514.09.use72_13ffc97e48606 X-HE-Tag: use72_13ffc97e48606 X-Filterd-Recvd-Size: 3400 Received: from us-smtp-delivery-1.mimecast.com (us-smtp-1.mimecast.com [205.139.110.61]) by imf38.hostedemail.com (Postfix) with ESMTP for ; Wed, 29 Apr 2020 14:05:37 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=redhat.com; s=mimecast20190719; t=1588169136; h=from:from:reply-to:subject:subject:date:date:message-id:message-id: to:to:cc:cc:mime-version:mime-version:content-type:content-type: in-reply-to:in-reply-to:references:references; bh=15mWh+Q+04E+O3p3+W4qaQIE3K1ImLyGac8MlS9sbR0=; b=UhtTEWO19igxVq0qpMW7n6EjDZzq6QqAU5Jdy47xs4wElqhbRphtcp/SANz5/i6nTzeAAI 9fw6W6VUkApDAO/XW1plkQrvEvKeYmaUiYq2LTj+HRWKxKyPkzufNbgQc6VtctvsyfkMps ACuShzBHQycvZUS/h2D63Lq7leRzh/g= Received: from mimecast-mx01.redhat.com (mimecast-mx01.redhat.com [209.132.183.4]) (Using TLS) by relay.mimecast.com with ESMTP id us-mta-174-4U-OHgS5MwmQkHZ3Cn2JOg-1; Wed, 29 Apr 2020 10:05:32 -0400 X-MC-Unique: 4U-OHgS5MwmQkHZ3Cn2JOg-1 Received: from smtp.corp.redhat.com (int-mx04.intmail.prod.int.phx2.redhat.com [10.5.11.14]) (using TLSv1.2 with cipher AECDH-AES256-SHA (256/256 bits)) (No client certificate requested) by mimecast-mx01.redhat.com (Postfix) with ESMTPS id 3B07118FF661; Wed, 29 Apr 2020 14:05:30 +0000 (UTC) Received: from T590 (ovpn-8-27.pek2.redhat.com [10.72.8.27]) by smtp.corp.redhat.com (Postfix) with ESMTPS id 193705D9C9; Wed, 29 Apr 2020 14:05:18 +0000 (UTC) Date: Wed, 29 Apr 2020 22:05:13 +0800 From: Ming Lei To: Luis Chamberlain Cc: axboe@kernel.dk, viro@zeniv.linux.org.uk, bvanassche@acm.org, gregkh@linuxfoundation.org, rostedt@goodmis.org, mingo@redhat.com, jack@suse.cz, nstange@suse.de, akpm@linux-foundation.org, mhocko@suse.com, yukuai3@huawei.com, linux-block@vger.kernel.org, linux-fsdevel@vger.kernel.org, linux-mm@kvack.org, linux-kernel@vger.kernel.org Subject: Re: [PATCH v3 6/6] loop: be paranoid on exit and prevent new additions / removals Message-ID: <20200429140513.GD700644@T590> References: <20200429074627.5955-1-mcgrof@kernel.org> <20200429074627.5955-7-mcgrof@kernel.org> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20200429074627.5955-7-mcgrof@kernel.org> X-Scanned-By: MIMEDefang 2.79 on 10.5.11.14 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 Wed, Apr 29, 2020 at 07:46:27AM +0000, Luis Chamberlain wrote: > Be pedantic on removal as well and hold the mutex. > This should prevent uses of addition while we exit. > > Signed-off-by: Luis Chamberlain > --- > drivers/block/loop.c | 4 ++++ > 1 file changed, 4 insertions(+) > > diff --git a/drivers/block/loop.c b/drivers/block/loop.c > index da693e6a834e..6dccba22c9b5 100644 > --- a/drivers/block/loop.c > +++ b/drivers/block/loop.c > @@ -2333,6 +2333,8 @@ static void __exit loop_exit(void) > > range = max_loop ? max_loop << part_shift : 1UL << MINORBITS; > > + mutex_lock(&loop_ctl_mutex); > + > idr_for_each(&loop_index_idr, &loop_exit_cb, NULL); > idr_destroy(&loop_index_idr); > > @@ -2340,6 +2342,8 @@ static void __exit loop_exit(void) > unregister_blkdev(LOOP_MAJOR, "loop"); > > misc_deregister(&loop_misc); > + > + mutex_unlock(&loop_ctl_mutex); > } > > module_init(loop_init); > -- > 2.25.1 > Reviewed-by: Ming Lei -- Ming