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=-2.2 required=3.0 tests=HEADER_FROM_DIFFERENT_DOMAINS, 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 28076CA9EAF for ; Thu, 24 Oct 2019 08:55:20 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id E974220684 for ; Thu, 24 Oct 2019 08:55:19 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1731933AbfJXIzS (ORCPT ); Thu, 24 Oct 2019 04:55:18 -0400 Received: from mx2.suse.de ([195.135.220.15]:54374 "EHLO mx1.suse.de" rhost-flags-OK-OK-OK-FAIL) by vger.kernel.org with ESMTP id S1730100AbfJXIzS (ORCPT ); Thu, 24 Oct 2019 04:55:18 -0400 X-Virus-Scanned: by amavisd-new at test-mx.suse.de Received: from relay2.suse.de (unknown [195.135.220.254]) by mx1.suse.de (Postfix) with ESMTP id 69814B75B; Thu, 24 Oct 2019 08:55:16 +0000 (UTC) Date: Thu, 24 Oct 2019 10:55:14 +0200 From: Michal =?iso-8859-1?Q?Such=E1nek?= To: Christoph Hellwig Cc: linux-scsi@vger.kernel.org, Jonathan Corbet , Jens Axboe , "James E.J. Bottomley" , "Martin K. Petersen" , Alexander Viro , Mauro Carvalho Chehab , Eric Biggers , "J. Bruce Fields" , Benjamin Coddington , Hannes Reinecke , Omar Sandoval , Ming Lei , Damien Le Moal , Bart Van Assche , Tejun Heo , linux-doc@vger.kernel.org, linux-kernel@vger.kernel.org, linux-fsdevel@vger.kernel.org Subject: Re: [PATCH v2 6/8] bdev: add open_finish. Message-ID: <20191024085514.GI938@kitsune.suse.cz> References: <20191024022232.GB11485@infradead.org> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20191024022232.GB11485@infradead.org> User-Agent: Mutt/1.10.1 (2018-07-13) Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Wed, Oct 23, 2019 at 07:22:32PM -0700, Christoph Hellwig wrote: > On Wed, Oct 23, 2019 at 02:52:45PM +0200, Michal Suchanek wrote: > > Opening a block device may require a long operation such as waiting for > > the cdrom tray to close. Performing this operation with locks held locks > > out other attempts to open the device. These processes waiting to open > > the device are not killable. > > > > To avoid this issue and still be able to perform time-consuming checks > > at open() time the block device driver can provide open_finish(). If it > > does opening the device proceeds even when an error is returned from > > open(), bd_mutex is released and open_finish() is called. If > > open_finish() succeeds the device is now open, if it fails release() is > > called. > > > > When -ERESTARTSYS is returned from open() blkdev_get may loop without > > calling open_finish(). On -ERESTARTSYS open_finish() is not called. > > > > Move a ret = 0 assignment up in the if/else branching to avoid returning > > -ENXIO. Previously the return value was ignored on the unhandled branch. > > This just doesn't make much sense. There is no point in messing up > the block API for ugly workarounds like that. If you have ideas how to do this better then share them. Thanks Michal