From mboxrd@z Thu Jan 1 00:00:00 1970 From: Douglas Gilbert Subject: Re: [PATCH v4] sg: O_EXCL and other lock handling Date: Fri, 13 Jun 2014 10:33:37 -0400 Message-ID: <539B0BC1.2020303@interlog.com> References: <539A453F.5020502@interlog.com> <20140613090316.GA18032@lst.de> Reply-To: dgilbert@interlog.com Mime-Version: 1.0 Content-Type: text/plain; charset=ISO-8859-1; format=flowed Content-Transfer-Encoding: 7bit Return-path: Received: from smtp.infotech.no ([82.134.31.41]:38434 "EHLO smtp.infotech.no" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751167AbaFMOdn (ORCPT ); Fri, 13 Jun 2014 10:33:43 -0400 In-Reply-To: <20140613090316.GA18032@lst.de> Sender: linux-scsi-owner@vger.kernel.org List-Id: linux-scsi@vger.kernel.org To: Christoph Hellwig Cc: SCSI development list , James Bottomley , Hannes Reinecke , vaughan On 14-06-13 05:03 AM, Christoph Hellwig wrote: > Hi Doug, > > this looks generally good to me, but I don't think open_cnt and exclude > have to use atomic_t, as they are only ever modified under open_rel_lock. They are read by 'cat /proc/scsi/sg/debug' [in sg_proc_seq_show_debug()] but transient off-by-1 reports are not so important. [Prior to locking that block with read_lock(sfd_lock) that routine sometimes printed wild results, so some care is required.] > Can you take a look at the version below? This changes open_cnt to an > int, exclude to a bool, removes the open_cnt underflow check that > the VFS takes care for, and streamlines the open path a little bit: sg_open() and sg_release() clean-up looks good. The back-up goto at the end of sg_open() reminds me of Fortran style :-) More importantly my sg_tst_excl* tests give this version the thumbs up. Acked-by: Douglas Gilbert