From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1755909AbbI2PD7 (ORCPT ); Tue, 29 Sep 2015 11:03:59 -0400 Received: from mail-yk0-f175.google.com ([209.85.160.175]:35342 "EHLO mail-yk0-f175.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1754154AbbI2PDu (ORCPT ); Tue, 29 Sep 2015 11:03:50 -0400 Date: Tue, 29 Sep 2015 11:03:46 -0400 From: Tejun Heo To: Jens Axboe Cc: Akinobu Mita , LKML , Ming Lei , Christoph Hellwig Subject: Re: [PATCH v4 6/7] blk-mq: fix freeze queue race Message-ID: <20150929150346.GB23411@mtj.duckdns.org> References: <1443287365-4244-1-git-send-email-akinobu.mita@gmail.com> <1443287365-4244-7-git-send-email-akinobu.mita@gmail.com> <20150926173256.GA3572@htj.duckdns.org> <20150928144839.GA2589@mtj.duckdns.org> <560AA7CB.2070107@kernel.dk> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <560AA7CB.2070107@kernel.dk> User-Agent: Mutt/1.5.23 (2014-03-12) Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Hello, On Tue, Sep 29, 2015 at 09:01:31AM -0600, Jens Axboe wrote: > I think that would be very useful, it seems sort of half-assed if the caller > side has to provide serialization for that. Yeah, the thing is init/exit are usually caller synchronized but percpu_rwsem's kill/reinit are more of mode-switching operations which can be performed concurrently during operation so I think the right thing to do here is making it synchronize itself. Will spin a patch. Thanks. -- tejun