From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mx1.redhat.com ([209.132.183.28]:6332 "EHLO mx1.redhat.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751305AbdFFMsc (ORCPT ); Tue, 6 Jun 2017 08:48:32 -0400 Date: Tue, 6 Jun 2017 20:48:08 +0800 From: Ming Lei To: Bart Van Assche Cc: "hch@infradead.org" , "linux-block@vger.kernel.org" , "axboe@fb.com" Subject: Re: [PATCH v4 10/11] blk-mq: clarify dispatch may not be drained/blocked by stopping queue Message-ID: <20170606124806.GB13877@ming.t460p> References: <20170605155925.7896-1-ming.lei@redhat.com> <20170605155925.7896-11-ming.lei@redhat.com> <1496706919.2623.36.camel@sandisk.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii In-Reply-To: <1496706919.2623.36.camel@sandisk.com> Sender: linux-block-owner@vger.kernel.org List-Id: linux-block@vger.kernel.org On Mon, Jun 05, 2017 at 11:55:20PM +0000, Bart Van Assche wrote: > On Mon, 2017-06-05 at 23:59 +0800, Ming Lei wrote: > > +/* > > + * We do not guarantee that dispatch can be drained or blocked > > + * after blk_mq_stop_hw_queue() returns. Please use > > + * blk_mq_quiesce_queue() for that requirement. > > + */ > > Hello Ming, > > This is comment explains what blk_mq_stop_hw_queue() should not be used for > and may leave the reader wondering what it is useful for. How about mentioning > first that this function is useful to pause .queue_rq() calls as long as the > block driver it will have to return BUSY if .queue_rq() is called? OK, will make that as one example. Thanks, Ming