From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1752907AbeDSC2C (ORCPT ); Wed, 18 Apr 2018 22:28:02 -0400 Received: from mx3-rdu2.redhat.com ([66.187.233.73]:54374 "EHLO mx1.redhat.com" rhost-flags-OK-OK-OK-FAIL) by vger.kernel.org with ESMTP id S1752245AbeDSC2B (ORCPT ); Wed, 18 Apr 2018 22:28:01 -0400 Date: Thu, 19 Apr 2018 10:27:41 +0800 From: Ming Lei To: "jianchao.wang" Cc: keith.busch@intel.com, sagi@grimberg.me, linux-kernel@vger.kernel.org, linux-nvme@lists.infradead.org, axboe@fb.com, hch@lst.de Subject: Re: PATCH V4 0/5 nvme-pci: fixes on nvme_timeout and nvme_dev_disable Message-ID: <20180419022735.GC5495@ming.t460p> References: <1520489971-31174-1-git-send-email-jianchao.w.wang@oracle.com> <20180417151700.GC16286@ming.t460p> <20180418154032.GA22533@ming.t460p> <2b985ef5-223f-6a11-45b4-e570c8a93bb3@oracle.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <2b985ef5-223f-6a11-45b4-e570c8a93bb3@oracle.com> User-Agent: Mutt/1.9.1 (2017-09-22) Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Thu, Apr 19, 2018 at 09:51:16AM +0800, jianchao.wang wrote: > Hi Ming > > Thanks for your kindly response. > > On 04/18/2018 11:40 PM, Ming Lei wrote: > >> Regarding to this patchset, it is mainly to fix the dependency between > >> nvme_timeout and nvme_dev_disable, as your can see: > >> nvme_timeout will invoke nvme_dev_disable, and nvme_dev_disable have to > >> depend on nvme_timeout when controller no response. > > Do you mean nvme_disable_io_queues()? If yes, this one has been handled > > by wait_for_completion_io_timeout() already, and looks the block timeout > > can be disabled simply. Or are there others? > > > Here is one possible scenario currently > > nvme_dev_disable // hold shutdown_lock nvme_timeout > -> nvme_set_host_mem -> nvme_dev_disable > -> nvme_submit_sync_cmd -> try to require shutdown_lock > -> __nvme_submit_sync_cmd > -> blk_execute_rq > //if sysctl_hung_task_timeout_secs == 0 > -> wait_for_completion_io > And maybe nvme_dev_disable need to issue other commands in the future. OK, thanks for sharing this one, for now I think it might need to be handled by wait_for_completion_io_timeout() for working around this issue. > > Even if we could fix these kind of issues as nvme_disable_io_queues, > it is still a risk I think. Yeah, I can't agree more, that is why I think the nvme time/eh code should be refactored, and solve the current issues in a more clean/maintainable way. Thanks, Ming