From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mail-bn3nam01on0071.outbound.protection.outlook.com ([104.47.33.71]:17488 "EHLO NAM01-BN3-obe.outbound.protection.outlook.com" rhost-flags-OK-OK-OK-FAIL) by vger.kernel.org with ESMTP id S1753086AbcJ2AUH (ORCPT ); Fri, 28 Oct 2016 20:20:07 -0400 From: Bart Van Assche Subject: [PATCH v5 0/14] Fix race conditions related to stopping block layer queues To: Jens Axboe CC: Christoph Hellwig , James Bottomley , "Martin K. Petersen" , Mike Snitzer , Doug Ledford , Keith Busch , Ming Lei , "Konrad Rzeszutek Wilk" , =?UTF-8?Q?Roger_Pau_Monn=c3=a9?= , Laurence Oberman , "linux-block@vger.kernel.org" , "linux-scsi@vger.kernel.org" , "linux-rdma@vger.kernel.org" , "linux-nvme@lists.infradead.org" Message-ID: <7460e8b2-2cfd-c0d5-7ae7-7f662d89dad3@sandisk.com> Date: Fri, 28 Oct 2016 17:18:17 -0700 MIME-Version: 1.0 Content-Type: text/plain; charset="utf-8"; format=flowed Sender: linux-block-owner@vger.kernel.org List-Id: linux-block@vger.kernel.org Hello Jens, Multiple block drivers need the functionality to stop a request queue and to wait until all ongoing request_fn() / queue_rq() calls have finished without waiting until all outstanding requests have finished. Hence this patch series that introduces the blk_mq_quiesce_queue() function. The dm-mq, SRP and NVMe patches in this patch series are three examples of where these functions are useful. These patches have been tested on top of kernel v4.9-rc2. The following tests have been run to verify this patch series: - Mike's mptest suite that stress-tests dm-multipath. - My own srp-test suite that stress-tests SRP on top of dm-multipath. - fio on top of the NVMeOF host driver that was connected to the NVMeOF target driver on the same host. - Laurence verified the previous version (v3) of this patch series by running it through the Red Hat SRP and NVMe test suites. The changes compared to the third version of this patch series are: - Added a blk_mq_stop_hw_queues() call in blk_mq_quiesce_queue() as requested by Ming Lei. - Modified scsi_unblock_target() such that it waits until .queuecommand() finished. Unexported scsi_wait_for_queuecommand(). - Reordered the two NVMe patches. - Added a patch that avoids that blk_mq_requeue_work() restarts stopped queues. - Added a patch that removes blk_mq_cancel_requeue_work(). Changes between v4 and v3: - Left out the dm changes from the patch that introduces blk_mq_hctx_stopped() because a later patch deletes the changed code from the dm core. - Moved the blk_mq_hctx_stopped() declaration from a public to a private block layer header file. - Added a new patch that moves more code into blk_mq_direct_issue_request(). This patch avoids that a new function has to be introduced to avoid code duplication. - Explained the implemented algorithm in the patch that introduces blk_mq_quiesce_queue() in the description of the patch that introduces this function. - Added "select SRCU" to the patch that introduces blk_mq_quiesce_queue() to avoid build failures. - Documented the shost argument in the scsi_wait_for_queuecommand() kerneldoc header. - Fixed an unintended behavior change in the last patch of this series. Changes between v3 and v2: - Changed the order of the patches in this patch series. - Added several new patches: a patch that avoids that .queue_rq() gets invoked from the direct submission path if a queue has been stopped and also a patch that introduces the helper function blk_mq_hctx_stopped(). - blk_mq_quiesce_queue() has been reworked (thanks to Ming Lin and Sagi for their feedback). - A bool 'kick' argument has been added to blk_mq_requeue_request(). - As proposed by Christoph, the code that waits for queuecommand() has been moved from the SRP transport driver to the SCSI core. Changes between v2 and v1: - Dropped the non-blk-mq changes from this patch series. - Added support for harware queues with BLK_MQ_F_BLOCKING set. - Added a call stack to the description of the dm race fix patch. - Dropped the non-scsi-mq changes from the SRP patch. - Added a patch that introduces blk_mq_queue_stopped() in the dm driver. The individual patches in this series are: 0001-blk-mq-Do-not-invoke-.queue_rq-for-a-stopped-queue.patch 0002-blk-mq-Introduce-blk_mq_hctx_stopped.patch 0003-blk-mq-Introduce-blk_mq_queue_stopped.patch 0004-blk-mq-Move-more-code-into-blk_mq_direct_issue_reque.patch 0005-blk-mq-Avoid-that-requeueing-starts-stopped-queues.patch 0006-blk-mq-Remove-blk_mq_cancel_requeue_work.patch 0007-blk-mq-Introduce-blk_mq_quiesce_queue.patch 0008-blk-mq-Add-a-kick_requeue_list-argument-to-blk_mq_re.patch 0009-dm-Use-BLK_MQ_S_STOPPED-instead-of-QUEUE_FLAG_STOPPE.patch 0010-dm-Fix-a-race-condition-related-to-stopping-and-star.patch 0011-SRP-transport-Move-queuecommand-wait-code-to-SCSI-co.patch 0012-SRP-transport-scsi-mq-Wait-for-.queue_rq-if-necessar.patch 0013-nvme-Fix-a-race-condition-related-to-stopping-queues.patch 0014-nvme-Use-BLK_MQ_S_STOPPED-instead-of-QUEUE_FLAG_STOP.patch Thanks, Bart.