Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S932342AbaGHT1n (ORCPT ); Tue, 8 Jul 2014 15:27:43 -0400 Received: from shadbolt.e.decadent.org.uk ([88.96.1.126]:54198 "EHLO shadbolt.e.decadent.org.uk" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1755710AbaGHTIl (ORCPT ); Tue, 8 Jul 2014 15:08:41 -0400 Content-Type: text/plain; charset="UTF-8" Content-Disposition: inline Content-Transfer-Encoding: 8bit MIME-Version: 1.0 From: Ben Hutchings To: linux-kernel@vger.kernel.org, stable@vger.kernel.org CC: akpm@linux-foundation.org, "Tejun Heo" , "Bart Van Assche" , "James Bottomley" , "Mike Christie" Date: Tue, 08 Jul 2014 20:01:50 +0100 Message-ID: X-Mailer: LinuxStableQueue (scripts by bwh) Subject: [PATCH 3.2 104/125] [SCSI] Stop accepting SCSI requests before removing a device In-Reply-To: X-SA-Exim-Connect-IP: 192.168.4.249 X-SA-Exim-Mail-From: ben@decadent.org.uk X-SA-Exim-Scanned: No (on shadbolt.decadent.org.uk); SAEximRunCond expanded to false Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org 3.2.61-rc1 review patch. If anyone has any objections, please let me know. ------------------ From: Bart Van Assche commit b485462aca7df4e32bcf7efb6f84a69e8b640243 upstream. Avoid that the code for requeueing SCSI requests triggers a crash by making sure that that code isn't scheduled anymore after a device has been removed. Also, source code inspection of __scsi_remove_device() revealed a race condition in this function: no new SCSI requests must be accepted for a SCSI device after device removal started. Signed-off-by: Bart Van Assche Reviewed-by: Mike Christie Acked-by: Tejun Heo Signed-off-by: James Bottomley [bwh: Backported to 3.2: adjust context] Signed-off-by: Ben Hutchings --- drivers/scsi/scsi_lib.c | 7 ++++--- drivers/scsi/scsi_sysfs.c | 11 +++++++++-- 2 files changed, 13 insertions(+), 5 deletions(-) --- a/drivers/scsi/scsi_lib.c +++ b/drivers/scsi/scsi_lib.c @@ -155,13 +155,14 @@ static int __scsi_queue_insert(struct sc /* * Requeue this command. It will go before all other commands - * that are already in the queue. + * that are already in the queue. Schedule requeue work under + * lock such that the kblockd_schedule_work() call happens + * before blk_cleanup_queue() finishes. */ spin_lock_irqsave(q->queue_lock, flags); blk_requeue_request(q, cmd->request); - spin_unlock_irqrestore(q->queue_lock, flags); - kblockd_schedule_work(q, &device->requeue_work); + spin_unlock_irqrestore(q->queue_lock, flags); return 0; } --- a/drivers/scsi/scsi_sysfs.c +++ b/drivers/scsi/scsi_sysfs.c @@ -963,13 +963,20 @@ void __scsi_remove_device(struct scsi_de device_del(dev); } else put_device(&sdev->sdev_dev); + + /* + * Stop accepting new requests and wait until all queuecommand() and + * scsi_run_queue() invocations have finished before tearing down the + * device. + */ scsi_device_set_state(sdev, SDEV_DEL); + blk_cleanup_queue(sdev->request_queue); + cancel_work_sync(&sdev->requeue_work); + if (sdev->host->hostt->slave_destroy) sdev->host->hostt->slave_destroy(sdev); transport_destroy_device(dev); - /* Freeing the queue signals to block that we're done */ - blk_cleanup_queue(sdev->request_queue); put_device(dev); } -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/