From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S965114AbeCCByA (ORCPT ); Fri, 2 Mar 2018 20:54:00 -0500 Received: from userp2120.oracle.com ([156.151.31.85]:42122 "EHLO userp2120.oracle.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S965064AbeCCBx6 (ORCPT ); Fri, 2 Mar 2018 20:53:58 -0500 From: Jianchao Wang To: jejb@linux.vnet.ibm.com, martin.petersen@oracle.com Cc: Bart.VanAssche@wdc.com, linux-scsi@vger.kernel.org, linux-kernel@vger.kernel.org, Christoph Hellwig Subject: [PATCH V4] scsi: core: use blk_mq_requeue_request in __scsi_queue_insert Date: Sat, 3 Mar 2018 09:54:09 +0800 Message-Id: <1520042049-8874-1-git-send-email-jianchao.w.wang@oracle.com> X-Mailer: git-send-email 2.7.4 X-Proofpoint-Virus-Version: vendor=nai engine=5900 definitions=8820 signatures=668682 X-Proofpoint-Spam-Details: rule=notspam policy=default score=0 suspectscore=0 malwarescore=0 phishscore=0 bulkscore=0 spamscore=0 mlxscore=0 mlxlogscore=999 adultscore=0 classifier=spam adjust=0 reason=mlx scancount=1 engine=8.0.1-1711220000 definitions=main-1803030017 Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org In scsi core, __scsi_queue_insert should just put request back on the queue and retry using the same command as before. However, for blk-mq, scsi_mq_requeue_cmd is employed here which will unprepare the request. To align with the semantics of __scsi_queue_insert, use blk_mq_requeue_request with kick_requeue_list == true and put the reference of scsi_device. Cc: Christoph Hellwig Signed-off-by: Jianchao Wang Reviewed-by: Bart Van Assche --- Changelog: V3 -> V4: - modify the comment and make it more clearly V2 -> V3: - add comment to explain why we need a put_device in __scsi_queue_insert - add reviewed-by V1 -> V2: - add put_device on scsi_device->sdev_gendev drivers/scsi/scsi_lib.c | 14 +++++++++++++- 1 file changed, 13 insertions(+), 1 deletion(-) diff --git a/drivers/scsi/scsi_lib.c b/drivers/scsi/scsi_lib.c index a86df9c..6ce33f6 100644 --- a/drivers/scsi/scsi_lib.c +++ b/drivers/scsi/scsi_lib.c @@ -191,7 +191,19 @@ static void __scsi_queue_insert(struct scsi_cmnd *cmd, int reason, bool unbusy) */ cmd->result = 0; if (q->mq_ops) { - scsi_mq_requeue_cmd(cmd); + /* + * Before a SCSI command is dispatched, + * get_device(&sdev->sdev_gendev) is called and the host, + * target and device busy counters are increased. Since + * requeuing a request causes these actions to be repeated and + * since scsi_device_unbusy() has already been called, + * put_device(&device->sdev_gendev) must still be called. Call + * put_device() after blk_mq_requeue_request() to avoid that + * removal of the SCSI device can start before requeueing has + * happened. + */ + blk_mq_requeue_request(cmd->request, true); + put_device(&device->sdev_gendev); return; } spin_lock_irqsave(q->queue_lock, flags); -- 2.7.4