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From:   Wenchao Hao <haowenchao@huawei.com>
To:     Lee Duncan <lduncan@suse.com>, Chris Leech <cleech@redhat.com>,
        "Mike Christie" <michael.christie@oracle.com>,
        "James E . J . Bottomley" <jejb@linux.ibm.com>,
        "Martin K . Petersen" <martin.petersen@oracle.com>,
        <open-iscsi@googlegroups.com>, <linux-scsi@vger.kernel.org>
CC:     <linux-kernel@vger.kernel.org>, <liuzhiqiang26@huawei.com>,
        <linfeilong@huawei.com>, Wenchao Hao <haowenchao@huawei.com>
Subject: [PATCH v3 1/2] scsi: increase scsi device's iodone_cnt in scsi_timeout()
Date:   Wed, 23 Nov 2022 20:21:36 +0800
Message-ID: <20221123122137.150776-2-haowenchao@huawei.com>
In-Reply-To: <20221123122137.150776-1-haowenchao@huawei.com>
References: <20221123122137.150776-1-haowenchao@huawei.com>
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If an scsi command time out and going to be aborted, we should
increase the iodone_cnt of the related scsi device, or the
iodone_cnt would be less than iorequest_cnt

Increase iodone_cnt in scsi_timeout() would not cause double
accounting issue, briefly analysed as following:

 - we add the iodone_cnt when BLK_EH_DONE would be returned in
   scsi_timeout(), so the related scsi command's timeout event
   would not happened

 - if the abort succeed and do not retry, the command would be done
   with scsi_finish_command() which would not increase iodone_cnt;

 - if the abort succeed and retry the command, it would be requeue,
   a scsi_dispatch_cmd() would be called and iorequest_cnt would be
   increased again

 - if the abort failed, the error handler successfully recover the
   device, do not retry this command, the command would be done
   with scsi_finish_command() which would not increase iodone_cnt;

 - if the abort failed, the error handler successfully recover the
   device, and retry this command, the iorequest_cnt would be
   increased again

Signed-off-by: Wenchao Hao <haowenchao@huawei.com>
Reviewed-by: Mike Christie <michael.christie@oracle.com>
---
 drivers/scsi/scsi_error.c | 1 +
 1 file changed, 1 insertion(+)

diff --git a/drivers/scsi/scsi_error.c b/drivers/scsi/scsi_error.c
index be2a70c5ac6d..613d5aeb1e3c 100644
--- a/drivers/scsi/scsi_error.c
+++ b/drivers/scsi/scsi_error.c
@@ -354,6 +354,7 @@ enum blk_eh_timer_return scsi_timeout(struct request *req)
 	 */
 	if (test_and_set_bit(SCMD_STATE_COMPLETE, &scmd->state))
 		return BLK_EH_DONE;
+	atomic_inc(&scmd->device->iodone_cnt);
 	if (scsi_abort_command(scmd) != SUCCESS) {
 		set_host_byte(scmd, DID_TIME_OUT);
 		scsi_eh_scmd_add(scmd);
-- 
2.32.0