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Message-ID: <3c7d52c7-6839-241e-c25e-05492bfdf115@huawei.com>
Date:   Mon, 21 Nov 2022 22:38:05 +0800
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Subject: Re: [PATCH v2 0/2] Fix scsi device's iodone_cnt mismatch with
 iorequest_cnt
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To:     "Martin K . Petersen" <martin.petersen@oracle.com>,
        <linux-scsi@vger.kernel.org>, <linux-kernel@vger.kernel.org>
CC:     Steffen Maier <maier@linux.ibm.com>
References: <20221021235638.1968832-1-haowenchao@huawei.com>
From:   Wenchao Hao <haowenchao@huawei.com>
In-Reply-To: <20221021235638.1968832-1-haowenchao@huawei.com>
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On 2022/10/22 7:56, Wenchao Hao wrote:
> Following scenario would make scsi_device's iodone_cnt mismatch with
> iorequest_cnt even if there is no request on this device any more.
> 
> 1. request timeout happened. If we do not retry the timeouted command,
>    this command would be finished in scsi_finish_command() which would
>    not increase the iodone_cnt; if the timeouted command is retried,
>    another increasement for iorequest_cnt would be performed, the
>    command might add iorequest_cnt for multiple times but iodone_cnt
>    only once. Increase iodone_cnt in scsi_timeout() can handle this
>    scenario.
> 
> 2. scsi_dispatch_cmd() failed, while the iorequest_cnt has already been
>    increased. If scsi_dispatch_cmd() failed, the request would be
>    requeued, then another iorequest_cnt would be added. So we should not
>    increase iorequest_cnt if dispatch command failed
> 
> V2:
> - Add description about why we can add iodone_cnt in scsi_timeout()
> - Do not increase iorequest_cnt if dispatch command failed
> 
> Wenchao Hao (2):
>   scsi: increase scsi device's iodone_cnt in scsi_timeout()
>   scsi: donot increase scsi_device's iorequest_cnt if dispatch failed
> 
>  drivers/scsi/scsi_error.c | 1 +
>  drivers/scsi/scsi_lib.c   | 3 +--
>  2 files changed, 2 insertions(+), 2 deletions(-)
> 

Hi Martin, these two count is useful for us, would like take a look?