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Date:   Tue, 04 Aug 2020 18:01:19 +0800
From:   Can Guo <cang@codeaurora.org>
To:     Stanley Chu <stanley.chu@mediatek.com>
Cc:     linux-scsi@vger.kernel.org, martin.petersen@oracle.com,
        avri.altman@wdc.com, alim.akhtar@samsung.com, jejb@linux.ibm.com,
        bvanassche@acm.org, beanhuo@micron.com, asutoshd@codeaurora.org,
        matthias.bgg@gmail.com, linux-mediatek@lists.infradead.org,
        linux-arm-kernel@lists.infradead.org, linux-kernel@vger.kernel.org,
        kuohong.wang@mediatek.com, peter.wang@mediatek.com,
        chun-hung.wu@mediatek.com, andy.teng@mediatek.com,
        chaotian.jing@mediatek.com, cc.chou@mediatek.com
Subject: Re: [PATCH v4] scsi: ufs: Cleanup completed request without interrupt
 notification
In-Reply-To: <20200724140246.19434-1-stanley.chu@mediatek.com>
References: <20200724140246.19434-1-stanley.chu@mediatek.com>
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On 2020-07-24 22:02, Stanley Chu wrote:
> If somehow no interrupt notification is raised for a completed request
> and its doorbell bit is cleared by host, UFS driver needs to cleanup
> its outstanding bit in ufshcd_abort(). Otherwise, system may behave
> abnormally by below flow:
> 
> After ufshcd_abort() returns, this request will be requeued by SCSI
> layer with its outstanding bit set. Any future completed request
> will trigger ufshcd_transfer_req_compl() to handle all "completed
> outstanding bits". In this time, the "abnormal outstanding bit"
> will be detected and the "requeued request" will be chosen to execute
> request post-processing flow. This is wrong because this request is
> still "alive".
> 
> Signed-off-by: Stanley Chu <stanley.chu@mediatek.com>
> ---
>  drivers/scsi/ufs/ufshcd.c | 3 ++-
>  1 file changed, 2 insertions(+), 1 deletion(-)
> 
> diff --git a/drivers/scsi/ufs/ufshcd.c b/drivers/scsi/ufs/ufshcd.c
> index 577cc0d7487f..9d180da77488 100644
> --- a/drivers/scsi/ufs/ufshcd.c
> +++ b/drivers/scsi/ufs/ufshcd.c
> @@ -6493,7 +6493,7 @@ static int ufshcd_abort(struct scsi_cmnd *cmd)
>  			/* command completed already */
>  			dev_err(hba->dev, "%s: cmd at tag %d successfully cleared from 
> DB.\n",
>  				__func__, tag);
> -			goto out;
> +			goto cleanup;
>  		} else {
>  			dev_err(hba->dev,
>  				"%s: no response from device. tag = %d, err %d\n",
> @@ -6527,6 +6527,7 @@ static int ufshcd_abort(struct scsi_cmnd *cmd)
>  		goto out;
>  	}
> 
> +cleanup:
>  	scsi_dma_unmap(cmd);
> 
>  	spin_lock_irqsave(host->host_lock, flags);

Reviewed-by: Can Guo <cang@codeaurora.org>