Re: [PATCH v4] scsi: ufs: Cleanup completed request without interrupt notification

[Can Guo]

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@xxxxxxxxxxxx>
> ---
>  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@xxxxxxxxxxxxxx>