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From:   Avri Altman <Avri.Altman@wdc.com>
To:     Stanley Chu <stanley.chu@mediatek.com>,
        "linux-scsi@vger.kernel.org" <linux-scsi@vger.kernel.org>,
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Subject: RE: [PATCH v4] scsi: ufs: Cleanup completed request without interrupt
 notification
Thread-Topic: [PATCH v4] scsi: ufs: Cleanup completed request without
 interrupt notification
Thread-Index: AQHWYcMiC3zRSkow3EiZadPqZ74zZKkbS2ZQ
Date:   Mon, 27 Jul 2020 11:18:08 +0000
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References: <20200724140246.19434-1-stanley.chu@mediatek.com>
In-Reply-To: <20200724140246.19434-1-stanley.chu@mediatek.com>
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Looks good to me.
But better wait and see if Bart have any further reservations.

Thanks,
Avri=20
>=20
> 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:
>=20
> 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".
>=20
> Signed-off-by: Stanley Chu <stanley.chu@mediatek.com>
> ---
>  drivers/scsi/ufs/ufshcd.c | 3 ++-
>  1 file changed, 2 insertions(+), 1 deletion(-)
>=20
> 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 =3D %d,=
 err %d\n",
> @@ -6527,6 +6527,7 @@ static int ufshcd_abort(struct scsi_cmnd *cmd)
>                 goto out;
>         }
>=20
> +cleanup:
>         scsi_dma_unmap(cmd);
>=20
>         spin_lock_irqsave(host->host_lock, flags);
> --
> 2.18.0