Re: [PATCH v1] scsi: ufs: no need to send one Abort Task TM in case the task in DB was cleared

[Can Guo <cang@codeaurora.org>]

Hi Bean,

On 2020-08-06 17:50, Bean Huo wrote:
>> 
>> Please check Stanley's recent change to ufshcd_abort, you may
>> want to rebase your change on his and do goto cleanup here.
>> @Stanley correct me if I am wrong.
>> 
>> But even if you do a goto cleanup here, we still lost the
>> chances to dump host infos/regs like it does in the old code.
>> If a cmd was completed but without a notifying intr, this is
>> kind of a problem that we/host should look into, because it's
>> pasted at least 30 sec since the cmd was sent, so those dumps
>> are necessary to debug the problem. How about moving blow prints
>> in front of this part?
>> 
>> Thanks,
>> 
>> Can Guo.
>> 
>> >  	}
>> >
>> >  	/* Print Transfer Request of aborted task */
> 
> Hi Can
> 
> Thanks, do you mean that change to like this:
> 
> 
> Author: Bean Huo <beanhuo@micron.com>
> Date:   Thu Aug 6 11:34:45 2020 +0200
> 
>     scsi: ufs: no need to send one Abort Task TM in case the task in
>   was cleared
> 
>     If the bit corresponds to a task in the Doorbell register has been
>     cleared, no need to poll the status of the task on the device side
>     and to send an Abort Task TM.
>     This patch also deletes dispensable dev_err() in case of the task
>     already completed.
> 
>     Signed-off-by: Bean Huo <beanhuo@micron.com>
> 
> diff --git a/drivers/scsi/ufs/ufshcd.c b/drivers/scsi/ufs/ufshcd.c
> index 307622284239..f7c91ce9e294 100644
> --- a/drivers/scsi/ufs/ufshcd.c
> +++ b/drivers/scsi/ufs/ufshcd.c
> @@ -6425,23 +6425,9 @@ static int ufshcd_abort(struct scsi_cmnd *cmd)
>                 return ufshcd_eh_host_reset_handler(cmd);
> 
>         ufshcd_hold(hba, false);
> -       reg = ufshcd_readl(hba, REG_UTP_TRANSFER_REQ_DOOR_BELL);
>         /* If command is already aborted/completed, return SUCCESS */
> -       if (!(test_bit(tag, &hba->outstanding_reqs))) {
> -               dev_err(hba->dev,
> -                       "%s: cmd at tag %d already completed,
> outstanding=0x%lx, doorbell=0x%x\n",
> -                       __func__, tag, hba->outstanding_reqs, reg);
> +       if (!(test_bit(tag, &hba->outstanding_reqs)))
>                 goto out;
> -       }
> -
> -       if (!(reg & (1 << tag))) {
> -               dev_err(hba->dev,
> -               "%s: cmd was completed, but without a notifying intr,
> tag = %d",
> -               __func__, tag);
> -       }
> -
> -       /* Print Transfer Request of aborted task */
> -       dev_err(hba->dev, "%s: Device abort task at tag %d\n",
> __func__, tag);
> 
>         /*
>          * Print detailed info about aborted request.
> @@ -6462,6 +6448,17 @@ static int ufshcd_abort(struct scsi_cmnd *cmd)
>         }
>         hba->req_abort_count++;
> 
> +       reg = ufshcd_readl(hba, REG_UTP_TRANSFER_REQ_DOOR_BELL);
> +       if (!(reg & (1 << tag))) {
> +               dev_err(hba->dev,
> +               "%s: cmd was completed, but without a notifying intr,
> tag = %d",
> +               __func__, tag);
> +               goto cleanup;
> +       }
> +
> +       /* Print Transfer Request of aborted task */
> +       dev_err(hba->dev, "%s: Device abort task at tag %d\n",
> __func__, tag);
> +

The rest looks good but let below two lines stay where they were.

        /* Print Transfer Request of aborted task */
        dev_err(hba->dev, "%s: Device abort task at tag %d\n",
__func__, tag);


Thanks,

Can Guo.

>         /* Skip task abort in case previous aborts failed and report
> failure */
>         if (lrbp->req_abort_skip) {
>                 err = -EIO;
> @@ -6526,6 +6523,7 @@ static int ufshcd_abort(struct scsi_cmnd *cmd)
>                 goto out;
>         }
> 
> +cleanup:
>         scsi_dma_unmap(cmd);
> 
>         spin_lock_irqsave(host->host_lock, flags);
> 
> 
> 
> 
> 
> Author: Stanley Chu <stanley.chu@mediatek.com>
> Date:   Thu Aug 6 11:48:00 2020 +0200
> 
>     scsi: ufs: Cleanup completed request without interrupt notification
> 
>     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>
> 
> diff --git a/drivers/scsi/ufs/ufshcd.c b/drivers/scsi/ufs/ufshcd.c
> index f7c91ce9e294..29d5e5e5d0e0 100644
> --- a/drivers/scsi/ufs/ufshcd.c
> +++ b/drivers/scsi/ufs/ufshcd.c
> @@ -6489,7 +6489,7 @@ 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",