Re: [PATCH v2 1/2] scsi: ufs: Abort tasks before clear them from doorbell

[James Bottomley]

I can't reconcile this hunk:

On Wed, 2020-09-02 at 19:24 -0700, Can Guo wrote:
> @@ -6504,6 +6505,80 @@ static void ufshcd_set_req_abort_skip(struct
> ufs_hba *hba, unsigned long bitmap)
>   * issued. To avoid that, first issue UFS_QUERY_TASK to check if the
> command is
>   * really issued and then try to abort it.
>   *
> + * Returns zero on success, non-zero on failure
> + */
> +static int ufshcd_try_to_abort_task(struct ufs_hba *hba, int tag)
> +{
> +	struct ufshcd_lrb *lrbp = &hba->lrb[tag];
> +	int err = 0;
> +	int poll_cnt;
> +	u8 resp = 0xF;
> +	u32 reg;
> +
> +	for (poll_cnt = 100; poll_cnt; poll_cnt--) {
> +		err = ufshcd_issue_tm_cmd(hba, lrbp->lun, lrbp-
> >task_tag,
> +				UFS_QUERY_TASK, &resp);
> +		if (!err && resp ==
> UPIU_TASK_MANAGEMENT_FUNC_SUCCEEDED) {
> +			/* cmd pending in the device */
> +			dev_err(hba->dev, "%s: cmd pending in the
> device. tag = %d\n",
> +				__func__, tag);
> +			break;
> +		} else if (!err && resp ==
> UPIU_TASK_MANAGEMENT_FUNC_COMPL) {
> +			/*
> +			 * cmd not pending in the device, check if
> it is
> +			 * in transition.
> +			 */
> +			dev_err(hba->dev, "%s: cmd at tag %d not
> pending in the device.\n",
> +				__func__, tag);
> +			reg = ufshcd_readl(hba,
> REG_UTP_TRANSFER_REQ_DOOR_BELL);
> +			if (reg & (1 << tag)) {
> +				/* sleep for max. 200us to stabilize
> */
> +				usleep_range(100, 200);
> +				continue;
> +			}
> +			/* command completed already */
> +			dev_err(hba->dev, "%s: cmd at tag %d
> successfully cleared from DB.\n",
> +				__func__, tag);
> +			goto out;
> +		} else {
> +			dev_err(hba->dev,
> +				"%s: no response from device. tag =
> %d, err %d\n",
> +				__func__, tag, err);
> +			if (!err)
> +				err = resp; /* service response
> error */
> +			goto out;
> +		}
> +	}
> +
> +	if (!poll_cnt) {
> +		err = -EBUSY;
> +		goto out;
> +	}
> +
> +	err = ufshcd_issue_tm_cmd(hba, lrbp->lun, lrbp->task_tag,
> +			UFS_ABORT_TASK, &resp);
> +	if (err || resp != UPIU_TASK_MANAGEMENT_FUNC_COMPL) {
> +		if (!err) {
> +			err = resp; /* service response error */
> +			dev_err(hba->dev, "%s: issued. tag = %d, err
> %d\n",
> +				__func__, tag, err);
> +		}
> +		goto out;
> +	}
> +
> +	err = ufshcd_clear_cmd(hba, tag);
> +	if (err)
> +		dev_err(hba->dev, "%s: Failed clearing cmd at tag
> %d, err %d\n",
> +			__func__, tag, err);
> +
> +out:
> +	return err;
> +}
> +
> +/**
> + * ufshcd_abort - scsi host template eh_abort_handler callback
> + * @cmd: SCSI command pointer
> + *
>   * Returns SUCCESS/FAILED
>   */
>  static int ufshcd_abort(struct scsi_cmnd *cmd)
> @@ -6513,8 +6588,6 @@ static int ufshcd_abort(struct scsi_cmnd *cmd)
>  	unsigned long flags;
>  	unsigned int tag;
>  	int err = 0;
> -	int poll_cnt;
> -	u8 resp = 0xF;
>  	struct ufshcd_lrb *lrbp;
>  	u32 reg;
>  
> @@ -6583,63 +6656,9 @@ static int ufshcd_abort(struct scsi_cmnd *cmd)
>  		goto out;
>  	}
>  
> -	for (poll_cnt = 100; poll_cnt; poll_cnt--) {
> -		err = ufshcd_issue_tm_cmd(hba, lrbp->lun, lrbp-
> >task_tag,
> -				UFS_QUERY_TASK, &resp);
> -		if (!err && resp ==
> UPIU_TASK_MANAGEMENT_FUNC_SUCCEEDED) {
> -			/* cmd pending in the device */
> -			dev_err(hba->dev, "%s: cmd pending in the
> device. tag = %d\n",
> -				__func__, tag);
> -			break;
> -		} else if (!err && resp ==
> UPIU_TASK_MANAGEMENT_FUNC_COMPL) {
> -			/*
> -			 * cmd not pending in the device, check if
> it is
> -			 * in transition.
> -			 */
> -			dev_err(hba->dev, "%s: cmd at tag %d not
> pending in the device.\n",
> -				__func__, tag);
> -			reg = ufshcd_readl(hba,
> REG_UTP_TRANSFER_REQ_DOOR_BELL);
> -			if (reg & (1 << tag)) {
> -				/* sleep for max. 200us to stabilize
> */
> -				usleep_range(100, 200);
> -				continue;
> -			}
> -			/* command completed already */
> -			dev_err(hba->dev, "%s: cmd at tag %d
> successfully cleared from DB.\n",
> -				__func__, tag);
> -			goto out;
> -		} else {
> -			dev_err(hba->dev,
> -				"%s: no response from device. tag =
> %d, err %d\n",
> -				__func__, tag, err);
> -			if (!err)
> -				err = resp; /* service response
> error */
> -			goto out;
> -		}
> -	}
> -
> -	if (!poll_cnt) {
> -		err = -EBUSY;
> -		goto out;
> -	}
> -
> -	err = ufshcd_issue_tm_cmd(hba, lrbp->lun, lrbp->task_tag,
> -			UFS_ABORT_TASK, &resp);
> -	if (err || resp != UPIU_TASK_MANAGEMENT_FUNC_COMPL) {
> -		if (!err) {
> -			err = resp; /* service response error */
> -			dev_err(hba->dev, "%s: issued. tag = %d, err
> %d\n",
> -				__func__, tag, err);
> -		}
> -		goto out;
> -	}
> -
> -	err = ufshcd_clear_cmd(hba, tag);
> -	if (err) {
> -		dev_err(hba->dev, "%s: Failed clearing cmd at tag
> %d, err %d\n",
> -			__func__, tag, err);
> +	err = ufshcd_try_to_abort_task(hba, tag);
> +	if (err)
>  		goto out;
> -	}
>  
>  	spin_lock_irqsave(host->host_lock, flags);
>  	__ufshcd_transfer_req_compl(hba, (1UL << tag));


With the change in this fix:

commit b10178ee7fa88b68a9e8adc06534d2605cb0ec23
Author: Stanley Chu <stanley.chu@xxxxxxxxxxxx>
Date:   Tue Aug 11 16:18:58 2020 +0200

    scsi: ufs: Clean up completed request without interrupt
notification


It looks like there have to be two separate error returns from your new
ufshcd_try_to_abort_function() so it knows to continue with
usfhcd_transfer_req_complete(), or the whole function needs to be
refactored, but if this goes upstream as is it looks like it will
eliminate the bug fix.

James