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

James Bottomley
2020-09-09T05:05:37Z

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@mediatek.com>
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