Some UFS devices may expose bLUQueueDepth field as zero indicating
that the queue depth depends on the number of resources available
for LUN at a particular instant to handle the outstanding transfer
requests. Currently, when response for SCSI command is TASK_FULL
the LLD decrements the queue depth but fails to increment when the
resources are available. The scsi mid-layer handles the change in
queue depth heuristically and offers simple interface with
->change_queue_depth.
Signed-off-by: Sujit Reddy Thumma <sthumma@xxxxxxxxxxxxxx>
Signed-off-by: Dolev Raviv <draviv@xxxxxxxxxxxxxx>
---
drivers/scsi/ufs/ufshcd.c | 97 ++++++++++++++++++++---------------------------
1 file changed, 42 insertions(+), 55 deletions(-)
diff --git a/drivers/scsi/ufs/ufshcd.c b/drivers/scsi/ufs/ufshcd.c
index b301ed8..b103e95 100644
--- a/drivers/scsi/ufs/ufshcd.c
+++ b/drivers/scsi/ufs/ufshcd.c
@@ -1991,27 +1991,55 @@ static int ufshcd_slave_alloc(struct scsi_device *sdev)
/* allow SCSI layer to restart the device in case of errors */
sdev->allow_restart = 1;
+
lun_qdepth = ufshcd_read_sdev_qdepth(hba, sdev);
- if (lun_qdepth == 0 || lun_qdepth > hba->nutrs) {
- dev_info(hba->dev, "%s, lun %d queue depth is %d\n", __func__,
- sdev->lun, lun_qdepth);
+ if (lun_qdepth <= 0)
+ /* eventually, we can figure out the real queue depth */
lun_qdepth = hba->nutrs;
- } else if (lun_qdepth < 0) {
- lun_qdepth = 1;
- }
+ else
+ lun_qdepth = min_t(int, lun_qdepth, hba->nutrs);
- /*
- * Inform SCSI Midlayer that the LUN queue depth is same as the
- * controller queue depth. If a LUN queue depth is less than the
- * controller queue depth and if the LUN reports
- * SAM_STAT_TASK_SET_FULL, the LUN queue depth will be adjusted
- * with scsi_adjust_queue_depth.
- */
+ dev_dbg(hba->dev, "%s: activate tcq with queue depth %d\n",
+ __func__, lun_qdepth);
scsi_activate_tcq(sdev, lun_qdepth);
+
return 0;
}
/**
+ * ufshcd_change_queue_depth - change queue depth
+ * @sdev: pointer to SCSI device
+ * @depth: required depth to set
+ * @reason: reason for changing the depth
+ *
+ * Change queue depth according to the reason and make sure
+ * the max. limits are not crossed.
+ */
+int ufshcd_change_queue_depth(struct scsi_device *sdev, int depth, int reason)
+{
+ struct ufs_hba *hba = shost_priv(sdev->host);
+
+ if (depth > hba->nutrs)
+ depth = hba->nutrs;
+
+ switch (reason) {
+ case SCSI_QDEPTH_DEFAULT:
+ case SCSI_QDEPTH_RAMP_UP:
+ if (!sdev->tagged_supported)
+ depth = 1;
+ scsi_adjust_queue_depth(sdev, scsi_get_tag_type(sdev), depth);
+ break;
+ case SCSI_QDEPTH_QFULL:
+ scsi_track_queue_full(sdev, depth);
+ break;
+ default:
+ return -EOPNOTSUPP;
+ }
+
+ return depth;
+}
+
+/**
* ufshcd_slave_destroy - remove SCSI device configurations
* @sdev: pointer to SCSI device
*/
@@ -2064,42 +2092,6 @@ static int ufshcd_task_req_compl(struct ufs_hba *hba, u32 index, u8 *resp)
}
/**
- * ufshcd_adjust_lun_qdepth - Update LUN queue depth if device responds with
- * SAM_STAT_TASK_SET_FULL SCSI command status.
- * @cmd: pointer to SCSI command
- */
-static void ufshcd_adjust_lun_qdepth(struct scsi_cmnd *cmd)
-{
- struct ufs_hba *hba;
- int i;
- int lun_qdepth = 0;
-
- hba = shost_priv(cmd->device->host);
-
- /*
- * LUN queue depth can be obtained by counting outstanding commands
- * on the LUN.
- */
- for (i = 0; i < hba->nutrs; i++) {
- if (test_bit(i, &hba->outstanding_reqs)) {
-
- /*
- * Check if the outstanding command belongs
- * to the LUN which reported SAM_STAT_TASK_SET_FULL.
- */
- if (cmd->device->lun == hba->lrb[i].lun)
- lun_qdepth++;
- }
- }
-
- /*
- * LUN queue depth will be total outstanding commands, except the
- * command for which the LUN reported SAM_STAT_TASK_SET_FULL.
- */
- scsi_adjust_queue_depth(cmd->device, MSG_SIMPLE_TAG, lun_qdepth - 1);
-}
-
-/**
* ufshcd_scsi_cmd_status - Update SCSI command result based on SCSI status
* @lrb: pointer to local reference block of completed command
* @scsi_status: SCSI command status
@@ -2120,12 +2112,6 @@ ufshcd_scsi_cmd_status(struct ufshcd_lrb *lrbp, int scsi_status)
scsi_status;
break;
case SAM_STAT_TASK_SET_FULL:
- /*
- * If a LUN reports SAM_STAT_TASK_SET_FULL, then the LUN queue
- * depth needs to be adjusted to the exact number of
- * outstanding commands the LUN can handle at any given time.
- */
- ufshcd_adjust_lun_qdepth(lrbp->cmd);
case SAM_STAT_BUSY:
case SAM_STAT_TASK_ABORTED:
ufshcd_copy_sense_data(lrbp);
@@ -3156,6 +3142,7 @@ static struct scsi_host_template ufshcd_driver_template = {
.queuecommand = ufshcd_queuecommand,
.slave_alloc = ufshcd_slave_alloc,
.slave_destroy = ufshcd_slave_destroy,
+ .change_queue_depth = ufshcd_change_queue_depth,
.eh_abort_handler = ufshcd_abort,
.eh_device_reset_handler = ufshcd_eh_device_reset_handler,
.eh_host_reset_handler = ufshcd_eh_host_reset_handler,
--
1.8.5.2
--
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