scsi: ata: libata: Change ata_eh_request_sense() to not set CHECK_CONDITION

Currently, ata_eh_request_sense() unconditionally sets the scsicmd->result
to SAM_STAT_CHECK_CONDITION.

For Command Duration Limits policy 0xD:

  The device shall complete the command without error (SAM_STAT_GOOD) with
  the additional sense code set to DATA CURRENTLY UNAVAILABLE.

It is perfectly fine to have sense data for a command that returned
completion without error.

In order to support for CDL policy 0xD, we have to remove this assumption
that having sense data means that the command failed
(SAM_STAT_CHECK_CONDITION).

Change ata_eh_request_sense() to not set SAM_STAT_CHECK_CONDITION, and
instead move the setting of SAM_STAT_CHECK_CONDITION to the single caller
that wants SAM_STAT_CHECK_CONDITION set, that way ata_eh_request_sense()
can be reused in a follow-up patch that adds support for CDL policy 0xD.

The only caller of ata_eh_request_sense() is protected by: if (!(qc->flags
& ATA_QCFLAG_SENSE_VALID)), so we can remove this duplicated check from
ata_eh_request_sense() itself.

Additionally, ata_eh_request_sense() is only called from
ata_eh_analyze_tf(), which is only called when iteratating the QCs using
ata_qc_for_each_raw(), which does not include the internal tag, so cmd can
never be NULL (all non-internal commands have qc->scsicmd set), so remove
the !cmd check as well.

Reviewed-by: Hannes Reinecke <hare@suse.de>
Signed-off-by: Niklas Cassel <niklas.cassel@wdc.com>
Link: https://lore.kernel.org/r/20230511011356.227789-14-nks@flawful.org
Signed-off-by: Martin K. Petersen <martin.petersen@oracle.com>

diff --git a/drivers/ata/libata-eh.c b/drivers/ata/libata-eh.c
index a6c9018..598ae07 100644 (file)
--- a/drivers/ata/libata-eh.c
+++ b/drivers/ata/libata-eh.c
@@ -1401,8 +1401,11 @@ unsigned int atapi_eh_tur(struct ata_device *dev, u8 *r_sense_key)
  *
  *     LOCKING:
  *     Kernel thread context (may sleep).
+ *
+ *     RETURNS:
+ *     true if sense data could be fetched, false otherwise.
  */
-static void ata_eh_request_sense(struct ata_queued_cmd *qc)
+static bool ata_eh_request_sense(struct ata_queued_cmd *qc)
 {
        struct scsi_cmnd *cmd = qc->scsicmd;
        struct ata_device *dev = qc->dev;
@@ -1411,15 +1414,12 @@ static void ata_eh_request_sense(struct ata_queued_cmd *qc)
 
        if (ata_port_is_frozen(qc->ap)) {
                ata_dev_warn(dev, "sense data available but port frozen\n");
-               return;
+               return false;
        }
 
-       if (!cmd || qc->flags & ATA_QCFLAG_SENSE_VALID)
-               return;
-
        if (!ata_id_sense_reporting_enabled(dev->id)) {
                ata_dev_warn(qc->dev, "sense data reporting disabled\n");
-               return;
+               return false;
        }
 
        ata_tf_init(dev, &tf);
@@ -1432,13 +1432,19 @@ static void ata_eh_request_sense(struct ata_queued_cmd *qc)
        /* Ignore err_mask; ATA_ERR might be set */
        if (tf.status & ATA_SENSE) {
                if (ata_scsi_sense_is_valid(tf.lbah, tf.lbam, tf.lbal)) {
-                       ata_scsi_set_sense(dev, cmd, tf.lbah, tf.lbam, tf.lbal);
+                       /* Set sense without also setting scsicmd->result */
+                       scsi_build_sense_buffer(dev->flags & ATA_DFLAG_D_SENSE,
+                                               cmd->sense_buffer, tf.lbah,
+                                               tf.lbam, tf.lbal);
                        qc->flags |= ATA_QCFLAG_SENSE_VALID;
+                       return true;
                }
        } else {
                ata_dev_warn(dev, "request sense failed stat %02x emask %x\n",
                             tf.status, err_mask);
        }
+
+       return false;
 }
 
 /**
@@ -1588,8 +1594,9 @@ static unsigned int ata_eh_analyze_tf(struct ata_queued_cmd *qc)
                 *  was not included in the NCQ command error log
                 *  (i.e. NCQ autosense is not supported by the device).
                 */
-               if (!(qc->flags & ATA_QCFLAG_SENSE_VALID) && (stat & ATA_SENSE))
-                       ata_eh_request_sense(qc);
+               if (!(qc->flags & ATA_QCFLAG_SENSE_VALID) &&
+                   (stat & ATA_SENSE) && ata_eh_request_sense(qc))
+                       set_status_byte(qc->scsicmd, SAM_STAT_CHECK_CONDITION);
                if (err & ATA_ICRC)
                        qc->err_mask |= AC_ERR_ATA_BUS;
                if (err & (ATA_UNC | ATA_AMNF))