[PATCH v6 13/19] ata: libata: change ata_eh_request_sense() to not set CHECK_CONDITION

Niklas Cassel
2023-04-06T11:47:48Z

From: Niklas Cassel <niklas.cassel@wdc.com>

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.

Signed-off-by: Niklas Cassel <niklas.cassel@wdc.com>
Reviewed-by: Hannes Reinecke <hare@suse.de>
---
drivers/ata/libata-eh.c | 25 ++++++++++++++++---------
1 file changed, 16 insertions(+), 9 deletions(-)

diff --git a/drivers/ata/libata-eh.c b/drivers/ata/libata-eh.c
index a6c901811802..598ae07195b6 100644
--- 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))
--
2.39.2