ata: libata: fix NCQ autosense logic

Currently, the logic if we should call ata_scsi_set_sense()
(and set flag ATA_QCFLAG_SENSE_VALID to indicate that we have
successfully added sense data to the struct ata_queued_cmd)
looks like this:

if (dev->class == ATA_DEV_ZAC &&
    ((qc->result_tf.status & ATA_SENSE) || qc->result_tf.auxiliary))

The problem with this is that a drive can support the NCQ command
error log without supporting NCQ autosense.

On such a drive, if the failing command has sense data, the status
field in the NCQ command error log will have the ATA_SENSE bit set.

It is just that this sense data is not included in the NCQ command
error log when NCQ autosense is not supported. Instead the sense
data has to be fetched using the REQUEST SENSE DATA EXT command.

Therefore, we should only add the sense data if the drive supports
NCQ autosense AND the ATA_SENSE bit is set in the status field.

Fix this, and at the same time, remove the duplicated ATA_DEV_ZAC
check. The struct ata_taskfile supplied to ata_eh_read_log_10h()
is memset:ed before calling the function, so simply checking if
qc->result_tf.auxiliary is set is sufficient to tell us that the
log actually contained sense data.

Fixes: d238ffd59d3c ("libata: do not attempt to retrieve sense code twice")
Signed-off-by: Niklas Cassel <niklas.cassel@wdc.com>
Signed-off-by: Damien Le Moal <damien.lemoal@opensource.wdc.com>

diff --git a/drivers/ata/libata-sata.c b/drivers/ata/libata-sata.c
index b6806d4..fd4dccc 100644 (file)
--- a/drivers/ata/libata-sata.c
+++ b/drivers/ata/libata-sata.c
@@ -1392,7 +1392,8 @@ static int ata_eh_read_log_10h(struct ata_device *dev,
        tf->hob_lbah = buf[10];
        tf->nsect = buf[12];
        tf->hob_nsect = buf[13];
-       if (dev->class == ATA_DEV_ZAC && ata_id_has_ncq_autosense(dev->id))
+       if (dev->class == ATA_DEV_ZAC && ata_id_has_ncq_autosense(dev->id) &&
+           (tf->status & ATA_SENSE))
                tf->auxiliary = buf[14] << 16 | buf[15] << 8 | buf[16];
 
        return 0;
@@ -1456,8 +1457,12 @@ void ata_eh_analyze_ncq_error(struct ata_link *link)
        memcpy(&qc->result_tf, &tf, sizeof(tf));
        qc->result_tf.flags = ATA_TFLAG_ISADDR | ATA_TFLAG_LBA | ATA_TFLAG_LBA48;
        qc->err_mask |= AC_ERR_DEV | AC_ERR_NCQ;
-       if (dev->class == ATA_DEV_ZAC &&
-           ((qc->result_tf.status & ATA_SENSE) || qc->result_tf.auxiliary)) {
+
+       /*
+        * If the device supports NCQ autosense, ata_eh_read_log_10h() will have
+        * stored the sense data in qc->result_tf.auxiliary.
+        */
+       if (qc->result_tf.auxiliary) {
                char sense_key, asc, ascq;
 
                sense_key = (qc->result_tf.auxiliary >> 16) & 0xff;