ata: libata: only set sense valid flag if sense data is valid

While this shouldn't be needed if all devices that claim that they
support NCQ autosense (ata_id_has_ncq_autosense()) and/or the sense
data reporting feature (ata_id_has_sense_reporting()), actually
supported those features.

However, there might be some old ATA devices that either have these
bits set, even when they don't support those features, or they simply
return malformed data when using those features.

These devices should be quirked, but in order to try to minimize the
impact for the users of these such devices, it was suggested by Damien
Le Moal that it might be a good idea to sanity check the sense data
received from the device. If the sense data looks bogus, then the
sense data is never added to the scsi_cmnd command.

Introduce a new function, ata_scsi_sense_is_valid(), and use it in all
places where sense data is received from the device.
Suggested-by: NDamien Le Moal <damien.lemoal@opensource.wdc.com>
Signed-off-by: NNiklas Cassel <niklas.cassel@wdc.com>
Signed-off-by: NDamien Le Moal <damien.lemoal@opensource.wdc.com>

drivers/ata/libata-eh.c

@@ -1428,8 +1428,10 @@ static void ata_eh_request_sense(struct ata_queued_cmd *qc)
 	err_mask = ata_exec_internal(dev, &tf, NULL, DMA_NONE, NULL, 0, 0);
 	/* 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);
 			qc->flags |= ATA_QCFLAG_SENSE_VALID;
+		}
 	} else {
 		ata_dev_warn(dev, "request sense failed stat %02x emask %x\n",
 			     tf.status, err_mask);

drivers/ata/libata-sata.c

@@ -1468,11 +1468,14 @@ void ata_eh_analyze_ncq_error(struct ata_link *link)
 		sense_key = (qc->result_tf.auxiliary >> 16) & 0xff;
 		asc = (qc->result_tf.auxiliary >> 8) & 0xff;
 		ascq = qc->result_tf.auxiliary & 0xff;
-		ata_scsi_set_sense(dev, qc->scsicmd, sense_key, asc, ascq);
+		if (ata_scsi_sense_is_valid(sense_key, asc, ascq)) {
+			ata_scsi_set_sense(dev, qc->scsicmd, sense_key, asc,
+					   ascq);
 			ata_scsi_set_sense_information(dev, qc->scsicmd,
 						       &qc->result_tf);
 			qc->flags |= ATA_QCFLAG_SENSE_VALID;
 		}
+	}
 
 	ehc->i.err_mask &= ~AC_ERR_DEV;
 }

drivers/ata/libata-scsi.c

@@ -188,6 +188,22 @@ DEVICE_ATTR(unload_heads, S_IRUGO | S_IWUSR,
 	    ata_scsi_park_show, ata_scsi_park_store);
 EXPORT_SYMBOL_GPL(dev_attr_unload_heads);
 
+bool ata_scsi_sense_is_valid(u8 sk, u8 asc, u8 ascq)
+{
+	/*
+	 * If sk == NO_SENSE, and asc + ascq == NO ADDITIONAL SENSE INFORMATION,
+	 * then there is no sense data to add.
+	 */
+	if (sk == 0 && asc == 0 && ascq == 0)
+		return false;
+
+	/* If sk > COMPLETED, sense data is bogus. */
+	if (sk > COMPLETED)
+		return false;
+
+	return true;
+}
+
 void ata_scsi_set_sense(struct ata_device *dev, struct scsi_cmnd *cmd,
 			u8 sk, u8 asc, u8 ascq)
 {

drivers/ata/libata.h

@@ -114,6 +114,7 @@ extern int ata_scsi_add_hosts(struct ata_host *host,
 			      struct scsi_host_template *sht);
 extern void ata_scsi_scan_host(struct ata_port *ap, int sync);
 extern int ata_scsi_offline_dev(struct ata_device *dev);
+extern bool ata_scsi_sense_is_valid(u8 sk, u8 asc, u8 ascq);
 extern void ata_scsi_set_sense(struct ata_device *dev,
 			       struct scsi_cmnd *cmd, u8 sk, u8 asc, u8 ascq);
 extern void ata_scsi_set_sense_information(struct ata_device *dev,