[PATCH v5 7/7] ata: libata-scsi: Check ATA_QCFLAG_RTF_FILLED before using result_tf

[Igor Pylypiv <ipylypiv@google.com>]

qc->result_tf contents are only valid when the ATA_QCFLAG_RTF_FILLED flag
is set. The ATA_QCFLAG_RTF_FILLED flag should be always set for commands
that failed or for commands that have the ATA_QCFLAG_RESULT_TF flag set.

Reviewed-by: Hannes Reinecke <hare@suse.de>
Reviewed-by: Damien Le Moal <dlemoal@kernel.org>
Reviewed-by: Niklas Cassel <cassel@kernel.org>
Signed-off-by: Igor Pylypiv <ipylypiv@google.com>
---
 drivers/ata/libata-scsi.c | 21 +++++++++++++++++++++
 1 file changed, 21 insertions(+)

diff --git a/drivers/ata/libata-scsi.c b/drivers/ata/libata-scsi.c
index 226a36c9504b..8f21b3b0bc75 100644
--- a/drivers/ata/libata-scsi.c
+++ b/drivers/ata/libata-scsi.c
@@ -242,10 +242,17 @@ void ata_scsi_set_sense_information(struct ata_device *dev,
  */
 static void ata_scsi_set_passthru_sense_fields(struct ata_queued_cmd *qc)
 {
+	struct ata_device *dev = qc->dev;
 	struct scsi_cmnd *cmd = qc->scsicmd;
 	struct ata_taskfile *tf = &qc->result_tf;
 	unsigned char *sb = cmd->sense_buffer;
 
+	if (!(qc->flags & ATA_QCFLAG_RTF_FILLED)) {
+		ata_dev_dbg(dev,
+			    "missing result TF: can't set ATA PT sense fields\n");
+		return;
+	}
+
 	if ((sb[0] & 0x7f) >= 0x72) {
 		unsigned char *desc;
 		u8 len;
@@ -923,10 +930,17 @@ static void ata_to_sense_error(u8 drv_stat, u8 drv_err, u8 *sk, u8 *asc,
  */
 static void ata_gen_passthru_sense(struct ata_queued_cmd *qc)
 {
+	struct ata_device *dev = qc->dev;
 	struct scsi_cmnd *cmd = qc->scsicmd;
 	struct ata_taskfile *tf = &qc->result_tf;
 	u8 sense_key, asc, ascq;
 
+	if (!(qc->flags & ATA_QCFLAG_RTF_FILLED)) {
+		ata_dev_dbg(dev,
+			    "missing result TF: can't generate ATA PT sense data\n");
+		return;
+	}
+
 	/*
 	 * Use ata_to_sense_error() to map status register bits
 	 * onto sense key, asc & ascq.
@@ -967,6 +981,13 @@ static void ata_gen_ata_sense(struct ata_queued_cmd *qc)
 		ata_scsi_set_sense(dev, cmd, NOT_READY, 0x04, 0x21);
 		return;
 	}
+
+	if (!(qc->flags & ATA_QCFLAG_RTF_FILLED)) {
+		ata_dev_dbg(dev,
+			    "missing result TF: can't generate sense data\n");
+		return;
+	}
+
 	/* Use ata_to_sense_error() to map status register bits
 	 * onto sense key, asc & ascq.
 	 */
-- 
2.45.2.803.g4e1b14247a-goog