[PATCH 03/12] scsi: hp_sw: Fix sshdr use

[Mike Christie <michael.christie@xxxxxxxxxx>]

If scsi_execute_cmd returns < 0, it doesn't initialize the sshdr, so we
shouldn't access the sshdr. If it returns 0, then the cmd executed
successfully, so there is no need to check the sshdr. This has us access
the sshdr when we get a return value > 0.

Signed-off-by: Mike Christie <michael.christie@xxxxxxxxxx>
Reviewed-by: Christoph Hellwig <hch@xxxxxx>
Reviewed-by: John Garry <john.g.garry@xxxxxxxxxx>
Reviewed-by: Martin Wilck <mwilck@xxxxxxxx>
---
 drivers/scsi/device_handler/scsi_dh_hp_sw.c | 79 +++++++++++----------
 1 file changed, 40 insertions(+), 39 deletions(-)

diff --git a/drivers/scsi/device_handler/scsi_dh_hp_sw.c b/drivers/scsi/device_handler/scsi_dh_hp_sw.c
index 5f2f943d926c..944ea4e0cc45 100644
--- a/drivers/scsi/device_handler/scsi_dh_hp_sw.c
+++ b/drivers/scsi/device_handler/scsi_dh_hp_sw.c
@@ -82,7 +82,7 @@ static int hp_sw_tur(struct scsi_device *sdev, struct hp_sw_dh_data *h)
 {
 	unsigned char cmd[6] = { TEST_UNIT_READY };
 	struct scsi_sense_hdr sshdr;
-	int ret = SCSI_DH_OK, res;
+	int ret, res;
 	blk_opf_t opf = REQ_OP_DRV_IN | REQ_FAILFAST_DEV |
 				REQ_FAILFAST_TRANSPORT | REQ_FAILFAST_DRIVER;
 	const struct scsi_exec_args exec_args = {
@@ -92,19 +92,18 @@ static int hp_sw_tur(struct scsi_device *sdev, struct hp_sw_dh_data *h)
 retry:
 	res = scsi_execute_cmd(sdev, cmd, opf, NULL, 0, HP_SW_TIMEOUT,
 			       HP_SW_RETRIES, &exec_args);
-	if (res) {
-		if (scsi_sense_valid(&sshdr))
-			ret = tur_done(sdev, h, &sshdr);
-		else {
-			sdev_printk(KERN_WARNING, sdev,
-				    "%s: sending tur failed with %x\n",
-				    HP_SW_NAME, res);
-			ret = SCSI_DH_IO;
-		}
-	} else {
+	if (res > 0 && scsi_sense_valid(&sshdr)) {
+		ret = tur_done(sdev, h, &sshdr);
+	} else if (res == 0) {
 		h->path_state = HP_SW_PATH_ACTIVE;
 		ret = SCSI_DH_OK;
+	} else {
+		sdev_printk(KERN_WARNING, sdev,
+			    "%s: sending tur failed with %x\n",
+			    HP_SW_NAME, res);
+		ret = SCSI_DH_IO;
 	}
+
 	if (ret == SCSI_DH_IMM_RETRY)
 		goto retry;
 
@@ -122,7 +121,7 @@ static int hp_sw_start_stop(struct hp_sw_dh_data *h)
 	unsigned char cmd[6] = { START_STOP, 0, 0, 0, 1, 0 };
 	struct scsi_sense_hdr sshdr;
 	struct scsi_device *sdev = h->sdev;
-	int res, rc = SCSI_DH_OK;
+	int res, rc;
 	int retry_cnt = HP_SW_RETRIES;
 	blk_opf_t opf = REQ_OP_DRV_IN | REQ_FAILFAST_DEV |
 				REQ_FAILFAST_TRANSPORT | REQ_FAILFAST_DRIVER;
@@ -133,35 +132,37 @@ static int hp_sw_start_stop(struct hp_sw_dh_data *h)
 retry:
 	res = scsi_execute_cmd(sdev, cmd, opf, NULL, 0, HP_SW_TIMEOUT,
 			       HP_SW_RETRIES, &exec_args);
-	if (res) {
-		if (!scsi_sense_valid(&sshdr)) {
-			sdev_printk(KERN_WARNING, sdev,
-				    "%s: sending start_stop_unit failed, "
-				    "no sense available\n", HP_SW_NAME);
-			return SCSI_DH_IO;
-		}
-		switch (sshdr.sense_key) {
-		case NOT_READY:
-			if (sshdr.asc == 0x04 && sshdr.ascq == 3) {
-				/*
-				 * LUN not ready - manual intervention required
-				 *
-				 * Switch-over in progress, retry.
-				 */
-				if (--retry_cnt)
-					goto retry;
-				rc = SCSI_DH_RETRY;
-				break;
-			}
-			fallthrough;
-		default:
-			sdev_printk(KERN_WARNING, sdev,
-				    "%s: sending start_stop_unit failed, "
-				    "sense %x/%x/%x\n", HP_SW_NAME,
-				    sshdr.sense_key, sshdr.asc, sshdr.ascq);
-			rc = SCSI_DH_IO;
+	if (!res) {
+		return SCSI_DH_OK;
+	} else if (res < 0 || !scsi_sense_valid(&sshdr)) {
+		sdev_printk(KERN_WARNING, sdev,
+			    "%s: sending start_stop_unit failed, "
+			    "no sense available\n", HP_SW_NAME);
+		return SCSI_DH_IO;
+	}
+
+	switch (sshdr.sense_key) {
+	case NOT_READY:
+		if (sshdr.asc == 0x04 && sshdr.ascq == 3) {
+			/*
+			 * LUN not ready - manual intervention required
+			 *
+			 * Switch-over in progress, retry.
+			 */
+			if (--retry_cnt)
+				goto retry;
+			rc = SCSI_DH_RETRY;
+			break;
 		}
+		fallthrough;
+	default:
+		sdev_printk(KERN_WARNING, sdev,
+			    "%s: sending start_stop_unit failed, "
+			    "sense %x/%x/%x\n", HP_SW_NAME,
+			    sshdr.sense_key, sshdr.asc, sshdr.ascq);
+		rc = SCSI_DH_IO;
 	}
+
 	return rc;
 }
 
-- 
2.34.1