scsi: core: Fixup calling convention for scsi_mode_sense()

The description for scsi_mode_sense() claims to return the number of valid
bytes on success, which is not what the code does.  Additionally there is
no gain in returning the SCSI status, as everything the callers do is to
check against scsi_result_is_good(), which is what scsi_mode_sense() does
already.  So change the calling convention to return a standard error code
on failure, and 0 on success, and adapt the description and all callers.

Link: https://lore.kernel.org/r/20210427083046.31620-4-hare@suse.de
Reviewed-by: Bart Van Assche <bvanassche@acm.org>
Signed-off-by: Hannes Reinecke <hare@suse.de>
Signed-off-by: Martin K. Petersen <martin.petersen@oracle.com>

1 files changed, 6 insertions, 4 deletions

diff --git a/drivers/scsi/scsi_lib.c b/drivers/scsi/scsi_lib.c
index 532304d42f00..8614f61e385d 100644
--- a/drivers/scsi/scsi_lib.c
+++ b/drivers/scsi/scsi_lib.c
@@ -2093,9 +2093,7 @@ EXPORT_SYMBOL_GPL(scsi_mode_select);
  *	@sshdr: place to put sense data (or NULL if no sense to be collected).
  *		must be SCSI_SENSE_BUFFERSIZE big.
  *
- *	Returns zero if unsuccessful, or the header offset (either 4
- *	or 8 depending on whether a six or ten byte command was
- *	issued) if successful.
+ *	Returns zero if successful, or a negative error number on failure
  */
 int
 scsi_mode_sense(struct scsi_device *sdev, int dbd, int modepage,
@@ -2142,6 +2140,8 @@ scsi_mode_sense(struct scsi_device *sdev, int dbd, int modepage,
 
 	result = scsi_execute_req(sdev, cmd, DMA_FROM_DEVICE, buffer, len,
 				  sshdr, timeout, retries, NULL);
+	if (result < 0)
+		return result;
 
 	/* This code looks awful: what it's doing is making sure an
 	 * ILLEGAL REQUEST sense return identifies the actual command
@@ -2186,13 +2186,15 @@ scsi_mode_sense(struct scsi_device *sdev, int dbd, int modepage,
 			data->block_descriptor_length = buffer[3];
 		}
 		data->header_length = header_length;
+		result = 0;
 	} else if ((status_byte(result) == CHECK_CONDITION) &&
 		   scsi_sense_valid(sshdr) &&
 		   sshdr->sense_key == UNIT_ATTENTION && retry_count) {
 		retry_count--;
 		goto retry;
 	}
-
+	if (result > 0)
+		result = -EIO;
 	return result;
 }
 EXPORT_SYMBOL(scsi_mode_sense);