[SCSI] Fix printing of failed 32-byte commands

Having the large CDB allocation logic in sd.c means that
scsi_io_completion does not have access to the command buffer. That in
turn causes garbage to be printed when a 32-byte command fails. Move the
command printing to sd_done where the command buffer is intact.  Clear
the command buffer pointer after the extended CDB has been freed.

Make scsi_print_command ignore commands with NULL CDB pointers to
inhibit printing of garbled command strings.

Signed-off-by: Martin K. Petersen <martin.petersen@oracle.com>
Reviewed-by: Boaz Harrosh <bharrosh@panasas.com>
Signed-off-by: James Bottomley <James.Bottomley@suse.de>
diff --git a/drivers/scsi/sd.c b/drivers/scsi/sd.c
index 908d400..1dd4d84 100644
--- a/drivers/scsi/sd.c
+++ b/drivers/scsi/sd.c
@@ -1209,8 +1209,19 @@
 		sd_dif_complete(SCpnt, good_bytes);
 
 	if (scsi_host_dif_capable(sdkp->device->host, sdkp->protection_type)
-	    == SD_DIF_TYPE2_PROTECTION && SCpnt->cmnd != SCpnt->request->cmd)
+	    == SD_DIF_TYPE2_PROTECTION && SCpnt->cmnd != SCpnt->request->cmd) {
+
+		/* We have to print a failed command here as the
+		 * extended CDB gets freed before scsi_io_completion()
+		 * is called.
+		 */
+		if (result)
+			scsi_print_command(SCpnt);
+
 		mempool_free(SCpnt->cmnd, sd_cdb_pool);
+		SCpnt->cmnd = NULL;
+		SCpnt->cmd_len = 0;
+	}
 
 	return good_bytes;
 }