[SCSI] qla2xxx: T10 DIF - Fix incorrect error reporting.

This fix:
    - Disables app tag peeking; correct tag check will be added when the
      SCSI API is available.
    - Always derive ref_tag from scsi_get_lba()
    - Removes incorrect swap of FCP_LUN in FCP_CMND
    - Moves app-tag error check before ref-tag check. The reason being,
      currently there is no interface in SCSI to retrieve the app-tag
      for protection I/Os, so driver puts zero for app-tag in the
      firmware interface, but requests not to validate it, but when a
      ref-tag error is detected by firmware, it would put
      expected/actual tags for all the protection tags (guard/app/ref).
      As driver checks for app tag error first, a ref-tag error is
      incorrectly flagged as app-tag error.
    - Convert HBA specific checks to capability based.

Signed-off-by: Arun Easi <arun.easi@qlogic.com>
Signed-off-by: Chad Dupuis <chad.dupuis@qlogic.com>
Signed-off-by: James Bottomley <JBottomley@Parallels.com>
diff --git a/drivers/scsi/qla2xxx/qla_isr.c b/drivers/scsi/qla2xxx/qla_isr.c
index 53339f1..ec53e87 100644
--- a/drivers/scsi/qla2xxx/qla_isr.c
+++ b/drivers/scsi/qla2xxx/qla_isr.c
@@ -1534,6 +1534,16 @@
 		return 1;
 	}
 
+	/* check ref tag */
+	if (e_ref_tag != a_ref_tag) {
+		scsi_build_sense_buffer(1, cmd->sense_buffer, ILLEGAL_REQUEST,
+		    0x10, 0x3);
+		set_driver_byte(cmd, DRIVER_SENSE);
+		set_host_byte(cmd, DID_ABORT);
+		cmd->result |= SAM_STAT_CHECK_CONDITION << 1;
+		return 1;
+	}
+
 	/* check appl tag */
 	if (e_app_tag != a_app_tag) {
 		scsi_build_sense_buffer(1, cmd->sense_buffer, ILLEGAL_REQUEST,
@@ -1544,15 +1554,6 @@
 		return 1;
 	}
 
-	/* check ref tag */
-	if (e_ref_tag != a_ref_tag) {
-		scsi_build_sense_buffer(1, cmd->sense_buffer, ILLEGAL_REQUEST,
-		    0x10, 0x3);
-		set_driver_byte(cmd, DRIVER_SENSE);
-		set_host_byte(cmd, DID_ABORT);
-		cmd->result |= SAM_STAT_CHECK_CONDITION << 1;
-		return 1;
-	}
 	return 1;
 }