From f4dc37cc72b475c043988e6793d9bdd417b02d39 Mon Sep 17 00:00:00 2001
From: Milan Broz <gmazyland@gmail.com>
Date: Sun, 28 Feb 2016 10:43:33 +0100
Subject: [PATCH] dm-table: Add flag to allow own target handling of integrity metadata.

This patch adds DM_TARGET_INTEGRITY flag that specifies
bio integrity metadata is not inherited but implemented in target itself.

Signed-off-by: Milan Broz <gmazyland@gmail.com>
---
 drivers/md/dm-table.c         |   11 +++++++++++
 include/linux/device-mapper.h |    6 ++++++
 2 files changed, 17 insertions(+)

Index: linux-4.6-rc6/drivers/md/dm-table.c
===================================================================
--- linux-4.6-rc6.orig/drivers/md/dm-table.c	2016-05-02 13:02:26.000000000 +0200
+++ linux-4.6-rc6/drivers/md/dm-table.c	2016-05-02 15:32:29.000000000 +0200
@@ -45,6 +45,7 @@ struct dm_table {
 	struct target_type *immutable_target_type;
 	unsigned integrity_supported:1;
 	unsigned singleton:1;
+	unsigned integrity_added:1;
 
 	/*
 	 * Indicates the rw permissions for the new logical
@@ -744,6 +745,9 @@ int dm_table_add_target(struct dm_table 
 		t->immutable_target_type = tgt->type;
 	}
 
+	if (dm_target_has_integrity(tgt->type))
+		t->integrity_added = 1;
+
 	tgt->table = t;
 	tgt->begin = start;
 	tgt->len = len;
@@ -1118,6 +1122,10 @@ static int dm_table_register_integrity(s
 	struct mapped_device *md = t->md;
 	struct gendisk *template_disk = NULL;
 
+	/* If target handles integrity itself do not register it here. */
+	if (t->integrity_added)
+		return 0;
+
 	template_disk = dm_table_get_integrity_disk(t);
 	if (!template_disk)
 		return 0;
@@ -1355,6 +1363,9 @@ static void dm_table_verify_integrity(st
 {
 	struct gendisk *template_disk = NULL;
 
+	if (t->integrity_added)
+		return;
+
 	if (t->integrity_supported) {
 		/*
 		 * Verify that the original integrity profile
Index: linux-4.6-rc6/include/linux/device-mapper.h
===================================================================
--- linux-4.6-rc6.orig/include/linux/device-mapper.h	2016-05-02 13:02:24.000000000 +0200
+++ linux-4.6-rc6/include/linux/device-mapper.h	2016-05-02 15:33:26.000000000 +0200
@@ -198,6 +198,12 @@ struct target_type {
 #define DM_TARGET_WILDCARD		0x00000008
 #define dm_target_is_wildcard(type)	((type)->features & DM_TARGET_WILDCARD)
 
+/*
+ * A target implements own bio data integrity.
+ */
+#define DM_TARGET_INTEGRITY		0x00000010
+#define dm_target_has_integrity(type)	((type)->features & DM_TARGET_INTEGRITY)
+
 struct dm_target {
 	struct dm_table *table;
 	struct target_type *type;