linux-kernel - [PATCH 13/22] Hibernation: Extent save/load routines.

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Date:	Sat, 25 Sep 2010 14:16:55 +1000
From:	Nigel Cunningham <nigel@...onice.net>
To:	"Rafael J. Wysocki" <rjw@...k.pl>,
	Linux PM <linux-pm@...ts.linux-foundation.org>,
	LKML <linux-kernel@...r.kernel.org>,
	TuxOnIce-devel <tuxonice-devel@...onice.net>
Subject: [PATCH 13/22] Hibernation: Extent save/load routines.

Add routines for saving and reloading a chain of extents. This will
be used to store the block extents in the image header, rather than
in swap map pages.

Signed-off-by: Nigel Cunningham <nigel@...onice.net>
---
 kernel/power/extents.c |   75 ++++++++++++++++++++++++++++++++++++++++++++++++
 kernel/power/extents.h |    5 +++
 2 files changed, 80 insertions(+), 0 deletions(-)

diff --git a/kernel/power/extents.c b/kernel/power/extents.c
index 172322d..75d2fb4 100644
--- a/kernel/power/extents.c
+++ b/kernel/power/extents.c
@@ -14,6 +14,7 @@
 
 #include <linux/slab.h>
 #include "extents.h"
+#include "block_io.h"
 
 int hib_extents_empty(struct hib_extent_state *pos)
 {
@@ -123,3 +124,77 @@ void hib_extents_clear(struct hib_extent_state *pos)
 		kfree(ext);
 	}
 }
+
+int hib_extents_storage_needed(struct hib_extent_state *pos)
+{
+	return sizeof(int) + pos->num_extents * 2 * sizeof(unsigned long);
+}
+
+int hib_extents_store(struct hib_extent_state *pos)
+{
+	struct rb_node *node;
+	struct hib_extent *ext;
+	int ret = hib_write_buffer((char *) &pos->num_extents, sizeof(int));
+
+	if (hib_extents_empty(pos))
+		return 0;
+
+	node = rb_first(&pos->root);
+	while (node) {
+		ext = container_of(node, struct hib_extent, node);
+		ret = hib_write_buffer((char *) &ext->start,
+				2 * sizeof(unsigned long));
+		if (ret)
+			return ret;
+		node = rb_next(node);
+	}
+
+	return 0;
+}
+
+int hib_extents_load(struct hib_extent_state *pos, int bootstrap)
+{
+	struct rb_node **new = &(pos->root.rb_node);
+	struct rb_node *parent = NULL;
+	struct hib_extent *existing, *adding;
+	int i;
+	int ret = hib_read_buffer((char *) &pos->num_extents, sizeof(int));
+
+	if (!pos->num_extents)
+		return 0;
+
+	for (i = 0; i < pos->num_extents; i++) {
+		adding = kzalloc(sizeof(struct hib_extent), GFP_KERNEL);
+		if (!adding)
+			return -ENOMEM;
+
+		ret = hib_read_buffer((char *) &adding->start,
+				2 * sizeof(unsigned long));
+		if (ret)
+			return ret;
+
+		/*
+		 * No need for some of the checks from inserting above -
+		 * they were done when preparing the image.
+		 */
+		while (*new) {
+			existing = container_of(*new, struct hib_extent, node);
+			parent = *new;
+			if (adding->end < existing->start)
+				new = &((*new)->rb_left);
+			else
+				new = &((*new)->rb_right);
+		}
+		rb_link_node(&adding->node, parent, new);
+		rb_insert_color(&adding->node, &pos->root);
+
+		if (bootstrap && !i) {
+			hib_reset_extent_pos(&sector_extents);
+
+			/* We have already read the first page */
+			hib_extent_next(&sector_extents);
+		}
+	}
+
+	return 0;
+}
diff --git a/kernel/power/extents.h b/kernel/power/extents.h
index 0b69b8e..4288f9e 100644
--- a/kernel/power/extents.h
+++ b/kernel/power/extents.h
@@ -33,3 +33,8 @@ unsigned long hib_extent_next(struct hib_extent_state *pos);
 int hib_extents_insert(struct hib_extent_state *pos, unsigned long value);
 void hib_extents_clear(struct hib_extent_state *pos);
 int hib_extents_empty(struct hib_extent_state *pos);
+
+/* Serialisation support */
+int hib_extents_storage_needed(struct hib_extent_state *pos);
+int hib_extents_store(struct hib_extent_state *pos);
+int hib_extents_load(struct hib_extent_state *pos, int bootstrap);
-- 
1.7.0.4

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