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Subject[PATCH 13/22] Hibernation: Extent save/load routines.
Date
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@tuxonice.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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