On Saturday, September 25, 2010, Nigel Cunningham wrote:
> 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@xxxxxxxxxxxx>
Well, I guess it would be better to move these functions to the patch where
they are used for the first time.
Thanks,
Rafael
> ---
> 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(§or_extents);
> +
> + /* We have already read the first page */
> + hib_extent_next(§or_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);
>
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