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Diffstat (limited to 'kernel/power/swap.c')
-rw-r--r--kernel/power/swap.c101
1 files changed, 101 insertions, 0 deletions
diff --git a/kernel/power/swap.c b/kernel/power/swap.c
index 890f6b11b1d3..0ce9b00f5d33 100644
--- a/kernel/power/swap.c
+++ b/kernel/power/swap.c
@@ -38,6 +38,107 @@ struct swsusp_header {
static struct swsusp_header *swsusp_header;
+/**
+ * The following functions are used for tracing the allocated
+ * swap pages, so that they can be freed in case of an error.
+ */
+
+struct swsusp_extent {
+ struct rb_node node;
+ unsigned long start;
+ unsigned long end;
+};
+
+static struct rb_root swsusp_extents = RB_ROOT;
+
+static int swsusp_extents_insert(unsigned long swap_offset)
+{
+ struct rb_node **new = &(swsusp_extents.rb_node);
+ struct rb_node *parent = NULL;
+ struct swsusp_extent *ext;
+
+ /* Figure out where to put the new node */
+ while (*new) {
+ ext = container_of(*new, struct swsusp_extent, node);
+ parent = *new;
+ if (swap_offset < ext->start) {
+ /* Try to merge */
+ if (swap_offset == ext->start - 1) {
+ ext->start--;
+ return 0;
+ }
+ new = &((*new)->rb_left);
+ } else if (swap_offset > ext->end) {
+ /* Try to merge */
+ if (swap_offset == ext->end + 1) {
+ ext->end++;
+ return 0;
+ }
+ new = &((*new)->rb_right);
+ } else {
+ /* It already is in the tree */
+ return -EINVAL;
+ }
+ }
+ /* Add the new node and rebalance the tree. */
+ ext = kzalloc(sizeof(struct swsusp_extent), GFP_KERNEL);
+ if (!ext)
+ return -ENOMEM;
+
+ ext->start = swap_offset;
+ ext->end = swap_offset;
+ rb_link_node(&ext->node, parent, new);
+ rb_insert_color(&ext->node, &swsusp_extents);
+ return 0;
+}
+
+/**
+ * alloc_swapdev_block - allocate a swap page and register that it has
+ * been allocated, so that it can be freed in case of an error.
+ */
+
+sector_t alloc_swapdev_block(int swap)
+{
+ unsigned long offset;
+
+ offset = swp_offset(get_swap_page_of_type(swap));
+ if (offset) {
+ if (swsusp_extents_insert(offset))
+ swap_free(swp_entry(swap, offset));
+ else
+ return swapdev_block(swap, offset);
+ }
+ return 0;
+}
+
+/**
+ * free_all_swap_pages - free swap pages allocated for saving image data.
+ * It also frees the extents used to register which swap entres had been
+ * allocated.
+ */
+
+void free_all_swap_pages(int swap)
+{
+ struct rb_node *node;
+
+ while ((node = swsusp_extents.rb_node)) {
+ struct swsusp_extent *ext;
+ unsigned long offset;
+
+ ext = container_of(node, struct swsusp_extent, node);
+ rb_erase(node, &swsusp_extents);
+ for (offset = ext->start; offset <= ext->end; offset++)
+ swap_free(swp_entry(swap, offset));
+
+ kfree(ext);
+ }
+}
+
+int swsusp_swap_in_use(void)
+{
+ return (swsusp_extents.rb_node != NULL);
+}
+
/*
* General things
*/