radix_tree_replace() replaces an old item with a new item.
This function is invoked from the memory migration code
to replace with a target page with a new page.
Signed-off-by: Hirokazu Takahashi <taka@valinux.co.jp>
Signed-off-by: Dave Hansen <haveblue@us.ibm.com>
---
memhotplug-dave/include/linux/radix-tree.h | 1
memhotplug-dave/lib/radix-tree.c | 55 ++++++++++++++++++++++++++++-
2 files changed, 55 insertions(+), 1 deletion(-)
diff -puN include/linux/radix-tree.h~P03-radix-tree-replace include/linux/radix-tree.h
--- memhotplug/include/linux/radix-tree.h~P03-radix-tree-replace 2004-12-08 14:57:32.000000000 -0800
+++ memhotplug-dave/include/linux/radix-tree.h 2004-12-08 14:57:32.000000000 -0800
@@ -48,6 +48,7 @@ int radix_tree_insert(struct radix_tree_
void *radix_tree_lookup(struct radix_tree_root *, unsigned long);
void **radix_tree_lookup_slot(struct radix_tree_root *, unsigned long);
void *radix_tree_delete(struct radix_tree_root *, unsigned long);
+void *radix_tree_replace(struct radix_tree_root *, unsigned long, void *);
unsigned int
radix_tree_gang_lookup(struct radix_tree_root *root, void **results,
unsigned long first_index, unsigned int max_items);
diff -puN lib/radix-tree.c~P03-radix-tree-replace lib/radix-tree.c
--- memhotplug/lib/radix-tree.c~P03-radix-tree-replace 2004-12-08 14:57:32.000000000 -0800
+++ memhotplug-dave/lib/radix-tree.c 2004-12-08 14:57:32.000000000 -0800
@@ -100,7 +100,13 @@ radix_tree_node_alloc(struct radix_tree_
static inline void
radix_tree_node_free(struct radix_tree_node *node)
{
- kmem_cache_free(radix_tree_node_cachep, node);
+ struct radix_tree_preload *rtp;
+
+ rtp = &__get_cpu_var(radix_tree_preloads);
+ if (rtp->nr < ARRAY_SIZE(rtp->nodes))
+ rtp->nodes[rtp->nr++] = node;
+ else
+ kmem_cache_free(radix_tree_node_cachep, node);
}
/*
@@ -757,6 +763,53 @@ out:
EXPORT_SYMBOL(radix_tree_delete);
/**
+ * radix_tree_replace - replace items in a radix tree
+ * @root: radix tree root
+ * @index: index key
+ * @item: item to insert
+ *
+ * Replace the item at @index with @item.
+ * Returns the address of the deleted item, or NULL if it was not present.
+ */
+void *radix_tree_replace(struct radix_tree_root *root,
+ unsigned long index, void *item)
+{
+ struct radix_tree_path path[RADIX_TREE_MAX_PATH], *pathp = path;
+ unsigned int height, shift;
+ void *ret = NULL;
+
+ height = root->height;
+ if (index > radix_tree_maxindex(height))
+ goto out;
+
+ shift = (height - 1) * RADIX_TREE_MAP_SHIFT;
+ pathp->node = NULL;
+ pathp->slot = &root->rnode;
+
+ while (height > 0) {
+ int offset;
+
+ if (*pathp->slot == NULL)
+ goto out;
+
+ offset = (index >> shift) & RADIX_TREE_MAP_MASK;
+ pathp[1].offset = offset;
+ pathp[1].node = *pathp[0].slot;
+ pathp[1].slot = (struct radix_tree_node **)
+ (pathp[1].node->slots + offset);
+ pathp++;
+ shift -= RADIX_TREE_MAP_SHIFT;
+ height--;
+ }
+
+ if ((ret = *pathp[0].slot))
+ *pathp[0].slot = item;
+out:
+ return ret;
+}
+EXPORT_SYMBOL(radix_tree_replace);
+
+/**
* radix_tree_tagged - test whether any items in the tree are tagged
* @root: radix tree root
* @tag: tag to test
_