From: "Pratyush Yadav (Google)" <[email protected]>

Add kho_radix_destroy_tree() which allows destroying the radix tree and
freeing all its pages.

Signed-off-by: Pratyush Yadav (Google) <[email protected]>
Signed-off-by: Jork Loeser <[email protected]>
---
 include/linux/kho_radix_tree.h     |  3 +++
 kernel/liveupdate/kexec_handover.c | 34 ++++++++++++++++++++++++++++++
 2 files changed, 37 insertions(+)

diff --git a/include/linux/kho_radix_tree.h b/include/linux/kho_radix_tree.h
index 6c0f7d82716b..617395a6647a 100644
--- a/include/linux/kho_radix_tree.h
+++ b/include/linux/kho_radix_tree.h
@@ -54,6 +54,7 @@ int kho_radix_add_key(struct kho_radix_tree *tree, unsigned 
long key);
 void kho_radix_del_key(struct kho_radix_tree *tree, unsigned long key);
 int kho_radix_walk_tree(struct kho_radix_tree *tree,
                        const struct kho_radix_walk_cb *cb, void *data);
+void kho_radix_destroy_tree(struct kho_radix_tree *tree);
 
 #else  /* #ifdef CONFIG_KEXEC_HANDOVER */
 
@@ -71,6 +72,8 @@ static inline int kho_radix_walk_tree(struct kho_radix_tree 
*tree,
        return -EOPNOTSUPP;
 }
 
+static inline void kho_radix_destroy_tree(struct kho_radix_tree *tree) { }
+
 #endif /* #ifdef CONFIG_KEXEC_HANDOVER */
 
 #endif /* _LINUX_KHO_RADIX_TREE_H */
diff --git a/kernel/liveupdate/kexec_handover.c 
b/kernel/liveupdate/kexec_handover.c
index 5c201e605b96..3f3ea71baa1a 100644
--- a/kernel/liveupdate/kexec_handover.c
+++ b/kernel/liveupdate/kexec_handover.c
@@ -286,6 +286,40 @@ void kho_radix_del_key(struct kho_radix_tree *tree, 
unsigned long key)
 }
 EXPORT_SYMBOL_GPL(kho_radix_del_key);
 
+static void __kho_radix_destroy_tree(struct kho_radix_node *root,
+                                    unsigned int level)
+{
+       unsigned long i;
+
+       if (level == 0) {
+               kho_radix_free_node(root);
+               return;
+       }
+
+       for (i = 0; i < PAGE_SIZE / sizeof(phys_addr_t); i++) {
+               if (root->table[i])
+                       __kho_radix_destroy_tree(phys_to_virt(root->table[i]),
+                                                level - 1);
+       }
+
+       kho_radix_free_node(root);
+}
+
+/**
+ * kho_radix_destroy_tree - Destroy the radix tree
+ * @tree: The radix tree to destroy
+ *
+ * Walk @tree and free all its nodes.
+ */
+void kho_radix_destroy_tree(struct kho_radix_tree *tree)
+{
+       if (!tree->root)
+               return;
+
+       __kho_radix_destroy_tree(tree->root, KHO_TREE_MAX_DEPTH - 1);
+}
+EXPORT_SYMBOL_GPL(kho_radix_destroy_tree);
+
 static int kho_radix_walk_leaf(struct kho_radix_leaf *leaf, unsigned long key,
                               const struct kho_radix_walk_cb *cb, void *data)
 {
-- 
2.43.0


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