[RFC PATCH 07/20] kho: allow destroying KHO radix tree
From: Jork Loeser <hidden>
Date: 2026-05-28 00:43:00
Also in:
kexec, linux-hyperv, linux-mm, lkml
Subsystem:
kexec handover (kho), live update, the rest · Maintainers:
Mike Rapoport, Pasha Tatashin, Pratyush Yadav, Linus Torvalds
From: "Pratyush Yadav (Google)" <pratyush@kernel.org> Add kho_radix_destroy_tree() which allows destroying the radix tree and freeing all its pages. Signed-off-by: Pratyush Yadav (Google) <pratyush@kernel.org> Signed-off-by: Jork Loeser <redacted> --- 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) {
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2.43.0