The current KHO restoration logic assumes all multi-page blocks are split into independent 4KB pages. Break out a helper to prepare for supporting high-order non-compound pages.
Extract kho_init_unsplit_pages() to handle the refcount pattern where only the head page is refcounted. Use the helper for folio restoration that requires a similar refcount logic. Signed-off-by: Pranjal Shrivastava <[email protected]> --- kernel/liveupdate/kexec_handover.c | 29 +++++++++++++++++++---------- 1 file changed, 19 insertions(+), 10 deletions(-) diff --git a/kernel/liveupdate/kexec_handover.c b/kernel/liveupdate/kexec_handover.c index 4834a809985a..07f6f453cd69 100644 --- a/kernel/liveupdate/kexec_handover.c +++ b/kernel/liveupdate/kexec_handover.c @@ -357,6 +357,24 @@ int kho_radix_walk_tree(struct kho_radix_tree *tree, } EXPORT_SYMBOL_GPL(kho_radix_walk_tree); +/* For physically contiguous pages. */ +static void kho_init_unsplit_pages(struct page *page, unsigned int order) +{ + unsigned long nr_pages = (1UL << order); + + /* Head page gets refcount of 1. */ + set_page_count(page, 1); + /* Clear head page's codetag to avoid accounting mismatch. */ + clear_page_tag_ref(page); + + /* For high-order blocks, tail pages get a page count of zero. */ + for (unsigned long i = 1; i < nr_pages; i++) { + set_page_count(page + i, 0); + /* Clear each page's codetag to avoid accounting mismatch. */ + clear_page_tag_ref(page + i); + } +} + /* For physically contiguous 0-order pages. */ static void kho_init_pages(struct page *page, unsigned long nr_pages) { @@ -369,16 +387,7 @@ static void kho_init_pages(struct page *page, unsigned long nr_pages) static void kho_init_folio(struct page *page, unsigned int order) { - unsigned long nr_pages = (1 << order); - - /* Head page gets refcount of 1. */ - set_page_count(page, 1); - /* Clear head page's codetag to avoid accounting mismatch. */ - clear_page_tag_ref(page); - - /* For higher order folios, tail pages get a page count of zero. */ - for (unsigned long i = 1; i < nr_pages; i++) - set_page_count(page + i, 0); + kho_init_unsplit_pages(page, order); if (order > 0) prep_compound_page(page, order); -- 2.55.0.141.g00534a21ce-goog
