[PATCH mm v4 09/39] kasan, page_alloc: refactor init checks in post_alloc_hook

andrey.konovalov
2021-12-20T21:59:20Z

Separate code for zeroing memory from the code clearing tags in
post_alloc_hook().

This patch is not useful by itself but makes the simplifications in
the following patches easier to follow.

This patch does no functional changes.

Signed-off-by: Andrey Konovalov <andreyknvl@google.com>
Reviewed-by: Alexander Potapenko <glider@google.com>

---

Changes v2->v3:
- Update patch description.
---
mm/page_alloc.c | 18 ++++++++++--------
1 file changed, 10 insertions(+), 8 deletions(-)

diff --git a/mm/page_alloc.c b/mm/page_alloc.c
index 73280222e0e8..9ecdf2124ac1 100644
--- a/mm/page_alloc.c
+++ b/mm/page_alloc.c
@@ -2419,19 +2419,21 @@ inline void post_alloc_hook(struct page *page, unsigned int order,
kasan_alloc_pages(page, order, gfp_flags);
} else {
bool init = !want_init_on_free() && want_init_on_alloc(gfp_flags);
+ bool init_tags = init && (gfp_flags & __GFP_ZEROTAGS);

kasan_unpoison_pages(page, order, init);

- if (init) {
- if (gfp_flags & __GFP_ZEROTAGS) {
- int i;
+ if (init_tags) {
+ int i;

- for (i = 0; i < 1 << order; i++)
- tag_clear_highpage(page + i);
- } else {
- kernel_init_free_pages(page, 1 << order);
- }
+ for (i = 0; i < 1 << order; i++)
+ tag_clear_highpage(page + i);
+
+ init = false;
}
+
+ if (init)
+ kernel_init_free_pages(page, 1 << order);
}

set_page_owner(page, order, gfp_flags);
--
2.25.1