[PATCH mm v4 11/39] kasan, page_alloc: combine tag_clear_highpage calls in post_alloc_hook

andrey.konovalov
2021-12-20T22:00:02Z

Move tag_clear_highpage() loops out of the kasan_has_integrated_init()
clause as a code simplification.

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 | 32 ++++++++++++++++----------------
1 file changed, 16 insertions(+), 16 deletions(-)

diff --git a/mm/page_alloc.c b/mm/page_alloc.c
index a2e32a8abd7f..2d1e63a01ed8 100644
--- a/mm/page_alloc.c
+++ b/mm/page_alloc.c
@@ -2418,30 +2418,30 @@ inline void post_alloc_hook(struct page *page, unsigned int order,
* KASAN unpoisoning and memory initializion code must be
* kept together to avoid discrepancies in behavior.
*/
+
+ /*
+ * If memory tags should be zeroed (which happens only when memory
+ * should be initialized as well).
+ */
+ if (init_tags) {
+ int i;
+
+ /* Initialize both memory and tags. */
+ for (i = 0; i != 1 << order; ++i)
+ tag_clear_highpage(page + i);
+
+ /* Note that memory is already initialized by the loop above. */
+ init = false;
+ }
if (kasan_has_integrated_init()) {
if (gfp_flags & __GFP_SKIP_KASAN_POISON)
SetPageSkipKASanPoison(page);

- if (init_tags) {
- int i;
-
- for (i = 0; i != 1 << order; ++i)
- tag_clear_highpage(page + i);
- } else {
+ if (!init_tags)
kasan_unpoison_pages(page, order, init);
- }
} else {
kasan_unpoison_pages(page, order, init);

- if (init_tags) {
- int i;
-
- for (i = 0; i < 1 << order; i++)
- tag_clear_highpage(page + i);
-
- init = false;
- }
-
if (init)
kernel_init_free_pages(page, 1 << order);
}
--
2.25.1