[PATCH v6 12/39] kasan, page_alloc: move SetPageSkipKASanPoison in post_alloc_hook

andrey.konovalov
2022-01-24T18:41:48Z

Pull the SetPageSkipKASanPoison() call in post_alloc_hook() out of the
big if clause for better code readability. This also allows for more
simplifications in the following patches.

Also turn the kasan_has_integrated_init() check into the proper
kasan_hw_tags_enabled() one. These checks evaluate to the same value,
but logically skipping kasan poisoning has nothing to do with
integrated init.

Signed-off-by: Andrey Konovalov <andreyknvl@google.com>

---

Changes v3->v4:
- Use proper kasan_hw_tags_enabled() check instead of
IS_ENABLED(CONFIG_KASAN_HW_TAGS).
---
mm/page_alloc.c | 6 +++---
1 file changed, 3 insertions(+), 3 deletions(-)

diff --git a/mm/page_alloc.c b/mm/page_alloc.c
index b3959327e06c..c51d637cdab3 100644
--- a/mm/page_alloc.c
+++ b/mm/page_alloc.c
@@ -2435,9 +2435,6 @@ inline void post_alloc_hook(struct page *page, unsigned int order,
init = false;
}
if (kasan_has_integrated_init()) {
- if (gfp_flags & __GFP_SKIP_KASAN_POISON)
- SetPageSkipKASanPoison(page);
-
if (!init_tags)
kasan_unpoison_pages(page, order, init);
} else {
@@ -2446,6 +2443,9 @@ inline void post_alloc_hook(struct page *page, unsigned int order,
if (init)
kernel_init_free_pages(page, 1 << order);
}
+ /* Propagate __GFP_SKIP_KASAN_POISON to page flags. */
+ if (kasan_hw_tags_enabled() && (gfp_flags & __GFP_SKIP_KASAN_POISON))
+ SetPageSkipKASanPoison(page);

set_page_owner(page, order, gfp_flags);
page_table_check_alloc(page, order);