[PATCH 04/31] kasan, page_alloc: simplify kasan_poison_pages call site

From: andrey . konovalov
Date: Tue Nov 30 2021 - 16:41:03 EST


From: Andrey Konovalov <andreyknvl@xxxxxxxxxx>

Simplify the code around calling kasan_poison_pages() in
free_pages_prepare().

Reording kasan_poison_pages() and kernel_init_free_pages() is OK,
since kernel_init_free_pages() can handle poisoned memory.

This patch does no functional changes besides reordering the calls.

Signed-off-by: Andrey Konovalov <andreyknvl@xxxxxxxxxx>
---
mm/page_alloc.c | 18 +++++-------------
1 file changed, 5 insertions(+), 13 deletions(-)

diff --git a/mm/page_alloc.c b/mm/page_alloc.c
index 3f3ea41f8c64..0673db27dd12 100644
--- a/mm/page_alloc.c
+++ b/mm/page_alloc.c
@@ -1289,6 +1289,7 @@ static __always_inline bool free_pages_prepare(struct page *page,
{
int bad = 0;
bool skip_kasan_poison = should_skip_kasan_poison(page, fpi_flags);
+ bool init = want_init_on_free();

VM_BUG_ON_PAGE(PageTail(page), page);

@@ -1359,19 +1360,10 @@ static __always_inline bool free_pages_prepare(struct page *page,
* With hardware tag-based KASAN, memory tags must be set before the
* page becomes unavailable via debug_pagealloc or arch_free_page.
*/
- if (kasan_has_integrated_init()) {
- bool init = want_init_on_free();
-
- if (!skip_kasan_poison)
- kasan_poison_pages(page, order, init);
- } else {
- bool init = want_init_on_free();
-
- if (init)
- kernel_init_free_pages(page, 1 << order);
- if (!skip_kasan_poison)
- kasan_poison_pages(page, order, init);
- }
+ if (!skip_kasan_poison)
+ kasan_poison_pages(page, order, init);
+ if (init && !kasan_has_integrated_init())
+ kernel_init_free_pages(page, 1 << order);

/*
* arch_free_page() can make the page's contents inaccessible. s390
--
2.25.1