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[v2,14/34] kasan, page_alloc: simplify kasan_unpoison_pages call site

Message ID 10ba3c7a7524a912098d3b1747c0ca2e1e626ebc.1638825394.git.andreyknvl@google.com (mailing list archive)
State New, archived
Headers show
Series kasan, vmalloc, arm64: add vmalloc tagging support for SW/HW_TAGS | expand

Commit Message

andrey.konovalov@linux.dev Dec. 6, 2021, 9:43 p.m. UTC 
From: Andrey Konovalov <andreyknvl@google.com>

Simplify the checks around kasan_unpoison_pages() call in
post_alloc_hook().

The logical condition for calling this function is:

- If a software KASAN mode is enabled, we need to mark shadow memory.
- Otherwise, HW_TAGS KASAN is enabled, and it only makes sense to
  set tags if they haven't already been cleared by tag_clear_highpage(),
  which is indicated by init_tags.

This patch concludes the simplifications for post_alloc_hook().

Signed-off-by: Andrey Konovalov <andreyknvl@google.com>
---
 mm/page_alloc.c | 17 ++++++++++-------
 1 file changed, 10 insertions(+), 7 deletions(-)
diff mbox series

Patch

diff --git a/mm/page_alloc.c b/mm/page_alloc.c
index 5c346375cff9..73e6500c9767 100644
--- a/mm/page_alloc.c
+++ b/mm/page_alloc.c
@@ -2419,15 +2419,18 @@  inline void post_alloc_hook(struct page *page, unsigned int order,
 		/* Note that memory is already initialized by the loop above. */
 		init = false;
 	}
-	if (kasan_has_integrated_init()) {
-		if (!init_tags) {
-			kasan_unpoison_pages(page, order, init);
+	/*
+	 * If either a software KASAN mode is enabled, or,
+	 * in the case of hardware tag-based KASAN,
+	 * if memory tags have not been cleared via tag_clear_highpage().
+	 */
+	if (!IS_ENABLED(CONFIG_KASAN_HW_TAGS) || !init_tags) {
+		/* Mark shadow memory or set memory tags. */
+		kasan_unpoison_pages(page, order, init);
 
-			/* Note that memory is already initialized by KASAN. */
+		/* Note that memory is already initialized by KASAN. */
+		if (kasan_has_integrated_init())
 			init = false;
-		}
-	} else {
-		kasan_unpoison_pages(page, order, init);
 	}
 	/* If memory is still not initialized, do it now. */
 	if (init)