[040/114] kasan, page_alloc: combine tag_clear_highpage calls in post_alloc_hook

Commit Message

Andrew Morton March 25, 2022, 1:10 a.m. UTC

From: Andrey Konovalov <[e-mail]>
Subject: kasan, page_alloc: combine tag_clear_highpage calls in post_alloc_hook

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

This patch does no functional changes.

Link: https://lkml.kernel.org/r/58[e-mail]
Signed-off-by: Andrey Konovalov <[e-mail]>
Reviewed-by: Alexander Potapenko <[e-mail]>
Acked-by: Marco Elver <[e-mail]>
Cc: Andrey Ryabinin <[e-mail]>
Cc: Catalin Marinas <[e-mail]>
Cc: Dmitry Vyukov <[e-mail]>
Cc: Evgenii Stepanov <[e-mail]>
Cc: Mark Rutland <[e-mail]>
Cc: Peter Collingbourne <[e-mail]>
Cc: Vincenzo Frascino <[e-mail]>
Cc: Will Deacon <[e-mail]>
Signed-off-by: Andrew Morton <[e-mail]>
---

 mm/page_alloc.c |   32 ++++++++++++++++----------------
 1 file changed, 16 insertions(+), 16 deletions(-)

Patch

--- a/mm/page_alloc.c~kasan-page_alloc-combine-tag_clear_highpage-calls-in-post_alloc_hook
+++ a/mm/page_alloc.c
@@ -2367,30 +2367,30 @@  inline void post_alloc_hook(struct page
 	 * 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);
 	}