linux-kernel - [PATCH v2 13/34] kasan, page_alloc: move kernel_init_free_pages in post_alloc

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Message-Id: <42626baf4ce66be7fb1538c074b6508d9d867312.1638825394.git.andreyknvl@google.com>
Date:   Mon,  6 Dec 2021 22:43:50 +0100
From:   andrey.konovalov@...ux.dev
To:     Marco Elver <elver@...gle.com>,
        Alexander Potapenko <glider@...gle.com>,
        Vincenzo Frascino <vincenzo.frascino@....com>,
        Catalin Marinas <catalin.marinas@....com>,
        Peter Collingbourne <pcc@...gle.com>
Cc:     Andrey Konovalov <andreyknvl@...il.com>,
        Dmitry Vyukov <dvyukov@...gle.com>,
        Andrey Ryabinin <ryabinin.a.a@...il.com>,
        kasan-dev@...glegroups.com,
        Andrew Morton <akpm@...ux-foundation.org>, linux-mm@...ck.org,
        Will Deacon <will@...nel.org>,
        Mark Rutland <mark.rutland@....com>,
        linux-arm-kernel@...ts.infradead.org,
        Evgenii Stepanov <eugenis@...gle.com>,
        linux-kernel@...r.kernel.org,
        Andrey Konovalov <andreyknvl@...gle.com>
Subject: [PATCH v2 13/34] kasan, page_alloc: move kernel_init_free_pages in post_alloc_hook

From: Andrey Konovalov <andreyknvl@...gle.com>

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

This patch does no functional changes.

Signed-off-by: Andrey Konovalov <andreyknvl@...gle.com>
---
 mm/page_alloc.c | 12 ++++++++----
 1 file changed, 8 insertions(+), 4 deletions(-)

diff --git a/mm/page_alloc.c b/mm/page_alloc.c
index cbbaf76db6d9..5c346375cff9 100644
--- a/mm/page_alloc.c
+++ b/mm/page_alloc.c
@@ -2420,14 +2420,18 @@ inline void post_alloc_hook(struct page *page, unsigned int order,
 		init = false;
 	}
 	if (kasan_has_integrated_init()) {
-		if (!init_tags)
+		if (!init_tags) {
 			kasan_unpoison_pages(page, order, init);
+
+			/* Note that memory is already initialized by KASAN. */
+			init = false;
+		}
 	} else {
 		kasan_unpoison_pages(page, order, init);
-
-		if (init)
-			kernel_init_free_pages(page, 1 << order);
 	}
+	/* If memory is still not initialized, do it now. */
+	if (init)
+		kernel_init_free_pages(page, 1 << order);
 	/* Propagate __GFP_SKIP_KASAN_POISON to page flags. */
 	if (IS_ENABLED(CONFIG_KASAN_HW_TAGS) &&
 	    (gfp_flags & __GFP_SKIP_KASAN_POISON))
-- 
2.25.1