From:   andrey.konovalov@linux.dev
To:     Marco Elver <elver@google.com>,
        Alexander Potapenko <glider@google.com>,
        Vincenzo Frascino <vincenzo.frascino@arm.com>,
        Catalin Marinas <catalin.marinas@arm.com>,
        Peter Collingbourne <pcc@google.com>
Cc:     Andrey Konovalov <andreyknvl@gmail.com>,
        Dmitry Vyukov <dvyukov@google.com>,
        Andrey Ryabinin <aryabinin@virtuozzo.com>,
        kasan-dev@googlegroups.com,
        Andrew Morton <akpm@linux-foundation.org>, linux-mm@kvack.org,
        Will Deacon <will@kernel.org>,
        linux-arm-kernel@lists.infradead.org,
        Evgenii Stepanov <eugenis@google.com>,
        linux-kernel@vger.kernel.org,
        Andrey Konovalov <andreyknvl@google.com>
Subject: [PATCH 11/31] kasan, page_alloc: move SetPageSkipKASanPoison in post_alloc_hook
Date:   Tue, 30 Nov 2021 23:05:17 +0100
Message-Id: <e38327856eb2cc233e478e22e618d9f0454db62a.1638308023.git.andreyknvl@google.com>
In-Reply-To: <cover.1638308023.git.andreyknvl@google.com>
References: <cover.1638308023.git.andreyknvl@google.com>
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From: Andrey Konovalov <andreyknvl@google.com>

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
CONFIG_KASAN_HW_TAGS 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>
---
 mm/page_alloc.c | 7 ++++---
 1 file changed, 4 insertions(+), 3 deletions(-)

diff --git a/mm/page_alloc.c b/mm/page_alloc.c
index e3e9fefbce43..c78befc4e057 100644
--- a/mm/page_alloc.c
+++ b/mm/page_alloc.c
@@ -2421,9 +2421,6 @@ 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 {
@@ -2432,6 +2429,10 @@ 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 (IS_ENABLED(CONFIG_KASAN_HW_TAGS) &&
+	    (gfp_flags & __GFP_SKIP_KASAN_POISON))
+		SetPageSkipKASanPoison(page);
 
 	set_page_owner(page, order, gfp_flags);
 }
-- 
2.25.1