From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mail-pa0-f51.google.com (mail-pa0-f51.google.com [209.85.220.51]) by kanga.kvack.org (Postfix) with ESMTP id 48D276B0253 for ; Sun, 13 Sep 2015 22:17:28 -0400 (EDT) Received: by pacfv12 with SMTP id fv12so130936353pac.2 for ; Sun, 13 Sep 2015 19:17:28 -0700 (PDT) Received: from szxga03-in.huawei.com (szxga03-in.huawei.com. [119.145.14.66]) by mx.google.com with ESMTPS id cy1si19607606pad.200.2015.09.13.19.17.26 for (version=TLS1 cipher=RC4-SHA bits=128/128); Sun, 13 Sep 2015 19:17:27 -0700 (PDT) Message-ID: <55F62C65.7070100@huawei.com> Date: Mon, 14 Sep 2015 10:09:41 +0800 From: Xishi Qiu MIME-Version: 1.0 Subject: [PATCH V2] kasan: use IS_ALIGNED in memory_is_poisoned_8() Content-Type: text/plain; charset="ISO-8859-1" Content-Transfer-Encoding: 7bit Sender: owner-linux-mm@kvack.org List-ID: To: Andrew Morton , Andrey Konovalov , Rusty Russell , Michal Marek , Andrey Ryabinin , "long.wanglong" Cc: Linux MM , LKML Use IS_ALIGNED() to determine whether the shadow span two bytes. It generates less code and more readable. Add some comments in shadow check functions. Please apply "kasan: fix last shadow judgement in memory_is_poisoned_16()" first. Signed-off-by: Xishi Qiu --- mm/kasan/kasan.c | 21 +++++++++++++++++++-- 1 file changed, 19 insertions(+), 2 deletions(-) diff --git a/mm/kasan/kasan.c b/mm/kasan/kasan.c index 8da2114..00d5605 100644 --- a/mm/kasan/kasan.c +++ b/mm/kasan/kasan.c @@ -86,6 +86,10 @@ static __always_inline bool memory_is_poisoned_2(unsigned long addr) if (memory_is_poisoned_1(addr + 1)) return true; + /* + * If the shadow spans two bytes, the first byte should + * be zero. + */ if (likely(((addr + 1) & KASAN_SHADOW_MASK) != 0)) return false; @@ -103,6 +107,10 @@ static __always_inline bool memory_is_poisoned_4(unsigned long addr) if (memory_is_poisoned_1(addr + 3)) return true; + /* + * If the shadow spans two bytes, the first byte should + * be zero. + */ if (likely(((addr + 3) & KASAN_SHADOW_MASK) >= 3)) return false; @@ -120,7 +128,11 @@ static __always_inline bool memory_is_poisoned_8(unsigned long addr) if (memory_is_poisoned_1(addr + 7)) return true; - if (likely(((addr + 7) & KASAN_SHADOW_MASK) >= 7)) + /* + * If the shadow spans two bytes, the first byte should + * be zero. + */ + if (likely(IS_ALIGNED(addr, KASAN_SHADOW_SCALE_SIZE))) return false; return unlikely(*(u8 *)shadow_addr); @@ -139,7 +151,12 @@ static __always_inline bool memory_is_poisoned_16(unsigned long addr) if (unlikely(shadow_first_bytes)) return true; - if (likely(IS_ALIGNED(addr, 8))) + /* + * If the shadow spans three bytes, we should continue to + * check the last byte. The first two bytes which we + * checked above should always be zero. + */ + if (likely(IS_ALIGNED(addr, KASAN_SHADOW_SCALE_SIZE))) return false; return memory_is_poisoned_1(addr + 15); -- 2.0.0 -- To unsubscribe, send a message with 'unsubscribe linux-mm' in the body to majordomo@kvack.org. For more info on Linux MM, see: http://www.linux-mm.org/ . Don't email: email@kvack.org