Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1754246AbaLHHrw (ORCPT ); Mon, 8 Dec 2014 02:47:52 -0500 Received: from cnbjrel02.sonyericsson.com ([219.141.167.166]:18696 "EHLO cnbjrel02.sonyericsson.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751007AbaLHHrv convert rfc822-to-8bit (ORCPT ); Mon, 8 Dec 2014 02:47:51 -0500 From: "Wang, Yalin" To: "'linux-kernel@vger.kernel.org'" , "'linux-mm@kvack.org'" , "'linux-arm-kernel@lists.infradead.org'" , "'akpm@linux-foundation.org'" , "'riel@redhat.com'" , "'nasa4836@gmail.com'" , "'sasha.levin@oracle.com'" Date: Mon, 8 Dec 2014 15:47:47 +0800 Subject: [PATCH] mm:add VM_BUG_ON() for page_mapcount() Thread-Topic: [PATCH] mm:add VM_BUG_ON() for page_mapcount() Thread-Index: AdAQaYTRBP+XSfzeRTCVl77g86jARgACuLQwAJFpAgA= Message-ID: <35FD53F367049845BC99AC72306C23D103E688B313F5@CNBJMBX05.corpusers.net> References: <35FD53F367049845BC99AC72306C23D103E688B313EE@CNBJMBX05.corpusers.net> <35FD53F367049845BC99AC72306C23D103E688B313F1@CNBJMBX05.corpusers.net> In-Reply-To: <35FD53F367049845BC99AC72306C23D103E688B313F1@CNBJMBX05.corpusers.net> Accept-Language: en-US Content-Language: en-US X-MS-Has-Attach: X-MS-TNEF-Correlator: acceptlanguage: en-US Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 8BIT MIME-Version: 1.0 Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org This patch add VM_BUG_ON() for slab page, because _mapcount is an union with slab struct in struct page, avoid access _mapcount if this page is a slab page. Also remove the unneeded bracket. Signed-off-by: Yalin Wang --- include/linux/mm.h | 3 ++- 1 file changed, 2 insertions(+), 1 deletion(-) diff --git a/include/linux/mm.h b/include/linux/mm.h index 11b65cf..34124c4 100644 --- a/include/linux/mm.h +++ b/include/linux/mm.h @@ -373,7 +373,8 @@ static inline void reset_page_mapcount(struct page *page) static inline int page_mapcount(struct page *page) { - return atomic_read(&(page)->_mapcount) + 1; + VM_BUG_ON(PageSlab(page)); + return atomic_read(&page->_mapcount) + 1; } static inline int page_count(struct page *page) -- 2.1.3 -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/