From patchwork Wed Jun 1 12:44:17 2022 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Chen Wandun X-Patchwork-Id: 12866858 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org Received: from kanga.kvack.org (kanga.kvack.org [205.233.56.17]) by smtp.lore.kernel.org (Postfix) with ESMTP id 8B476C433F5 for ; Wed, 1 Jun 2022 12:23:34 +0000 (UTC) Received: by kanga.kvack.org (Postfix) id 6758C8D0012; Wed, 1 Jun 2022 08:23:31 -0400 (EDT) Received: by kanga.kvack.org (Postfix, from userid 40) id 5AE838D000E; Wed, 1 Jun 2022 08:23:31 -0400 (EDT) X-Delivered-To: int-list-linux-mm@kvack.org Received: by kanga.kvack.org (Postfix, from userid 63042) id 3FA6F8D0012; Wed, 1 Jun 2022 08:23:31 -0400 (EDT) X-Delivered-To: linux-mm@kvack.org Received: from relay.hostedemail.com (smtprelay0015.hostedemail.com [216.40.44.15]) by kanga.kvack.org (Postfix) with ESMTP id 24C178D000E for ; Wed, 1 Jun 2022 08:23:31 -0400 (EDT) Received: from smtpin31.hostedemail.com (a10.router.float.18 [10.200.18.1]) by unirelay09.hostedemail.com (Postfix) with ESMTP id F06EE34279 for ; Wed, 1 Jun 2022 12:23:30 +0000 (UTC) X-FDA: 79529582580.31.3E44367 Received: from szxga08-in.huawei.com (szxga08-in.huawei.com [45.249.212.255]) by imf29.hostedemail.com (Postfix) with ESMTP id 09F4F12005C for ; Wed, 1 Jun 2022 12:23:16 +0000 (UTC) Received: from dggpemm500023.china.huawei.com (unknown [172.30.72.56]) by szxga08-in.huawei.com (SkyGuard) with ESMTP id 4LCpDC2Bw4z1K9BD; Wed, 1 Jun 2022 20:21:47 +0800 (CST) Received: from dggpemm500002.china.huawei.com (7.185.36.229) by dggpemm500023.china.huawei.com (7.185.36.83) with Microsoft SMTP Server (version=TLS1_2, cipher=TLS_ECDHE_RSA_WITH_AES_128_GCM_SHA256) id 15.1.2375.24; Wed, 1 Jun 2022 20:23:27 +0800 Received: from localhost.localdomain (10.175.112.125) by dggpemm500002.china.huawei.com (7.185.36.229) with Microsoft SMTP Server (version=TLS1_2, cipher=TLS_ECDHE_RSA_WITH_AES_128_GCM_SHA256) id 15.1.2375.24; Wed, 1 Jun 2022 20:23:26 +0800 From: Chen Wandun To: , , , CC: Subject: [PATCH 4/4] mm/shmem: rework calculation of inflated_addr in shmem_get_unmapped_area Date: Wed, 1 Jun 2022 20:44:17 +0800 Message-ID: <20220601124417.2872001-5-chenwandun@huawei.com> X-Mailer: git-send-email 2.25.1 In-Reply-To: <20220601124417.2872001-1-chenwandun@huawei.com> References: <20220601124417.2872001-1-chenwandun@huawei.com> MIME-Version: 1.0 X-Originating-IP: [10.175.112.125] X-ClientProxiedBy: dggems705-chm.china.huawei.com (10.3.19.182) To dggpemm500002.china.huawei.com (7.185.36.229) X-CFilter-Loop: Reflected Authentication-Results: imf29.hostedemail.com; dkim=none; spf=pass (imf29.hostedemail.com: domain of chenwandun@huawei.com designates 45.249.212.255 as permitted sender) smtp.mailfrom=chenwandun@huawei.com; dmarc=pass (policy=quarantine) header.from=huawei.com X-Rspamd-Server: rspam03 X-Rspamd-Queue-Id: 09F4F12005C X-Rspam-User: X-Stat-Signature: zmigmey7syznkq5tohpbarn95ma6rxwn X-HE-Tag: 1654086196-222977 X-Bogosity: Ham, tests=bogofilter, spamicity=0.000000, version=1.2.4 Sender: owner-linux-mm@kvack.org Precedence: bulk X-Loop: owner-majordomo@kvack.org List-ID: In function shmem_get_unmapped_area, inflated_offset and offset are unsigned long, it will result in underflow when offset below inflated_offset, a little confusing, no functional change. Signed-off-by: Chen Wandun --- mm/shmem.c | 7 +++++-- 1 file changed, 5 insertions(+), 2 deletions(-) diff --git a/mm/shmem.c b/mm/shmem.c index ca04f3975a8a..f12163bd0f69 100644 --- a/mm/shmem.c +++ b/mm/shmem.c @@ -2201,9 +2201,12 @@ unsigned long shmem_get_unmapped_area(struct file *file, return addr; inflated_offset = inflated_addr & (HPAGE_PMD_SIZE-1); - inflated_addr += offset - inflated_offset; - if (inflated_offset > offset) + if (offset > inflated_offset) + inflated_addr += offset - inflated_offset; + else if (offset < inflated_offset) { + inflated_addr -= inflated_offset - offset; inflated_addr += HPAGE_PMD_SIZE; + } if (inflated_addr > TASK_SIZE - len) return addr;