From patchwork Mon Jun 6 03:45:30 2022 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Chen Wandun X-Patchwork-Id: 12869909 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 EB4F1C43334 for ; Mon, 6 Jun 2022 03:25:10 +0000 (UTC) Received: by kanga.kvack.org (Postfix) id 7D8F28D0006; Sun, 5 Jun 2022 23:25:10 -0400 (EDT) Received: by kanga.kvack.org (Postfix, from userid 40) id 78A708D0005; Sun, 5 Jun 2022 23:25:10 -0400 (EDT) X-Delivered-To: int-list-linux-mm@kvack.org Received: by kanga.kvack.org (Postfix, from userid 63042) id 69E5E8D0006; Sun, 5 Jun 2022 23:25:10 -0400 (EDT) X-Delivered-To: linux-mm@kvack.org Received: from relay.hostedemail.com (smtprelay0013.hostedemail.com [216.40.44.13]) by kanga.kvack.org (Postfix) with ESMTP id 56BAE8D0005 for ; Sun, 5 Jun 2022 23:25:10 -0400 (EDT) Received: from smtpin10.hostedemail.com (a10.router.float.18 [10.200.18.1]) by unirelay11.hostedemail.com (Postfix) with ESMTP id 301A6803CE for ; Mon, 6 Jun 2022 03:25:10 +0000 (UTC) X-FDA: 79546369980.10.D137D0E Received: from szxga02-in.huawei.com (szxga02-in.huawei.com [45.249.212.188]) by imf04.hostedemail.com (Postfix) with ESMTP id 5659B40039 for ; Mon, 6 Jun 2022 03:24:47 +0000 (UTC) Received: from dggpemm500022.china.huawei.com (unknown [172.30.72.57]) by szxga02-in.huawei.com (SkyGuard) with ESMTP id 4LGf2z0V6bzjXDJ; Mon, 6 Jun 2022 11:23:39 +0800 (CST) Received: from dggpemm500002.china.huawei.com (7.185.36.229) by dggpemm500022.china.huawei.com (7.185.36.162) with Microsoft SMTP Server (version=TLS1_2, cipher=TLS_ECDHE_RSA_WITH_AES_128_GCM_SHA256) id 15.1.2375.24; Mon, 6 Jun 2022 11:24:56 +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; Mon, 6 Jun 2022 11:24:55 +0800 From: Chen Wandun To: , , , , , , CC: Subject: [PATCH v3 3/3] mm/shmem: rework calculation of inflated_addr in shmem_get_unmapped_area Date: Mon, 6 Jun 2022 11:45:30 +0800 Message-ID: <20220606034530.153505-4-chenwandun@huawei.com> X-Mailer: git-send-email 2.25.1 In-Reply-To: <20220606034530.153505-1-chenwandun@huawei.com> References: <20220606034530.153505-1-chenwandun@huawei.com> MIME-Version: 1.0 X-Originating-IP: [10.175.112.125] X-ClientProxiedBy: dggems701-chm.china.huawei.com (10.3.19.178) To dggpemm500002.china.huawei.com (7.185.36.229) X-CFilter-Loop: Reflected X-Rspamd-Server: rspam07 X-Rspamd-Queue-Id: 5659B40039 X-Stat-Signature: oeif71w9qygo6mh3fg3k6z7z7qry8hi3 X-Rspam-User: Authentication-Results: imf04.hostedemail.com; dkim=none; spf=pass (imf04.hostedemail.com: domain of chenwandun@huawei.com designates 45.249.212.188 as permitted sender) smtp.mailfrom=chenwandun@huawei.com; dmarc=pass (policy=quarantine) header.from=huawei.com X-HE-Tag: 1654485887-238655 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 48b7172f81d6..ac277b11bdfa 100644 --- a/mm/shmem.c +++ b/mm/shmem.c @@ -2200,9 +2200,12 @@ 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;