From nobody Mon Feb 9 23:00:25 2026 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 vger.kernel.org (vger.kernel.org [23.128.96.18]) by smtp.lore.kernel.org (Postfix) with ESMTP id F2CA8C6FD1F for ; Sat, 25 Mar 2023 06:56:24 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S231862AbjCYG4X (ORCPT ); Sat, 25 Mar 2023 02:56:23 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:43068 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S231772AbjCYG4T (ORCPT ); Sat, 25 Mar 2023 02:56:19 -0400 Received: from szxga02-in.huawei.com (szxga02-in.huawei.com [45.249.212.188]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id D9CEA15570 for ; Fri, 24 Mar 2023 23:56:18 -0700 (PDT) Received: from kwepemm600020.china.huawei.com (unknown [172.30.72.57]) by szxga02-in.huawei.com (SkyGuard) with ESMTP id 4Pk8sW1n6VzSnxP; Sat, 25 Mar 2023 14:52:47 +0800 (CST) Received: from localhost.localdomain (10.175.112.125) by kwepemm600020.china.huawei.com (7.193.23.147) with Microsoft SMTP Server (version=TLS1_2, cipher=TLS_ECDHE_RSA_WITH_AES_128_GCM_SHA256) id 15.1.2507.21; Sat, 25 Mar 2023 14:56:15 +0800 From: Peng Zhang To: , , , CC: , , , , , , ZhangPeng Subject: [PATCH v3 2/6] userfaultfd: use kmap_local_page() in copy_huge_page_from_user() Date: Sat, 25 Mar 2023 14:56:04 +0800 Message-ID: <20230325065608.601391-3-zhangpeng362@huawei.com> X-Mailer: git-send-email 2.25.1 In-Reply-To: <20230325065608.601391-1-zhangpeng362@huawei.com> References: <20230325065608.601391-1-zhangpeng362@huawei.com> MIME-Version: 1.0 Content-Transfer-Encoding: quoted-printable X-Originating-IP: [10.175.112.125] X-ClientProxiedBy: dggems705-chm.china.huawei.com (10.3.19.182) To kwepemm600020.china.huawei.com (7.193.23.147) X-CFilter-Loop: Reflected Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Type: text/plain; charset="utf-8" From: ZhangPeng kmap() and kmap_atomic() are being deprecated in favor of kmap_local_page() which is appropriate for any thread local context.[1] Let's replace the kmap() and kmap_atomic() with kmap_local_page() in copy_huge_page_from_user(). When allow_pagefault is false, disable page faults to prevent potential deadlock.[2] [1] https://lore.kernel.org/all/20220813220034.806698-1-ira.weiny@intel.com/ [2] https://lkml.kernel.org/r/20221025220136.2366143-1-ira.weiny@intel.com Signed-off-by: ZhangPeng --- mm/memory.c | 14 ++++++-------- 1 file changed, 6 insertions(+), 8 deletions(-) diff --git a/mm/memory.c b/mm/memory.c index f456f3b5049c..062bd215bea8 100644 --- a/mm/memory.c +++ b/mm/memory.c @@ -5781,16 +5781,14 @@ long copy_huge_page_from_user(struct page *dst_page, =20 for (i =3D 0; i < pages_per_huge_page; i++) { subpage =3D nth_page(dst_page, i); - if (allow_pagefault) - page_kaddr =3D kmap(subpage); - else - page_kaddr =3D kmap_atomic(subpage); + page_kaddr =3D kmap_local_page(subpage); + if (!allow_pagefault) + pagefault_disable(); rc =3D copy_from_user(page_kaddr, usr_src + i * PAGE_SIZE, PAGE_SIZE); - if (allow_pagefault) - kunmap(subpage); - else - kunmap_atomic(page_kaddr); + if (!allow_pagefault) + pagefault_enable(); + kunmap_local(page_kaddr); =20 ret_val -=3D (PAGE_SIZE - rc); if (rc) --=20 2.25.1