From nobody Mon Feb 9 16:51:35 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 DB138C77B61 for ; Mon, 10 Apr 2023 13:39:48 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S229773AbjDJNjr (ORCPT ); Mon, 10 Apr 2023 09:39:47 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:59868 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S229536AbjDJNjp (ORCPT ); Mon, 10 Apr 2023 09:39:45 -0400 Received: from szxga03-in.huawei.com (szxga03-in.huawei.com [45.249.212.189]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 420D94C09 for ; Mon, 10 Apr 2023 06:39:44 -0700 (PDT) Received: from kwepemm600020.china.huawei.com (unknown [172.30.72.56]) by szxga03-in.huawei.com (SkyGuard) with ESMTP id 4Pw96q713xzKrfJ; Mon, 10 Apr 2023 21:38:59 +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 15.1.2507.23; Mon, 10 Apr 2023 21:39:41 +0800 From: Peng Zhang To: , , , , , , CC: , , , ZhangPeng Subject: [PATCH v6 2/6] userfaultfd: use kmap_local_page() in copy_huge_page_from_user() Date: Mon, 10 Apr 2023 21:39:28 +0800 Message-ID: <20230410133932.32288-3-zhangpeng362@huawei.com> X-Mailer: git-send-email 2.25.1 In-Reply-To: <20230410133932.32288-1-zhangpeng362@huawei.com> References: <20230410133932.32288-1-zhangpeng362@huawei.com> MIME-Version: 1.0 Content-Transfer-Encoding: quoted-printable X-Originating-IP: [10.175.112.125] X-ClientProxiedBy: dggems702-chm.china.huawei.com (10.3.19.179) 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 Reviewed-by: Mike Kravetz --- mm/memory.c | 14 ++++++-------- 1 file changed, 6 insertions(+), 8 deletions(-) diff --git a/mm/memory.c b/mm/memory.c index 387226d6094d..808f354bce65 100644 --- a/mm/memory.c +++ b/mm/memory.c @@ -5880,16 +5880,14 @@ 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