From nobody Thu Dec 18 18:51:52 2025 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 31891C7619A for ; Sat, 15 Apr 2023 09:08:56 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S229911AbjDOJIw (ORCPT ); Sat, 15 Apr 2023 05:08:52 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:37294 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S229931AbjDOJIp (ORCPT ); Sat, 15 Apr 2023 05:08:45 -0400 Received: from mail-wm1-x331.google.com (mail-wm1-x331.google.com [IPv6:2a00:1450:4864:20::331]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 3B4545B8F for ; Sat, 15 Apr 2023 02:08:44 -0700 (PDT) Received: by mail-wm1-x331.google.com with SMTP id 5b1f17b1804b1-3f09df54430so1972465e9.1 for ; Sat, 15 Apr 2023 02:08:44 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=20221208; t=1681549722; x=1684141722; h=content-transfer-encoding:mime-version:references:in-reply-to :message-id:date:subject:cc:to:from:from:to:cc:subject:date :message-id:reply-to; bh=N3KXMf3LCMhF+M2dvABgEBrAeCcDHD/N5/gKopMor18=; b=SYa2oo+tbd38XlYtz/d6/e4pzQ6P9G6OsJ4dhx3B8+SYR/d9O8tSkD2RPu9kJexrpZ i26FJrReB1ZKb/fpTLOOe4FKafPWtUANQys34PP6Hnve60y2Edj85EK6A8FT939vLW7t o6ImUDfeJQnyy7P8bgYoVtDkMFNfwWzWzKnP/Wz49VshkCfOapwdRglzz4DIe/Plmpod LFm6mrdZ0ZmnCmhhSbSkELW3VN2PopBHBPlJyrHZEdjrruFmqrfV9Kpe6V2rBm5oVmdm St4ps/8jKsHniSU28kM6ig2cNONUd5+UmdF5K+kJ4vQvz5Am44dTz2FexI5QiejlF0Tb tCFw== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20221208; t=1681549722; x=1684141722; h=content-transfer-encoding:mime-version:references:in-reply-to :message-id:date:subject:cc:to:from:x-gm-message-state:from:to:cc :subject:date:message-id:reply-to; bh=N3KXMf3LCMhF+M2dvABgEBrAeCcDHD/N5/gKopMor18=; b=Z5D/iM8s/YGmVCJVKScKMNuhTKWumH9aTllqbZc6DJz99DalMtsBSQvR2+vQxWlTyy OWDQGcbpTgYDO9et1SLMDirZMhSX+hNl5qitmqyLghEiovF4W48rg4OSfyY66I8O139y iDFO1hoiX0dZetl0u5Esho6i7eKlcI8BQli7ixP4zDbHMgD0ZeirnTGdm49CELlZrdSq NAesyBGVuBQkNZoGrlliqqO7m2TBtUl0DtxC5AXJl84s8/UVevEKmhn7ipqgXL69vgyz d7fXVmEIAEh+Xfhr+AY260cAPCM1Fvh7vMUcntsjXRAzEjYOzDKZwjNlEIMdz/gHiuu0 O3/g== X-Gm-Message-State: AAQBX9dDUud4fQ/rlKsU/jivohga7I0+qrOHsOGGJFrehwdS6TgbZ+xk T/wcBkdyzGo57TR4Vdq9j6E= X-Google-Smtp-Source: AKy350YaMFKbNrifL4gowACdl7mWvuAicO7Q3u/ayqigKnCZIONTCLQFkFKBA27JxTqB3gMFabKuyA== X-Received: by 2002:a5d:4c4d:0:b0:2cf:e67c:8245 with SMTP id n13-20020a5d4c4d000000b002cfe67c8245mr1122023wrt.44.1681549722284; Sat, 15 Apr 2023 02:08:42 -0700 (PDT) Received: from lucifer.home ([2a00:23c5:dc8c:8701:1663:9a35:5a7b:1d76]) by smtp.googlemail.com with ESMTPSA id r16-20020a056000015000b002f21a96c161sm5364756wrx.70.2023.04.15.02.08.41 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Sat, 15 Apr 2023 02:08:41 -0700 (PDT) From: Lorenzo Stoakes To: linux-mm@kvack.org, linux-kernel@vger.kernel.org, Andrew Morton Cc: Matthew Wilcox , David Hildenbrand , Lorenzo Stoakes Subject: [PATCH v2 4/7] mm/gup: introduce the FOLL_SAME_FILE GUP flag Date: Sat, 15 Apr 2023 10:08:39 +0100 Message-Id: <45702c7b87c8487455783b482b67dfcf2d24e6a9.1681547405.git.lstoakes@gmail.com> X-Mailer: git-send-email 2.40.0 In-Reply-To: References: MIME-Version: 1.0 Content-Transfer-Encoding: quoted-printable Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Type: text/plain; charset="utf-8" This flag causes GUP to assert that all VMAs within the input range possess the same vma->vm_file. If not, the operation fails. This is part of a patch series which eliminates the vmas parameter from the GUP API, implementing the one remaining assertion within the entire kernel that requires access to the VMAs associated with a GUP range. Signed-off-by: Lorenzo Stoakes --- include/linux/mm_types.h | 2 ++ mm/gup.c | 16 ++++++++++++---- 2 files changed, 14 insertions(+), 4 deletions(-) diff --git a/include/linux/mm_types.h b/include/linux/mm_types.h index 3fc9e680f174..84d1aec9dbab 100644 --- a/include/linux/mm_types.h +++ b/include/linux/mm_types.h @@ -1185,6 +1185,8 @@ enum { FOLL_PCI_P2PDMA =3D 1 << 10, /* allow interrupts from generic signals */ FOLL_INTERRUPTIBLE =3D 1 << 11, + /* assert that the range spans VMAs with the same vma->vm_file */ + FOLL_SAME_FILE =3D 1 << 12, =20 /* See also internal only FOLL flags in mm/internal.h */ }; diff --git a/mm/gup.c b/mm/gup.c index 9440aa54c741..3954ce499a4a 100644 --- a/mm/gup.c +++ b/mm/gup.c @@ -959,7 +959,8 @@ static int faultin_page(struct vm_area_struct *vma, return 0; } =20 -static int check_vma_flags(struct vm_area_struct *vma, unsigned long gup_f= lags) +static int check_vma_flags(struct vm_area_struct *vma, struct file *file, + unsigned long gup_flags) { vm_flags_t vm_flags =3D vma->vm_flags; int write =3D (gup_flags & FOLL_WRITE); @@ -968,7 +969,7 @@ static int check_vma_flags(struct vm_area_struct *vma, = unsigned long gup_flags) if (vm_flags & (VM_IO | VM_PFNMAP)) return -EFAULT; =20 - if (gup_flags & FOLL_ANON && !vma_is_anonymous(vma)) + if ((gup_flags & FOLL_ANON) && !vma_is_anonymous(vma)) return -EFAULT; =20 if ((gup_flags & FOLL_LONGTERM) && vma_is_fsdax(vma)) @@ -977,6 +978,9 @@ static int check_vma_flags(struct vm_area_struct *vma, = unsigned long gup_flags) if (vma_is_secretmem(vma)) return -EFAULT; =20 + if ((gup_flags & FOLL_SAME_FILE) && vma->vm_file !=3D file) + return -EFAULT; + if (write) { if (!(vm_flags & VM_WRITE)) { if (!(gup_flags & FOLL_FORCE)) @@ -1081,6 +1085,7 @@ static long __get_user_pages(struct mm_struct *mm, long ret =3D 0, i =3D 0; struct vm_area_struct *vma =3D NULL; struct follow_page_context ctx =3D { NULL }; + struct file *file =3D NULL; =20 if (!nr_pages) return 0; @@ -1111,10 +1116,13 @@ static long __get_user_pages(struct mm_struct *mm, ret =3D -EFAULT; goto out; } - ret =3D check_vma_flags(vma, gup_flags); + ret =3D check_vma_flags(vma, i =3D=3D 0 ? vma->vm_file : file, + gup_flags); if (ret) goto out; =20 + file =3D vma->vm_file; + if (is_vm_hugetlb_page(vma)) { i =3D follow_hugetlb_page(mm, vma, pages, vmas, &start, &nr_pages, i, @@ -1595,7 +1603,7 @@ long faultin_vma_page_range(struct vm_area_struct *vm= a, unsigned long start, * We want to report -EINVAL instead of -EFAULT for any permission * problems or incompatible mappings. */ - if (check_vma_flags(vma, gup_flags)) + if (check_vma_flags(vma, vma->vm_file, gup_flags)) return -EINVAL; =20 ret =3D __get_user_pages(mm, start, nr_pages, gup_flags, --=20 2.40.0