From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-7.0 required=3.0 tests=HEADER_FROM_DIFFERENT_DOMAINS, INCLUDES_PATCH,MAILING_LIST_MULTI,SIGNED_OFF_BY,SPF_PASS autolearn=ham autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id 1DD3DC282CE for ; Tue, 12 Feb 2019 03:00:22 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id EADD821773 for ; Tue, 12 Feb 2019 03:00:21 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1728227AbfBLDAU (ORCPT ); Mon, 11 Feb 2019 22:00:20 -0500 Received: from mx1.redhat.com ([209.132.183.28]:34210 "EHLO mx1.redhat.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1726751AbfBLDAT (ORCPT ); Mon, 11 Feb 2019 22:00:19 -0500 Received: from smtp.corp.redhat.com (int-mx01.intmail.prod.int.phx2.redhat.com [10.5.11.11]) (using TLSv1.2 with cipher AECDH-AES256-SHA (256/256 bits)) (No client certificate requested) by mx1.redhat.com (Postfix) with ESMTPS id 0FC7D85362; Tue, 12 Feb 2019 03:00:19 +0000 (UTC) Received: from xz-x1.nay.redhat.com (dhcp-14-116.nay.redhat.com [10.66.14.116]) by smtp.corp.redhat.com (Postfix) with ESMTP id 15BC8600CC; Tue, 12 Feb 2019 03:00:12 +0000 (UTC) From: Peter Xu To: linux-mm@kvack.org, linux-kernel@vger.kernel.org Cc: David Hildenbrand , Hugh Dickins , Maya Gokhale , Jerome Glisse , Pavel Emelyanov , Johannes Weiner , peterx@redhat.com, Martin Cracauer , Shaohua Li , Marty McFadden , Andrea Arcangeli , Mike Kravetz , Denis Plotnikov , Mike Rapoport , Mel Gorman , "Kirill A . Shutemov" , "Dr . David Alan Gilbert" Subject: [PATCH v2 19/26] userfaultfd: introduce helper vma_find_uffd Date: Tue, 12 Feb 2019 10:56:25 +0800 Message-Id: <20190212025632.28946-20-peterx@redhat.com> In-Reply-To: <20190212025632.28946-1-peterx@redhat.com> References: <20190212025632.28946-1-peterx@redhat.com> X-Scanned-By: MIMEDefang 2.79 on 10.5.11.11 X-Greylist: Sender IP whitelisted, not delayed by milter-greylist-4.5.16 (mx1.redhat.com [10.5.110.25]); Tue, 12 Feb 2019 03:00:19 +0000 (UTC) Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org We've have multiple (and more coming) places that would like to find a userfault enabled VMA from a mm struct that covers a specific memory range. This patch introduce the helper for it, meanwhile apply it to the code. Suggested-by: Mike Rapoport Signed-off-by: Peter Xu --- mm/userfaultfd.c | 54 +++++++++++++++++++++++++++--------------------- 1 file changed, 30 insertions(+), 24 deletions(-) diff --git a/mm/userfaultfd.c b/mm/userfaultfd.c index 80bcd642911d..fefa81c301b7 100644 --- a/mm/userfaultfd.c +++ b/mm/userfaultfd.c @@ -20,6 +20,34 @@ #include #include "internal.h" +/* + * Find a valid userfault enabled VMA region that covers the whole + * address range, or NULL on failure. Must be called with mmap_sem + * held. + */ +static struct vm_area_struct *vma_find_uffd(struct mm_struct *mm, + unsigned long start, + unsigned long len) +{ + struct vm_area_struct *vma = find_vma(mm, start); + + if (!vma) + return NULL; + + /* + * Check the vma is registered in uffd, this is required to + * enforce the VM_MAYWRITE check done at uffd registration + * time. + */ + if (!vma->vm_userfaultfd_ctx.ctx) + return NULL; + + if (start < vma->vm_start || start + len > vma->vm_end) + return NULL; + + return vma; +} + static int mcopy_atomic_pte(struct mm_struct *dst_mm, pmd_t *dst_pmd, struct vm_area_struct *dst_vma, @@ -228,20 +256,9 @@ static __always_inline ssize_t __mcopy_atomic_hugetlb(struct mm_struct *dst_mm, */ if (!dst_vma) { err = -ENOENT; - dst_vma = find_vma(dst_mm, dst_start); + dst_vma = vma_find_uffd(dst_mm, dst_start, len); if (!dst_vma || !is_vm_hugetlb_page(dst_vma)) goto out_unlock; - /* - * Check the vma is registered in uffd, this is - * required to enforce the VM_MAYWRITE check done at - * uffd registration time. - */ - if (!dst_vma->vm_userfaultfd_ctx.ctx) - goto out_unlock; - - if (dst_start < dst_vma->vm_start || - dst_start + len > dst_vma->vm_end) - goto out_unlock; err = -EINVAL; if (vma_hpagesize != vma_kernel_pagesize(dst_vma)) @@ -488,20 +505,9 @@ static __always_inline ssize_t __mcopy_atomic(struct mm_struct *dst_mm, * both valid and fully within a single existing vma. */ err = -ENOENT; - dst_vma = find_vma(dst_mm, dst_start); + dst_vma = vma_find_uffd(dst_mm, dst_start, len); if (!dst_vma) goto out_unlock; - /* - * Check the vma is registered in uffd, this is required to - * enforce the VM_MAYWRITE check done at uffd registration - * time. - */ - if (!dst_vma->vm_userfaultfd_ctx.ctx) - goto out_unlock; - - if (dst_start < dst_vma->vm_start || - dst_start + len > dst_vma->vm_end) - goto out_unlock; err = -EINVAL; /* -- 2.17.1