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[209.132.183.28]) by mx.google.com with ESMTPS id h8si3902581qtb.258.2019.06.19.19.23.53 for (version=TLS1_2 cipher=ECDHE-RSA-AES128-GCM-SHA256 bits=128/128); Wed, 19 Jun 2019 19:23:54 -0700 (PDT) Received-SPF: pass (google.com: domain of peterx@redhat.com designates 209.132.183.28 as permitted sender) client-ip=209.132.183.28; Authentication-Results: mx.google.com; spf=pass (google.com: domain of peterx@redhat.com designates 209.132.183.28 as permitted sender) smtp.mailfrom=peterx@redhat.com; dmarc=pass (p=NONE sp=NONE dis=NONE) header.from=redhat.com Received: from smtp.corp.redhat.com (int-mx07.intmail.prod.int.phx2.redhat.com [10.5.11.22]) (using TLSv1.2 with cipher AECDH-AES256-SHA (256/256 bits)) (No client certificate requested) by mx1.redhat.com (Postfix) with ESMTPS id 1CF9B21BA4; Thu, 20 Jun 2019 02:23:53 +0000 (UTC) Received: from xz-x1.redhat.com (ovpn-12-78.pek2.redhat.com [10.72.12.78]) by smtp.corp.redhat.com (Postfix) with ESMTP id 89BBD1001E69; Thu, 20 Jun 2019 02:23:43 +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 , Denis Plotnikov , Shaohua Li , Andrea Arcangeli , Mike Kravetz , Marty McFadden , Mike Rapoport , Mel Gorman , "Kirill A . Shutemov" , "Dr . David Alan Gilbert" Subject: [PATCH v5 17/25] userfaultfd: introduce helper vma_find_uffd Date: Thu, 20 Jun 2019 10:20:00 +0800 Message-Id: <20190620022008.19172-18-peterx@redhat.com> In-Reply-To: <20190620022008.19172-1-peterx@redhat.com> References: <20190620022008.19172-1-peterx@redhat.com> MIME-Version: 1.0 X-Scanned-By: MIMEDefang 2.84 on 10.5.11.22 X-Greylist: Sender IP whitelisted, not delayed by milter-greylist-4.5.16 (mx1.redhat.com [10.5.110.30]); Thu, 20 Jun 2019 02:23:53 +0000 (UTC) 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: X-Virus-Scanned: ClamAV using ClamSMTP 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 Reviewed-by: Jerome Glisse Reviewed-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 5363376cb07a..6b9dd5b66f64 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)) @@ -487,20 +504,9 @@ 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; /*