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[209.132.183.28]) by mx.google.com with ESMTPS id d27si2083937qtk.55.2019.02.21.10.19.42 for (version=TLS1_2 cipher=ECDHE-RSA-AES128-GCM-SHA256 bits=128/128); Thu, 21 Feb 2019 10:19:42 -0800 (PST) Received-SPF: pass (google.com: domain of jglisse@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 jglisse@redhat.com designates 209.132.183.28 as permitted sender) smtp.mailfrom=jglisse@redhat.com; dmarc=pass (p=NONE sp=NONE dis=NONE) header.from=redhat.com Received: from smtp.corp.redhat.com (int-mx04.intmail.prod.int.phx2.redhat.com [10.5.11.14]) (using TLSv1.2 with cipher AECDH-AES256-SHA (256/256 bits)) (No client certificate requested) by mx1.redhat.com (Postfix) with ESMTPS id 3E0B459452; Thu, 21 Feb 2019 18:19:41 +0000 (UTC) Received: from redhat.com (unknown [10.20.6.236]) by smtp.corp.redhat.com (Postfix) with ESMTPS id 932D95D9D3; Thu, 21 Feb 2019 18:19:33 +0000 (UTC) Date: Thu, 21 Feb 2019 13:19:32 -0500 From: Jerome Glisse To: Peter Xu Cc: linux-mm@kvack.org, linux-kernel@vger.kernel.org, David Hildenbrand , Hugh Dickins , Maya Gokhale , Pavel Emelyanov , Johannes Weiner , Martin Cracauer , Shaohua Li , Marty McFadden , Andrea Arcangeli , Mike Kravetz , Denis Plotnikov , Mike Rapoport , Mel Gorman , "Kirill A . Shutemov" , "Dr . David Alan Gilbert" Subject: Re: [PATCH v2 19/26] userfaultfd: introduce helper vma_find_uffd Message-ID: <20190221181931.GS2813@redhat.com> References: <20190212025632.28946-1-peterx@redhat.com> <20190212025632.28946-20-peterx@redhat.com> MIME-Version: 1.0 Content-Type: text/plain; charset=iso-8859-1 Content-Disposition: inline Content-Transfer-Encoding: 8bit In-Reply-To: <20190212025632.28946-20-peterx@redhat.com> User-Agent: Mutt/1.10.0 (2018-05-17) X-Scanned-By: MIMEDefang 2.79 on 10.5.11.14 X-Greylist: Sender IP whitelisted, not delayed by milter-greylist-4.5.16 (mx1.redhat.com [10.5.110.39]); Thu, 21 Feb 2019 18:19:41 +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: On Tue, Feb 12, 2019 at 10:56:25AM +0800, Peter Xu wrote: > 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 Reviewed-by: Jérôme Glisse > --- > 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 >