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[209.132.183.28]) by mx.google.com with ESMTPS id g35si4805492qvg.175.2019.02.21.09.29.24 for (version=TLS1_2 cipher=ECDHE-RSA-AES128-GCM-SHA256 bits=128/128); Thu, 21 Feb 2019 09:29:24 -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-mx08.intmail.prod.int.phx2.redhat.com [10.5.11.23]) (using TLSv1.2 with cipher AECDH-AES256-SHA (256/256 bits)) (No client certificate requested) by mx1.redhat.com (Postfix) with ESMTPS id A128430821BE; Thu, 21 Feb 2019 17:29:23 +0000 (UTC) Received: from redhat.com (unknown [10.20.6.236]) by smtp.corp.redhat.com (Postfix) with ESMTPS id 79F0319C58; Thu, 21 Feb 2019 17:29:21 +0000 (UTC) Date: Thu, 21 Feb 2019 12:29:19 -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 10/26] userfaultfd: wp: add UFFDIO_COPY_MODE_WP Message-ID: <20190221172919.GJ2813@redhat.com> References: <20190212025632.28946-1-peterx@redhat.com> <20190212025632.28946-11-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: <20190212025632.28946-11-peterx@redhat.com> User-Agent: Mutt/1.10.0 (2018-05-17) X-Scanned-By: MIMEDefang 2.84 on 10.5.11.23 X-Greylist: Sender IP whitelisted, not delayed by milter-greylist-4.5.16 (mx1.redhat.com [10.5.110.47]); Thu, 21 Feb 2019 17:29:23 +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 10:56:16AM +0800, Peter Xu wrote: > From: Andrea Arcangeli > > This allows UFFDIO_COPY to map pages wrprotected. > > Signed-off-by: Andrea Arcangeli > Signed-off-by: Peter Xu Minor nitpick down below, but in any case: Reviewed-by: Jérôme Glisse > --- > fs/userfaultfd.c | 5 +++-- > include/linux/userfaultfd_k.h | 2 +- > include/uapi/linux/userfaultfd.h | 11 +++++----- > mm/userfaultfd.c | 36 ++++++++++++++++++++++---------- > 4 files changed, 35 insertions(+), 19 deletions(-) > [...] > diff --git a/mm/userfaultfd.c b/mm/userfaultfd.c > index d59b5a73dfb3..73a208c5c1e7 100644 > --- a/mm/userfaultfd.c > +++ b/mm/userfaultfd.c > @@ -25,7 +25,8 @@ static int mcopy_atomic_pte(struct mm_struct *dst_mm, > struct vm_area_struct *dst_vma, > unsigned long dst_addr, > unsigned long src_addr, > - struct page **pagep) > + struct page **pagep, > + bool wp_copy) > { > struct mem_cgroup *memcg; > pte_t _dst_pte, *dst_pte; > @@ -71,9 +72,9 @@ static int mcopy_atomic_pte(struct mm_struct *dst_mm, > if (mem_cgroup_try_charge(page, dst_mm, GFP_KERNEL, &memcg, false)) > goto out_release; > > - _dst_pte = mk_pte(page, dst_vma->vm_page_prot); > - if (dst_vma->vm_flags & VM_WRITE) > - _dst_pte = pte_mkwrite(pte_mkdirty(_dst_pte)); > + _dst_pte = pte_mkdirty(mk_pte(page, dst_vma->vm_page_prot)); > + if (dst_vma->vm_flags & VM_WRITE && !wp_copy) > + _dst_pte = pte_mkwrite(_dst_pte); I like parenthesis around around and :) ie: (dst_vma->vm_flags & VM_WRITE) && !wp_copy I feel it is easier to read. [...] > @@ -416,11 +418,13 @@ static __always_inline ssize_t mfill_atomic_pte(struct mm_struct *dst_mm, > if (!(dst_vma->vm_flags & VM_SHARED)) { > if (!zeropage) > err = mcopy_atomic_pte(dst_mm, dst_pmd, dst_vma, > - dst_addr, src_addr, page); > + dst_addr, src_addr, page, > + wp_copy); > else > err = mfill_zeropage_pte(dst_mm, dst_pmd, > dst_vma, dst_addr); > } else { > + VM_WARN_ON(wp_copy); /* WP only available for anon */ Don't you want to return with error here ? > if (!zeropage) > err = shmem_mcopy_atomic_pte(dst_mm, dst_pmd, > dst_vma, dst_addr, [...]