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[209.132.183.28]) by mx.google.com with ESMTPS id k22si1267440qvg.31.2019.04.18.15.04.22 for (version=TLS1_2 cipher=ECDHE-RSA-AES128-GCM-SHA256 bits=128/128); Thu, 18 Apr 2019 15:04:22 -0700 (PDT) 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-mx03.intmail.prod.int.phx2.redhat.com [10.5.11.13]) (using TLSv1.2 with cipher AECDH-AES256-SHA (256/256 bits)) (No client certificate requested) by mx1.redhat.com (Postfix) with ESMTPS id F159830832D8; Thu, 18 Apr 2019 22:04:20 +0000 (UTC) Received: from redhat.com (unknown [10.20.6.236]) by smtp.corp.redhat.com (Postfix) with ESMTPS id 1648D60851; Thu, 18 Apr 2019 22:04:17 +0000 (UTC) Date: Thu, 18 Apr 2019 18:04:15 -0400 From: Jerome Glisse To: Laurent Dufour Cc: akpm@linux-foundation.org, mhocko@kernel.org, peterz@infradead.org, kirill@shutemov.name, ak@linux.intel.com, dave@stgolabs.net, jack@suse.cz, Matthew Wilcox , aneesh.kumar@linux.ibm.com, benh@kernel.crashing.org, mpe@ellerman.id.au, paulus@samba.org, Thomas Gleixner , Ingo Molnar , hpa@zytor.com, Will Deacon , Sergey Senozhatsky , sergey.senozhatsky.work@gmail.com, Andrea Arcangeli , Alexei Starovoitov , kemi.wang@intel.com, Daniel Jordan , David Rientjes , Ganesh Mahendran , Minchan Kim , Punit Agrawal , vinayak menon , Yang Shi , zhong jiang , Haiyan Song , Balbir Singh , sj38.park@gmail.com, Michel Lespinasse , Mike Rapoport , linux-kernel@vger.kernel.org, linux-mm@kvack.org, haren@linux.vnet.ibm.com, npiggin@gmail.com, paulmck@linux.vnet.ibm.com, Tim Chen , linuxppc-dev@lists.ozlabs.org, x86@kernel.org Subject: Re: [PATCH v12 05/31] mm: prepare for FAULT_FLAG_SPECULATIVE Message-ID: <20190418220415.GE11645@redhat.com> References: <20190416134522.17540-1-ldufour@linux.ibm.com> <20190416134522.17540-6-ldufour@linux.ibm.com> MIME-Version: 1.0 Content-Type: text/plain; charset=iso-8859-1 Content-Disposition: inline Content-Transfer-Encoding: 8bit In-Reply-To: <20190416134522.17540-6-ldufour@linux.ibm.com> User-Agent: Mutt/1.11.3 (2019-02-01) X-Scanned-By: MIMEDefang 2.79 on 10.5.11.13 X-Greylist: Sender IP whitelisted, not delayed by milter-greylist-4.5.16 (mx1.redhat.com [10.5.110.44]); Thu, 18 Apr 2019 22:04:21 +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, Apr 16, 2019 at 03:44:56PM +0200, Laurent Dufour wrote: > From: Peter Zijlstra > > When speculating faults (without holding mmap_sem) we need to validate > that the vma against which we loaded pages is still valid when we're > ready to install the new PTE. > > Therefore, replace the pte_offset_map_lock() calls that (re)take the > PTL with pte_map_lock() which can fail in case we find the VMA changed > since we started the fault. > > Signed-off-by: Peter Zijlstra (Intel) > > [Port to 4.12 kernel] > [Remove the comment about the fault_env structure which has been > implemented as the vm_fault structure in the kernel] > [move pte_map_lock()'s definition upper in the file] > [move the define of FAULT_FLAG_SPECULATIVE later in the series] > [review error path in do_swap_page(), do_anonymous_page() and > wp_page_copy()] > Signed-off-by: Laurent Dufour Reviewed-by: Jérôme Glisse > --- > mm/memory.c | 87 +++++++++++++++++++++++++++++++++++------------------ > 1 file changed, 58 insertions(+), 29 deletions(-) > > diff --git a/mm/memory.c b/mm/memory.c > index c6ddadd9d2b7..fc3698d13cb5 100644 > --- a/mm/memory.c > +++ b/mm/memory.c > @@ -2073,6 +2073,13 @@ int apply_to_page_range(struct mm_struct *mm, unsigned long addr, > } > EXPORT_SYMBOL_GPL(apply_to_page_range); > > +static inline bool pte_map_lock(struct vm_fault *vmf) I am not fan of the name maybe pte_offset_map_lock_if_valid() ? But that just a taste thing. So feel free to ignore this comment. > +{ > + vmf->pte = pte_offset_map_lock(vmf->vma->vm_mm, vmf->pmd, > + vmf->address, &vmf->ptl); > + return true; > +} > + > /* > * handle_pte_fault chooses page fault handler according to an entry which was > * read non-atomically. Before making any commitment, on those architectures