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[142.162.115.133]) by smtp.gmail.com with ESMTPSA id c5sm9349747qkg.99.2021.02.05.05.49.27 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Fri, 05 Feb 2021 05:49:27 -0800 (PST) Received: from jgg by mlx with local (Exim 4.94) (envelope-from ) id 1l81UF-003qUb-5e; Fri, 05 Feb 2021 09:49:27 -0400 Date: Fri, 5 Feb 2021 09:49:27 -0400 From: Jason Gunthorpe To: Paolo Bonzini Cc: linux-kernel@vger.kernel.org, kvm@vger.kernel.org, linux-mm@kvack.org, Andrew Morton , dan.j.williams@intel.com Subject: Re: [PATCH 1/2] mm: provide a sane PTE walking API for modules Message-ID: <20210205134927.GL4718@ziepe.ca> References: <20210205103259.42866-1-pbonzini@redhat.com> <20210205103259.42866-2-pbonzini@redhat.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20210205103259.42866-2-pbonzini@redhat.com> 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 Fri, Feb 05, 2021 at 05:32:58AM -0500, Paolo Bonzini wrote: > Currently, the follow_pfn function is exported for modules but > follow_pte is not. However, follow_pfn is very easy to misuse, > because it does not provide protections (so most of its callers > assume the page is writable!) and because it returns after having > already unlocked the page table lock. > > Provide instead a simplified version of follow_pte that does > not have the pmdpp and range arguments. The older version > survives as follow_invalidate_pte() for use by fs/dax.c. > > Signed-off-by: Paolo Bonzini > --- > arch/s390/pci/pci_mmio.c | 2 +- > fs/dax.c | 5 +++-- > include/linux/mm.h | 6 ++++-- > mm/memory.c | 35 ++++++++++++++++++++++++++++++----- > 4 files changed, 38 insertions(+), 10 deletions(-) Looks good to me, thanks Reviewed-by: Jason Gunthorpe Jason