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[47.55.122.23]) by smtp.gmail.com with ESMTPSA id n7-20020ac86747000000b00399ad646794sm9480378qtp.41.2022.11.16.16.45.22 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Wed, 16 Nov 2022 16:45:22 -0800 (PST) Received: from jgg by wakko with local (Exim 4.95) (envelope-from ) id 1ovT1t-0066TN-E8; Wed, 16 Nov 2022 20:45:21 -0400 Date: Wed, 16 Nov 2022 20:45:21 -0400 From: Jason Gunthorpe To: David Hildenbrand Subject: Re: [PATCH mm-unstable v1 10/20] RDMA/umem: remove FOLL_FORCE usage Message-ID: References: <20221116102659.70287-1-david@redhat.com> <20221116102659.70287-11-david@redhat.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20221116102659.70287-11-david@redhat.com> X-BeenThere: linuxppc-dev@lists.ozlabs.org X-Mailman-Version: 2.1.29 Precedence: list List-Id: Linux on PowerPC Developers Mail List List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Cc: linux-ia64@vger.kernel.org, Greg Kroah-Hartman , dri-devel@lists.freedesktop.org, linux-kernel@vger.kernel.org, linux-mm@kvack.org, Nadav Amit , linux-kselftest@vger.kernel.org, sparclinux@vger.kernel.org, Shuah Khan , Andrea Arcangeli , linux-samsung-soc@vger.kernel.org, Leon Romanovsky , linux-rdma@vger.kernel.org, David Airlie , x86@kernel.org, Hugh Dickins , Matthew Wilcox , Christoph Hellwig , Vlastimil Babka , linux-media@vger.kernel.org, Arnd Bergmann , John Hubbard , linux-um@lists.infradead.org, etnaviv@lists.freedesktop.org, Alex Williamson , Peter Xu , Muchun Song , linux-arm-kernel@lists.infradead.org, linuxppc-dev@lists.ozlabs.org, Oded Gabbay , lin ux-mips@vger.kernel.org, linux-perf-users@vger.kernel.org, linux-security-module@vger.kernel.org, linux-alpha@vger.kernel.org, linux-fsdevel@vger.kernel.org, Andrew Morton , Lucas Stach , Linus Torvalds , Leon Romanovsky , Mike Kravetz Errors-To: linuxppc-dev-bounces+linuxppc-dev=archiver.kernel.org@lists.ozlabs.org Sender: "Linuxppc-dev" On Wed, Nov 16, 2022 at 11:26:49AM +0100, David Hildenbrand wrote: > GUP now supports reliable R/O long-term pinning in COW mappings, such > that we break COW early. MAP_SHARED VMAs only use the shared zeropage so > far in one corner case (DAXFS file with holes), which can be ignored > because GUP does not support long-term pinning in fsdax (see > check_vma_flags()). > > Consequently, FOLL_FORCE | FOLL_WRITE | FOLL_LONGTERM is no longer required > for reliable R/O long-term pinning: FOLL_LONGTERM is sufficient. So stop > using FOLL_FORCE, which is really only for ptrace access. > > Tested-by: Leon Romanovsky # Over mlx4 and mlx5. > Cc: Jason Gunthorpe > Cc: Leon Romanovsky > Signed-off-by: David Hildenbrand > --- > drivers/infiniband/core/umem.c | 8 ++++---- > 1 file changed, 4 insertions(+), 4 deletions(-) Reviewed-by: Jason Gunthorpe Jason