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[141.239.159.203]) by smtp.gmail.com with ESMTPSA id d9443c01a7336-1f72a6c5a5fsm39546885ad.233.2024.06.12.10.29.33 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Wed, 12 Jun 2024 10:29:33 -0700 (PDT) Sender: Tejun Heo Date: Wed, 12 Jun 2024 07:29:32 -1000 From: Tejun Heo To: Martin Oliveira Cc: linux-rdma@vger.kernel.org, linux-kernel@vger.kernel.org, linux-mm@kvack.org, Jason Gunthorpe , Leon Romanovsky , Greg Kroah-Hartman , Andrew Morton , Logan Gunthorpe , Mike Marciniszyn , Shiraz Saleem , Michael Guralnik , Artemy Kovalyov Subject: Re: [PATCH v2 1/4] kernfs: remove page_mkwrite() from vm_operations_struct Message-ID: References: <20240611182732.360317-1-martin.oliveira@eideticom.com> <20240611182732.360317-2-martin.oliveira@eideticom.com> Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20240611182732.360317-2-martin.oliveira@eideticom.com> On Tue, Jun 11, 2024 at 12:27:29PM -0600, Martin Oliveira wrote: > The .page_mkwrite operator of kernfs just calls file_update_time(). > This is the same behaviour that the fault code does if .page_mkwrite is > not set. > > Furthermore, having the page_mkwrite() operator causes > writable_file_mapping_allowed() to fail due to > vma_needs_dirty_tracking() on the gup flow, which is a pre-requisite for > enabling P2PDMA over RDMA. > > There are no users of .page_mkwrite and no known valid use cases, so > just remove the .page_mkwrite from kernfs_ops and return -EINVAL if an > mmap() implementation sets .page_mkwrite. > > Co-developed-by: Logan Gunthorpe > Signed-off-by: Logan Gunthorpe > Signed-off-by: Martin Oliveira Acked-by: Tejun Heo Thanks. -- tejun