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[2003:cb:c708:db00:6510:da8d:df40:abbb]) by smtp.gmail.com with ESMTPSA id n10-20020a5d420a000000b0023682011c1dsm9563940wrq.104.2022.11.08.01.29.18 (version=TLS1_3 cipher=TLS_AES_128_GCM_SHA256 bits=128/128); Tue, 08 Nov 2022 01:29:19 -0800 (PST) Message-ID: Date: Tue, 8 Nov 2022 10:29:17 +0100 MIME-Version: 1.0 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:102.0) Gecko/20100101 Thunderbird/102.4.0 Subject: Re: [PATCH RFC 00/19] mm/gup: remove FOLL_FORCE usage from drivers (reliable R/O long-term pinning) To: Linus Torvalds Cc: linux-kernel@vger.kernel.org, linux-mm@kvack.org, etnaviv@lists.freedesktop.org, dri-devel@lists.freedesktop.org, linux-arm-kernel@lists.infradead.org, linux-samsung-soc@vger.kernel.org, linux-rdma@vger.kernel.org, linux-media@vger.kernel.org, linux-kselftest@vger.kernel.org, Andrew Morton , Jason Gunthorpe , John Hubbard , Peter Xu , Greg Kroah-Hartman , Andrea Arcangeli , Hugh Dickins , Nadav Amit , Vlastimil Babka , Matthew Wilcox , Mike Kravetz , Muchun Song , Lucas Stach , David Airlie , Oded Gabbay , Arnd Bergmann References: <20221107161740.144456-1-david@redhat.com> Content-Language: en-US From: David Hildenbrand Organization: Red Hat In-Reply-To: Content-Type: text/plain; charset=UTF-8; format=flowed Content-Transfer-Encoding: 7bit Precedence: bulk List-ID: X-Mailing-List: linux-rdma@vger.kernel.org On 07.11.22 18:27, Linus Torvalds wrote: > On Mon, Nov 7, 2022 at 8:18 AM David Hildenbrand wrote: >> >> So instead, make R/O long-term pinning work as expected, by breaking COW >> in a COW mapping early, such that we can remove any FOLL_FORCE usage from >> drivers. > > Nothing makes me unhappy from a quick scan through these patches. > > And I'd really love to just have this long saga ended, and FOLL_FORCE > finally relegated to purely ptrace accesses. > > So an enthusiastic Ack from me. Thanks Linus! My hope is that we can remove it from all drivers and not have to leave it in for some corner cases; so far it looks promising. -- Thanks, David / dhildenb