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[2003:cb:c715:ee00:4e24:cf8e:3de0:8819]) by smtp.gmail.com with ESMTPSA id l1-20020a5d4bc1000000b00323287186b2sm1615554wrt.29.2023.10.06.05.56.59 (version=TLS1_3 cipher=TLS_AES_128_GCM_SHA256 bits=128/128); Fri, 06 Oct 2023 05:57:00 -0700 (PDT) Message-ID: <387a6703-b8fb-d2ed-16b1-5264b2c901aa@redhat.com> Date: Fri, 6 Oct 2023 14:56:59 +0200 MIME-Version: 1.0 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:102.0) Gecko/20100101 Thunderbird/102.15.1 Subject: Re: [PATCH v2 3/4] mm/gup: make failure to pin an error if FOLL_NOWAIT not specified Content-Language: en-US To: Lorenzo Stoakes , linux-mm@kvack.org, linux-kernel@vger.kernel.org, Andrew Morton , Catalin Marinas , Will Deacon , Peter Zijlstra , Ingo Molnar , Arnaldo Carvalho de Melo , Mark Rutland Cc: Alexander Shishkin , Jiri Olsa , Namhyung Kim , Ian Rogers , Adrian Hunter , Oleg Nesterov , Richard Cochran , Jason Gunthorpe , John Hubbard , Arnd Bergmann References: <2a42d96dd1e37163f90a0019a541163dafb7e4c3.1696288092.git.lstoakes@gmail.com> From: David Hildenbrand Organization: Red Hat In-Reply-To: <2a42d96dd1e37163f90a0019a541163dafb7e4c3.1696288092.git.lstoakes@gmail.com> Content-Type: text/plain; charset=UTF-8; format=flowed Content-Transfer-Encoding: 7bit X-Spam-Status: No, score=-0.1 required=5.0 tests=DKIMWL_WL_HIGH,DKIM_SIGNED, DKIM_VALID,DKIM_VALID_AU,HEADER_FROM_DIFFERENT_DOMAINS, MAILING_LIST_MULTI,NICE_REPLY_A,RCVD_IN_SBL_CSS,SPF_HELO_NONE,SPF_PASS autolearn=unavailable autolearn_force=no version=3.4.6 X-Spam-Checker-Version: SpamAssassin 3.4.6 (2021-04-09) on lipwig.vger.email Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org X-Greylist: Sender passed SPF test, not delayed by milter-greylist-4.6.4 (lipwig.vger.email [0.0.0.0]); Fri, 06 Oct 2023 05:57:58 -0700 (PDT) On 03.10.23 01:14, Lorenzo Stoakes wrote: > There really should be no circumstances under which a non-FOLL_NOWAIT GUP > operation fails to return any pages, so make this an error and warn on it. > > To catch the trivial case, simply exit early if nr_pages == 0. > > This brings __get_user_pages_locked() in line with the behaviour of its > nommu variant. > > Reviewed-by: Arnd Bergmann > Signed-off-by: Lorenzo Stoakes > --- Reviewed-by: David Hildenbrand -- Cheers, David / dhildenb