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[2003:cb:c707:9d00:9303:90ce:6dcb:2bc9]) by smtp.gmail.com with ESMTPSA id l18-20020a1c7912000000b003db00747fdesm13592874wme.15.2023.01.24.06.52.52 (version=TLS1_3 cipher=TLS_AES_128_GCM_SHA256 bits=128/128); Tue, 24 Jan 2023 06:52:53 -0800 (PST) Message-ID: Date: Tue, 24 Jan 2023 15:52:52 +0100 MIME-Version: 1.0 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:102.0) Gecko/20100101 Thunderbird/102.6.0 To: David Howells Cc: Al Viro , Christoph Hellwig , Matthew Wilcox , Jens Axboe , Jan Kara , Jeff Layton , Logan Gunthorpe , linux-fsdevel@vger.kernel.org, linux-block@vger.kernel.org, linux-kernel@vger.kernel.org, Christoph Hellwig , John Hubbard , linux-mm@kvack.org References: <5bc85aff-e21e-ab83-d47a-e7b7c1081ab0@redhat.com> <1b1eb3d8-c6b4-b264-1baa-1b3eb088173d@redhat.com> <20230123173007.325544-1-dhowells@redhat.com> <20230123173007.325544-3-dhowells@redhat.com> <874093.1674570959@warthog.procyon.org.uk> <874737.1674571549@warthog.procyon.org.uk> From: David Hildenbrand Organization: Red Hat Subject: Re: [PATCH v8 02/10] iov_iter: Add a function to extract a page list from an iterator In-Reply-To: <874737.1674571549@warthog.procyon.org.uk> X-Mimecast-Spam-Score: 0 X-Mimecast-Originator: redhat.com Content-Language: en-US Content-Type: text/plain; charset=UTF-8; format=flowed Content-Transfer-Encoding: 7bit X-Rspam-User: X-Rspamd-Server: rspam03 X-Stat-Signature: wgxipcrnr8ti1sd6cw7cc7h53tmck9cy X-Rspamd-Queue-Id: D6F188001F X-HE-Tag: 1674571978-942220 X-HE-Meta: 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 gZ1/P8Ex 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 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 24.01.23 15:45, David Howells wrote: > David Hildenbrand wrote: > >> At least reduces the occurrences of FOLL_PIN :) > > I don't see where the problem is in letting people supply FOLL_PIN or > FOLL_GET. Why even have pin_user_pages() and get_user_pages() since they end > up at the same place. They should be inline wrappers, if separate functions > at all. There once was a proposed goal of restricting FOLL_GET to core-mm and allowing other drivers etc. to only use FOLL_PIN. Providing pin_user_pages() and the corresponding unpin part seemed very clean to me. To me that makes perfect sense and will prevent any misuse once we converted everything relevant to FOLL_PIN. To be precise, I think we could get away in this patch set by not using FOLL_PIN and FOLL_GET and it wouldn't really reduce readability of the code ... -- Thanks, David / dhildenb