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[2003:cb:c707:9d00:9303:90ce:6dcb:2bc9]) by smtp.gmail.com with ESMTPSA id t24-20020adfa2d8000000b002bdc129c8f6sm2020545wra.43.2023.01.24.06.37.43 (version=TLS1_3 cipher=TLS_AES_128_GCM_SHA256 bits=128/128); Tue, 24 Jan 2023 06:37:44 -0800 (PST) Message-ID: <5bc85aff-e21e-ab83-d47a-e7b7c1081ab0@redhat.com> Date: Tue, 24 Jan 2023 15:37:43 +0100 MIME-Version: 1.0 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:102.0) Gecko/20100101 Thunderbird/102.6.0 Subject: Re: [PATCH v8 02/10] iov_iter: Add a function to extract a page list from an iterator 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: <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> From: David Hildenbrand Organization: Red Hat In-Reply-To: <874093.1674570959@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-Queue-Id: 2AF1040017 X-Rspamd-Server: rspam01 X-Stat-Signature: y164ck3jot1qzk6dqciesiax6kx5tzhu X-HE-Tag: 1674571068-291500 X-HE-Meta: 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 9tsi0bdv 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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 15:35, David Howells wrote: > David Hildenbrand wrote: > >>> +#define iov_iter_extract_mode(iter) (user_backed_iter(iter) ? FOLL_PIN : 0) >>> + >> >> Does it make sense to move that to the patch where it is needed? (do we need >> it at all anymore?) > > Yes, we need something. Granted, there are now only two alternatives, not > three: either the pages are going to be pinned or they're not going to be > pinned, but I would rather have a specific function that tells you than just > use, say, user_backed_iter() to make it easier to adjust it later if we need > to - and easier to find the places where we need to adjust. > > But if it's preferred we could require people to use user_backed_iter() > instead. At least reduces the occurrences of FOLL_PIN :) -- Thanks, David / dhildenb