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[216.228.121.143]) by mx.google.com with ESMTPS id j83si1834413ywa.51.2019.02.08.12.45.00 for (version=TLS1_2 cipher=ECDHE-RSA-AES128-GCM-SHA256 bits=128/128); Fri, 08 Feb 2019 12:45:00 -0800 (PST) Received-SPF: pass (google.com: domain of jhubbard@nvidia.com designates 216.228.121.143 as permitted sender) client-ip=216.228.121.143; Authentication-Results: mx.google.com; dkim=pass header.i=@nvidia.com header.s=n1 header.b=sAWi2INA; spf=pass (google.com: domain of jhubbard@nvidia.com designates 216.228.121.143 as permitted sender) smtp.mailfrom=jhubbard@nvidia.com; dmarc=pass (p=NONE sp=NONE dis=NONE) header.from=nvidia.com Received: from hqpgpgate102.nvidia.com (Not Verified[216.228.121.13]) by hqemgate14.nvidia.com (using TLS: TLSv1.2, DES-CBC3-SHA) id ; Fri, 08 Feb 2019 12:45:03 -0800 Received: from hqmail.nvidia.com ([172.20.161.6]) by hqpgpgate102.nvidia.com (PGP Universal service); Fri, 08 Feb 2019 12:44:59 -0800 X-PGP-Universal: processed; by hqpgpgate102.nvidia.com on Fri, 08 Feb 2019 12:44:59 -0800 Received: from [10.2.164.159] (10.124.1.5) by HQMAIL101.nvidia.com (172.20.187.10) with Microsoft SMTP Server (TLS) id 15.0.1395.4; Fri, 8 Feb 2019 20:44:58 +0000 Subject: Re: [PATCH 1/2] mm: introduce put_user_page*(), placeholder versions To: Mike Rapoport , CC: Andrew Morton , , Al Viro , Christian Benvenuti , Christoph Hellwig , Christopher Lameter , Dan Williams , Dave Chinner , Dennis Dalessandro , Doug Ledford , Jan Kara , Jason Gunthorpe , Jerome Glisse , Matthew Wilcox , Michal Hocko , Mike Marciniszyn , Ralph Campbell , Tom Talpey , LKML , References: <20190208075649.3025-1-jhubbard@nvidia.com> <20190208075649.3025-2-jhubbard@nvidia.com> <20190208103211.GD11096@rapoport-lnx> X-Nvconfidentiality: public From: John Hubbard Message-ID: <9c1985cc-cd99-a950-5ea2-9df9f93eb98b@nvidia.com> Date: Fri, 8 Feb 2019 12:44:48 -0800 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:60.0) Gecko/20100101 Thunderbird/60.5.0 MIME-Version: 1.0 In-Reply-To: <20190208103211.GD11096@rapoport-lnx> X-Originating-IP: [10.124.1.5] X-ClientProxiedBy: HQMAIL104.nvidia.com (172.18.146.11) To HQMAIL101.nvidia.com (172.20.187.10) Content-Type: text/plain; charset="utf-8"; format=flowed Content-Language: en-US Content-Transfer-Encoding: 7bit DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=nvidia.com; s=n1; t=1549658703; bh=ogIholLrpKztcsDoAScWgBL1e5vfshGcZY+vwNC42rg=; h=X-PGP-Universal:Subject:To:CC:References:X-Nvconfidentiality:From: Message-ID:Date:User-Agent:MIME-Version:In-Reply-To: X-Originating-IP:X-ClientProxiedBy:Content-Type:Content-Language: Content-Transfer-Encoding; b=sAWi2INAdMFVha1o+0PxFQFpRxw0XUDZH6EHdS0tXI6IMWQabh2rAzTr96FGKQxAK r0aikr3jTyoS3DxaYwrKX5T7q8ls1Aq584uHk8oBkugOH6hSCm3cDIQyxqepV0cPOn QuUVL0k04OQP5WPYD9lo2wvJbSKKRMl3l9Xoaqhcad5u/ej2y8PCq9Y/ViixMdQHKb kLoMbizF1iqWwlOGrhJoNu2oVKogaWbBomZlQxjQ6TdKT504r9P8hqkIi9AwKZnZB1 8OpYjxjN40TYgY15Ro/ABg0ylD2edugYItbNuT4lLwlr8I6X5zIoOE1csq+a+zruhC 5itwstqUV7DNw== 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 2/8/19 2:32 AM, Mike Rapoport wrote: > On Thu, Feb 07, 2019 at 11:56:48PM -0800, john.hubbard@gmail.com wrote: >> From: John Hubbard [...] >> +/** >> + * put_user_page() - release a gup-pinned page >> + * @page: pointer to page to be released >> + * >> + * Pages that were pinned via get_user_pages*() must be released via >> + * either put_user_page(), or one of the put_user_pages*() routines >> + * below. This is so that eventually, pages that are pinned via >> + * get_user_pages*() can be separately tracked and uniquely handled. In >> + * particular, interactions with RDMA and filesystems need special >> + * handling. >> + * >> + * put_user_page() and put_page() are not interchangeable, despite this early >> + * implementation that makes them look the same. put_user_page() calls must > > I just hope we'll remember to update when the real implementation will be > merged ;-) > > Other than that, feel free to add > > Reviewed-by: Mike Rapoport # docs > Thanks for the review! Yes, the follow-on patch that turns this into a real implementation is posted [1], and its documentation is updated accordingly. (I've already changed "@Returns" to "@Return" locally in that patch, btw.) [1] https://lore.kernel.org/r/20190204052135.25784-5-jhubbard@nvidia.com thanks, -- John Hubbard NVIDIA