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[216.228.121.143]) by mx.google.com with ESMTPS id f20si16167247yba.3.2019.07.23.16.24.26 for (version=TLS1_2 cipher=ECDHE-RSA-AES128-GCM-SHA256 bits=128/128); Tue, 23 Jul 2019 16:24:26 -0700 (PDT) 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=FMl+YlnD; 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 hqpgpgate101.nvidia.com (Not Verified[216.228.121.13]) by hqemgate14.nvidia.com (using TLS: TLSv1.2, DES-CBC3-SHA) id ; Tue, 23 Jul 2019 16:24:25 -0700 Received: from hqmail.nvidia.com ([172.20.161.6]) by hqpgpgate101.nvidia.com (PGP Universal service); Tue, 23 Jul 2019 16:24:24 -0700 X-PGP-Universal: processed; by hqpgpgate101.nvidia.com on Tue, 23 Jul 2019 16:24:24 -0700 Received: from [10.110.48.28] (10.124.1.5) by HQMAIL107.nvidia.com (172.20.187.13) with Microsoft SMTP Server (TLS) id 15.0.1473.3; Tue, 23 Jul 2019 23:24:24 +0000 Subject: Re: [PATCH 3/3] net/xdp: convert put_page() to put_user_page*() To: Ira Weiny CC: , Andrew Morton , Alexander Viro , =?UTF-8?B?QmrDtnJuIFTDtnBlbA==?= , Boaz Harrosh , Christoph Hellwig , Daniel Vetter , Dan Williams , Dave Chinner , David Airlie , "David S . Miller" , Ilya Dryomov , Jan Kara , Jason Gunthorpe , Jens Axboe , =?UTF-8?B?SsOpcsO0bWUgR2xpc3Nl?= , Johannes Thumshirn , Magnus Karlsson , Matthew Wilcox , Miklos Szeredi , Ming Lei , Sage Weil , Santosh Shilimkar , Yan Zheng , , , , , , LKML References: <20190722223415.13269-1-jhubbard@nvidia.com> <20190722223415.13269-4-jhubbard@nvidia.com> <20190723002534.GA10284@iweiny-DESK2.sc.intel.com> <20190723180612.GB29729@iweiny-DESK2.sc.intel.com> X-Nvconfidentiality: public From: John Hubbard Message-ID: <69540e85-b527-0252-7b29-8932660af72d@nvidia.com> Date: Tue, 23 Jul 2019 16:24:23 -0700 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:60.0) Gecko/20100101 Thunderbird/60.8.0 MIME-Version: 1.0 In-Reply-To: <20190723180612.GB29729@iweiny-DESK2.sc.intel.com> X-Originating-IP: [10.124.1.5] X-ClientProxiedBy: HQMAIL105.nvidia.com (172.20.187.12) To HQMAIL107.nvidia.com (172.20.187.13) Content-Type: text/plain; charset="utf-8" Content-Language: en-US Content-Transfer-Encoding: 7bit DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=nvidia.com; s=n1; t=1563924265; bh=Dc+54X4TKuVoIQ6IGOnhUFUhE0Dy4dW4jkSZ2LHVHns=; 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=FMl+YlnDhGCsZKKh1L0ErV+31siNAXGqpbM4Ti099eQ263WNqONoZoDhA6w28dloW DANKq7E2Y7kdWPUACeMGcsz7IGCwEWqiwPgDnX3E9DHqqaxxYj9TrmIKWYGcLWA8z9 HaYbTpYicIHv06kxhQ58/gdGYse2x3h25DFKRTKYtQq+80JPY4IzGMpBTYSaFvHkoA 7F9/p/2HEcQ7syxo9toMK0sf5uUtUlNauO/KxNX+D2TkcJKNWZP3//+ZXgl5mcNywg K1EWHc3E5G7xnnEUtcQBaKfZD5VJFBdwU+bLpLJtcvUt/rKIgSGElbmpHYwBZFPLKu YnW6V/fpJl4Ag== 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 7/23/19 11:06 AM, Ira Weiny wrote: > On Mon, Jul 22, 2019 at 09:41:34PM -0700, John Hubbard wrote: >> On 7/22/19 5:25 PM, Ira Weiny wrote: >>> On Mon, Jul 22, 2019 at 03:34:15PM -0700, john.hubbard@gmail.com wrote: ... >> Obviously, this stuff is all subject to a certain amount of opinion, but I >> think I'm on really solid ground as far as precedent goes. So I'm pushing >> back on the NAK... :) > > Fair enough... However, we have discussed in the past how GUP can be a > confusing interface to use. > > So I'd like to see it be more directed. Only using the __put_user_pages() > version allows us to ID callers easier through a grep of PUP_FLAGS_DIRTY_LOCK > in addition to directing users to use that interface rather than having to read > the GUP code to figure out that the 2 calls above are equal. It is not a huge > deal but... > OK, combining all the feedback to date, which is: * the leading double underscore is unloved, * set_page_dirty() is under investigation, but likely guilty of incitement to cause bugs, ...we end up with this: void put_user_pages_dirty_lock(struct page **pages, unsigned long npages, bool make_dirty) ...which I have a v2 patchset for, ready to send out. It makes IB all pretty too. :) thanks, -- John Hubbard NVIDIA