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Howlett" , Suren Baghdasaryan , Vlastimil Babka , linux-kselftest@vger.kernel.org, linux-mm@kvack.org, linux-fsdevel@vger.kernel.org, linux-api@vger.kernel.org, linux-kernel@vger.kernel.org, Oliver Sang References: <788fdfcc9ef602b408951d68097918d6ae379395.1729848252.git.lorenzo.stoakes@oracle.com> <828674d9-e862-4438-86b6-61977f4cf3b5@nvidia.com> Content-Language: en-US From: John Hubbard In-Reply-To: Content-Type: text/plain; charset=UTF-8; format=flowed Content-Transfer-Encoding: 8bit X-ClientProxiedBy: SJ0PR13CA0089.namprd13.prod.outlook.com (2603:10b6:a03:2c4::34) To SJ0PR12MB5469.namprd12.prod.outlook.com (2603:10b6:a03:37f::16) Precedence: bulk X-Mailing-List: linux-api@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 X-MS-PublicTrafficType: Email X-MS-TrafficTypeDiagnostic: SJ0PR12MB5469:EE_|BY5PR12MB4211:EE_ X-MS-Office365-Filtering-Correlation-Id: c5e0775b-9df3-4f43-8020-08dcf5251229 X-MS-Exchange-SenderADCheck: 1 X-MS-Exchange-AntiSpam-Relay: 0 X-Microsoft-Antispam: BCL:0;ARA:13230040|1800799024|7416014|376014|366016|10070799003; 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>>>> +} >>> >>> Do we want this in the uapi header? Even if this is useful, it might >>> come with several drawbacks such as breaking scripts that parse kernel >>> headers (and a quick git grep suggests we do have static inlines in >>> headers, but in rather obscure ones) and breaking C89: >>> >> >> Let's please not say "C89" anymore, we've moved on! :) >> >> The notes in [1], which is now nearly 2.5 years old, discuss the move to >> C11, and specifically how to handle the inline keyword. > > That seems to only apply to the kernel internally, uapi headers are Yes. > included from userspace too (-std=c89 -pedantic doesn't know what a > gnu extension is). And uapi headers _generally_ keep to defining > constants and structs, nothing more. OK > I don't know what the guidelines for uapi headers are nowadays, but we > generally want to not break userspace. > >> >> I think it's quite clear at this point, that we should not hold up new >> work, based on concerns about handling the inline keyword, nor about >> C89. > > Right, but the correct solution is probably to move > pidfd_is_self_sentinel to some other place, since it's not even > supposed to be used by userspace (it's semantically useless to > userspace, and it's only two users are in the kernel, kernel/pid.c and > exit.c). > Yes, if userspace absolutely doesn't need nor want this, then putting it in a non-uapi header does sound like the right move. thanks, -- John Hubbard