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Tue, 13 Sep 2022 13:00:28 -0700 Date: Tue, 13 Sep 2022 13:00:27 -0700 From: Nicolin Chen To: Jeff Johnson CC: , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , Subject: Re: [PATCH 3/5] iommu: Add return errno rules to ->attach_dev ops Message-ID: References: <20220913082448.31120-1-nicolinc@nvidia.com> <20220913082448.31120-4-nicolinc@nvidia.com> MIME-Version: 1.0 Content-Type: text/plain; charset="us-ascii" Content-Disposition: inline In-Reply-To: X-EOPAttributedMessage: 0 X-MS-PublicTrafficType: Email X-MS-TrafficTypeDiagnostic: DM6NAM11FT040:EE_|DM4PR12MB5167:EE_ X-MS-Office365-Filtering-Correlation-Id: eb3b88e3-1aa6-47b3-b11a-08da95c29cc4 X-MS-Exchange-SenderADCheck: 1 X-MS-Exchange-AntiSpam-Relay: 0 X-Microsoft-Antispam: BCL:0; X-Microsoft-Antispam-Message-Info: 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 X-Forefront-Antispam-Report: CIP:12.22.5.238;CTRY:US;LANG:en;SCL:1;SRV:;IPV:NLI;SFV:NSPM;H:mail.nvidia.com;PTR:InfoNoRecords;CAT:NONE;SFS:(13230022)(4636009)(39860400002)(376002)(396003)(136003)(346002)(451199015)(46966006)(40470700004)(36840700001)(7416002)(47076005)(186003)(9686003)(40480700001)(356005)(82310400005)(86362001)(81166007)(41300700001)(316002)(40460700003)(7406005)(36860700001)(478600001)(33716001)(54906003)(82740400003)(8936002)(6916009)(70206006)(4326008)(70586007)(336012)(5660300002)(26005)(426003)(8676002)(55016003)(2906002)(36900700001);DIR:OUT;SFP:1101; X-OriginatorOrg: Nvidia.com X-MS-Exchange-CrossTenant-OriginalArrivalTime: 13 Sep 2022 20:00:31.1582 (UTC) X-MS-Exchange-CrossTenant-Network-Message-Id: eb3b88e3-1aa6-47b3-b11a-08da95c29cc4 X-MS-Exchange-CrossTenant-Id: 43083d15-7273-40c1-b7db-39efd9ccc17a X-MS-Exchange-CrossTenant-OriginalAttributedTenantConnectingIp: TenantId=43083d15-7273-40c1-b7db-39efd9ccc17a;Ip=[12.22.5.238];Helo=[mail.nvidia.com] X-MS-Exchange-CrossTenant-AuthSource: DM6NAM11FT040.eop-nam11.prod.protection.outlook.com X-MS-Exchange-CrossTenant-AuthAs: Anonymous X-MS-Exchange-CrossTenant-FromEntityHeader: HybridOnPrem X-MS-Exchange-Transport-CrossTenantHeadersStamped: DM4PR12MB5167 Precedence: bulk List-ID: X-Mailing-List: linux-tegra@vger.kernel.org Hi Jeff, On Tue, Sep 13, 2022 at 11:41:35AM -0700, Jeff Johnson wrote: > > diff --git a/include/linux/iommu.h b/include/linux/iommu.h > > index ea30f00dc145..c5d7ec0187c7 100644 > > --- a/include/linux/iommu.h > > +++ b/include/linux/iommu.h > > @@ -266,6 +266,17 @@ struct iommu_ops { > > /** > > * struct iommu_domain_ops - domain specific operations > > * @attach_dev: attach an iommu domain to a device > > + * Rules of its return errno: > > + * EINVAL - Exclusively, device and domain are incompatible. Must > > + * avoid kernel prints along with this errno. Any EINVAL > > + * returned from kAPIs must be converted to ENODEV if it > > + * is device-specific, or to some other reasonable errno > > + * being listed below > > + * ENOMEM - Out of memory > > + * ENOSPC - No space left on device > > + * EBUSY - Device is attached to a domain and cannot be changed > > + * ENODEV - Device specific errors, not able to be attached > > + * - Treated as ENODEV by the caller. Use is discouraged > > It is my understanding that kernel-doc won't preserve your formatting > without extra directives. See the "Note" after > Thanks for the review! Perhaps the following one would work: diff --git a/include/linux/iommu.h b/include/linux/iommu.h index ea30f00dc145..14f078b58e17 100644 --- a/include/linux/iommu.h +++ b/include/linux/iommu.h @@ -266,6 +266,17 @@ struct iommu_ops { /** * struct iommu_domain_ops - domain specific operations * @attach_dev: attach an iommu domain to a device + * Return: + * * 0 - success + * * EINVAL - Exclusively, device and domain are incompatible. Must avoid + * kernel prints along with this errno. Any EINVAL returned from + * a kAPI must be converted to ENODEV if it is device-specific, + * or to some other reasonable errno being listed below + * * ENOMEM - Out of memory + * * ENOSPC - No space left on device + * * EBUSY - Device is attached to a domain and cannot be changed + * * ENODEV - Device specific errors, not able to be attached + * * - Treated as ENODEV by the caller. Use is discouraged * @detach_dev: detach an iommu domain from a device * @map: map a physically contiguous memory region to an iommu domain * @map_pages: map a physically contiguous set of pages of the same size to