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Thu, 20 Nov 2025 05:13:14 -0800 From: Tariq Toukan To: Eric Dumazet , Jakub Kicinski , Paolo Abeni , Andrew Lunn , "David S. Miller" CC: Donald Hunter , Jiri Pirko , Jonathan Corbet , Saeed Mahameed , "Leon Romanovsky" , Tariq Toukan , Mark Bloch , , , , , Gal Pressman , Moshe Shemesh , Carolina Jubran , Cosmin Ratiu , Jiri Pirko Subject: [PATCH net-next 02/14] documentation: networking: add shared devlink documentation Date: Thu, 20 Nov 2025 15:09:14 +0200 Message-ID: <1763644166-1250608-3-git-send-email-tariqt@nvidia.com> X-Mailer: git-send-email 2.8.0 In-Reply-To: <1763644166-1250608-1-git-send-email-tariqt@nvidia.com> References: <1763644166-1250608-1-git-send-email-tariqt@nvidia.com> Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 X-NV-OnPremToCloud: ExternallySecured X-EOPAttributedMessage: 0 X-MS-PublicTrafficType: Email X-MS-TrafficTypeDiagnostic: MWH0EPF000A6734:EE_|CY3PR12MB9555:EE_ X-MS-Office365-Filtering-Correlation-Id: 41c07bc5-75b9-47f0-6dbd-08de2836a049 X-MS-Exchange-SenderADCheck: 1 X-MS-Exchange-AntiSpam-Relay: 0 X-Microsoft-Antispam: BCL:0;ARA:13230040|36860700013|7416014|376014|1800799024|82310400026; X-Microsoft-Antispam-Message-Info: =?us-ascii?Q?EK7vN3SloDSJ+sSapITP8HxVcvNqgNR2IQr+8pT3612RHUKN5SZOiS7hbd/F?= =?us-ascii?Q?82GIl6R9hS9uQxh2BC8PXXFRl3FUwcZ03Tr43Bx0pX00c8wRqiPYbFLixpPd?= =?us-ascii?Q?rfkSxcF2Ob8Fym/aX8pxNTdEHsqWZq/C/w1f9TH7ZxSkRxkH2YhrkAGKQr1P?= =?us-ascii?Q?m+zOqbxL1C6lJRT2wZHoqA7oLsE9fRozIgVZfuDG1tx7XYqfUWk19KWvvthk?= =?us-ascii?Q?+w1niwapr4dlxmCkcSRwu8zE2fMMsPVFMBYG4v5uNMYyJUuSkX7fmXd/Y6cr?= =?us-ascii?Q?6qo9ge5lsnHZxS4G6JM7kvmfnUahsJj8IaHc8cNKL4VtTTot0W3tJKJxbFDc?= =?us-ascii?Q?RHEnfYebrHS/zKhMcrPpj6TJFe2NZRhMLYy69On+mBpr0xaI5EMwpdSAOq+/?= =?us-ascii?Q?/BxlkXIHRPOPnnwAuD79gFaDPp8XKHA9S/tpc8vBY4o4aq+FS5fy8w+KxHgf?= =?us-ascii?Q?Rffi70ML4PyJb1pKSRSq9YA3Ls8S8jS7XstaSOBWrMT0S2OIgBWUSISm2Bgp?= =?us-ascii?Q?1UCxZEA9V1Kd4QwomJTDYufDdb2qUsVVGPMRutpSw9iFCke4lRVS4i4X//ls?= =?us-ascii?Q?Z8Od6OkNA0UrJY639lJAkRBsIO292i90LNksuQHISyKdIB8cNUApGHabJIz0?= =?us-ascii?Q?1UtjpVxturTPqO55XaPjdC6BBjY5uHidJFbgvrpBw8g8IvRCqz1BOtKUpPej?= =?us-ascii?Q?DJ7NMizMTSHP1cWxA3cTI+0FetYYySdYmFX1kJ16OViFxHZCxvBKja1mIA87?= =?us-ascii?Q?z5mgSvQhf4UBCU82FuEKdmjR91fi8NuzodOBzac14+h93vu2ygr6iFWulTUS?= =?us-ascii?Q?HFbdbsvBOD1y2nWe0KmofANLy2IYJt6pi86lHiEHs9JTiP7WxtzBVnIjPrGi?= =?us-ascii?Q?uthz3lWIOo8WuB4H3LzUxBDUPfIWuZhEdq1oChpdWrG0wIXUZmgrQFiu9LJE?= =?us-ascii?Q?sNT0P3D8nNtVlvuvUDah2+ppinGHtJk4f9aKGO6y5Tkn0wu3C76VPYHfZXsb?= =?us-ascii?Q?PGzjPIL+J0/Xwv7f/OV5sDQxv1bxnbsWh2d1begxJ/HSsDWnJCRCdwSM7wC3?= =?us-ascii?Q?KnklVi1JW92oxkfd92z8t1j9/qSGEmqEygrvo5WhsNIqvI793qERlU2kL/YV?= =?us-ascii?Q?RCo8zK/MKo/QYDOGKnWAu0MXFksI92GTnXZ+8vNY1FZ0ky4P9mgrJuYyDhCD?= =?us-ascii?Q?4yRUofm00G+eeEQuqHNUFDVuW/qAm1HnuUNWqk8wuPXoiKEGl2gEfYSRyOHh?= =?us-ascii?Q?ubbgXX9KLDxfWSZDRCQH91YdS/bMSGKCNyUXnLWwieN22zwadFADshxL5PhV?= =?us-ascii?Q?yh0d95TbGpnXCATZwgfgw4PkSmLWlJ5U0x8BVTV9pd+rDO0rUPpr1Vq4K2eT?= =?us-ascii?Q?5fTi51kPEQXHo6NXB3fZDGfYj+TLe46dRoOQr5E9Okjy9FPCjquoaYVn6M0H?= =?us-ascii?Q?UbdjUhahhweT2WtCFVFaQTFGtWVcNIVUw1qCfvwU8iYMhoKa8v9OVQd0q49v?= =?us-ascii?Q?fm0MAf6drMTrAysF7Kp0qDbBYh3e1PY4EUqUy36pgEUx3qeb02Db2BApi/XD?= =?us-ascii?Q?Vv7N8uRhVV2PPFu2xlg=3D?= X-Forefront-Antispam-Report: CIP:216.228.117.160;CTRY:US;LANG:en;SCL:1;SRV:;IPV:NLI;SFV:NSPM;H:mail.nvidia.com;PTR:dc6edge1.nvidia.com;CAT:NONE;SFS:(13230040)(36860700013)(7416014)(376014)(1800799024)(82310400026);DIR:OUT;SFP:1101; X-OriginatorOrg: Nvidia.com X-MS-Exchange-CrossTenant-OriginalArrivalTime: 20 Nov 2025 13:13:41.4786 (UTC) X-MS-Exchange-CrossTenant-Network-Message-Id: 41c07bc5-75b9-47f0-6dbd-08de2836a049 X-MS-Exchange-CrossTenant-Id: 43083d15-7273-40c1-b7db-39efd9ccc17a X-MS-Exchange-CrossTenant-OriginalAttributedTenantConnectingIp: TenantId=43083d15-7273-40c1-b7db-39efd9ccc17a;Ip=[216.228.117.160];Helo=[mail.nvidia.com] X-MS-Exchange-CrossTenant-AuthSource: MWH0EPF000A6734.namprd04.prod.outlook.com X-MS-Exchange-CrossTenant-AuthAs: Anonymous X-MS-Exchange-CrossTenant-FromEntityHeader: HybridOnPrem X-MS-Exchange-Transport-CrossTenantHeadersStamped: CY3PR12MB9555 Content-Transfer-Encoding: quoted-printable Content-Type: text/plain; charset="utf-8" From: Jiri Pirko Document shared devlink instances for multiple PFs on the same chip. Signed-off-by: Jiri Pirko Reviewed-by: Cosmin Ratiu Signed-off-by: Tariq Toukan --- .../networking/devlink/devlink-shared.rst | 66 +++++++++++++++++++ Documentation/networking/devlink/index.rst | 3 + 2 files changed, 69 insertions(+) create mode 100644 Documentation/networking/devlink/devlink-shared.rst diff --git a/Documentation/networking/devlink/devlink-shared.rst b/Document= ation/networking/devlink/devlink-shared.rst new file mode 100644 index 000000000000..8377d524998f --- /dev/null +++ b/Documentation/networking/devlink/devlink-shared.rst @@ -0,0 +1,66 @@ +.. SPDX-License-Identifier: GPL-2.0 + +=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D= =3D=3D=3D=3D +Devlink Shared Instances +=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D= =3D=3D=3D=3D + +Overview +=3D=3D=3D=3D=3D=3D=3D=3D + +Shared devlink instances allow multiple physical functions (PFs) on the sa= me +chip to share an additional devlink instance for chip-wide operations. This +should be implemented within individual drivers alongside the individual PF +devlink instances, not replacing them. + +The shared devlink instance should be backed by a faux device and should +provide a common interface for operations that affect the entire chip +rather than individual PFs. + +Implementation +=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D + +Architecture +------------ + +The implementation should use: + +* **Faux device**: Virtual device backing the shared devlink instance +* **Chip identification**: PFs are grouped by chip using a driver-specific= identifier +* **Shared instance management**: Global list of shared instances with ref= erence counting + +Initialization Flow +------------------- + +1. **PF calls shared devlink init** during driver probe +2. **Chip identification** using driver-specific method to determine devic= e identity +3. **Lookup existing shared instance** for this chip identifier +4. **Create new shared instance** if none exists: + + * Create faux device with chip identifier as name + * Allocate and register devlink instance + * Add to global shared instances list + +5. **Add PF to shared instance** PF list +6. **Set nested devlink instance** dor the PF devlink instance + +Cleanup Flow +------------ + +1. **Cleanup** when PF is removed; destroy shared instance when last PF is= removed + +Chip Identification +------------------- + +PFs belonging to the same chip are identified using a driver-specific meth= od. +The driver is free to choose any identifier that is suitable for determini= ng +whether two PFs are part of the same device. Examples include VPD serial n= umbers, +device tree properties, or other hardware-specific identifiers. + +Locking +------- + +A global per-driver mutex protects the shared instances list and individua= l shared +instance PF lists during registration/deregistration. + +Similarly to other nested devlink instance relationships, devlink lock of +the shared instance should be always taken after the devlink lock of PF. diff --git a/Documentation/networking/devlink/index.rst b/Documentation/net= working/devlink/index.rst index 35b12a2bfeba..d14a764e9b1d 100644 --- a/Documentation/networking/devlink/index.rst +++ b/Documentation/networking/devlink/index.rst @@ -68,6 +68,9 @@ general. devlink-resource devlink-selftests devlink-trap + devlink-linecard + devlink-eswitch-attr + devlink-shared =20 Driver-specific documentation ----------------------------- --=20 2.31.1