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Wed, 28 Jan 2026 03:28:00 -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 , Randy Dunlap , Simon Horman , Krzysztof Kozlowski Subject: [PATCH net-next V7 07/14] devlink: Add parent dev to devlink API Date: Wed, 28 Jan 2026 13:25:37 +0200 Message-ID: <20260128112544.1661250-8-tariqt@nvidia.com> X-Mailer: git-send-email 2.44.0 In-Reply-To: <20260128112544.1661250-1-tariqt@nvidia.com> References: <20260128112544.1661250-1-tariqt@nvidia.com> Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Transfer-Encoding: quoted-printable X-NV-OnPremToCloud: ExternallySecured X-EOPAttributedMessage: 0 X-MS-PublicTrafficType: Email X-MS-TrafficTypeDiagnostic: BN1PEPF00004682:EE_|PH7PR12MB8123:EE_ X-MS-Office365-Filtering-Correlation-Id: 2accfab3-f5ad-420f-4c80-08de5e605566 X-MS-Exchange-SenderADCheck: 1 X-MS-Exchange-AntiSpam-Relay: 0 X-Microsoft-Antispam: BCL:0;ARA:13230040|36860700013|1800799024|7416014|376014|82310400026; X-Microsoft-Antispam-Message-Info: =?us-ascii?Q?OILIFHJAd/kFIQEatw/JcVA9znxTnhIjVdSX/e03zzi6+bgK+rGF73cG1kzb?= =?us-ascii?Q?OeqsdHzLPX9irzEFy2YntIiscbAep8+s04AWLRsg39AsHCAHdDC/pE8+nzQF?= =?us-ascii?Q?iZlnN1+8/3vYI+P/sRXeV4eWQjrFX4yXM4rQ3hwa71ouKiZPmyiMbyL1FpkQ?= =?us-ascii?Q?IygGs32+8RenaUVSsbWhnVoN25P0v9OVybzPrDVn/bb+gl8XOlTprblnFcOR?= =?us-ascii?Q?YbAZ6WrdlLSjWN4Au8ytGQM24KAjrE15SpKrWHtyAXMKEFf1ueK39HjtOsHH?= =?us-ascii?Q?5hBqRcYjtgYU2tQ+J4VPgP5mPMuzj4067kSbPFhxtZHbmcBZWvQe/krW2C68?= =?us-ascii?Q?A4xhhbCjp3MKssAShwshtH773qYGpNU1Axa++LN/jZS7jwTSwlltI5u5hwi6?= =?us-ascii?Q?fNLaO6Me4aF/4ziT8Qy+dElYHTEga7PSCnqHDJF/cvAo9uasrp26oo5fdYel?= =?us-ascii?Q?4l9a+b3Ni7fHh+QRw6jeel+Jq6iccT7dDwlEsMyH39pzeQpY1HuIofogDRpo?= =?us-ascii?Q?0Tr2HvdbB0COs0kXLJXgPw+cn2pgy9jtAp5IGONPYYSVHir+U/88/tyAonaq?= =?us-ascii?Q?CHBpavsYSTNpq2lLLW49VX8FFbgHwT+HCYh81RAzATR0AjQEPWM/jX/f2OgZ?= =?us-ascii?Q?bXug0tLVGGi3O0PdiZn4jYWTFvo9LpsKpc0xS3VvKkx6BbPsXaSDSwqm1GC2?= =?us-ascii?Q?batKLkQTkxUDCzJMkud0nVBi5gdL/hucSZcOnKLnwNpqPJBw/RimQisiCsks?= =?us-ascii?Q?D/8cGA0Oqd/FWYksXKf3Y96tH3+YGeiNkcN9PictlflNwRaPKhMuyJ+g27nB?= =?us-ascii?Q?LI1tz/nNTduLDEf4UIdzepVD2SGOimTgkjsFvJcp6AjnqOvSBrpwVosBe1Lz?= =?us-ascii?Q?l2qc23ILjbXiUVClbeAPUJ/2+/VhNdYxm5Ag9awpgO0V1BqatqdLwIZp4ubZ?= =?us-ascii?Q?ZHcFfHfNSoDUVBvtWmuiOGlosLFZTiS6X+Ku8x259E7maqzVsPpEIu8KlEPf?= =?us-ascii?Q?+ZzkH9RQzOd/q+q6tQzyoPZfqoioXhQ0nr5lHOlZIDqUwOmDbY5FwomGh5cX?= =?us-ascii?Q?4KA2Tyb0nGHR4WmnEAjMpPYJlWhNjcm1BpHB/yh3zK0+w8jyKhiECHKvlBQB?= =?us-ascii?Q?8B9F5n81YUHNEdh6/T4W9i8ehkJX8028742viZkgz7n0au24OolWXwJ/AZoQ?= =?us-ascii?Q?RvM4iLHbFDqurdT9Xv1fW7/fTp5K/qvFAKaW3iPsTLDc9UUNZiPiNfrA04gY?= =?us-ascii?Q?wT6mlqs1yA7slOgCYD/TGLDEZOsQFbuUOhP/oLqLobQXwWzkjHcKUPh8ugEf?= =?us-ascii?Q?OO7MKDaUKt2ypwWqq5ZY/oS6DD1kR748TgWUQQA6iIJXSlEIFzDaogB5Ou4S?= =?us-ascii?Q?TXoFMwhhBCwyhkyfmbJcQIqAieqfo4Qg+LaOMVb4NDDIHCBGN8ut+IbA5JiC?= =?us-ascii?Q?qnox8stXmNE345zVJEAgoL1wv21i2HTR9lLdZlI2C/rONPIeldcwtu60bahC?= =?us-ascii?Q?xpiJonbOFxm3pLiKNUh5TVUirD3Rvwz+FqBX9MzOE3OxG8ln2nHlHAbOoee/?= =?us-ascii?Q?HwWOqgu0Ii6n4CBFj7vfotT7u+42zFc7yJWEWBzPFYTkvP57HB681DRY5cps?= =?us-ascii?Q?nWAnci/nzcEMPeS7IrqyA3oK5mLK+HEo7XvOfFyOnV3Xr/TtinUpQvOpUDlu?= =?us-ascii?Q?EPcMkA=3D=3D?= X-Forefront-Antispam-Report: CIP:216.228.117.161;CTRY:US;LANG:en;SCL:1;SRV:;IPV:NLI;SFV:NSPM;H:mail.nvidia.com;PTR:dc6edge2.nvidia.com;CAT:NONE;SFS:(13230040)(36860700013)(1800799024)(7416014)(376014)(82310400026);DIR:OUT;SFP:1101; X-OriginatorOrg: Nvidia.com X-MS-Exchange-CrossTenant-OriginalArrivalTime: 28 Jan 2026 11:28:17.4033 (UTC) X-MS-Exchange-CrossTenant-Network-Message-Id: 2accfab3-f5ad-420f-4c80-08de5e605566 X-MS-Exchange-CrossTenant-Id: 43083d15-7273-40c1-b7db-39efd9ccc17a X-MS-Exchange-CrossTenant-OriginalAttributedTenantConnectingIp: TenantId=43083d15-7273-40c1-b7db-39efd9ccc17a;Ip=[216.228.117.161];Helo=[mail.nvidia.com] X-MS-Exchange-CrossTenant-AuthSource: BN1PEPF00004682.namprd03.prod.outlook.com X-MS-Exchange-CrossTenant-AuthAs: Anonymous X-MS-Exchange-CrossTenant-FromEntityHeader: HybridOnPrem X-MS-Exchange-Transport-CrossTenantHeadersStamped: PH7PR12MB8123 Content-Type: text/plain; charset="utf-8" From: Cosmin Ratiu Upcoming changes to the rate commands need the parent devlink specified. This change adds a nested 'parent-dev' attribute to the API and helpers to obtain and put a reference to the parent devlink instance in info->user_ptr[1]. To avoid deadlocks, the parent devlink is unlocked before obtaining the main devlink instance that is the target of the request. A reference to the parent is kept until the end of the request to avoid it suddenly disappearing. This means that this reference is of limited use without additional protection. Signed-off-by: Cosmin Ratiu Reviewed-by: Carolina Jubran Reviewed-by: Jiri Pirko Signed-off-by: Tariq Toukan --- Documentation/netlink/specs/devlink.yaml | 12 ++++++ include/uapi/linux/devlink.h | 2 + net/devlink/devl_internal.h | 2 + net/devlink/netlink.c | 51 +++++++++++++++++++++--- 4 files changed, 62 insertions(+), 5 deletions(-) diff --git a/Documentation/netlink/specs/devlink.yaml b/Documentation/netli= nk/specs/devlink.yaml index 837112da6738..a8fd0a815c0d 100644 --- a/Documentation/netlink/specs/devlink.yaml +++ b/Documentation/netlink/specs/devlink.yaml @@ -867,6 +867,10 @@ attribute-sets: type: flag doc: Request restoring parameter to its default value. value: 183 + + - name: parent-dev + type: nest + nested-attributes: dl-parent-dev - name: dl-dev-stats subset-of: devlink @@ -1289,6 +1293,14 @@ attribute-sets: Specifies the bandwidth share assigned to the Traffic Class. The bandwidth for the traffic class is determined in proportion to the sum of the shares of all configured clas= ses. + - + name: dl-parent-dev + subset-of: devlink + attributes: + - + name: bus-name + - + name: dev-name =20 operations: enum-model: directional diff --git a/include/uapi/linux/devlink.h b/include/uapi/linux/devlink.h index e7d6b6d13470..94b8a4437bac 100644 --- a/include/uapi/linux/devlink.h +++ b/include/uapi/linux/devlink.h @@ -642,6 +642,8 @@ enum devlink_attr { DEVLINK_ATTR_PARAM_VALUE_DEFAULT, /* dynamic */ DEVLINK_ATTR_PARAM_RESET_DEFAULT, /* flag */ =20 + DEVLINK_ATTR_PARENT_DEV, /* nested */ + /* Add new attributes above here, update the spec in * Documentation/netlink/specs/devlink.yaml and re-generate * net/devlink/netlink_gen.c. diff --git a/net/devlink/devl_internal.h b/net/devlink/devl_internal.h index 8374c9cab6ce..3ca4cc8517cd 100644 --- a/net/devlink/devl_internal.h +++ b/net/devlink/devl_internal.h @@ -162,6 +162,8 @@ typedef int devlink_nl_dump_one_func_t(struct sk_buff *= msg, struct devlink * devlink_get_from_attrs_lock(struct net *net, struct nlattr **attrs, bool dev_lock); +struct devlink * +devlink_get_parent_from_attrs_lock(struct net *net, struct nlattr **attrs); =20 int devlink_nl_dumpit(struct sk_buff *msg, struct netlink_callback *cb, devlink_nl_dump_one_func_t *dump_one); diff --git a/net/devlink/netlink.c b/net/devlink/netlink.c index 593605c1b1ef..72897b19c372 100644 --- a/net/devlink/netlink.c +++ b/net/devlink/netlink.c @@ -12,6 +12,7 @@ #define DEVLINK_NL_FLAG_NEED_PORT BIT(0) #define DEVLINK_NL_FLAG_NEED_DEVLINK_OR_PORT BIT(1) #define DEVLINK_NL_FLAG_NEED_DEV_LOCK BIT(2) +#define DEVLINK_NL_FLAG_OPTIONAL_PARENT_DEV BIT(3) =20 static const struct genl_multicast_group devlink_nl_mcgrps[] =3D { [DEVLINK_MCGRP_CONFIG] =3D { .name =3D DEVLINK_GENL_MCGRP_CONFIG_NAME }, @@ -206,19 +207,51 @@ devlink_get_from_attrs_lock(struct net *net, struct n= lattr **attrs, return ERR_PTR(-ENODEV); } =20 +struct devlink * +devlink_get_parent_from_attrs_lock(struct net *net, struct nlattr **attrs) +{ + struct nlattr *tb[DEVLINK_ATTR_DEV_NAME + 1]; + int err; + + if (!attrs[DEVLINK_ATTR_PARENT_DEV]) + return ERR_PTR(-EINVAL); + + err =3D nla_parse_nested(tb, DEVLINK_ATTR_DEV_NAME, + attrs[DEVLINK_ATTR_PARENT_DEV], + NULL, NULL); + if (err) + return ERR_PTR(err); + + return devlink_get_from_attrs_lock(net, tb, false); +} + static int __devlink_nl_pre_doit(struct sk_buff *skb, struct genl_info *in= fo, u8 flags) { + bool parent_dev =3D flags & DEVLINK_NL_FLAG_OPTIONAL_PARENT_DEV; bool dev_lock =3D flags & DEVLINK_NL_FLAG_NEED_DEV_LOCK; + struct devlink *devlink, *parent_devlink =3D NULL; + struct net *net =3D genl_info_net(info); + struct nlattr **attrs =3D info->attrs; struct devlink_port *devlink_port; - struct devlink *devlink; int err; =20 - devlink =3D devlink_get_from_attrs_lock(genl_info_net(info), info->attrs, - dev_lock); - if (IS_ERR(devlink)) - return PTR_ERR(devlink); + if (parent_dev && attrs[DEVLINK_ATTR_PARENT_DEV]) { + parent_devlink =3D devlink_get_parent_from_attrs_lock(net, attrs); + if (IS_ERR(parent_devlink)) + return PTR_ERR(parent_devlink); + info->user_ptr[1] =3D parent_devlink; + /* Drop the parent devlink lock but don't release the reference. + * This will keep it alive until the end of the request. + */ + devl_unlock(parent_devlink); + } =20 + devlink =3D devlink_get_from_attrs_lock(net, attrs, dev_lock); + if (IS_ERR(devlink)) { + err =3D PTR_ERR(devlink); + goto parent_put; + } info->user_ptr[0] =3D devlink; if (flags & DEVLINK_NL_FLAG_NEED_PORT) { devlink_port =3D devlink_port_get_from_info(devlink, info); @@ -237,6 +270,9 @@ static int __devlink_nl_pre_doit(struct sk_buff *skb, s= truct genl_info *info, unlock: devl_dev_unlock(devlink, dev_lock); devlink_put(devlink); +parent_put: + if (parent_dev && parent_devlink) + devlink_put(parent_devlink); return err; } =20 @@ -274,6 +310,11 @@ static void __devlink_nl_post_doit(struct sk_buff *skb= , struct genl_info *info, devlink =3D info->user_ptr[0]; devl_dev_unlock(devlink, dev_lock); devlink_put(devlink); + if ((flags & DEVLINK_NL_FLAG_OPTIONAL_PARENT_DEV) && + info->user_ptr[1]) { + devlink =3D info->user_ptr[1]; + devlink_put(devlink); + } } =20 void devlink_nl_post_doit(const struct genl_split_ops *ops, --=20 2.44.0