# \[PATCH net-next v2 05/10\] devlink: support index-based lookup via bus\_name/dev\_name handle - From: Jiri Pirko \ - Date: 2026-02-25 13:34:32 - List: linux-trace-kernel - Page: https://ratatoskr.run/linux-trace-kernel/2026/02/8535524 - Thread: https://ratatoskr.run/netdev/2026/02/8535523/t.md ```text From: Jiri Pirko Devlink instances without a backing device use bus_name "devlink_index" and dev_name set to the decimal index string. When user space sends this handle, detect the pattern and perform a direct xarray lookup by index instead of iterating all instances. Signed-off-by: Jiri Pirko --- v1->v2: - moved DEVLINK_INDEX_BUS_NAME definition here from patch #7 --- include/uapi/linux/devlink.h | 2 ++ net/devlink/netlink.c | 9 +++++++++ 2 files changed, 11 insertions(+) diff --git a/include/uapi/linux/devlink.h b/include/uapi/linux/devlink.h index 1ba3436db4ae..7de2d8cc862f 100644 --- a/include/uapi/linux/devlink.h +++ b/include/uapi/linux/devlink.h @@ -19,6 +19,8 @@ #define DEVLINK_GENL_VERSION 0x1 #define DEVLINK_GENL_MCGRP_CONFIG_NAME "config" +#define DEVLINK_INDEX_BUS_NAME "devlink_index" + enum devlink_command { /* don't change the order or add anything between, this is ABI! */ DEVLINK_CMD_UNSPEC, diff --git a/net/devlink/netlink.c b/net/devlink/netlink.c index b73cec31089f..127f337489c0 100644 --- a/net/devlink/netlink.c +++ b/net/devlink/netlink.c @@ -200,6 +200,15 @@ devlink_get_from_attrs_lock(struct net *net, struct nlattr **attrs, busname = nla_data(attrs[DEVLINK_ATTR_BUS_NAME]); devname = nla_data(attrs[DEVLINK_ATTR_DEV_NAME]); + if (!strcmp(busname, DEVLINK_INDEX_BUS_NAME)) { + if (kstrtoul(devname, 10, &index)) + return ERR_PTR(-EINVAL); + devlink = devlinks_xa_lookup_get(net, index); + if (!devlink) + return ERR_PTR(-ENODEV); + goto found; + } + devlinks_xa_for_each_registered_get(net, index, devlink) { if (strcmp(devlink->bus_name, busname) == 0 && strcmp(devlink->dev_name, devname) == 0) -- 2.51.1 ```