netdev_get_xmit_slave(9)

💅 netdev_get_xmit_slave — the kernel API manual, bestie edition ✨

So this is a page from the kernel API manual, section 9 (netdev_get_xmit_slave(9)), and it's about grabbing the xmit slave of a master device. Short page, big vibes, one very important lock warning. Let's go 🫶

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🌸 NAME 🌸

netdev_get_xmit_slave — get the xmit slave of the master device 🎀

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✨ SYNOPSIS ✨

struct net_device * netdev_get_xmit_slave (struct net_device *dev ,
struct sk_buff *skb , bool all_slaves );

That's it, that's the whole signature, no cap. Three args, returns a struct net_device *. 💖

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🦋 ARGUMENTS 🦋

• dev — the device. literally just the device. that's the whole description and honestly? iconic.
• skb — the packet 📦
• all_slaves — assume all the slaves are active 👑

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🔥 DESCRIPTION 🔥

Okay so here's the part you actually need to read, bestie, don't skip it 🙈

The reference counters are not incremented, so the caller must be careful with locks. The caller must hold the RCU lock. That's not a suggestion, that's the whole deal — if you don't hold it, that's on you 💀

And if no slave is found, NULL is returned. So vibe check your return value, always. ⭐

Not holding the RCU lock here is not slay behaviour. The caller must hold the RCU lock. periodt.

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🧚 SEE ALSO 🧚

Everything lives in the kernel file ./net/core/dev.c, and the cross-reference list is long — like, the way this list ate and left no crumbs 👑

dev_add_pack(9), __dev_remove_pack(9), dev_remove_pack(9), dev_get_iflink(9), dev_fill_metadata_dst(9), netdev_napi_by_id_lock(9), __dev_get_by_name(9), dev_get_by_name_rcu(9), netdev_get_by_name(9), __dev_get_by_index(9), dev_get_by_index_rcu(9), netdev_get_by_index(9), dev_get_by_napi_id(9), netdev_get_by_index_lock(9), netdev_get_name(9), dev_getbyhwaddr_rcu(9), dev_getbyhwaddr(9), netdev_get_by_flags_rcu(9), dev_valid_name(9), __dev_alloc_name(9), dev_alloc_name(9), dev_get_alias(9), netdev_features_change(9), __netdev_notify_peers(9), netdev_notify_peers(9), dev_disable_gro_hw(9), register_netdevice_notifier(9), unregister_netdevice_notifier(9), register_netdevice_notifier_net(9), unregister_netdevice_notifier_net(9), call_netdevice_notifiers_info(9), call_netdevice_notifiers_info_robust(9), call_netdevice_notifiers(9), call_netdevice_notifiers_mtu(9), dev_forward_skb(9), dev_nit_active_rcu(9), netif_setup_tc(9), netif_set_real_num_rx_queues(9), netif_set_real_num_queues(9), netif_set_tso_max_size(9), netif_set_tso_max_segs(9), netif_inherit_tso_max(9), netif_get_num_default_rss_queues(9), netif_device_detach(9), netif_device_attach(9), dev_loopback_xmit(9), __dev_queue_xmit(9), rps_flow_is_active(9), rps_may_expire_flow(9), __netif_rx(9), netif_rx(9), netdev_is_rx_handler_busy(9), netdev_rx_handler_register(9), netdev_rx_handler_unregister(9), netif_receive_skb_core(9), netif_receive_skb(9), netif_receive_skb_list(9), __napi_schedule(9), napi_schedule_prep(9), __napi_schedule_irqoff(9), netif_threaded_enable(9), netif_queue_set_napi(9), napi_disable(9), napi_enable(9),

netdev_has_upper_dev(9), netdev_has_upper_dev_all_rcu(9), netdev_has_any_upper_dev(9), netdev_master_upper_dev_get(9), netdev_has_any_lower_dev(9), netdev_upper_get_next_dev_rcu(9), netdev_lower_get_next_private(9), netdev_lower_get_next_private_rcu(9), netdev_lower_get_next(9), netdev_lower_get_first_private_rcu(9), netdev_master_upper_dev_get_rcu(9), netdev_upper_dev_link(9), netdev_master_upper_dev_link(9), netdev_upper_dev_unlink(9), netdev_bonding_info_change(9), netdev_sk_get_lowest_dev(9), netdev_lower_state_changed(9), netif_get_flags(9), netif_set_mtu_ext(9), netif_pre_changeaddr_notify(9), dev_get_phys_port_id(9), dev_get_phys_port_name(9), netif_get_port_parent_id(9), netdev_port_same_parent_id(9), netdev_change_proto_down_reason_locked(9), dev_change_xdp_fd(9), dev_index_reserve(9), netdev_update_features(9), netdev_change_features(9), netif_stacked_transfer_operstate(9), register_netdevice(9), register_netdev(9), netdev_wait_allrefs_any(9), dev_get_stats(9), dev_fetch_sw_netstats(9), dev_get_tstats64(9), netdev_sw_irq_coalesce_default_on(9), alloc_netdev_mqs(9), free_netdev(9), alloc_netdev_dummy(9), synchronize_net(9), unregister_netdevice_queue(9), unregister_netdevice_many(9), unregister_netdev(9), netdev_increment_features(9), netdev_compute_master_upper_features(9), netdev_drivername(9)

Yeah. All of them. Every single one. We don't do "etc." here 💅✨

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🎀 the sign-off 🎀

This cutie lives in the source ./net/core, dated October 2026, and it's page netdev_get_xmit_slave(9) of the kernel API manual. Hold that RCU lock, check for NULL, and go be the main character of your network stack 🌈👑💜