netif_setup_tc(9)

📦 version 7.3.1, in nixpkgs unstable

✨ NAME ✨

Okay so, bestie, welcome to the Kernel API Manual page for netif_setup_tc(9) — yes, the (9) means kernel API, iykyk. 💅 This one is all about handling tc mappings on a real_num_tx_queues change. Lowkey iconic, highkey important. 🎀

🎀 SYNOPSIS 🎀

Here's the signature, no cap — copy it exactly:

void netif_setup_tc (struct net_device *dev , unsigned int txq );

🦋 ARGUMENTS 🦋

  • dev — the network device. Your main character struct, fr fr. 🌐
  • txq — the number of queues available. The queue count, bestie. 🎟️

🌸 DESCRIPTION 🌸

Okay so here's the tea. If real_num_tx_queues changes, the tc mappings may no longer be valid. Not cute. 😭 To resolve this, the function verifies that the tc mapping remains valid and, if it doesn't, it NULLs the mapping. Periodt. 💅

With no priorities mapping to this offset/count pair, it will no longer be used. Simple as that. 🦋

🚨 worst case alert: TC0 is invalid and nothing can be done — so priority mappings get disabled. Not a slay, but it's what happens. 💀

It's expected that drivers will fix this mapping if they can before calling netif_set_real_num_tx_queues. So do your homework first, bestie. 📚✨

🌈 SEE ALSO 🌈

This is the part where I hold your hand and we go through the whole friend group. Not one link left behind, no cap. The kernel file is ./net/core/dev.c, and here's every single reference:

Source/version check: this page is from ./net/core, dated October 2026. That's the footer, bestie — and that's the whole page. You ate. 💅✨

📦 where this page comes from