tb_tunnel_alloc_dma(9)

📦 version 7.3.1, in nixpkgs unstable

💖 tb_tunnel_alloc_dma(9) 💖

okay so this is a page from the Kernel API Manual and bestie, it's literally about allocating a DMA tunnel. Strap in, it's giving kernel-internals realness and honestly? kind of iconic.

✨ NAME ✨

tb_tunnel_alloc_dma — allocate a DMA tunnel 🌀

🎀 SYNOPSIS 🎀

struct tb_tunnel * tb_tunnel_alloc_dma (struct tb *tb , struct tb_port
*nhi , struct tb_port *dst , int transmit_path , int transmit_ring , int
receive_path , int receive_ring );

(yes it's a whole mouthful, copy it exactly, don't @ me 💅)

🦋 ARGUMENTS 🦋

  • tb — Pointer to the domain structure. like, the whole domain vibe check 🌈
  • nhi — Host controller port. the main character port fr 👑
  • dst — Destination null port which the other domain is connected to. it's the port on the other side, slay 💫
  • transmit_path — HopID used for transmitting packets. that's the ID for the send-direction hops 🛫
  • transmit_ring — NHI ring number used to send packets towards the other domain. set this to -1 if the TX path is not needed, k? lowkey important 🙈
  • receive_path — HopID used for receiving packets. the ID for the receive-direction hops 🛬
  • receive_ring — NHI ring number used to receive packets from the other domain. set this to -1 if the RX path is not needed either 💀

⭐ RETURN ⭐

Pointer to struct tb_tunnel, or NULL in case of failure. so like, check it before you use it bestie, no cap 🫶

🌸 SEE ALSO 🌸

Kernel file ./drivers/thunderbolt/tunnel.c — and the whole friend group:

💡 friendly reminder: -1 on transmit_ring or receive_ring means that direction isn't needed — don't come for me if you pass -1 and then wonder why a path is missing, iykyk 😭

and that's the whole page, bestie!! sourced from ./drivers/thunderbolt, dated October 2026 — go forth and allocate responsibly 🧚‍♀️✨💜

📦 where this page comes from