tty_ldisc_ref_wait(9)

📦 version 7.3.1, in nixpkgs unstable

✨ tty_ldisc_ref_wait ✨

okay so bestie, welcome to the kernel API manual for tty_ldisc_ref_wait — yes it's giving obscure-subsystem energy but honestly it's kind of iconic once you get it 🎀

🌸 SYNOPSIS 🌸

struct tty_ldisc * tty_ldisc_ref_wait (struct tty_struct *tty );

💖 ARGUMENTS 💖

  • tty — the tty device, bestie. that's the one. the terminal in question 🖥️✨

🦋 DESCRIPTION 🦋

So what this does is: it dereferences the line discipline for the terminal and takes a reference to it. That's the whole vibe. 💅

And if the line discipline is in flux — like, mid-change, going through it, having a moment — then it just waits patiently until it changes. no cap. it literally waits. 🫶

⚠️ Note 1

Must not be called from an IRQ/timer context. periodt. 🙅‍♀️

The caller also has to be careful not to hold other locks that will deadlock against a discipline change — like, for example, an existing ldisc reference (which, fun fact, we check for 👀).

💀 Note 2

A file_operations routine (read/poll/write) should use this function to wait for any ldisc lifetime events to finish. like it's literally the designated waiter for that job 🍓

🔥 RETURN 🔥

  • NULL — if the tty has been hungup and not re-opened with a new file descriptor 😭
  • otherwise — a valid ldisc reference 👑✨

🌈 SEE ALSO 🌈

Kernel file ./drivers/tty/tty_ldisc.c, plus the whole friend group:

and that's the page, babe 💜 this iconic little number lives in ./drivers/tty, dated October 2026, and it's part of the Kernel API Manual — go forth and reference your line disciplines responsibly, mwah 🧚‍♀️💋

📦 where this page comes from