raw_atomic_...xchg_acquire(9)

📦 version 7.3.1, in nixpkgs unstable

💅 raw_atomic_...xchg_acquire(9) — like, the Kernel API Manual page you actually wanna read 🎀

okay bestie, so you opened the Kernel API Manual entry for raw_atomic_...xchg_acquire(9) and I'm gonna walk you through it like we're texting at 2am, except every single fact is still here. no cap. 🦋

✨ NAME ✨

raw_atomic_long_try_cmpxchg_acquire — atomic compare and exchange with acquire ordering 💅

✨ SYNOPSIS ✨

bool raw_atomic_long_try_cmpxchg_acquire (atomic_long_t *v , long *old ,
long new );

✨ ARGUMENTS ✨

  • v — pointer to atomic_long_t. it's the thing we're side-eyeing 👀
  • old — pointer to a long value to compare with. yes, a pointer, not the value itself, we'll get to why that slays
  • new — the long value to assign if the vibe check passes ✨

✨ DESCRIPTION ✨

so here's the tea 🍓: if (v == old), it atomically updates v to new with acquire ordering. iconic. main character behavior.

otherwise? v is not modified 🚫, old gets updated to the current value of v (that's why it's a pointer, bestie — it's giving you the receipts), and relaxed ordering is provided.

safe to use in noinstr code 🫶 but prefer atomic_long_try_cmpxchg_acquire everywhere else. like, raw_ is the backstage pass, not the everyday fit 💀

✨ RETURN ✨

true if the exchange occurred 💖 false otherwise 🙈

✨ SEE ALSO ✨

first up, the source of truth, the origin story 👑:

  • Kernel file ./include/linux/atomic/atomic-long.h

and then the whole friend group 😭 — literally the entire atomic_long roster, all of them, no one left out:

the read/set girlies 🌸

add arc ➕

sub arc ➖

inc arc ⬆️

dec arc ⬇️

bitwise era 🧚

the exchange / compare-and-exchange section, aka our whole family 🔥

test / negative / unless squad 💀✨

and that's the whole page bestie, you ate that 🫶 the manual source directory is ./include/linux/atomic and this one's stamped October 2026, which honestly is giving time-traveler energy 👑 stay atomic, stay acquire-ordered, mwah 💜💖✨

📦 where this page comes from