raw_atomic_long_try_cmpxchg(9)

📦 version 7.3.1, in nixpkgs unstable

💅 raw_atomic_long_try_cmpxchg (9) 💅

okay so you found the page bestie — this is from the Kernel API Manual and it's literally the "compare and swap, but make it raw" girlie. full ordering, no notes, let's go 🫶

✨ SYNOPSIS ✨

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

look at her. three args, one bool, zero drama 💖

🎀 ARGUMENTS 🎀

  • v — pointer to atomic_long_t. the thing we're plotting against 👀
  • old — pointer to the long value you wanna compare with. note: pointer, not the value itself. yes, really, it's a whole thing 💀
  • new — the long value to assign. the glow-up you're trying to give v ✨

🌸 DESCRIPTION 🌸

so here's the tea ☕ if (v == old), she atomically updates v to new with full ordering. slay, iconic, no cap 🔥

but if that comparison does not hold? then nope — v is not modified at all. instead, old gets updated to the current value of v, and relaxed ordering is provided. it's giving "the boomerang of information" 🪃 iykyk

✨ wild but true: this one is safe to use in noinstr code. but the page says to prefer atomic_long_try_cmpxchg everywhere else — so she's the specialist, not the default 💅

🦋 RETURN 🦋

true if the exchange actually occurred, false otherwise. binary queen 👑

🌈 SEE ALSO 🌈

the whole friend group fr fr — she's not doing this alone:

reading & setting

adding

subtracting

incrementing

decrementing

bitwise and / andnot

bitwise or / xor

exchanging

the cmpxchg cousins (our girl's whole bloodline 💜)

tests & negativity

the "unless" girlies (conditional queens) 👑

the source — Kernel file ./include/linux/atomic/atomic-long.h 📁

and that's the whole page bestie, no crumbs left 🍓 she lives in ./include/linux/atomic, she's stamped October 2026, and she's out here representing the Kernel API Manual with main character energy. periodt. 💅✨

📦 where this page comes from