atomic_long...xchg_relaxed(9)

📦 version 7.3.1, in nixpkgs unstable

💅 NAME 💅

okay so this page is titled atomic_long...xchg_relaxed(9) (yes, abbreviated, it's giving mystery 💀) but the actual star of the show is atomic_long_try_cmpxchg_relaxed — an atomic compare and exchange with relaxed ordering. bestie, it's a compare-and-swap, but chill about it. 🫶

✨ SYNOPSIS ✨

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

like, that's the whole signature. no cap. ✨

🎀 ARGUMENTS 🎀

  • v — pointer to atomic_long_t — the vibe (and the value) lives here 💖
  • old — pointer to long value to compare with — the "are you the one I'm thinking of?" check 🦋
  • new — long value to assign — the glow-up you're swapping in 🌸

🦋 DESCRIPTION 🦋

okay so here's the tea ☕: if (v == old), it atomically updates v to new with relaxed ordering. slay. that's the whole point. 🔥

otherwise? v is not modified 😭 — instead, old gets updated to the current value of v, and relaxed ordering is provided. so it's like, "oops, here's what's actually there, bestie, sorry for the mix-up". 🙈

⚠️ heads up fr fr: this is unsafe to use in noinstr code. if you're in noinstr land, use raw_atomic_long_try_cmpxchg_relaxed there instead. don't be that girl. 💅

🌸 RETURN 🌸

  • true if the exchange occurred 👑 (you ate, congrats)
  • false otherwise 💀 (no exchange, but old got a lil update)

🫶 SEE ALSO 🫶

the kernel file is ./include/linux/atomic/atomic-instrumented.h, and it is one hundred percent holding the entire friend group of atomics. prepare yourself, this list is a long one but every single one of them is here 🧚:

✨ and that's the whole page, bestie ✨ this lil gem comes from the source file ./include/linux/atomic, dated October 2026, and it signs off as atomic_long...xchg_relaxed(9) — go forth and compare-and-exchange responsibly, ily 💜🦋

📦 where this page comes from