atomic_fetch_xor_acquire(9)

📦 version 7.3.1, in nixpkgs unstable

💅 atomic_fetch_xor_acquire — kernel API manual, bestie edition 🦋

Okay so we're looking at atomic_fetch_xor_acquire from the Kernel API Manual, and honestly? She's a little icon of a function. Let's get into it ✨

🌸 NAME 🌸

atomic_fetch_xor_acquire — atomic bitwise XOR with acquire ordering, periodt 💅

🎀 SYNOPSIS 🎀

int atomic_fetch_xor_acquire (int i , atomic_t *v );

💖 ARGUMENTS 💖

  • i — an int value, that's it, that's her 🫶
  • v — pointer to atomic_t, i.e. the vibe we're about to update

✨ DESCRIPTION ✨

So what she does is: atomically updates v to (v ^ i) — with acquire ordering 🧚 Like, the whole thing happens in one go, no one can catch her mid-XOR, and the acquire ordering is doing its memory-ordering thing while she slays.

⚠️ Real talk though: this is unsafe to use in noinstr code. If you're in there, use raw_atomic_fetch_xor_acquire instead. No exceptions, bestie 😭

🔥 RETURN 🔥

She gives you back the original value of v — the one from before the XOR. Like getting a receipt for the past 💀

👑 SEE ALSO 👑

The kernel file is ./include/linux/atomic/atomic-instrumented.h, and here's the whole friend group, no cap — every single one of them:

That's the whole squad, iykyk 🌈 Go forth and XOR atomically, bestie 💜

Source: ./include/linux/atomic · Dated: October 2026 · Page: atomic_fetch_xor_acquire(9) 🎀 slay and goodbye 🎀

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