raw_atomic_fetch_or_acquire(9)

💅 raw_atomic_fetch_or_acquire — bestie edition ✨

okay so this is a page from the Kernel API Manual (section 9, kernel devs only, iykyk) and honestly? it's a little baddie with one job and she does it flawlessly. let's get into it 🎀

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🌸 NAME 🌸

raw_atomic_fetch_or_acquire — atomic bitwise OR with acquire ordering

like, atomic. bitwise. OR. with acquire ordering. the way she does all three at once? main character energy tbh 👑

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✨ SYNOPSIS ✨

int raw_atomic_fetch_or_acquire (int i , atomic_t *v );

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🦋 ARGUMENTS 🦋

• i — int value. just a plain lil int, your OR-ingredient 💖
• v — pointer to atomic_t. this is the lucky variable getting updated 🫶

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💫 DESCRIPTION 💫

okay so bestie, here's the tea: this function atomically updates v to (v | i) — with acquire ordering. atomic means nobody can catch her mid-update, no cap 🔥

and the acquire ordering part? that's the memory-barrier vibe, she's making sure stuff is properly ordered before you peek at anything after. iconic behavior honestly.

also: she's safe to use in noinstr code. but — and listen — prefer atomic_fetch_or_acquire elsewhere. the raw_ one is for the special instrumented-free situations, not your everyday flex 💅

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👑 RETURN 👑

the original value of v — like, the value before the OR happened. she gives you the receipts of what it used to be 🧾✨

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🌈 SEE ALSO 🌈

okay so there are like a MILLION siblings and cousins in this family, and honestly they're all serving. here's the whole group chat, in order, no one left out 💜

raw_atomic_read(9), raw_atomic_read_acquire(9), raw_atomic_set(9), raw_atomic_set_release(9), raw_atomic_add(9), raw_atomic_add_return(9), raw_atomic_add_return_acquire(9), raw_atomic_add_return_release(9), raw_atomic_add_return_relaxed(9), raw_atomic_fetch_add(9), raw_atomic_fetch_add_acquire(9), raw_atomic_fetch_add_release(9), raw_atomic_fetch_add_relaxed(9), raw_atomic_sub(9), raw_atomic_sub_return(9), raw_atomic_sub_return_acquire(9), raw_atomic_sub_return_release(9), raw_atomic_sub_return_relaxed(9), raw_atomic_fetch_sub(9), raw_atomic_fetch_sub_acquire(9), raw_atomic_fetch_sub_release(9), raw_atomic_fetch_sub_relaxed(9), raw_atomic_inc(9), raw_atomic_inc_return(9), raw_atomic_inc_return_acquire(9), raw_atomic_inc_return_release(9), raw_atomic_inc_return_relaxed(9), raw_atomic_fetch_inc(9), raw_atomic_fetch_inc_acquire(9), raw_atomic_fetch_inc_release(9), raw_atomic_fetch_inc_relaxed(9), raw_atomic_dec(9), raw_atomic_dec_return(9), raw_atomic_dec_return_acquire(9), raw_atomic_dec_return_release(9), raw_atomic_dec_return_relaxed(9), raw_atomic_fetch_dec(9), raw_atomic_fetch_dec_acquire(9), raw_atomic_fetch_dec_release(9), raw_atomic_fetch_dec_relaxed(9)

raw_atomic_and(9), raw_atomic_fetch_and(9), raw_atomic_fetch_and_acquire(9), raw_atomic_fetch_and_release(9), raw_atomic_fetch_and_relaxed(9), raw_atomic_andnot(9), raw_atomic_fetch_andnot(9), raw_atomic_fetch_andnot_acquire(9), raw_atomic_fetch_andnot_release(9), raw_atomic_fetch_andnot_relaxed(9), raw_atomic_or(9), raw_atomic_fetch_or(9), raw_atomic_fetch_or_release(9), raw_atomic_fetch_or_relaxed(9), raw_atomic_xor(9), raw_atomic_fetch_xor(9), raw_atomic_fetch_xor_acquire(9), raw_atomic_fetch_xor_release(9), raw_atomic_fetch_xor_relaxed(9), raw_atomic_xchg(9), raw_atomic_xchg_acquire(9), raw_atomic_xchg_release(9), raw_atomic_xchg_relaxed(9), raw_atomic_cmpxchg(9), raw_atomic_cmpxchg_acquire(9), raw_atomic_cmpxchg_release(9), raw_atomic_cmpxchg_relaxed(9), raw_atomic_try_cmpxchg(9), raw_atomic_try_cmpxchg_acquire(9), raw_atomic_try_cmpxchg_release(9), raw_atomic_try_cmpxchg_relaxed(9), raw_atomic_sub_and_test(9), raw_atomic_dec_and_test(9), raw_atomic_inc_and_test(9), raw_atomic_add_negative(9), raw_atomic_add_negative_acquire(9), raw_atomic_add_negative_release(9), raw_atomic_add_negative_relaxed(9), raw_atomic_fetch_add_unless(9), raw_atomic_add_unless(9), raw_atomic_inc_not_zero(9), raw_atomic_inc_unless_negative(9), raw_atomic_dec_unless_positive(9), raw_atomic_dec_if_positive(9)

raw_atomic64_read(9), raw_atomic64_read_acquire(9), raw_atomic64_set(9), raw_atomic64_set_release(9), raw_atomic64_add(9), raw_atomic64_add_return(9), raw_atomic64_add_return_acquire(9), raw_atomic64_add_return_release(9), raw_atomic64_add_return_relaxed(9), raw_atomic64_fetch_add(9), raw_atomic64_fetch_add_acquire(9), raw_atomic64_fetch_add_release(9), raw_atomic64_fetch_add_relaxed(9), raw_atomic64_sub(9), raw_atomic64_sub_return(9), raw_atomic64_sub_return_acquire(9), raw_atomic64_sub_return_release(9), raw_atomic64_sub_return_relaxed(9), raw_atomic64_fetch_sub(9), raw_atomic64_fetch_sub_acquire(9), raw_atomic64_fetch_sub_release(9), raw_atomic64_fetch_sub_relaxed(9), raw_atomic64_inc(9), raw_atomic64_inc_return(9), raw_atomic64_inc_return_acquire(9), raw_atomic64_inc_return_release(9), raw_atomic64_inc_return_relaxed(9), raw_atomic64_fetch_inc(9), raw_atomic64_fetch_inc_acquire(9), raw_atomic64_fetch_inc_release(9), raw_atomic64_fetch_inc_relaxed(9), raw_atomic64_dec(9), raw_atomic64_dec_return(9), raw_atomic64_dec_return_acquire(9), raw_atomic64_dec_return_release(9), raw_atomic64_dec_return_relaxed(9), raw_atomic64_fetch_dec(9), raw_atomic64_fetch_dec_acquire(9), raw_atomic64_fetch_dec_release(9), raw_atomic64_fetch_dec_relaxed(9)

raw_atomic64_and(9), raw_atomic64_fetch_and(9), raw_atomic64_fetch_and_acquire(9), raw_atomic64_fetch_and_release(9), raw_atomic64_fetch_and_relaxed(9), raw_atomic64_andnot(9), raw_atomic64_fetch_andnot(9), raw_atomic64_fetch_andnot_acquire(9), raw_atomic64_fetch_andnot_release(9), raw_atomic64_fetch_andnot_relaxed(9), raw_atomic64_or(9), raw_atomic64_fetch_or(9), raw_atomic64_fetch_or_acquire(9), raw_atomic64_fetch_or_release(9), raw_atomic64_fetch_or_relaxed(9), raw_atomic64_xor(9), raw_atomic64_fetch_xor(9), raw_atomic64_fetch_xor_acquire(9), raw_atomic64_fetch_xor_release(9), raw_atomic64_fetch_xor_relaxed(9), raw_atomic64_xchg(9), raw_atomic64_xchg_acquire(9), raw_atomic64_xchg_release(9), raw_atomic64_xchg_relaxed(9), raw_atomic64_cmpxchg(9), raw_atomic64_cmpxchg_acquire(9), raw_atomic64_cmpxchg_release(9), raw_atomic64_cmpxchg_relaxed(9), raw_atomic64_try_cmpxchg(9), raw_atomic64_try_cmpxchg_acquire(9), raw_atomic64_try_cmpxchg_release(9), raw_atomic64_try_cmpxchg_relaxed(9), raw_atomic64_sub_and_test(9), raw_atomic64_dec_and_test(9), raw_atomic64_inc_and_test(9), raw_atomic64_add_negative(9), raw_atomic64_add_negative_acquire(9), raw_atomic64_add_negative_release(9), raw_atomic64_add_negative_relaxed(9), raw_atomic64_fetch_add_unless(9), raw_atomic64_add_unless(9), raw_atomic64_inc_not_zero(9), raw_atomic64_inc_unless_negative(9), raw_atomic64_dec_unless_positive(9), raw_atomic64_dec_if_positive(9)

fr fr that's the whole squad, not one of them skipped 🫶

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and the actual source file for all this is ./include/linux/atomic — which lives in ./include/linux/atomic/atomic-arch-fallback.h for the arch fallback bits (yes bestie, the path is giving nesting-doll realness 🪆). this edition of the Kernel API Manual is dated October 2026 ✨

that's the whole page, mwah, go write some lock-free code and stay hydrated 💖🎀🦋