atomic64_fetch_or_acquire(9)

💅 atomic64_fetch_or_acquire 💅

okay so first things first, bestie: this page lives in the Kernel API Manual, section 9, and it's about one (1) extremely specific little function. She's not famous. She's not flashy. But she does her one job perfectly and honestly we respect that so much. 🫶

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💖 NAME 💖

atomic64_fetch_or_acquire — atomic bitwise OR with acquire ordering ✨

that's it, that's the whole name. bitwise OR, done atomically, with acquire ordering on top. slay.

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🎀 SYNOPSIS 🎀

s64 atomic64_fetch_or_acquire (s64 i , atomic64_t *v );

yes the spacing in there is a little chaotic, no we are not fixing it, it's part of her lore 💀

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🌸 ARGUMENTS 🌸

• i — an s64 value. this is the thing getting OR'd in, she's just happy to be here.
• v — pointer to atomic64_t. this is the target, the main character, the one getting updated. 👑

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🦋 DESCRIPTION 🦋

Atomically updates v to (v | i) with acquire ordering. 💫

read that again slowly because it's kind of a lot: the old v gets OR'd with i, and that new value lands in v, all as one atomic operation — nobody catches it mid-pipeline, it's giving full main character energy with zero half-finished moments. and it's an acquire ordering version, hence the very long last name. 🧚

⚠️ Unsafe to use in noinstr code — use raw_atomic64_fetch_or_acquire there instead. this is a real warning, not a vibe, pls respect it 🙈

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🔥 RETURN 🔥

The original value of v. not the new one, not the OR'd one — the one from before. so you get the receipt while the update still happens. iconic behaviour honestly 💖

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💜 SEE ALSO 💜

Kernel file: ./include/linux/atomic/atomic-instrumented.h

and now... the guest list. literally everyone showed up. every single one of these is real and you're gonna need snacks for the atomic_long_* section 🍓

atomic_read(9), atomic_read_acquire(9), atomic_set(9), atomic_set_release(9),
atomic_add(9), atomic_add_return(9), atomic_add_return_acquire(9),
atomic_add_return_release(9), atomic_add_return_relaxed(9),
atomic_fetch_add(9), atomic_fetch_add_acquire(9),
atomic_fetch_add_release(9), atomic_fetch_add_relaxed(9), atomic_sub(9),
atomic_sub_return(9), atomic_sub_return_acquire(9),
atomic_sub_return_release(9), atomic_sub_return_relaxed(9),
atomic_fetch_sub(9), atomic_fetch_sub_acquire(9),
atomic_fetch_sub_release(9), atomic_fetch_sub_relaxed(9), atomic_inc(9),
atomic_inc_return(9), atomic_inc_return_acquire(9),
atomic_inc_return_release(9), atomic_inc_return_relaxed(9),
atomic_fetch_inc(9), atomic_fetch_inc_acquire(9),
atomic_fetch_inc_release(9), atomic_fetch_inc_relaxed(9), atomic_dec(9),
atomic_dec_return(9), atomic_dec_return_acquire(9),
atomic_dec_return_release(9), atomic_dec_return_relaxed(9),
atomic_fetch_dec(9), atomic_fetch_dec_acquire(9),
atomic_fetch_dec_release(9), atomic_fetch_dec_relaxed(9), atomic_and(9),
atomic_fetch_and(9), atomic_fetch_and_acquire(9),
atomic_fetch_and_release(9), atomic_fetch_and_relaxed(9),
atomic_andnot(9), atomic_fetch_andnot(9),
atomic_fetch_andnot_acquire(9), atomic_fetch_andnot_release(9),
atomic_fetch_andnot_relaxed(9), atomic_or(9), atomic_fetch_or(9),
atomic_fetch_or_acquire(9), atomic_fetch_or_release(9),
atomic_fetch_or_relaxed(9), atomic_xor(9), atomic_fetch_xor(9),
atomic_fetch_xor_acquire(9), atomic_fetch_xor_release(9),
atomic_fetch_xor_relaxed(9), atomic_xchg(9), atomic_xchg_acquire(9),
atomic_xchg_release(9), atomic_xchg_relaxed(9), atomic_cmpxchg(9),
atomic_cmpxchg_acquire(9), atomic_cmpxchg_release(9),
atomic_cmpxchg_relaxed(9), atomic_try_cmpxchg(9),
atomic_try_cmpxchg_acquire(9), atomic_try_cmpxchg_release(9),
atomic_try_cmpxchg_relaxed(9), atomic_sub_and_test(9),
atomic_dec_and_test(9), atomic_inc_and_test(9), atomic_add_negative(9),
atomic_add_negative_acquire(9), atomic_add_negative_release(9),
atomic_add_negative_relaxed(9), atomic_fetch_add_unless(9),
atomic_add_unless(9), atomic_inc_not_zero(9),
atomic_inc_unless_negative(9), atomic_dec_unless_positive(9),
atomic_dec_if_positive(9), atomic64_read(9), atomic64_read_acquire(9),
atomic64_set(9), atomic64_set_release(9), atomic64_add(9),
atomic64_add_return(9), atomic64_add_return_acquire(9),
atomic64_add_return_release(9), atomic64_add_return_relaxed(9),
atomic64_fetch_add(9), atomic64_fetch_add_acquire(9),
atomic64_fetch_add_release(9), atomic64_fetch_add_relaxed(9),
atomic64_sub(9), atomic64_sub_return(9), atomic64_sub_return_acquire(9),
atomic64_sub_return_release(9), atomic64_sub_return_relaxed(9),
atomic64_fetch_sub(9), atomic64_fetch_sub_acquire(9),
atomic64_fetch_sub_release(9), atomic64_fetch_sub_relaxed(9),
atomic64_inc(9), atomic64_inc_return(9), atomic64_inc_return_acquire(9),
atomic64_inc_return_release(9), atomic64_inc_return_relaxed(9),
atomic64_fetch_inc(9), atomic64_fetch_inc_acquire(9),
atomic64_fetch_inc_release(9), atomic64_fetch_inc_relaxed(9),
atomic64_dec(9), atomic64_dec_return(9), atomic64_dec_return_acquire(9),
atomic64_dec_return_release(9), atomic64_dec_return_relaxed(9),
atomic64_fetch_dec(9), atomic64_fetch_dec_acquire(9),
atomic64_fetch_dec_release(9), atomic64_fetch_dec_relaxed(9),
atomic64_and(9), atomic64_fetch_and(9), atomic64_fetch_and_acquire(9),
atomic64_fetch_and_release(9), atomic64_fetch_and_relaxed(9),
atomic64_andnot(9), atomic64_fetch_andnot(9),
atomic64_fetch_andnot_acquire(9), atomic64_fetch_andnot_release(9),
atomic64_fetch_andnot_relaxed(9), atomic64_or(9), atomic64_fetch_or(9),
atomic64_fetch_or_release(9), atomic64_fetch_or_relaxed(9),
atomic64_xor(9), atomic64_fetch_xor(9), atomic64_fetch_xor_acquire(9),
atomic64_fetch_xor_release(9), atomic64_fetch_xor_relaxed(9),
atomic64_xchg(9), atomic64_xchg_acquire(9), atomic64_xchg_release(9),
atomic64_xchg_relaxed(9), atomic64_cmpxchg(9),
atomic64_cmpxchg_acquire(9), atomic64_cmpxchg_release(9),
atomic64_cmpxchg_relaxed(9), atomic64_try_cmpxchg(9),
atomic64_try_cmpxchg_acquire(9), atomic64_try_cmpxchg_release(9),
atomic64_try_cmpxchg_relaxed(9), atomic64_sub_and_test(9),
atomic64_dec_and_test(9), atomic64_inc_and_test(9),
atomic64_add_negative(9), atomic64_add_negative_acquire(9),
atomic64_add_negative_release(9), atomic64_add_negative_relaxed(9),
atomic64_fetch_add_unless(9), atomic64_add_unless(9),
atomic64_inc_not_zero(9), atomic64_inc_unless_negative(9),
atomic64_dec_unless_positive(9), atomic64_dec_if_positive(9),
atomic_long_read(9), atomic_long_read_acquire(9), atomic_long_set(9),
atomic_long_set_release(9), atomic_long_add(9),
atomic_long_add_return(9), atomic_long_add_return_acquire(9),
atomic_long_add_return_release(9), atomic_long_add_return_relaxed(9),
atomic_long_fetch_add(9), atomic_long_fetch_add_acquire(9),
atomic_long_fetch_add_release(9), atomic_long_fetch_add_relaxed(9),
atomic_long_sub(9), atomic_long_sub_return(9),
atomic_long_sub_return_acquire(9), atomic_long_sub_return_release(9),
atomic_long_sub_return_relaxed(9), atomic_long_fetch_sub(9),
atomic_long_fetch_sub_acquire(9), atomic_long_fetch_sub_release(9),
atomic_long_fetch_sub_relaxed(9), atomic_long_inc(9),
atomic_long_inc_return(9), atomic_long_inc_return_acquire(9),
atomic_long_inc_return_release(9), atomic_long_inc_return_relaxed(9),
atomic_long_fetch_inc(9), atomic_long_fetch_inc_acquire(9),
atomic_long_fetch_inc_release(9), atomic_long_fetch_inc_relaxed(9),
atomic_long_dec(9), atomic_long_dec_return(9),
atomic_long_dec_return_acquire(9), atomic_long_dec_return_release(9),
atomic_long_dec_return_relaxed(9), atomic_long_fetch_dec(9),
atomic_long_fetch_dec_acquire(9), atomic_long_fetch_dec_release(9),
atomic_long_fetch_dec_relaxed(9), atomic_long_and(9),
atomic_long_fetch_and(9), atomic_long_fetch_and_acquire(9),
atomic_long_fetch_and_release(9), atomic_long_fetch_and_relaxed(9),
atomic_long_andnot(9), atomic_long_fetch_andnot(9),
atomic_long_fetch_andnot_acquire(9),
atomic_long_fetch_andnot_release(9),
atomic_long_fetch_andnot_relaxed(9), atomic_long_or(9),
atomic_long_fetch_or(9), atomic_long_fetch_or_acquire(9),
atomic_long_fetch_or_release(9), atomic_long_fetch_or_relaxed(9),
atomic_long_xor(9), atomic_long_fetch_xor(9),
atomic_long_fetch_xor_acquire(9), atomic_long_fetch_xor_release(9),
atomic_long_fetch_xor_relaxed(9), atomic_long_xchg(9),
atomic_long_xchg_acquire(9), atomic_long_xchg_release(9),
atomic_long_xchg_relaxed(9), atomic_long_cmpxchg(9),
atomic_long_cmpxchg_acquire(9), atomic_long_cmpxchg_release(9),
atomic_long_cmpxchg_relaxed(9), atomic_long_try_cmpxchg(9),
atomic_long_try_cmpxchg_acquire(9), atomic_long_try_cmpxchg_release(9),
atomic_long_try_cmpxchg_relaxed(9), atomic_long_sub_and_test(9),
atomic_long_dec_and_test(9), atomic_long_inc_and_test(9),
atomic_long_add_negative(9), atomic_long_add_negative_acquire(9),
atomic_long_add_negative_release(9),
atomic_long_add_negative_relaxed(9), atomic_long_fetch_add_unless(9),
atomic_long_add_unless(9), atomic_long_inc_not_zero(9),
atomic_long_inc_unless_negative(9), atomic_long_dec_unless_positive(9),
atomic_long_dec_if_positive(9)

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and that's the whole page, bestie, you ate that 💅✨ go forth and OR things atomically. this came to you from ./include/linux/atomic, dated October 2026 — kiss kiss, iykyk 🎀🦋💖