atomic_fetch_or_acquire(9)

okay bestie 💖 welcome to atomic_fetch_or_acquire(9) — yep, from the Kernel API Manual. this is gonna be iconic, let's go ✨

🌸 NAME 🌸

atomic_fetch_or_acquire — atomic bitwise OR with acquire ordering. periodt. 💅

✨ SYNOPSIS ✨

int atomic_fetch_or_acquire (int i , atomic_t *v );

🎀 ARGUMENTS 🎀

• i — an int value. that's the value, bestie.
• v — pointer to atomic_t. literally a pointer to the atomic thing.

🦋 DESCRIPTION 🦋

okay so here's the tea: it atomically updates v to (v | i) with acquire ordering. no cap. 🔥

⚠️ unsafe to use in noinstr code — like, for real — use raw_atomic_fetch_or_acquire there instead. do not play with that one. 💀

👑 RETURN 👑

it gives you back the original value of v. that's the whole return vibe. 🫶

🔥 SEE ALSO 🔥

the whole atomic bestie family is here, plus the kernel file ./include/linux/atomic/atomic-instrumented.h. iykyk:

Kernel file ./include/linux/atomic/atomic-instrumented.h 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_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_acquire(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)

and that's the whole page! cute little sign-off: source/version is ./include/linux/atomic, dated October 2026, page atomic_fetch_or_acquire(9) 🫶✨💖