atomic64_sub_and_test(9)

okay so bestie, you're on the atomic64_sub_and_test(9) page in the Kernel API Manual, and it's literally giving atomic subtract-and-check-if-zero energy 💅✨

🌸 NAME 🌸

atomic64_sub_and_test — atomic subtract and test if zero with full ordering. That's the whole vibe, no cap.

---

✨ SYNOPSIS ✨

bool atomic64_sub_and_test (s64 i , atomic64_t *v );

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🎀 ARGUMENTS 🎀

• i — an s64 value to subtract, aka the amount getting taken off the atomic counter.
• v — pointer to atomic64_t, the atomic bestie that's getting updated.

---

💅 DESCRIPTION 💅

It atomically updates v to (v - i) with full ordering. Iconic, synchronized, zero vibes lost.

🚨 Safety vibe check: this is unsafe to use in noinstr code. Use raw_atomic64_sub_and_test there instead, periodt.

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🦋 RETURN 🦋

true if the resulting value of v is zero, false otherwise. That's the whole test, bestie.

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🔥 SEE ALSO 🔥

Kernel file ./include/linux/atomic/atomic-instrumented.h — that's the source file, and then the entire atomic family roll call. Every single ref is here, because we do not drop links in this house 🫶

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_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_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)

source/version ./include/linux/atomic, dated October 2026, on the atomic64_sub_and_test(9) page — bye bestie, stay atomic 💖