atomic_dec_unless_positive(9)

💅 atomic_dec_unless_positive(9) — Kernel API Manual ✨

okay so bestie, welcome to the page for atomic_dec_unless_positive(9) from the Kernel API Manual. This is the atomic decrement that only does its thing when the value isn’t positive, and it brings full ordering energy. 🎀

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🌸 NAME 🌸

atomic_dec_unless_positive — atomic decrement unless positive with full ordering. Periodt. 💅

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✨ SYNOPSIS ✨

The signature is giving:

bool atomic_dec_unless_positive (atomic_t *v );

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🎀 ARGUMENTS 🎀

• v — pointer to atomic_t (the atomic value you’re checking, bestie).

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💅 DESCRIPTION 💅

Okay so here’s the vibe: If (v <= 0), it atomically updates v to (v - 1) with full ordering. Otherwise, v is not modified and relaxed ordering is provided. That’s the whole behavior — no extra lore. 🦋

🚨 Unsafe to use in noinstr code — use raw_atomic_dec_unless_positive there instead. That’s literally the rule, not me being dramatic. 😭

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🦋 RETURN 🦋

true if v was updated, false otherwise. Iconic. ✨

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🌈 SEE ALSO 🌈

Kernel file: ./include/linux/atomic/atomic-instrumented.h — that’s the home base. The whole (9) friend group is below, exact names, no cap: 👑

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_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)

xoxo 💖 source/version and date: ./include/linux/atomic · October 2026 — atomic_dec_unless_positive(9) out ✨