atomic_sub_return_acquire(9)

💅 atomic_sub_return_acquire 💅

okay bestie, so this page is from the Kernel API Manual, and it's about one (1) little function that does a very specific thing. it's giving "small but mighty" energy. let's go 🫶

---

✨ NAME ✨

atomic_sub_return_acquire — atomic subtract with acquire ordering

literally what it says on the tin. subtract, atomically, and give you the result back. with acquire ordering. slay 💅

---

🌸 SYNOPSIS 🌸

int atomic_sub_return_acquire (int i , atomic_t *v );

that's the whole signature. two args, returns an int. clean, iconic, no notes. ✨

---

🎀 ARGUMENTS 🎀

• i — an int value: the thing you're subtracting. this is how much you want to take off, okay? 💖
• v — pointer to atomic_t. this is the counter itself, the main character of the whole operation 👑

---

🦋 DESCRIPTION 🦋

so the whole vibe is this: it atomically updates v to (v - i), and it does it with acquire ordering. atomically means nobody can sneak in halfway through and mess up your math — no cap, it's one indivisible operation. 🧚

⚠️ important warning bestie: this is unsafe to use in noinstr code. if you're in noinstr land, use raw_atomic_sub_return_acquire there instead. don't argue with me on this one, just use the raw one 🙈

---

⭐ RETURN ⭐

it returns the updated value of v. not the old one, not the difference — the new value after the subtraction. that's the whole tea ☕✨

---

🌈 SEE ALSO 🌈

okay so the kernel file is ./include/linux/atomic/atomic-instrumented.h, and the cross-reference list on this page is genuinely the entire atomic cinematic universe — like, every single cousin showed up to the function family reunion 🎉

the atomic_* crew: 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_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)

the atomic64_* girlies (big numbers, big energy): 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)

the atomic_long_* squad: 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)

like I said. everyone came. 💀🔥

---

and that's the page!! 🫶 this lil gem lives in ./include/linux/atomic and the dated stamp on it is October 2026 — so yeah, mark your calendar, bestie, that's the version you're reading. go forth and subtract atomically ✨💖