atomic_dec_and_mutex_lock(9)

✨ atomic_dec_and_mutex_lock(9) ✨

okay so this is a page from the Kernel API Manual, and the main character is atomic_dec_and_mutex_lock(9) — she decrements an atomic and maybe hands you a held mutex, iykyk 💅

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🌸 NAME 🌸

• atomic_dec_and_mutex_lock — return holding mutex if we dec to 0

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🦋 SYNOPSIS 🦋

int atomic_dec_and_mutex_lock (atomic_t *cnt , struct mutex *lock );

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💅 ARGUMENTS 💅

• cnt — the atomic which we are to dec, bestie 🎀
• lock — the mutex to return holding if we dec to 0

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🔥 DESCRIPTION 🔥

the vibe is literally this: return true and hold lock if we dec to 0, return false otherwise. periodt. no cap, that’s the whole behavior ✨

lowkey important: if it returns true, you’re holding the mutex. if it returns false, you’re not. keep that energy in mind 🫶

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🌈 SEE ALSO 🌈

• Kernel file: ./kernel/locking/mutex.c
• mutex_lock(9)
• mutex_unlock(9)
• ww_mutex_unlock(9)
• ww_mutex_trylock(9)
• mutex_lock_interruptible(9)
• mutex_lock_killable(9)
• mutex_lock_io(9)
• mutex_trylock(9)

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so yeah, this iconic little page comes from the ./kernel/locking source/version situation, dated October 2026 — and that’s the cute sign-off, bestie 💜🦋✨