down_timeout(9)

💅 down_timeout(9) — the kernel semaphore page, bestie edition ✨

okay so real talk, this is down_timeout(9) from the Kernel API Manual, and it's genuinely one of those little functions that eats. let's get into it 🫶

---

✨ NAME ✨

down_timeout — acquire the semaphore, but like… within a specified time ⏰ no cap, there's a deadline

---

🎀 SYNOPSIS 🎀

int down_timeout (struct semaphore *sem , long timeout );

look at her. tiny signature, huge main character energy 👑

---

🌸 ARGUMENTS 🌸

• sem — the semaphore you're trying to acquire. yes that semaphore. the one. 💅
• timeout — how long you're willing to wait before it all falls apart and the function fails 😭 literally the patience meter

---

🦋 DESCRIPTION 🦋

so the whole vibe here is: this function attempts to acquire the semaphore. that's the goal, that's the dream ✨

but bestie, plot twist — if no more tasks are allowed to acquire the semaphore, calling this function will put the task to sleep 😴 like it's not ghosting you, it's just napping until the semaphore's available, iykyk.

and here's the part where you gotta pay attention 👀 if the semaphore is not released within the specified number of jiffies, this function returns -ETIME. the clock runs out, the vibe check fails, you get -ETIME, periodt 💀

but if it does work out? it returns 0 because the semaphore was acquired 🎉 slay. iconic. we love a success return.

so like, 0 = you got it 💖 and -ETIME = time ran out, sorry babe 🕰️

---

🌈 SEE ALSO 🌈

• Kernel file ./kernel/locking/semaphore.c
• down(9)
• down_interruptible(9)
• down_killable(9)
• down_trylock(9)
• up(9)

go read the whole semaphore friend group, they're all lowkey linked 🧚

---

and that's the page!! brought to you by ./kernel/locking, dated October 2026, mwah 💜 see you in the next manpage bestie 🎀✨