dma_resv_reserve_fences(9)

📦 version 7.3.1, in nixpkgs unstable

💖 dma_resv_reserve_fences(9) — Kernel API Manual, but make it make sense 💖

okay bestie, sit down, we're learning dma_resv_reserve_fences today and honestly? she's a prep girlie — you have to book the space before the party even starts 🎀

✨ NAME ✨

dma_resv_reserve_fences — literally just reserving space so you can add fences to a dma_resv object later. that's the whole vibe 🦋

🌸 SYNOPSIS 🌸

int dma_resv_reserve_fences (struct dma_resv *obj , unsigned int num_fences );

like, she takes two things and returns an int. slay.

🎀 ARGUMENTS 🎀

  • obj — the reservation object. your main character, fr fr 🫶
  • num_fences — how many fences we wanna add. the headcount for the function 💅

💜 DESCRIPTION 💜

okay so the way this works: you call this before dma_resv_add_fence. not after, not during — before. it's giving "RSVP before the event," iykyk 🌈

and you must be holding obj locked through dma_resv_lock when you call it. no lock, no service 🙈

⚠️ important caveat bestie: if obj gets unlocked at any point before you call dma_resv_add_fence, those preallocated slots have to be re-reserved. like, the reservation expires. this gets validated when CONFIG_DEBUG_MUTEXES is enabled, so the kernel will catch you if you skip it 😭

RETURNS — 0 for success, or -errno if things went sideways 💀

🔥 SEE ALSO 🔥

🧚 catch you in ./drivers/dma-buf, dated October 2026 — brought to you by the Kernel API Manual, version dma_resv_reserve_fences(9). that's the tea, go reserve those fences 💖✨

📦 where this page comes from