dma_fence_is_signaled(9)

📦 version 7.3.1, in nixpkgs unstable

okay bestie, welcome to the dma_fence_is_signaled(9) page straight out of the Kernel API Manual — yes it's a kernel thing, no you don't have to be scared, we're gonna get through it together 🫶✨

🌸 NAME 🌸

dma_fence_is_signaled — the little function that tells you whether a fence has been signaled yet. that's it, that's the whole vibe 💅

✨ SYNOPSIS ✨

bool dma_fence_is_signaled (struct dma_fence *fence );

like, look at her. one argument. returns a bool. main character energy honestly 👑

🎀 ARGUMENTS 🎀

  • fence — the fence you wanna check. that's the one, bestie, that's who we're asking about 🔍

🦋 DESCRIPTION 🦋

So here's the tea ☕ — this function returns true if the fence was already signaled, and false if it wasn't. simple as that.

BUT — and this is the important part, don't skip it — because this function doesn't enable signaling, it is not guaranteed to ever return true if dma_fence_add_callback, dma_fence_wait or dma_fence_enable_signaling haven't been called before. so like, if nobody set up the signaling, she might just keep saying false forever. not her fault, she's just reporting what she knows 😭

lowkey this is the one that gets people — no cap, check that the signaling machinery is actually running before you trust a false 💀

Also, for seqno fences it's recommended to call dma_fence_signal when the operation is complete. why? because it makes it possible to prevent issues from wraparound</> between time of issue and time of use — by checking the return value of this function before calling hardware-specific wait instructions. so you check first, wait second. that's the order. iykyk 🌈

See also dma_fence_is_signaled_locked — her locked cousin, iconic in her own right 💖

🔥 SEE ALSO 🔥

okay this list is long but we're not skipping a single one, we respect every link here 🫡

Kernel file ./include/linux/dma-fence.h:

like, twenty-five whole friends. she's got a whole group chat going on 💅✨

and that's the page, bestie 🎀 this came out of ./include/linux, dated October 2026, and the whole thing is filed under dma_fence_is_signaled(9) — go forth, check your fences, slay 👑💜

📦 where this page comes from