kfifo_dma_ou...epare_mapped(9)

📦 version 7.3.1, in nixpkgs unstable

💅 kfifo_dma_out_prepare_mapped(9) 💅

okay so bestie, this is a page straight out of the Kernel API Manual (yes, the kernel has a manual, she's iconic) and it's all about kfifo_dma_out_prepare_mapped — the little macro that sets you up for DMA output. pull up a chair, we're getting into it 🎀

✨ NAME ✨

kfifo_dma_out_prepare_mapped — setup a scatterlist for DMA output 🦋

🌸 SYNOPSIS 🌸

kfifo_dma_out_prepare_mapped (fifo , sgl , nents , len , dma );

💖 ARGUMENTS 💖

  • fifo — the address of the fifo to be used, like, the actual fifo you're working with 🫶
  • sgl — a pointer to the scatterlist array. that's your scatterlist, bestie, point at it
  • nents — the number of entries in the scatterlist array. count 'em, no cap
  • len — the number of elements to transfer
  • dma — the mapped dma address to fill into sgl ⭐

🔥 DESCRIPTION 🔥

so this macro fills a scatterlist for DMA output, and it'll do at most len bytes to transfer. literally that's the job 💅

it returns the number of entries in the scatterlist array — and heads up, a zero means there is no space available and the scatterlist is not filled. so if you get a zero, don't go thinking you've got data in there, because you do not 😭

ngl the vibe here is immaculate: with only one concurrent reader and one concurrent writer, you don't need extra locking to use these macros. one reader, one writer, no drama, no locks 🔥

🧚 SEE ALSO 🧚

kernel file ./include/linux/kfifo.h — and honestly the whole kfifo fam showed up for this one, we love a supportive ensemble 👑

and that's the whole page, periodt 💜 this lil gem lives in ./include/linux and it's dated October 2026 — so yeah, future energy fr fr. go forth and fill those scatterlists, bestie, you're gonna slay 🌈✨🎀

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