dma_sync_sgtable_for_cpu(9)

💅 dma_sync_sgtable_for_cpu(9) — like, the whole glow-up

okay so bestie, welcome to the Kernel API Manual ✨ this one is a single function that does one job and does it iconically — it hands a buffer back to the CPU so your code can actually touch it without the DMA engine side-eyeing you. no cap.

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🌸 NAME 🌸

dma_sync_sgtable_for_cpu — Synchronize the given buffer for CPU access 🫶

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✨ SYNOPSIS ✨

void dma_sync_sgtable_for_cpu (struct device *dev , struct sg_table *sgt
, enum dma_data_direction dir );

literally that's the whole vibe. three args, void return, no drama.

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🎀 ARGUMENTS 🎀

• dev — the device you're doing the DMA operation for. like, the main character of this whole thing 👑
• sgt — the sg_table object that describes the buffer. it's the map, the receipt, the whole description ok 💅
• dir — the DMA direction. which way the data's flowing, iykyk 🌈

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🦋 DESCRIPTION 🦋

so what does it actually do? it performs the needed cache synchronization and moves the ownership of the buffer back to the CPU domain 🔥 which means: it is safe to perform any access to it by the CPU. yes bestie, go ahead, read it, write it, it's yours now 💖

but listen — this is a handoff, not a forever thing. before doing any further DMA operations, one has to transfer the ownership of the buffer back to the DMA domain by calling the dma_sync_sgtable_for_device. don't ghost the DMA engine, it will Not be cute 😭

think of it like passing the aux cord back and forth 🎧 CPU has it now, but the second DMA wants a turn you must formally hand it over. no vibes-based ownership. periodt.

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⭐ SEE ALSO ⭐

• Kernel file ./include/linux/dma-mapping.h
• dma_use_iova(9)
• dma_unmap_sgtable(9)
• dma_sync_sgtable_for_device(9)
• dma_get_seg_boundary_nr_pages(9)

all of these are lowkey the friend group of this function. go say hi 🌸

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and that's the page, bestie!! 🧚 this lil' beauty lives in ./include/linux and it's dated October 2026, and yeah the page itself is dma_sync_sgtable_for_cpu(9) — slay, ate, no crumbs 💜✨🎀