dma_buf_phys_vec_to_sgt(9)

🦋 dma_buf_phys_vec_to_sgt(9) 🦋

okay bestie, welcome to the Kernel API Manual ✨ this one's about dma_buf_phys_vec_to_sgt and it's giving "I turn physical vectors into a scatterlist table" energy, and honestly? iconic.

💖 NAME 💖

dma_buf_phys_vec_to_sgt — returns the scatterlist table of the attachment from arrays of physical vectors. This function is intended for MMIO memory only. 🎀

(and yes, the original source spells it "funciton" — we're leaving that typo alone, she's doing her best 💅)

✨ SYNOPSIS ✨

struct sg_table * dma_buf_phys_vec_to_sgt (struct dma_buf_attachment
*attach , struct p2pdma_provider *provider , struct phys_vec *phys_vec ,
size_t nr_ranges , size_t size , enum dma_data_direction dir );

🎀 ARGUMENTS 🎀

• attach [in] — the attachment whose scatterlist is gonna be returned, bestie. that's the whole assignment.
• provider [in] — the p2pdma provider 🫶
• phys_vec [in] — an array of physical vectors. like, a whole little squad of them.
• nr_ranges [in] — how many entries are chillin' in the phys_vec array 🔢
• size [in] — the total size of phys_vec, no cap
• dir [in] — the direction of the DMA transfer ⭐

🌸 DESCRIPTION 🌸

So what does she actually do? She returns an sg_table containing the scatterlist to be returned 💖 — and on error she returns ERR_PTR. She may also return -EINTR if she gets interrupted by a signal 😭 (relatable, honestly, sometimes you just gotta bail).

On success, the DMA addresses and lengths in the returned scatterlist are PAGE_SIZE aligned ✨ — tidy, lined up, main character energy.

⚠️ heads up bestie: a mapping must be unmapped by using dma_buf_free_sgt. do not leave her hanging, that's not the vibe. 🚨

🧚 NOTE 🧚

This function is intended for exporters 👑. And if direct traffic routing is mandatory, the exporter should call the routing pci_p2pdma_map_type before calling this function — order matters, iykyk 🫶

🔥 SEE ALSO 🔥

• Kernel file ./drivers/dma-buf/dma-buf-mapping.c
• struct dma_buf_dma(9)
• dma_buf_free_sgt(9)

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okay that's the whole page, bestie, you ate that 💅💖

she lives in ./drivers/dma-buf, she's dated October 2026, and she's part of the Kernel API Manual — go forth and map responsibly, mwah 🎀🦋✨