sg_virt(9)

💫 sg_virt(9) — the kernel API manual, bestie edition 💫

okay so real quick: this is sg_virt(9) from the Kernel API Manual, and it lives over in ./include/linux. come on a little tour with me 🎀

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✨ NAME ✨

sg_virt — returns the virtual address of an sg entry. that's it. that's the whole vibe. 🦋

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🌸 SYNOPSIS 🌸

void * sg_virt (struct scatterlist *sg );

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💖 ARGUMENTS 💖

• sg — the SG entry, bestie. the one you want the virtual address of. 👑

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🔥 DESCRIPTION 🔥

so what actually happens: this calls page_address on the page inside this sg entry, and then it adds the sg offset. that's the whole recipe 🍓

⚠️ but here's the catch, and it's a big one: the caller must know that the sg page has a valid virtual mapping. no cap. this function is not out here checking for you — that's on you, and if you're wrong, that's a you problem. 💀

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🌈 SEE ALSO 🌈

kernel file ./include/linux/scatterlist.h — and literally the whole sg friend group:

• sg_next(9)
• sg_assign_page(9)
• sg_set_page(9)
• sg_set_folio(9)
• sg_set_buf(9)
• sg_chain(9)
• sg_mark_end(9)
• sg_unmark_end(9)
• sg_dma_is_bus_address(9)
• sg_dma_mark_bus_address(9)
• sg_dma_unmark_bus_address(9)
• sg_dma_is_swiotlb(9)
• sg_dma_mark_swiotlb(9)
• sg_phys(9)
• sg_init_marker(9)
• sg_alloc_table_from_pages(9)
• sg_page_iter_page(9)
• sg_page_iter_dma_address(9)
• for_each_sg_page(9)
• for_each_sg_dma_page(9)
• for_each_sgtable_page(9)
• for_each_sgtable_dma_page(9)

like, the entire friend group showed up to the function. obsessed. 🫶

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okay that's the page!! sign-off time: this one shipped out of ./include/linux, dated October 2026, and it's filed under sg_virt(9). periodt. 💅✨