dma_unmap_host_va(9)

💖 dma_unmap_host_va (9) — Kernel API Manual 💖

okay bestie, so this is a page from the Kernel API Manual, and it's about a lil function called dma_unmap_host_va — the one that does the DMA unmapping of the host virtual address you hand it. yes, the "put it back" side of the story. literally the cleanup era. no cap. 🧹✨

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🌸 NAME 🌸

dma_unmap_host_va — DMA unmapping of the given host virtual address. that's it, that's the whole vibe. 💅

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✨ SYNOPSIS ✨

void dma_unmap_host_va (struct hl_device *hdev , struct hl_userptr
*userptr );

look at her go — returns void, so nothing comes back. she just does the thing and dips. 🫶

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🎀 ARGUMENTS 🎀

• hdev — the habanalabs device structure. that's your device baddie, the main character of the hardware world. 👑
• userptr — the userptr to free. yep, this is the one getting released. say bye bestie 🦋

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💜 DESCRIPTION 💜

so what does this function actually do? here's the rundown:

• Unpins the physical pages. 📌 the pages were pinned, and now they are not, because we're being responsible and giving them back.
• Frees the userptr structure. 🎈 that struct is free now. literally free. it's giving liberation.

that's it! two steps, both iconic, both necessary. don't skip them. 😌

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🌈 SEE ALSO 🌈

kernel file: ./drivers/accel/habanalabs/common/memory.c

and the whole friend group, in this exact order (yes, all of them, I'm not dropping a single one of my girls):

• dma_map_host_va(9)
• dram_pg_pool_do_release(9)
• free_phys_pg_pack(9)
• free_device_memory(9)
• clear_va_list_locked(9)
• print_va_list_locked(9)
• merge_va_blocks_locked(9)
• add_va_block_locked(9)
• add_va_block(9)
• is_hint_crossing_range(9)
• get_va_block(9)
• hl_get_va_range_type(9)
• hl_unreserve_va_block(9)
• init_phys_pg_pack_from_userptr(9)
• map_phys_pg_pack(9)
• unmap_phys_pg_pack(9)
• map_device_va(9)
• unmap_device_va(9)
• hl_hw_block_mmap(9)
• export_dmabuf_from_addr(9)
• allocate_timestamps_buffers(9)
• hl_pin_host_memory(9)
• hl_userptr_delete_list(9)
• hl_userptr_is_pinned(9)
• va_range_init(9)
• va_range_fini(9)
• vm_ctx_init_with_ranges(9)
• hl_vm_ctx_fini(9)
• hl_vm_init(9)
• hl_vm_fini(9)
• hl_hw_block_mem_init(9)
• hl_hw_block_mem_fini(9)

like, that's a whole group chat right there. iykyk. 💀💖

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live from ./drivers/accel/habanalabs/common, dated October 2026, and this page is dma_unmap_host_va(9) — sending you off with a group-chat mwah and a reminder that unpinning pages is self-care. mwah 💋🎀🌸