acpi_os_unmap_iomem(9)

💅 acpi_os_unmap_iomem 💅

okay so bestie, this one lives in the Kernel API Manual and it's literally the "un-reference a mapping" girlie — the counterpart to mapping stuff in the first place. No cap.

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✨ NAME ✨

acpi_os_unmap_iomem — drop a memory mapping reference. that's it, that's the whole vibe 🎀

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🦋 SYNOPSIS 🦋

void __ref acpi_os_unmap_iomem (void __iomem *virt , acpi_size size );

like, look at her. void __ref, two args, she's iconic. 👑

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🌸 ARGUMENTS 🌸

• virt — start of the address range to drop a reference to. the beginning of the situation, fr fr.
• size — size of the address range to drop a reference to. how much of it we're un-referencing 💖

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🌈 DESCRIPTION 🌈

so here's what she does: she looks up the given virtual address range in the list of existing ACPI memory mappings, drops a reference to it, and if there are no more active references to it, she queues it up for later removal. it's giving "bye bestie, you're on the cleanup list" 🧹✨

lowkey important: later removal. she doesn't nuke it on the spot, she queues it. that's the whole point of the reference counting, iykyk.

during early init — and this is the key part, so pay attention 🙈 — when acpi_permanent_mmap has not been set yet, this routine simply calls __acpi_unmap_table to get the job done. no reference-counting drama, just straight to the function. periodt.

and because __acpi_unmap_table is an __init function, the __ref annotation is needed here. that's the whole reason __ref is in the synopsis — it's not decoration, it's required so the early-init call path works 💅

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💜 SEE ALSO 💜

• Kernel file ./drivers/acpi/osl.c — acpi_os_map_iomem(9), acpi_os_unmap_memory(9)

go read acpi_os_map_iomem(9) first if you haven't, she's the main character, this page is the sequel 🫶

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mwah 💋 that's the page! sourced from ./drivers/acpi, dated October 2026, and yes she's still acpi_os_unmap_iomem(9) in the Kernel API Manual — go drop those references responsibly, bestie 🍓⭐