unpack_orig_pfns(9)

unpack_orig_pfns(9) 💅✨

okay so bestie, welcome to the kernel API manual — this one's all about unpack_orig_pfns, and honestly? it's giving "underrated little helper" energy. let's get into it 🫶

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✨ NAME ✨

unpack_orig_pfns — sets the bits corresponding to the given PFNs in a memory bitmap. that's literally the whole vibe, no cap 💖

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🎀 SYNOPSIS 🎀

int unpack_orig_pfns (unsigned long *buf , struct memory_bitmap *bm ,
       struct memory_bitmap *zero_bm );

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🌸 ARGUMENTS 🌸

• buf — the area of memory containing the PFNs. it's the source data, the main character of this operation 👑
• bm — a memory bitmap. this is where the bits get set, bestie ��
• zero_bm — a memory bitmap with the zero PFNs marked. it's the special little tracker for the zero-page girlies 💅

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🦋 DESCRIPTION 🦋

so here's what's happening, fr fr. for each element of the array pointed to by buf — and we're doing this one page at a time, okay, one at a time, no rushing the process ✨ — we set the corresponding bit in bm.

and if the page was originally populated with only zeros? then a corresponding bit gets set in zero_bm too. it's double duty, and it ate, honestly 💀🔥

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🧚 SEE ALSO 🧚

okay, this is the extended friend group, so let's introduce everybody 👑

the kernel file: ./kernel/power/snapshot.c — that's where the magic lives, iykyk

the getters & setters:

• get_image_page(9)
• free_image_page(9)

the rtree & extent crew:

• alloc_rtree_node(9)
• free_mem_extents(9)
• create_mem_extents(9)

the bitmap besties:

• memory_bm_next_pfn(9)
• mark_nosave_pages(9)
• create_basic_memory_bitmaps(9)
• free_basic_memory_bitmaps(9)

the page counters, they're iconic:

• snapshot_additional_pages(9)
• count_free_highmem_pages(9)
• count_highmem_pages(9)
• count_data_pages(9)
• count_highmem_image_pages(9)

the free & preallocate squad:

• swsusp_free(9)
• preallocate_image_pages(9)
• free_unnecessary_pages(9)
• minimum_image_size(9)
• hibernate_preallocate_memory(9)

the pack/unpack duo (pack's literally the sibling, go say hi):

• pack_pfns(9)

the snapshot read/write girlies:

• snapshot_read_next(9)
• prepare_highmem_image(9)
• copy_last_highmem_page(9)
• prepare_image(9)
• snapshot_write_next(9)
• restore_highmem(9)

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head's up bestie — the original page gives no warning about NULL pointers or bad input here, so i'm not gonna invent one 💖 just know that bm and zero_bm are expected to be real memory bitmaps, and buf needs to actually point at PFNs. that's just what the signature is telling you, periodt.

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and that's a wrap on unpack_orig_pfns(9), from the ./kernel/power corner of the kernel, dated October 2026 — source/version vibes included because we don't gatekeep 💜 stay hydrated, keep your bitmaps close, and slay your snapshot logic bestie 🌈⭐💖