folio_copy(9)

💖 folio_copy(9) — like, the whole scoop

okay so picture this: you're deep in the Kernel API Manual (yes, that one), and you land on folio_copy(9). She's small, she's mighty, and she's about to become your new fave. Let's get into it bestie 🎀

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✨ NAME ✨

folio_copy — Copy the contents of one folio to another. That's it, that's the whole vibe. No cap. 💅

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🌸 SYNOPSIS 🌸

void folio_copy (struct folio *dst , struct folio *src );

Look at her. Clean. Iconic. Returns nothing because she's not here to chat, she's here to work. 👑

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🦋 ARGUMENTS 🦋

• dst — the folio you're copying to. The destination. The main character receiving all the attention. 🫶
• src — the folio you're copying from. The source. The origin story. Where the bytes are coming from. 🌈

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💜 DESCRIPTION 💜

So the bytes living inside the folio that src represents get copied over into dst. Simple as that, fr fr. 🍓

⚠️ Heads up bestie: this function assumes the caller has already validated that dst is at least as large as src. It does not check. It trusts you. Do not betray that trust. 😭

And here's the multitasking part 👇

• You can call it in atomic context — but only for order-0 folios.
• If the folio is larger than that, it may sleep. 💀

So like... know which one you've got before you go calling her from somewhere she can't nap. Periodt.

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🔥 SEE ALSO 🔥

Everything below lives in the kernel file ./mm/util.c — and yes, she has friends. A whole friend group. A whole squad. Look at this roster 👑

kfree_const(9), __kmemdup_nul(9), kstrdup(9),
kstrdup_const(9), kstrndup(9), kmemdup(9), kmemdup_array(9),
kvmemdup(9), kmemdup_nul(9), memdup_user(9), vmemdup_user(9),
strndup_user(9), memdup_user_nul(9), randomize_page(9),
__account_locked_vm(9), account_locked_vm(9), __vmalloc_array(9),
vmalloc_array(9), __vcalloc(9), vcalloc(9), folio_mapping(9),
get_cmdline(9), mem_dump_obj(9), compat_set_desc_from_vma(9),
__compat_vma_mmap(9), compat_vma_mmap(9), snapshot_page(9),
mmap_action_prepare(9), mmap_action_complete(9), folio_pte_batch(9),
page_range_contiguous(9)

Not me listing all of them because every single one deserves a shoutout 💖 iykyk

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and that's the whole page, babes — go forth and copy your folios responsibly 🧚

mwah 💋 this one's brought to you by the ./mm sources, dated October 2026, and filed under folio_copy(9). See you in the next manpage, bestie! 🌸✨