iov_iter_folio_queue(9)

💖 iov_iter_folio_queue(9) — the Kernel API Manual glow-up 💖

okay bestie, so this one lives in the Kernel API Manual, and it's literally the function that sets up an I/O iterator to vibe with the folios in a folio queue. no cap, it's giving "plumbing but make it cute" 🫶

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✨ NAME ✨

iov_iter_folio_queue — Initialise an I/O iterator to use the folios in a folio queue

like… that's the whole job. it initialises. it iterates. it folio-queues. iconic behaviour honestly 💅

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🌸 SYNOPSIS 🌸

void iov_iter_folio_queue (struct iov_iter *i , unsigned int direction ,
const struct folio_queue *folioq , unsigned int first_slot , unsigned
int offset , size_t count );

she takes six arguments and returns void, because she's a doer, not a reporter 💜

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🎀 ARGUMENTS 🎀

• i — The iterator to initialise. that's your main character right there, bestie, she's getting set up ✨
• direction — The direction of the transfer. which way are we going? that way. 👉
• folioq — The starting point in the folio queue. your entry point, your launchpad, your moment 🚀
• first_slot — The first slot in the folio queue to use. not the second slot. not the third. the first one 🥇
• offset — The offset into the folio in the first slot to start at. we're not starting at zero, we're starting precisely where we're told, and honestly? respect 🫡
• count — The size of the I/O buffer in bytes. how much I/O is in this I/O buffer, measured in bytes, as one does 📏

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🦋 DESCRIPTION 🦋

so here's the tea ☕ — this sets up an I/O iterator to either draw data out of the pages attached to an inode or to inject data into those pages. two directions, one iterator, endless possibilities, we love a versatile queen 👑

⚠️ the important part, do not skip this, I'm serious ⚠️ The pages *must* be prevented from evaporation, either by taking a ref on them or locking them by the caller. "must" with asterisks around it, bestie. the manpage is yelling. do not let those pages evaporate, or it's going to be a whole situation 😭 💀

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🌈 SEE ALSO 🌈

• Kernel file ./lib/iov_iter.c
• _copy_mc_to_iter(9)
• _copy_from_iter_flushcache(9)
• iov_iter_xarray(9)
• iov_iter_discard(9)
• import_iovec(9)
• iov_iter_restore(9)
• iov_iter_extract_pages(9)
• iov_iter_extract_bvecs(9)

go read the whole friend group, they're all slaying in their own lanes 💖

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and that's the page!! brought to you by the fine folks over at ./lib, dated October 2026 — mark your calendars bestie, mwah 💋 🎀 bye!!