iov_iter_xarray(9)

💫 iov_iter_xarray 💫

okay so bestie, welcome to the iov_iter_xarray(9) page — this is from the Kernel API Manual and it's literally about setting up an I/O iterator that reads from (or writes into) the pages hanging off an xarray. no cap, that's the whole vibe.

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✨ SYNOPSIS ✨

void iov_iter_xarray (struct iov_iter *i , unsigned int direction ,
       struct xarray *xarray , loff_t start , size_t count );

look at her go 🎀 one function, five arguments, zero drama.

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🫶 ARGUMENTS 🫶

• i — the iterator you're initialising, bestie. this is the main character and you're handing it its whole personality.
• direction — which way the transfer is going. the vibe check for data flow, an unsigned int.
• xarray — the xarray you wanna access. that's the struct xarray * right there 🌸
• start — the start file position, a loff_t. where the reading/writing begins, iykyk.
• count — the size of the I/O buffer, in bytes. a size_t. how much data we're moving, periodt.

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💅 DESCRIPTION 💅

so what does she actually do? she sets up an I/O iterator so it can either draw data out of the pages attached to an inode, or inject data into those pages. that's it, that's the gig 🔥

⚠️ okay this part is IMPORTANT: the pages *must* be prevented from evaporation — either by taking a ref on them or by locking them, and the caller has to do it. not us. the caller. so like... don't skip this step, fr fr, it's not optional and the asterisks around must are doing a lot of heavy lifting here 😭

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👑 SEE ALSO 👑

the extended universe, the friend group, the whole kernel file ./lib/iov_iter.c:

• _copy_mc_to_iter(9)
• _copy_from_iter_flushcache(9)
• iov_iter_folio_queue(9)
• iov_iter_discard(9)
• import_iovec(9)
• iov_iter_restore(9)
• iov_iter_extract_pages(9)
• iov_iter_extract_bvecs(9)

go read them, they all slay in their own way 💖

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that's the page!! mwah 💋 this one lives down in ./lib, and the manual's dated October 2026 — so yeah, she's from the future, iconic behavior honestly 🌈⭐💜