io_init(9)

💅 io_init(9) — bestie, let's init this I/O sub-system

okay so this is io_init(9) from the Kernel API Manual, and honestly? it's giving "small function, big responsibilities." we're setting up the I/O sub-system for one specific UBI device, and there are exactly three offsets you need to care about. come on, let's go 🦋

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✨ NAME ✨

io_init — initialize the I/O sub-system for a given UBI device. that's it. that's the whole vibe. 🎀

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🌸 SYNOPSIS 🌸

int io_init (struct ubi_device *ubi , int max_beb_per1024 );

literally just two arguments, no cap. look at her go 💅

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🫶 ARGUMENTS 🫶

• ubi — the UBI device description object. the main character of this whole operation 👑
• max_beb_per1024 — the maximum expected number of bad PEB per 1024 PEBs. yes it's a mouthful, yes it matters, no we're not skipping it 💀

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🔥 DESCRIPTION 🔥

so here's the tea: if ubi->vid_hdr_offset or ubi->leb_start is zero, then default offsets get assumed. it's giving "we'll figure it out for you" energy. and the defaults are:

• the EC header is always at offset zero — and this cannot be changed. periodt. that one's locked in forever 🔒
• the VID header starts just after the EC header, at the closest address aligned to io->hdrs_min_io_size
• the data starts just after the VID header, at the closest address aligned to io->min_io_size

the way this function just lines everything up in a row like a little procession... iconic ✨

this function returns zero in case of success, and a negative error code in case of failure. so like, 0 = slay, negative = something went sideways 😭

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🧚 SEE ALSO 🧚

Kernel file ./drivers/mtd/ubi/build.c, plus this whole extended friend group right here — say hi to everybody 👋

• struct mtd_dev_param(9)
• ubi_volume_notify(9)
• ubi_notify_all(9)
• ubi_enumerate_volumes(9)
• ubi_get_device(9)
• ubi_put_device(9)
• ubi_get_by_major(9)
• ubi_major2num(9)
• kill_volumes(9)
• uif_init(9)
• uif_close(9)
• ubi_free_volumes_from(9)
• ubi_free_all_volumes(9)
• ubi_free_internal_volumes(9)
• autoresize(9)
• ubi_attach_mtd_dev(9)
• ubi_detach_mtd_dev(9)
• open_mtd_by_chdev(9)
• open_mtd_device(9)
• bytes_str_to_int(9)
• ubi_mtd_param_parse(9)

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ok that's the whole page bestie, go forth and init responsibly 🌈

🥹 this lil page lives in ./drivers/mtd/ubi, dated October 2026, and it's titled io_init(9) — mwah, take care, iykyk 💖