submit_bio(9)

✨ submit_bio(9) ✨

okay so welcome to the submit_bio(9) page from the Kernel API Manual, bestie — this is the one that actually yeets your I/O at the block device layer 💅

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🌸 SYNOPSIS 🌸

void submit_bio (struct bio *bio );

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🎀 ARGUMENTS 🎀

• bio — the struct bio that's describing the I/O you want done. like, the whole vibe of the request lives in here 🦋

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💖 DESCRIPTION 💖

Bestie. Listen. submit_bio is the function for submitting I/O requests to block devices. You hand it a fully set up struct bio that describes the I/O that needs to be done, and it takes it from there. The bio gets sent to whatever device is described by the bi_bdev field — no cap, that field is literally picking the destination 🫶

The success/failure status of the request — plus the notification that it's done — comes back asynchronously through the ->bi_end_io callback in bio. So it's giving "we'll text you when it's ready" energy ✨

💀 MAJOR WARNING, fr fr: the bio must NOT be touched by the caller until ->bi_end_io has been called. do not poke it. do not peek at it. do not look at it in a weird way. hands off until the callback says you're allowed 🙈

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👑 SEE ALSO 👑

Kernel file ./block/blk-core.c — and the whole friend group:

• blk_queue_flag_set(9)
• blk_queue_flag_clear(9)
• blk_op_str(9)
• blk_sync_queue(9)
• blk_set_pm_only(9)
• blk_put_queue(9)
• blk_queue_enter(9)
• blk_get_queue(9)
• submit_bio_noacct(9)
• bio_poll(9)
• bio_start_io_acct(9)
• blk_lld_busy(9)
• blk_start_plug(9)
• blk_finish_plug(9)

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and that's the page!! 💜 this lil beauty lives in the ./block directory, dated October 2026, and its manual name is submit_bio(9) — go submit something iconic, bestie, and remember: don't touch the bio until the callback says so 🧚‍♀️✨