bio_chain(9)

okay bestie, welcome to bio_chain(9) from the Kernel API Manual ✨ this one is literally about chaining bio completions, and it’s giving “wait for your friend before you leave” energy 🎀

🌸 NAME 🌸

bio_chain - chain bio completions

✨ SYNOPSIS ✨

void bio_chain (struct bio *bio , struct bio *parent );

🦋 ARGUMENTS 🦋

• bio — the target bio 💅
• parent — the parent bio of bio 🫶

💖 DESCRIPTION 💖

okay so here’s the vibe: when bio completes, the caller won’t have a bi_end_io called for it. instead, parent’s bi_end_io won’t be called until both parent and bio have completed. and yes, the chained bio will also be freed when it completes 🧚

⚠️ bestie, important: the caller must not set bi_private or bi_end_io in bio. not the move. periodt 💀

🌈 SEE ALSO 🌈

Kernel file ./block/bio.c, plus these iconic references:

• bio_reset(9)
• bio_reuse(9)
• bio_chain_and_submit(9)
• bio_alloc_bioset(9)
• bio_kmalloc(9)
• bio_truncate(9)
• guard_bio_eod(9)
• bio_put(9)
• bio_alloc_clone(9)
• bio_init_clone(9)
• bio_full(9)
• __bio_add_page(9)
• bio_add_virt_nofail(9)
• bio_add_page(9)
• bio_add_folio(9)
• bio_add_vmalloc_chunk(9)
• bio_add_vmalloc(9)
• bio_iov_iter_get_pages(9)
• bio_iov_iter_bounce(9)
• bio_iov_iter_unbounce(9)
• bio_await(9)
• submit_bio_wait(9)
• bdev_rw_virt(9)
• bio_copy_data(9)
• bio_endio(9)
• bio_split(9)
• bio_trim(9)
• bioset_init(9)

byeee bestie — this little page lives in ./block and is dated October 2026 🫶💖