bioset_init(9)

✨ bioset_init(9) ✨

Okay bestie, welcome to the bioset_init(9) page from the Kernel API Manual 🎀 — this is the glow-up ritual that gets your bio_set ready for the party, and we're gonna walk through it together, no cap 💅

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🌸 NAME 🌸

bioset_init — literally just: initialize a bio_set 👑

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🦋 SYNOPSIS 🦋

int bioset_init (struct bio_set *bs , unsigned int pool_size , unsigned
int front_pad , int flags );

That's the whole vibe check right there — four args, one int coming back atcha ⭐

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💖 ARGUMENTS 💖

• bs — the pool you're about to initialize. This is the main character here, the bio_set that's getting set up 🫶
• pool_size — how many bios and bio_vecs you want cached in the mempool. Pick your number, that's your stash ✨
• front_pad — number of bytes to allocate in front of the returned bio. Sneaky little headroom situation 🙈
• flags — flags that modify behavior. Currently that's BIOSET_NEED_BVECS and BIOSET_NEED_RESCUER, and yes those are the only two on the menu rn 💀

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🔥 DESCRIPTION 🔥

So what this does: it sets up a bio_set meant to be used with bio_alloc_bioset. It also lets the caller ask for a number of bytes to be allocated in front of the bio 💫

And why would you want a front pad? Because it's genuinely useful for embedding the bio inside another structure, so you don't have to allocate extra data to go with the bio. Iconic, efficient, obsessed 🧚

⚠️ But hear me loud and clear: the bio must be embedded at the END of that structure, always. Not the middle, not the front, the END. Otherwise things will break badly 😭💀 That's not a vibe check, that's a hard requirement.

Now the flags, one at a time, because details matter and we don't skip:

• If BIOSET_NEED_BVECS is set in flags, a separate pool gets allocated for allocating iovecs. That pool is not needed e.g. for bio_init_clone — so don't come for it if you skip it 🎀
• If BIOSET_NEED_RESCUER is set, a workqueue is created, and it can be used to dispatch queued requests when the mempool runs out of space. Rescue mission energy fr fr 🚑

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👑 SEE ALSO 👑

Kernel file ./block/bio.c — the whole friend group 💜

• bio_reset(9)
• bio_reuse(9)
• bio_chain(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)

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That's the whole page, bestie — go init that bio_set and slay 💅✨

Sign-off szn 🎀: this one lives in ./block, dated October 2026, and it's bioset_init(9) all day long. Catch you in the next manpage! 🦋🫶