bio_alloc_clone(9)

📦 version 7.3.1, in nixpkgs unstable

💅 bio_alloc_clone — Kernel API Manual, section 9

okay so bestie, welcome to bio_alloc_clone(9) from the Kernel API Manual (yes, section 9, we're in kernel-dev territory now 🎀). This is the one where you make a brand-new bio that's a total clone of another one and they share the same biovec situation. It's giving "twins but they share a closet" energy. Let's get into it ✨

✨ SYNOPSIS ✨

struct bio * bio_alloc_clone (struct block_device *bdev , struct bio
*bio_src , gfp_t gfp , struct bio_set *bs );

literally one function call, four arguments, and a struct bio * coming back at you 🫶

🌸 ARGUMENTS 🌸

  • bdev — the block_device you're cloning onto. this is the destination vibe 🦋
  • bio_src — the bio you're cloning from. your source material, your blueprint, your blueprint-bio 💜
  • gfp — the allocation priority. like, how hard should we be trying to get memory rn 😤
  • bs — the bio_set you're allocating out of. that's the pool, bestie 🏊‍♀️

👑 DESCRIPTION 👑

So what actually happens? You allocate a new bio, and it's a clone of bio_src. ✅

Here's the part that matters (highkey important, ngl): this reuses the bio_vecs that bio_src->bi_io_vec points to — it does not copy them, it shares them. It also clones the iterator that's pointing at the current position inside them 🎯

And now the ownership bit, listen up because this is the whole thing fr fr:

The caller owns the returned bio, but not the bio_vecs. And you must make sure the bio is freed before the memory pointed to by bio_Src->bi_io_vecs. Like, that's the rule. Break it and things get real bad real fast 💀

so: you own the bio 🫵, you do not own the vecs 🙅‍♀️, and free order is not optional, it's the law periodt ✨

🦋 SEE ALSO 🦋

Kernel file ./block/bio.c, plus this whole iconic little squad of friends 👯‍♀️:

anyway that's the whole page, ily, go free your bios in the right order 💖

sign-off szn: this one lives in ./block, and it's dated October 2026 — so yeah, future-dated manpage, main character energy only 🌈⭐🫶

📦 where this page comes from