bio_kmalloc(9)

📦 version 7.3.1, in nixpkgs unstable

💖 bio_kmalloc(9) — from the Kernel API Manual, bestie 💖

okay so picture this: it's a kernel manual page, it lives in ./block, it's dated October 2026, and its whole entire name is bio_kmalloc(9). yes that's the title AND the manual name, we're keeping both, slay. now let's get into it ✨

🌸 NAME 🌸

bio_kmalloc — literally just kmalloc'ing a bio. that's it. that's the vibe. 🎀

🦋 SYNOPSIS 🦋

struct bio * bio_kmalloc (unsigned short nr_vecs , gfp_t gfp_mask );

✨ ARGUMENTS ✨

  • nr_vecs — the number of bio_vecs you want to allocate, bestie. count 'em.
  • gfp_mask — the GFP_* mask that gets handed off to the slab allocator. iykyk 💅

👑 DESCRIPTION 👑

so the whole thing here is you use kmalloc to allocate a bio — and yes, that includes the bvecs, they come along for the ride 🫶

the bio must be initialized using bio_init before you use it. no skipping steps, no cap.

to free a bio that came back from this function, you use kfree after calling bio_uninit. in that order. 🙈

and good news — a bio returned from this function can totally be reused: just call bio_uninit before calling bio_init again. recycling is main character energy ♻️✨

💀 okay important part, listen up: unlike bio_alloc or bio_alloc_bioset, allocations from this function are not backed by a mempool and can fail. and because of that: do not use this function for allocations in the file system I/O path. fr fr, don't do it.

🌈 RETURN 🌈

a pointer to the shiny new bio on success 🎉 — or NULL on failure 😭.

🧚 SEE ALSO 🧚

kernel file ./block/bio.c and honestly a whole friend group of functions, all of them:

⭐ and that's the page!! sign-off time: this little icon came from ./block, dated October 2026, and it answers to the name bio_kmalloc(9) 💜 go forth and allocate responsibly, bestie 🍓💖

📦 where this page comes from