bvec_split_segs(9)

📦 version 7.3.1, in nixpkgs unstable

💅 bvec_split_segs(9) — like, the Kernel API Manual page, bestie

okay so this is bvec_split_segs, and it's from the Kernel API Manual — yes, the actual kernel manual, we're in the big leagues now 🎀

✨ NAME ✨

bvec_split_segs — bestie, this one checks whether or not a bvec should be split in the middle 🦋

🌸 SYNOPSIS 🌸

bool bvec_split_segs (const struct queue_limits *lim , const struct bio_vec *bv , unsigned *nsegs , unsigned *bytes , unsigned max_segs , unsigned max_bytes );

💖 ARGUMENTS 💖

  • lim — [in] the queue limits we're splitting based on, that's the vibe check source ✨
  • bv — [in] the bvec to examine. yes, we're looking at this one 👀
  • nsegs — [in,out] Number of segments in the bio being built. It gets incremented by the number of segments from bv that may be appended to that bio without exceeding max_segs 🧮
  • bytes — [in,out] Number of bytes in the bio being built. It gets incremented by the number of bytes from bv that may be appended to that bio without exceeding max_bytes 📏
  • max_segs — [in] upper bound for *nsegs. the ceiling, the limit, the "no more than this" 🚧
  • max_bytes — [in] upper bound for *bytes. same energy, but for bytes 💅

🔥 DESCRIPTION 🔥

So when you're splitting a bio, it can totally happen that you run into a bvec that is lowkey too big to fit in a single segment — and hence it has to be split in the middle 😭 That's the whole situation.

This function verifies whether or not that should happen. no cap, that's its entire job.

The value true is returned if and only if appending the entire bv to a bio with *nsegs segments and *sectors sectors would make that bio unacceptable for the block driver 💀 like, that's the exact condition, we're not being loose with it.

🫶 SEE ALSO 🫶

Kernel file ./block/blk-merge.c — plus these iconic siblings, go give them a read:

and that's the page, bestie 🧚 lived in ./block, dated October 2026 — mwah, take care, go split those segments responsibly 💜⭐

📦 where this page comes from