bio_split_io_at(9)

πŸ“¦ version 7.3.1, in nixpkgs unstable

πŸ’… bio_split_io_at(9) β€” Kernel API Manual, but make it make sense

okay bestie, welcome to the group chat for <rainbow>bio_split_io_at</rainbow> β€” like, the kernel API manual page for it, and honestly? it's giving "small function, huge responsibility" ✨ (manual name: bio_split_io_at(9), iykyk 🫢)

🌸 NAME 🌸

bio_split_io_at β€” lowkey checks if a bio needs to be split, and where πŸ‘€

✨ SYNOPSIS ✨

int bio_split_io_at (struct bio *bio , const struct queue_limits *lim ,
unsigned *segs , unsigned max_bytes , unsigned len_align_mask );

no cap, that's the whole signature, character for character, don't @ me πŸ’…

πŸŽ€ ARGUMENTS πŸŽ€

okay so here's the cast of characters, and every single one of them matters:

  • bio β€” [in] the bio that's gonna get split πŸ’” like, this is our main character
  • lim β€” [in] the queue limits we're splitting based on β€” the rules of the vibes, basically
  • segs β€” [out]</紫色> number of segments in the bio with the first half of the sectors πŸ“ (yes, first half β€” it's literally half-and-half energy)

wait, tiny correction, that tag is [out] πŸŽ€ β€” the value comes out of the function, bestie, don't forget

  • max_bytes β€” [in] maximum number of bytes per bio β€” the hard ceiling, the limit, the "you shall not pass" πŸ”₯
  • len_align_mask β€” [in] length alignment mask for each vector 🌈 (each vector! alignment! iconic attention to detail)

πŸ¦‹ DESCRIPTION πŸ¦‹

so the whole point of this function: find out if bio needs to be split so it fits the queue limits in lim and a maximum size of max_bytes πŸ‘‘

and then it returns one of three things, and the way that each value means something completely different is so real:

  • a negative error number if bio can't be split πŸ’€ β€” like, it's just not happening, sorry babe
  • 0 if the bio doesn't have to be split 😌 β€” she's already perfect, no notes, slay
  • a positive sector offset if bio needs to be split βœ‚οΈ β€” that's where the split happens, periodt
ngl the return-value switch-up here is the entire personality of this function. negative = nope, 0 = we're good, positive = here's your offset, go off πŸ”₯

πŸ’œ SEE ALSO πŸ’œ

bestie these are the linked pages, all of them, no skipping πŸ™ˆ (kernel file ./block/blk-merge.c):

go read those too, it's giving "the extended universe" 🧚✨

and that's the whole page, bestie πŸ’– this lil gem lives in ./block and the version/date on it is October 2026 β€” so yeah, future-coded manual page, obsessed πŸ‘‘πŸ«Ά mwah, go split some bios responsibly 🌈⭐

πŸ“¦ where this page comes from