nx842_pseries_compress(9)

📦 version 7.3.1, in nixpkgs unstable

💅 nx842_pseries_compress(9) — Kernel API Manual, but make it make sense

okay so bestie, welcome to the Kernel API Manual entry for nx842_pseries_compress ✨ this is the little function that squeezes your data down using the 842 algorithm, and honestly? she's iconic for it 🎀

✨ NAME ✨

nx842_pseries_compress — compress data using the 842 algorithm 🗜️💖

🌸 SYNOPSIS 🌸

int nx842_pseries_compress (const unsigned char *in , unsigned int inlen
, unsigned char *out , unsigned int *outlen , void *wmem );

like, look at her. five arguments, one int coming back at you. slay 💅

🦋 ARGUMENTS 🦋

  • in — pointer to the input buffer 🌸 this is the stuff you're about to squish
  • inlen — length of the input buffer, i.e. how much stuff there is 📏
  • out — pointer to the output buffer, where the squeezed result goes 🎀
  • outlen — length of the output buffer (and yeah, she gets updated on the way out, keep reading 👀)
  • wmem — ptr to a buffer for working memory, and its size is determined by nx842_pseries_driver.workmem_size 🧠✨ don't just make one up, check that field

🔥 DESCRIPTION 🔥

so the compression here is provided by the NX842 coprocessor on IBM Power systems 👑 like, actual hardware doing the work, not your sad little CPU. the input buffer gets compressed and the result is stored in the provided output buffer. that's the whole vibe 💫

upon return from this function, outlen contains the length of the compressed data 📬 — so yes, she rewrites that variable, that's on purpose, that's the whole point.

⚠️ but if there's an error? outlen will be 0, and the error will be specified by the return code from this function 😭 so fr fr, check your return code, bestie. don't be out here reading stale outlen values and acting surprised.

💀 RETURN 💀

okay so the return values, let's do a vibe check on each one:

  • 0 — success 🎉 output of length outlen is stored in the buffer at out. go off queen.
  • -ENOMEM — unable to allocate internal buffers 😭 out of memory, not it
  • -ENOSPC — output buffer is to small 💀 there's literally no space left, she tried
  • -EIO — internal error 🙈 something went weird inside
  • -ENODEV — hardware unavailable 🫠 the coprocessor isn't there, so like… nothing to do

🌈 SEE ALSO 🌈

go read these next, iykwim 👀

🫶 that's the whole page, no cap. from ./drivers/crypto/nx, dated October 2026 — and this has been your girl nx842_pseries_compress(9), signing off. periodt. 💅✨
📦 where this page comes from