kmalloc_flex(9)

📦 version 7.3.1, in nixpkgs unstable

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

okay so picture this: you're in the kernel, you have a struct with a flexible array member at the end, and you need exactly one of them — sized just right for however many FAM elements you want. that's the whole vibe of kmalloc_flex. it's giving one-stop-shop, no cap. ✨

🌸 SYNOPSIS 🌸

kmalloc_flex (VAR_OR_TYPE , FAM , COUNT , ... );

like, that's it. that's the call. four-ish things and you're done 🫶

✨ ARGUMENTS ✨

  • VAR_OR_TYPE — the variable or the type you wanna allocate (flex array included, obviously 💅). you can hand it a type or a var, either eats.
  • FAM — the name of the flexible array member on that struct. yes, the one doing all the work at the end of the struct. she's the main character 🔥
  • COUNT — how many flexible-array-member elements you want, fr fr. just the number, bestie.
  • ... — optional GFP flags for the allocation. and if you don't specify any? it defaults to GFP_KERNEL like a sweetie. no stress 💜

👑 RETURN 👑

on success you get a newly allocated pointer to VAR_OR_TYPE — iconic, slay, allocated. on failure you get NULL, and that's your cue to handle it (don't ignore her 😭).

⚠️ ngl there's a catch worth knowing: if FAM has been annotated with __counted_by, the allocation will immediately fail if COUNT is larger than what the type of the struct's counter variable can represent. like it just says no. no graceful degradation, no vibes — straight to fail town 💀

🦋 SEE ALSO 🦋

okay the friend group is large, but they're all icons, so:

Kernel file ./include/linux/slab.h 💫 plus the whole crew:

and that's the page, bestie 🌈 this one comes from ./include/linux and it's dated October 2026 — go forth and allocate responsibly, mwah 💅💖

📦 where this page comes from