vmf_insert_pfn(9)

📦 version 7.3.1, in nixpkgs unstable

💅 vmf_insert_pfn — from the Kernel API Manual, bestie 💖

okay so picture this: you're a driver, you've got a page, and you desperately need it in a user vma. this little icon does exactly that. one pfn, one insert, one slay. ✨

🌸 SYNOPSIS 🌸

vm_fault_t vmf_insert_pfn (struct vm_area_struct *vma , unsigned long
addr , unsigned long pfn );

🎀 ARGUMENTS 🎀

  • vma — the user vma you're mapping into. the destination. the venue. 💒
  • addr — the target user address where this page is gonna live. drop the pin right here 📍
  • pfn — the source kernel pfn. the actual page, coming straight from the kernel side 🫶

🦋 DESCRIPTION 🦋

so it's giving vm_insert_page energy, honestly. this is the function that lets drivers insert individual pages they've allocated straight into a user vma. same comments apply, bestie — same rules, same vibes. no cap.

okay and here's the important part, listen up 🙈 — this function should only be called from a vm_ops->fault handler. and when you do that, that handler should return the result of this function. like, don't be weird about it, just return it. periodt.

also? vma cannot be a COW mapping. not today, not ever. 🚫

good news though: since this only gets called for pages that don't currently exist, we do not need to flush old virtual caches or the TLB. no cleanup arc, we're literally fine. 🔥

⭐ CONTEXT ⭐

Process context. it may allocate using GFP_KERNEL. so like, be normal about where you call it, yk? 💅

🌈 RETURN 🌈

a vm_fault_t value. that's it, that's the whole return. 👑

🧚 SEE ALSO 🧚

Kernel file ./mm/memory.c — and honestly the whole friend group showed up:

okay that's the whole page, ily, go insert some pfns responsibly 💜✨

so this came out of ./mm and it's dated October 2026, and yeah — the page is vmf_insert_pfn(9), obviously. mwah 🎀

📦 where this page comes from