is_buf_mapped(9)

📦 version 7.3.1, in nixpkgs unstable

💅 is_buf_mapped — Kernel API Manual ✨

okay bestie, welcome to the is_buf_mapped(9) page, from the Kernel API Manual (yes the whole manual, she's fancy like that 🎀). This is the "is this buffer, like, actually mapped for DMA?" check. tiny function, huge main-character energy, let's go 🦋

🌸 NAME 🌸

is_buf_mapped — is buffer mapped for DMA? 💭

✨ SYNOPSIS ✨

bool is_buf_mapped (const struct rx_sw_desc *sdesc );

that's it. that's the whole signature. she's short and she knows it 🫶

🎀 ARGUMENTS 🎀

  • sdesc — pointer to the software buffer descriptor 💖 like, the descriptor's softer, software-side self, not the hardware one. this is the thing you're asking the question about.

💅 DESCRIPTION 💅

so here's the vibe check 🔍: this function determines whether the buffer associated with a software descriptor is mapped for DMA or not.

that's the whole personality. you hand her an sdesc, she tells you if that buffer's DMA-mapped. no drama, no side quests, just a bool. iconic behavior honestly 👑

ngl it's giving "tiny helper that keeps the whole rx path from falling apart" and we love her for it 😭✨

🦋 SEE ALSO 🦋

bestie, the friend group is HUGE. she literally knows everyone in ./drivers/net/ethernet/chelsio/cxgb4vf/sge.c — that's the kernel file she lives in 🏠 (and yes, the manpage footer just calls it ./drivers/net/ethernet/chelsio... because life is short 💀)

💀 real talk: don't @ me about the truncated-looking footer path, that's literally just how the page renders it. ./drivers/net/ethernet/chelsio... and we move on 😌

and that's the whole page, bestie!! source is that same chelsio cxgb4vf corner of the kernel (./drivers/net/ethernet/chelsio...), dated October 2026 — so she's fresh, she's current, she's thriving 🌈👑 ok bye, go map some buffers, ily 🫶💖

📦 where this page comes from