libnvme(2)

✨ libnvme(2) ✨

okay bestie, pull up a chair, we're doing some kernel-adjacent lore today 💅 this is a page out of the libnvme API manual, and it's all about one lil struct that's honestly giving main character energy in the NVMe-MI world.

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💖 NAME 💖

struct nvme_mi_control_req — The Control Primitive request.

like. it's the thing you send. it's the request. the control primitive one. no cap 🫶

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🎀 SYNOPSIS 🎀

struct nvme_mi_control_req {
    struct nvme_mi_msg_hdr hdr;
    __u8 opcode;
    __u8 tag;
    __le16 cpsp;
 };

four fields. that's it. that's the whole vibe. short, sweet, iconic ✨

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🌸 Members 🌸

okay so let's break down every single one of these, because every field is doing something, and we do NOT skip fields in this house 🏠

• hdr — the Generic MI message header. yes it's generic, yes it's doing the heavy lifting, we respect it 💜
• opcode — the control primitive opcode, handled via the enum nvme_mi_control_opcode 👑 this is the "what am I even asking for" field, iykyk
• tag — described as a flag — an opaque value that gets passed from the request straight through to the response 🔁 you don't peek inside it, you just carry it along like a lil emotional support number. it literally travels with the request and comes back to you on the response side 🦋
• cpsp — the Control Primitive Specific Parameter 🎀 genuinely the most "it depends on the primitive" field to ever depend on a primitive. very choose-your-own-adventure of it

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fr fr: hdr is generic, opcode picks the primitive, tag is opaque and round-trips from request to response, and cpsp is whatever the specific primitive needs. that's the whole struct, bestie 🍓

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💜 the sign-off 💜

okay that's the whole page!! this came to you straight from the libnvme API manual, dated July 2026, and if you remember nothing else, remember: struct nvme_mi_control_req is the request, it's got a generic header, an opcode, an opaque tag, and a primitive-specific param.

slay, go build something, and drink some water 🧚✨👑 🫶