libnvme_mi_mi_xfer(9)

✨ libnvme_mi_mi_xfer — raw mi transfer interface ✨

okay so bestie, this is a page straight out of the libnvme API manual and it's giving "low-level but iconic" 💅 like no cap, this is the raw MI transfer girlie. she does exactly one thing and she does it slayfully. let's get into it 🫶

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🌸 SYNOPSIS 🌸

int libnvme_mi_mi_xfer (struct libnvme_mi_ep *ep , struct
       nvme_mi_mi_req_hdr *mi_req , size_t req_data_size , struct
       nvme_mi_mi_resp_hdr *mi_resp , size_t *resp_data_size );

literally that's the whole signature, copy it exactly bestie, don't get creative with it 🙈

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🎀 ARGUMENTS 🎀

• ep — the endpoint you're sending the MI command to. like, this is where the vibes go 💌
• mi_req — your request data. the main character of the request, honestly 👑
• req_data_size — the size of the request data payload. just the payload, okay? we'll talk about the header thing in a sec 🍓
• mi_resp — the buffer where the response data lands. think of it as the reply-guy's seat 🪑
• resp_data_size — the size of the response data buffer, and it gets updated to the received size. so it comes back changed, like a glow-up ✨

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💖 DESCRIPTION 💖

so what she does is: she performs an arbitrary NVMe MI command, using the request data you handed her in mi_req. no cap, arbitrary, she's flexible like that 🌈

now here's the part people mess up, so listen up bestie 👂 — the size of the request data payload goes in req_data_size, and that does not include the standard header length. so a header-only request would have a size of 0. periodt. 💀

also important, don't sleep on this: the Management Request Doublewords are considered part of the header data. like they're header girlies, not payload girlies, iykyk 🧚

on success, the response data is stored in mi_resp, which has an optional appended payload buffer of resp_data_size bytes. and the actual payload size transferred gets stored in resp_data_size. this size does not include the MI response header, so 0 represents no payload. zero means nothing came through, no cap 🫥

see also: struct nvme_mi_mi_req_hdr and struct nvme_mi_mi_resp_hdr — go read those, they're the supporting cast 💜

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🔥 RETURN 🔥

she returns the nvme command status if a response was received (see enum nvme_status_field), or a negative error code otherwise. so either you get a status, or you get a negative number and you go "not me getting an error code 😭" — that's the whole deal, fr fr 👑

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and that's the tea bestie 🍵 — go forth and transfer, you absolute icon ⭐💅

with love, the libnvme API manual girlies, October 2026 — libnvme_mi_mi_xfer, page libnvme_mi_mi_xfer(9), mwah 🎀