libnvme(2)

💖 libnvme(2) — API Manual 💖

okay so bestie, welcome to the libnvme manual, section 2 (that's the API/system-calls girlies ✨). today's main character is a little struct called struct nbft_info_subsystem_ns, and she's literally the blueprint for Subsystem Namespace (SSNS) info. no cap, she's kind of a big deal 🎀

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🌸 NAME 🌸

struct nbft_info_subsystem_ns — Subsystem Namespace (SSNS) info 💅

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✨ SYNOPSIS ✨

here's the whole fit, every field, verbatim, because we do not gatekeep 🫶

struct nbft_info_subsystem_ns {
    int index;
    struct nbft_info_discovery *discovery;
    struct nbft_info_security *security;
    int num_hfis;
    struct nbft_info_hfi **hfis;
    char transport[8];
    char traddr[40];
    char *trsvcid;
    __u16 subsys_port_id;
    __u32 nsid;
    enum nbft_info_nid_type nid_type;
    __u8 *nid;
    char *subsys_nqn;
    bool pdu_header_digest_required;
    bool data_digest_required;
    int controller_id;
    int asqsz;
    char *dhcp_root_path_string;
    bool discovered;
    bool unavailable;
 };

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👑 Members 👑

field by field, no skipping, we're thorough in this house 💖

• index — the SSNS Descriptor Index in the descriptor list. basically her seat number at the table 📋
• discovery — the Primary Discovery Controller that's associated with this SSNS Descriptor. her bestie, her plus-one 💫
• security — the Security Profile Descriptor associated with this namespace. the bodyguard situation 🛡️
• num_hfis — Number of HFIs. just the count, periodt 🔢
• hfis — the List of HFIs associated with this namespace. it includes the primary HFI at the first position and all the secondary HFIs. and bestie, listen: this array is null-terminated, so don't go wandering past the end, she'll let you know when she's done 💀
• transport — the Transport Type string (like tcp, for example). think of it as her vibe/flavor of transport 🌈
• traddr — Subsystem Transport Address. where she lives 📍
• trsvcid — Subsystem Transport Service Identifier. the "which door" of it all 🚪
• subsys_port_id — The Subsystem Port ID. lowkey just the port's whole identity ✨
• nsid — The Namespace ID of this descriptor, or when nid should be used instead. she's conditional, she contains multitudes 🦋
• nid_type — the Namespace Identifier Type, see enum nbft_info_nid_type if you wanna know more 👀
• nid — The Namespace Identifier value itself 💅
• subsys_nqn — Subsystem and Namespace NQN. her government name, fr fr 📛
• pdu_header_digest_required — PDU Header Digest (HDGST) Flag: the use of NVM Header Digest Enabled is required. so like, required-required, no skipping 🚨
• data_digest_required — Data Digest (DDGST) Flag: the use of NVM Data Digest Enabled is required. same energy, also mandatory 🔥
• controller_id — Controller ID (SSNS Extended Information Descriptor): the controller ID associated with the Admin Queue, or 0 if not supported. zero means "girl, not supported" 🙈
• asqsz — Admin Submission Queue Size (SSNS Extended Information Descriptor), or 0 if not supported. same deal, 0 = no support 🫠
• dhcp_root_path_string — DHCP Root Path Override string (SSNS Extended Information Descriptor). she's the override, she's the exception, she's THAT girl 💜
• discovered — Indicates that this namespace was acquired through discovery. so she was found, not assigned 🔍
• unavailable — Namespace is unavailable as indicated by the pre-OS driver. she's on do-not-disturb, pls respect it 😭

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ngl none of this is dangerous, it's all just descriptor info. the only real trap is that hfis array being null-terminated — respect the terminator or you'll be reading garbage memory and that's giving undefined behaviour 💀

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that's the whole page bestie, you ate it 🍓🧚 go forth and query your SSNS with confidence ✨

kisses, this was struct nbft_info_subsystem_ns from the libnvme(2) API Manual — July 2026 edition. mwah 💋