STRUCT NVMF_CTRL_OPTIONS(9)

👑 struct nvmf_ctrl_options(9) 👑

okay so bestie, welcome to the Kernel API Manual entry for struct nvmf_ctrl_options — literally the little container that holds all the options you specified with the parsing opts enum. she's a struct, she's a vibe, she's holding every knob you get to twist when you're bringing up an NVMe controller 🎀

✨ SYNOPSIS ✨

here's the whole shape of her, no cap, every field exactly where it lives:

struct nvmf_ctrl_options {
    unsigned mask;
    int max_reconnects;
    char *transport;
    char *subsysnqn;
    char *traddr;
    char *trsvcid;
    char *host_traddr;
    char *host_iface;
    size_t queue_size;
    unsigned int            nr_io_queues;
    unsigned int            reconnect_delay;
    bool discovery_nqn;
    bool duplicate_connect;
    unsigned int            kato;
    struct nvmf_host        *host;
    char *dhchap_secret;
    char *dhchap_ctrl_secret;
    struct key              *keyring;
    struct key              *tls_key;
    bool tls;
    bool concat;
    bool disable_sqflow;
    bool hdr_digest;
    bool data_digest;
    unsigned int            nr_write_queues;
    unsigned int            nr_poll_queues;
    int tos;
    int fast_io_fail_tmo;
 };

like, look at her. an icon. 💅

🦋 Members 🦋

every field gets her moment, so let's go one by one, no skipping, we don't do that here:

• mask — this one's for the fabrics library, bestie: it uses it to parse through the sysfs options when you're adding an NVMe controller. lowkey the backstage pass of the whole struct.
• max_reconnects — the maximum number of reconnect attempts allowed before the controller gets removed. and listen: (-1) means reconnect forever 🔥, and zero means remove immediately 🫶. those are very different energies.
• transport — holds the fabric transport "technology name" (their words, for a lack of better description 😭) that the NVMe controller being added is gonna use.
• subsysnqn — holds the fully qualified NQN subsystem name. the format is defined in the NVMe specification, "NVMe Qualified Names", iykyk ✨
• traddr — the transport-specific TRADDR field for a port on the subsystem that's adding a controller.
• trsvcid — the transport-specific TRSVCID field for a port on the subsystem that's adding a controller. yes she's traddr's sibling, they come as a pair 🎀
• host_traddr — a transport-specific field identifying the NVME host port to use for the connection to the controller.
• host_iface — a transport-specific field identifying the NVME host interface to use for the connection to the controller.
• queue_size — number of IO queue elements. simple, clean, iconic.
• nr_io_queues — number of controller IO queues that will be established. that's a lot of queues, and honestly? she deserves them 💜
• reconnect_delay — the time between two consecutive reconnect attempts. the chill-out period between tries 🌸
• discovery_nqn — indicates if the subsysnqn is the well-known discovery NQN.
• kato — keep-alive timeout. she stays alive, she stays connected, that's the whole point 🫶
• host — the virtual NVMe host, which contains the NQN and Host ID.
• dhchap_secret — DH-HMAC-CHAP secret. secret secret, don't tell 🤫
• dhchap_ctrl_secret — DH-HMAC-CHAP controller secret for bi-directional authentication, so both sides are in on it, fr fr 💖
• keyring — keyring to use for key lookups 🔑
• tls_key — TLS key for encrypted connections (TCP). secure girl summer 🌈
• tls — start TLS encrypted connections (TCP).
• concat — enabled Secure channel concatenation (TCP).
• disable_sqflow — disable controller sq flow control.
• hdr_digest — generate/verify header digest (TCP).
• data_digest — generate/verify data digest (TCP).
• nr_write_queues — number of queues for write I/O.
• nr_poll_queues — number of queues for polling I/O.
• tos — type of service.
• fast_io_fail_tmo — Fast I/O fail timeout in seconds. when things go wrong, she doesn't drag it out 💀

also side note: duplicate_connect is chilling up there in the struct definition, and no, we're not making up a description for her. the page doesn't give one, and we don't invent lore 🙈

🌟 SEE ALSO 🌟

go peek at the kernel file ./drivers/nvme/host/fabrics.h — that's where the real tea is 🍓

and that's the whole page, bestie!! ✨ this one lives over in ./drivers/nvme/host, and the version drop is from October 2026 — so like, mark your calendar, mwah 💜🦋