STRUCT TB_CFG_REQUEST(9)

💅 struct tb_cfg_request(9) — Kernel API Manual

okay so bestie, welcome to the Kernel API Manual ✨ and today's main character is struct tb_cfg_request, which is literally just a Control channel request 🎀 like that's the whole NAME vibe, it's giving "i am a request, i live on a control channel, i'm booked and busy" 💜

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✨ SYNOPSIS ✨

here's the whole struct in all its glory, no edits, no notes, she's perfect 🌸

struct tb_cfg_request {
    struct kref kref;
    struct tb_ctl *ctl;
    const void *request;
    size_t request_size;
    enum tb_cfg_pkg_type request_type;
    void *response;
    size_t response_size;
    enum tb_cfg_pkg_type response_type;
    size_t npackets;
    bool (*match)(const struct tb_cfg_request *req, const struct ctl_pkg *pkg);
    bool (*copy)(struct tb_cfg_request *req, const struct ctl_pkg *pkg);
    void (*callback)(void *callback_data);
    void *callback_data;
    unsigned long flags;
    struct work_struct work;
    struct tb_cfg_result result;
    struct list_head list;
};

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🫶 Members

like a group chat roll call but for struct fields, everybody say hi 👑

• kref — Reference count 💫 (she's counting her refs, respect it)
• ctl — Pointer to the control channel structure. ngl this one's only set when the request is queued 📬
• request — Request is stored here 📥
• request_size — Size of the request packet (in bytes), yes in bytes, keep up bestie 🔥
• request_type — Type of the request packet 🏷️
• response — Response is stored here 📤
• response_size — Maximum size of one response packet, maximum, not a suggestion 💀
• response_type — Expected type of the response packet 👀
• npackets — Number of packets expected to be returned with this request 🎁
• match — Function used to match the incoming packet 🕵️‍♀️
• copy — Function used to copy the incoming packet to response 📋
• callback — Callback called when the request is finished successfully ✅ (emphasis on successfully, she's picky)
• callback_data — Data to be passed to callback 🎒
• flags — Flags for the request 🚩
• work — Work item used to complete the request 🛠️
• result — Result after the request has been completed 🏁
• list — Requests are queued using this field 🧵 (the queue is a group chat and this is the invite link)

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🌈 Description

so basically this is an arbitrary request over the Thunderbolt control channel 🦋 that's the whole gig. she's flexible, she's a generalist, she's arbitrary ✨

but like — for a standard control channel message, you should really use tb_cfg_read/write and friends if possible 🫶 that's the polite thing to do, okay? no cap. don't make this struct do a job the friend group already handles 💅

fr fr bestie: this is the arbitrary path. the standard-message path has tb_cfg_read/write and friends waiting for you, so use those when you can 🙈

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👀 SEE ALSO

• Kernel file ./drivers/thunderbolt/ctl.h 📂 go read it, she's iconic

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pink and that's the whole page!! 💖 courtesy of ./drivers/thunderbolt, dated October 2026, living in the Kernel API Manual as struct tb_cfg_request(9) — mwah, slay, periodt ✨🎀🦋