STRUCT DMA_TEST(9)

🦋 struct dma_test(9) — the Kernel API Manual glow-up 🦋

okay bestie, so this is a page from the Kernel API Manual (that's the manual name, we're not copying the whole header line, you're welcome ✨) and today's main character is struct dma_test — literally the private data of the DMA test device driver. no cap, it's just a lil struct holding all the state, but she's iconic 💅

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✨ NAME ✨

struct dma_test — the DMA test device driver's private data, periodt.

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🎀 SYNOPSIS 🎀

struct dma_test {
    const struct tb_service *svc;
    struct tb_xdomain *xd;
    struct tb_ring *rx_ring;
    int rx_hopid;
    struct tb_ring *tx_ring;
    int tx_hopid;
    unsigned int packets_to_send;
    unsigned int packets_to_receive;
    unsigned int packets_sent;
    unsigned int packets_received;
    unsigned int link_speed;
    enum tb_link_width link_width;
    unsigned int crc_errors;
    unsigned int buffer_overflow_errors;
    enum dma_test_result result;
    enum dma_test_test_error error_code;
    struct completion complete;
    struct mutex lock;
 };

ngl that's the whole vibe right there 🫶 copy it exactly, don't freestyle it.

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💖 Members 💖

okay so let's meet every single field, one by one, no skipping, we don't do that here 🍓

• svc — the XDomain service the driver is bound to. her whole situation 💫
• xd — the XDomain that the service belongs to. the bigger picture, iykyk.
• rx_ring — the software ring holding RX frames. receiving queen 👑
• rx_hopid — the HopID used for receiving frames.
• tx_ring — the software ring holding TX frames. sending queen, matching set 🌸
• tx_hopid — the HopID used for sending frames.
• packets_to_send — number of packets to send. the goal, the dream ✨
• packets_to_receive — number of packets to receive.
• packets_sent — the actual number of packets sent. reality check 😭
• packets_received — the actual number of packets received.
• link_speed — expected link speed in (Gb/s), and 0 means "use whatever is negotiated". lowkey the chill option 🦋
• link_width — expected link width in (Gb/s), and 0 means "use whatever is negotiated". same energy 💜
• crc_errors — number of CRC errors during the test run. the oopsie counter 💀
• buffer_overflow_errors — number of buffer overflow errors during the test run. the bigger oopsie counter 🙈
• result — result of the last run. the vibe check results, fr fr.
• error_code — error code of the last run.
• complete — used to wait for the Rx to complete. very "wait for me bestie" of her ⭐
• lock — lock serializing access to this structure. she's the bouncer at the door, one at a time please 💅

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🌈 SEE ALSO 🌈

• Kernel file ./drivers/thunderbolt/dma_test.c — go read the source, it ate 🔥

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yes, every single member got her moment. nobody left behind, that's the rule 🫶

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and that's the whole page bestie!! 🧚💖 this one came from ./drivers/thunderbolt and it's dated October 2026 — so mark your calendar, screenshot it, send it to the group chat, it's giving archival slay 💅✨