blk_add_driver_data(9)

💖 blk_add_driver_data(9) 💖

okay so bestie, welcome to the kernel API manual — this one lives in the <pink>Kernel API Manual</pink> section and it's literally all about slipping your own custom binary data into the block trace stream. no cap, it's a whole vibe.

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✨ NAME ✨

blk_add_driver_data — add a binary message carrying driver-specific data 🎀

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✨ SYNOPSIS ✨

void blk_add_driver_data (struct request *rq , void *data , size_t len );

that's the whole signature, bestie — no return value, it's giving void main character energy 💅

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✨ ARGUMENTS ✨

• rq — the io request 🦋 (yep, the request struct, the one and only)
• data — the driver-specific data 🌸 (whatever blob you wanna send)
• len — the length of that driver-specific data ⭐ (size_t, so, like, byte counts)

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✨ DESCRIPTION ✨

so like — some drivers might want to write driver-specific data, per request. that's it, that's the whole point 🫶. this function is literally the doorway for that. it's giving "custom payload, but make it traceable" 😭

ngl, that's the entire description in the original too — it's a short one, so enjoy the chill.

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✨ SEE ALSO ✨

the kernel file ./kernel/trace/blktrace.c is where this all goes down, and here's the friend group 👑

• blk_trace_ioctl(9)
• blk_trace_shutdown(9)
• blk_add_trace_rq(9)
• blk_add_trace_bio(9)
• blk_add_trace_bio_remap(9)
• blk_add_trace_rq_remap(9)
• blk_fill_rwbs(9)

all of them are lowkey iconic in their own right, go read 'em 💜

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sign-off time, bestie 🧚: this page comes from the ./kernel/trace source, from the <lavender>October 2026</lavender> drop, and it's blk_add_driver_data(9) forever and always ✨ periodt 💖