blk_add_trace_rq(9)

💅 blk_add_trace_rq — the Kernel API Manual, but make it make sense

okay bestie, so we're in the Kernel API Manual today and the star of the show is blk_add_trace_rq. it's giving lowkey iconic tracing energy, and honestly? you're gonna slay this one 🫶

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✨ NAME ✨

blk_add_trace_rq — literally adds a trace for a request-oriented action. that's it, that's the vibe 💖

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🌸 SYNOPSIS 🌸

void blk_add_trace_rq (struct request *rq , blk_status_t error ,
unsigned int nr_bytes , u64 what , u64 cgid );

no cap, that's the whole signature. five arguments, zero drama ✨

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🎀 ARGUMENTS 🎀

• rq — the source request 👑 this is the main character we're tracing
• error — the return status to log 💀 whatever status you're returning, it goes in the record
• nr_bytes — number of completed bytes 🍓
• what — the action, like, the actual thing that happened ✨
• cgid — the cgroup info 🧚

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🦋 DESCRIPTION 🦋

so what does it actually do?? it records an action against a request 💅 and bestie, it will log the bio offset + size. that's the whole bit. no extra lore, no hidden side quest — just offset and size, logged, periodt 🔥

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🌈 SEE ALSO 🌈

like, go read these too, they're all in the same friend group:

• Kernel file ./kernel/trace/blktrace.c
• blk_trace_ioctl(9)
• blk_trace_shutdown(9)
• blk_add_trace_bio(9)
• blk_add_trace_bio_remap(9)
• blk_add_trace_rq_remap(9)
• blk_add_driver_data(9)
• blk_fill_rwbs(9)

ngl, blktrace.c is the source file for all of this — that's where the lore lives 💜

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k bye bestie, this page came from ./kernel/trace and it's dated October 2026 — so go forth and trace those requests, you absolute icon 🌟💅🎀