hfi1_make_ruc_header_9B(9)

💅 hfi1_make_ruc_header_9B(9) — bestie's guide to building a 9B header ✨

okay so this is a page from the Kernel API Manual, and honestly? it's giving niche-but-iconic. we're talking about hfi1_make_ruc_header_9B, a function that literally builds a 9B header. that's the whole vibe. let's get into it 🫶

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🌸 NAME 🌸

hfi1_make_ruc_header_9B — bestie, it builds a 9B header. that's it, that's the tweet. 💖

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🎀 SYNOPSIS 🎀

void hfi1_make_ruc_header_9B (struct rvt_qp *qp , struct
ib_other_headers *ohdr , u32 bth0 , u32 bth1 , u32 bth2 , int middle ,
struct hfi1_pkt_state *ps );

no return value, no drama, just vibes and a void. 💅

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🦋 ARGUMENTS 🦋

• qp — the queue pair. the main character of this whole situation, ngl.
• ohdr — a pointer to the destination header memory. this is where the header gets to live its best life. ✨
• bth0 — bth0, passed in from the RC/UC builder. it's a hand-me-down and we respect it.
• bth1 — bth1, also passed in from the RC/UC builder. siblings, honestly.
• bth2 — bth2, passed in from the RC/UC builder too. the third one. periodt. 💀
• middle — non zero implies indicates ahg "could" be used. yes, the original says "implies indicates" and we are not fixing it, and yes the quotes around "could" are load-bearing, lowkey. 🙈
• ps — the current packet state. the situation, the context, the whole vibe check. 🔥

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👑 DESCRIPTION 👑

so this routine may disarm ahg under these situations — and bestie, when i say may, i mean it, that's literally what it says:

• packet needs a GRH
• BECN needed
• migration state not IB_MIG_MIGRATED

that's the list. three things. ahg gets disarmed. slay. 🌈

heads up: these are the exact situations the page lists, no more no less — don't come for me with extra lore, i'm just the messenger 💜

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🧚 SEE ALSO 🧚

the kernel file ./drivers/infiniband/hw/hfi1/ruc.c, plus these absolute icons:

• hfi1_make_grh(9)
• build_ahg(9)
• hfi1_make_ruc_header_16B(9) — yes the 16B one, the sequel 🍓
• hfi1_schedule_send_yield(9)
• hfi1_do_send(9)

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and that's the page!! 💖 source lives in ./drivers/infiniband/hw/hfi1, dated October 2026 — go off, king. 🎀✨ bye bestie, ily, read your manpages!! 💅