update_num_rd_atomic(9)

💅 update_num_rd_atomic(9) 💅

Okay bestie, welcome to the Kernel API Manual — this one's a little hfi1 deep-dive and honestly it's giving "small function, big responsibilities". Let's get into it 🫶

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✨ NAME ✨

update_num_rd_atomic — the function whose whole entire job is to update the qp->s_num_rd_atomic. That's it. That's the gig. Iconic, honestly 👑

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🦋 SYNOPSIS 🦋

void update_num_rd_atomic (struct rvt_qp *qp , u32 psn , struct rvt_swqe
*wqe );

Three args, returns nothing (void), no cap. Copy it exactly like that, don't get creative 💅

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🎀 ARGUMENTS 🎀

• qp — the QP, obvs. The main character of this whole situation.
• psn — the packet sequence number to restart at. Yes, restart. We're picking up where we left off ✨
• wqe — the wqe. That's the wqe. It's right there. Love that for us 🍓

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🌸 DESCRIPTION 🌸

So here's the tea: this function gets called from reset_psn, and its whole purpose in life is to update qp->s_num_rd_atomic for the current wqe. That's the assignment. That's what we're doing here 🔥

⚠️ Important vibe check: this one is called at interrupt level with the QP s_lock held. So like... be normal about it. Don't go doing anything spicy in there. The lock is literally being held, bestie 😭

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👑 SEE ALSO 👑

If you're going down the rabbit hole (and you know you are, iykyk), the kernel file to look at is ./drivers/infiniband/hw/hfi1/rc.c, plus all these besties:

• make_rc_ack(9)
• hfi1_make_rc_req(9)
• reset_psn(9)
• hfi1_rc_verbs_aborted(9)
• update_qp_retry_state(9)
• rc_rcv_resp(9)
• rc_rcv_error(9)
• hfi1_rc_rcv(9)

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💖 and that's the whole page, bestie 💖

Cute lil sign-off: this one lives over in ./drivers/infiniband/hw/hfi1, dated October 2026 — same energy as ever, update_num_rd_atomic(9), we love her, periodt 🧚💜