rvt_ruc_loopback(9)

💅 rvt_ruc_loopback — from the Kernel API Manual, bestie ✨

Okay so this is rvt_ruc_loopback(9), straight out of the Kernel API Manual — and no cap, it's a little function with a very specific job. Let's get into it 🎀

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✨ NAME ✨

rvt_ruc_loopback — the one that handles UC and RC loopback requests 🦋

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🌸 SYNOPSIS 🌸

void rvt_ruc_loopback (struct rvt_qp *sqp );

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💖 ARGUMENTS 💖

• sqp — literally just the sending QP. That's it. The main character of this whole function 🫶

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👑 DESCRIPTION 👑

So here's the tea ☕: this gets called from rvt_do_send to forward a WQE addressed to the same HFI. Iconic behavior, honestly.

Now, the part you need to know: even though we're single threaded due to the send engine, we still have to protect against post_send. Like, yes, it feels like we should be safe, but nope — gotta keep that guard up 💅

And the good news? We don't have to worry about receive interrupts, because this is a connected protocol and all packets will pass through here. Every single one. Slay for us, honestly 😭✨

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🌈 SEE ALSO 🌈

The kernel file lives at ./drivers/infiniband/sw/rdmavt/qp.c — and here's the whole friend group 🧚💜:

• init_qpn_table(9)
• free_qpn_table(9)
• rvt_driver_qp_init(9)
• rvt_free_qp_cb(9)
• rvt_free_all_qps(9)
• rvt_qp_exit(9)
• alloc_qpn(9)
• rvt_clear_mr_refs(9)
• rvt_swqe_has_lkey(9)
• rvt_qp_sends_has_lkey(9)
• rvt_qp_acks_has_lkey(9)
• rvt_qp_mr_clean(9)
• rvt_remove_qp(9)
• rvt_alloc_rq(9)
• rvt_init_qp(9)
• _rvt_reset_qp(9)
• rvt_reset_qp(9)
• rvt_free_qpn(9)
• get_allowed_ops(9)
• free_ud_wq_attr(9)
• alloc_ud_wq_attr(9)
• rvt_create_qp(9)
• rvt_error_qp(9)
• rvt_modify_qp(9)
• rvt_destroy_qp(9)
• rvt_query_qp(9)
• rvt_post_recv(9)
• rvt_qp_valid_operation(9)
• rvt_qp_is_avail(9)
• rvt_post_one_wr(9)
• rvt_post_send(9)
• rvt_post_srq_recv(9)
• get_rvt_head(9)
• rvt_get_rwqe(9)
• rvt_comm_est(9)
• rvt_add_rnr_timer(9)
• rvt_stop_rc_timers(9)
• rvt_stop_rnr_timer(9)
• rvt_del_timers_sync(9)
• rvt_qp_iter_init(9)
• rvt_qp_iter_next(9)
• rvt_qp_iter(9)
• rvt_copy_sge(9)

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Lowkey a whole squad, right? Go read them if you're curious — they're all in ./drivers/infiniband/sw/rdmavt. 💀📚

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Okay bye bestie 🫶 this page came from ./drivers/infiniband/sw/rdmavt, dated October 2026, and it's filed under rvt_ruc_loopback(9) — periodt 💅✨