rdma_max_mad_size(9)

✨ rdma_max_mad_size(9) ✨

okay bestie so we're in the Kernel API Manual today and the function is literally called rdma_max_mad_size — yes it's kernel-doc for the kernel, but i promise it's a vibe 🎀

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💜 NAME

rdma_max_mad_size — returns the maximum MAD size that this RDMA Port needs. That's it, that's the whole gig 🫶

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🌸 SYNOPSIS

size_t rdma_max_mad_size (const struct ib_device *device , u32 port_num );

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🦋 ARGUMENTS

• device — the device, bestie. the struct ib_device in question 💅
• port_num — the port number, u32 style ✨

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🌈 DESCRIPTION

okay so the way this works: this MAD size includes the MAD headers AND the MAD payload. that's it. no other headers get counted, no sneaky extras, not a single crumb 😌

it returns the max MAD size that's required by the Port.

and the plot twist: it will return 0 if the port does not support MADs. so like, if you get a zero back, that port is not giving MAD energy 😭 zero stars, no MADs, go home 🍓

lowkey important bestie: MAD headers and MAD payload are included — nothing else. don't be out here assuming extra headers got folded in 🙈

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👑 SEE ALSO

this list? iconic. legendary. extremely long. every single one of these is your new bestie, no cap:

Kernel file ./include/rdma/ib_verbs.h struct rdma_stat_desc(9), struct rdma_hw_stats(9), ib_rate_to_mult(9), ib_rate_to_mbps(9), ib_port_attr_to_speed_info(9), enum ib_mr_type(9), struct ib_mr_status(9), mult_to_ib_rate(9), struct ib_udata(9), struct rdma_netdev(9), struct ib_device_ops(9), ib_get_client_data(9), ib_modify_qp_is_ok(9), rdma_cap_ib_switch(9), rdma_start_port(9), rdma_for_each_port(9), rdma_end_port(9), rdma_cap_ib_mad(9), rdma_cap_opa_mad(9), rdma_cap_ib_smi(9), rdma_cap_ib_cm(9), rdma_cap_iw_cm(9), rdma_cap_ib_sa(9), rdma_cap_ib_mcast(9), rdma_cap_af_ib(9), rdma_cap_eth_ah(9), rdma_cap_opa_ah(9), rdma_cap_roce_gid_table(9), rdma_core_cap_opa_port(9), rdma_mtu_enum_to_int(9), rdma_mtu_from_attr(9), ib_alloc_pd(9), ib_dealloc_pd(9), rdma_create_ah(9), rdma_create_user_ah(9), ib_get_gids_from_rdma_hdr(9), ib_get_rdma_header_version(9), ib_init_ah_attr_from_wc(9), ib_create_ah_from_wc(9), rdma_modify_ah(9), rdma_query_ah(9), rdma_destroy_ah_user(9), rdma_destroy_ah(9), ib_modify_srq(9), ib_query_srq(9), ib_destroy_srq_user(9), ib_destroy_srq(9), ib_post_srq_recv(9), ib_create_qp(9), ib_modify_qp_with_udata(9), ib_modify_qp(9), ib_query_qp(9), ib_destroy_qp(9), ib_open_qp(9), ib_close_qp(9), ib_post_send(9), ib_post_recv(9), ib_alloc_cq_any(9), rdma_set_cq_moderation(9), ib_destroy_cq_user(9), ib_destroy_cq(9), ib_poll_cq(9), ib_req_notify_cq(9), ib_virt_dma_to_ptr(9), ib_virt_dma_to_page(9), ib_dma_mapping_error(9), ib_dma_map_single(9), ib_dma_unmap_single(9), ib_dma_map_page(9), ib_dma_unmap_page(9), ib_dma_map_bvec(9), ib_dma_unmap_bvec(9), ib_dma_map_sgtable_attrs(9), ib_dma_map_sg(9), ib_dma_unmap_sg(9), ib_dma_max_seg_size(9), ib_dma_sync_single_for_cpu(9), ib_dma_sync_single_for_device(9), ib_dereg_mr_user(9), ib_dereg_mr(9), ib_update_fast_reg_key(9), ib_inc_rkey(9), ib_attach_mcast(9), ib_detach_mcast(9), ib_check_mr_status(9), ib_device_try_get(9), rdma_ah_find_type(9), ib_lid_cpu16(9), ib_lid_be16(9), rdma_roce_rescan_device(9), rdma_device_to_ibdev(9), ibdev_to_node(9), rdma_device_to_drv_device(9), rdma_flow_label_to_udp_sport(9), rdma_calc_flow_label(9), rdma_get_udp_sport(9)

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and that's the tea, bestie 💖 this whole lil' page lives under ./include/rdma in the kernel tree, dated October 2026 — so like, future vibes only 🧚‍♀️ slay, go read some ib_verbs.h 🎀✨