lpfc_sli3_bs...oopback_mode(9)

💅 lpfc_sli3_bsg_diag_loopback_mode(9) — the Kernel API Manual, but make it make sense ✨

okay so first things first, bestie: this is a page from the Kernel API Manual, and the star of the show is lpfc_sli3_bsg_diag_loopback_mode. yeah the header clips it to lpfc_sli3_bs...oopback_mode(9) because even the manpage system ran out of screen, but we know her full name 🎀

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✨ NAME ✨

lpfc_sli3_bsg_diag_loopback_mode — literally just processes an sli3 bsg vendor command. that's the whole job description. she's a specialist 💅

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🦋 SYNOPSIS 🦋

int lpfc_sli3_bsg_diag_loopback_mode (struct lpfc_hba *phba , struct
bsg_job *job );

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🌸 ARGUMENTS 🌸

• phba — a pointer to the HBA context object. the whole personality of the adapter lives in here 🫶
• job — LPFC_BSG_VENDOR_DIAG_MODE. that's the value, no cap.

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👑 DESCRIPTION 👑

ok so here's the vibe. this function is responsible for placing an sli3 port into diagnostic loopback mode so a diagnostic loopback test can actually happen. it's giving backstage crew energy — nobody sees her, but the show does not go on without her 💀

the sequence is, in order:

1. all new scsi requests are blocked. door's closed, sorry besties 🙈
2. a small delay — literally just giving the in-flight scsi requests a sec to wrap up so nobody gets ghosted mid-request ⭐
3. the link is brought down. dramatic but necessary 💅
4. if the link is placed in loopback mode, then scsi requests are again allowed — this is the thoughtful part, fr fr, so the scsi mid-layer doesn't give up on the port 😭

and the kicker: all of this is done in-line. no handing it off, no queueing, she's doing it right there, main character energy 🔥

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🧚 SEE ALSO 🧚

the kernel file lives at ./drivers/scsi/lpfc/lpfc_bsg.c — that's the source of truth, iykyk 📁

and here's the whole group chat, everyone she's adjacent to:

• lpfc_bsg_send_mgmt_cmd_cmp(9)
• lpfc_bsg_send_mgmt_cmd(9)
• lpfc_bsg_rport_els_cmp(9)
• lpfc_bsg_rport_els(9)
• lpfc_bsg_event_free(9)
• lpfc_bsg_event_ref(9)
• lpfc_bsg_event_unref(9)
• lpfc_bsg_event_new(9)
• diag_cmd_data_free(9)
• lpfc_bsg_ct_unsol_abort(9)
• lpfc_bsg_hba_set_event(9)
• lpfc_bsg_hba_get_event(9)
• lpfc_issue_ct_rsp_cmp(9)
• lpfc_issue_ct_rsp(9)
• lpfc_bsg_send_mgmt_rsp(9)
• lpfc_bsg_diag_mode_enter(9)
• lpfc_bsg_diag_mode_exit(9)
• lpfc_sli4_bsg_set_link_diag_state(9)
• lpfc_sli4_bsg_set_loopback_mode(9)
• lpfc_sli4_diag_fcport_reg_setup(9)
• lpfc_sli4_bsg_diag_loopback_mode(9)
• lpfc_bsg_diag_loopback_mode(9)
• lpfc_sli4_bsg_diag_mode_end(9)
• lpfc_sli4_bsg_link_diag_test(9)
• lpfcdiag_loop_self_reg(9)
• lpfcdiag_loop_self_unreg(9)
• lpfcdiag_loop_get_xri(9)
• lpfc_bsg_dma_page_alloc(9)
• lpfc_bsg_dma_page_free(9)
• lpfc_bsg_dma_page_list_free(9)
• diag_cmd_data_alloc(9)
• lpfcdiag_sli3_loop_post_rxbufs(9)
• lpfc_bsg_diag_loopback_run(9)
• lpfc_bsg_get_dfc_rev(9)
• lpfc_bsg_issue_mbox_cmpl(9)
• lpfc_bsg_check_cmd_access(9)
• lpfc_bsg_mbox_ext_session_reset(9)
• lpfc_rd_obj_emb0_handle_job(9)
• lpfc_bsg_issue_mbox_ext_handle_job(9)
• lpfc_bsg_issue_read_mbox_ext_cmpl(9)
• lpfc_bsg_issue_write_mbox_ext_cmpl(9)
• lpfc_bsg_sli_cfg_read_cmd_ext(9)
• lpfc_bsg_sli_cfg_write_cmd_ext(9)
• lpfc_bsg_handle_sli_cfg_mbox(9)
• lpfc_bsg_mbox_ext_abort(9)
• lpfc_bsg_read_ebuf_get(9)
• lpfc_bsg_write_ebuf_set(9)
• lpfc_bsg_handle_sli_cfg_ebuf(9)
• lpfc_bsg_handle_sli_cfg_ext(9)
• lpfc_bsg_issue_mbox(9)
• lpfc_bsg_mbox_cmd(9)
• lpfc_check_fwlog_support(9)
• lpfc_bsg_get_ras_config(9)
• lpfc_bsg_set_ras_config(9)
• lpfc_bsg_get_ras_lwpd(9)
• lpfc_bsg_get_ras_fwlog(9)
• lpfc_bsg_hst_vendor(9)
• lpfc_bsg_request(9)
• lpfc_bsg_timeout(9)

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lowkey? read the ones about lpfc_bsg_diag_mode_enter(9) and lpfc_bsg_diag_mode_exit(9) next, they're literally the setup and cleanup for this whole bit 🫶

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🌸 okay that's the page!! tiny sign-off before you go: this one ships from ./drivers/scsi/lpfc, dated October 2026, and it's filed under lpfc_sli3_bs...oopback_mode(9) in case you need to find her again. slay, go run some diagnostics bestie 💖✨🎀🦋