scsi_add_device(9)

💅 scsi_add_device — a Kernel API Manual moment

okay so bestie, this one's scsi_add_device(9) from the Kernel API Manual and honestly? it's giving "small function, big consequences." let's get into it 🫶

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✨ NAME ✨

scsi_add_device — creates a new SCSI (LU) instance. that's it, that's the whole vibe. it makes a device appear ✨

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🌸 SYNOPSIS 🌸

int scsi_add_device (struct Scsi_Host *host , uint channel , uint target
, u64 lun );

literally four args, no cap. hand it a host, a channel, a target and a lun and it'll go off and do its thing 💫

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🎀 ARGUMENTS 🎀

• host — the Scsi_Host instance where the device is located. like, where does this thing even live, that's the host 🏠
• channel — the target channel number. and ngl, it's rarely other than 0 🙈
• target — the target id number, iconic little identifier, we love her 👑
• lun — the LUN of the target device. yes, u64. yes, she's big 💜

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🦋 DESCRIPTION 🦋

Probe for a specific LUN and add it if found. that's the entire job description and she ate 🔥

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⭐ NOTES ⭐

okay this part MATTERS so listen up bestie, no skimming 👀

This call is usually performed internally during a SCSI bus scan when an HBA is added (i.e. scsi_scan_host). so it's mostly a behind-the-scenes girly doing her work without being asked 💅

so it should only be called if the HBA becomes aware of a new SCSI device (LU) after scsi_scan_host has completed. like, don't jump the queue, the scan has to finish first, periodt ✋

and if it's successful, this call can lead to sdev_init and sdev_configure callbacks into the LLD. so your callbacks are gonna get pinged, be ready for it 💖

lowkey important: this is not a "call it whenever" function. timing is everything, fr fr 🌸

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🌈 RETURN 🌈

• 0 on success (slay 💅)
• negative error code on failure (the 😭 path)

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🧚 SEE ALSO 🧚

Kernel file ./drivers/scsi/scsi_scan.c is the home base for all of these besties, so go say hi:

• scsi_complete_async_scans(9)
• scsi_unlock_floptical(9)
• scsi_alloc_sdev(9)
• scsi_target_reap_ref_release(9)
• scsi_alloc_target(9)
• scsi_target_reap(9)
• scsi_sanitize_inquiry_string(9)
• scsi_probe_lun(9)
• scsi_add_lun(9)
• scsi_inq_str(9)
• scsi_probe_and_add_lun(9)
• scsi_sequential_lun_scan(9)
• scsi_report_lun_scan(9)
• scsi_scan_target(9)
• scsi_prep_async_scan(9)
• scsi_finish_async_scan(9)
• scsi_scan_host(9)
• scsi_get_pseudo_sdev(9)

that's a whole group chat of scan-related functions and they're all linked, iykyk 💫

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okay that's the page 🎀 it lives over in ./drivers/scsi, dated October 2026, and it's part of the Kernel API Manual (so yes, scsi_add_device(9) is the name-and-section combo, going in the header where it belongs). mwah, go add some devices responsibly 💖✨🦋