dev_uc_unsync(9)

💅 dev_uc_unsync(9) — the Kernel API Manual, bestie edition

okay so this is dev_uc_unsync from the kernel API manual, and it's lowkey iconic for what it does: it un-syncs. it's the cleanup queen. let's get into it 🎀

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✨ NAME ✨

dev_uc_unsync — Remove synchronized addresses from the destination device

like literally, it takes the addresses that got synced over and yeets them back out. it's giving "you don't belong here anymore" 💅

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🦋 SYNOPSIS 🦋

void dev_uc_unsync (struct net_device *to , struct net_device *from );

two struct net_device * pointers, one called to, one called from, and it returns void because it's not here to give you answers, it's here to do the work. periodt.

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🌸 ARGUMENTS 🌸

• to — destination device. the one getting its addresses removed. main character of this operation honestly 👑
• from — source device. the place those addresses originally came from. the origin story, if you will ✨

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🔥 DESCRIPTION 🔥

Remove all addresses that were added to the destination device by dev_uc_sync.

that's it. that's the whole vibe. it undoes what dev_uc_sync did, and it's not subtle about it — all the addresses, gone, no cap.

This function is intended to be called from the dev->stop function of layered software devices.

so like, when your layered software device is shutting down its dev->stop, that's your moment 🫶. that's where you call this. it's the "closing time, turn the lights off" function of the address-syncing world. ngl it's kind of a slay that it's this straightforward.

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💜 SEE ALSO 💜

Kernel file ./net/core/dev_addr_lists.c and its whole friend group — these are all in the same file, iykyk:

• __hw_addr_sync_dev(9)
• __hw_addr_ref_sync_dev(9)
• __hw_addr_ref_unsync_dev(9)
• __hw_addr_unsync_dev(9)
• __hw_addr_list_snapshot(9)
• __hw_addr_list_reconcile(9)
• dev_addr_flush(9)
• dev_addr_init(9)
• dev_addr_add(9)
• dev_addr_del(9)
• dev_uc_add_excl(9)
• dev_uc_add(9)
• dev_uc_del(9)
• dev_uc_sync(9)
• dev_uc_sync_multiple(9)
• dev_uc_flush(9)
• dev_uc_init(9)
• dev_mc_add_excl(9)
• dev_mc_add(9)
• dev_mc_add_global(9)
• dev_mc_del(9)
• dev_mc_del_global(9)
• dev_mc_sync(9)
• dev_mc_sync_multiple(9)
• dev_mc_unsync(9)
• dev_mc_flush(9)
• dev_mc_init(9)
• netif_uc_promisc_update(9)
• __dev_set_rx_mode(9)
• netif_rx_mode_sync(9)

literally the entire multicast/unicast address family reunion, and dev_uc_unsync is the cousin who shows up, does one thing, and dips 🙈

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bestie reminder: this one only removes what dev_uc_sync put there. it's a targeted cleanup, not a dev_uc_flush. don't mix up your vibes 💀

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and that's the page! 💖 this masterpiece lives in ./net/core, comes from the October 2026 edition of the kernel docs, and honestly? she ate. 🌈⭐ stay synced (or don't, that's literally the point) 🧚🍓