dev_open(9)

💖 dev_open(9) — like, the "wake up bestie" call for network interfaces 💖

okay so this is dev_open, straight out of the Kernel API Manual — section 9, kernel-land, no user-facing shenanigans here. buckle up 🎀

---

✨ NAME ✨

dev_open — prepare an interface for use 🦋

---

🌸 SYNOPSIS 🌸

int dev_open (struct net_device *dev , struct netlink_ext_ack *extack );

---

🎀 ARGUMENTS 🎀

• dev — the device you're opening. the main character, literally 💅
• extack — netlink extended ack. it's the receipts-holder 📬

---

💫 DESCRIPTION 💫

okay so picture this: your device is down and you want it up. that's the whole gig, bestie. dev_open takes a device from down state to up state, and it does it in a very specific order — no cap:

1. the device's private open function gets invoked 🔥
2. then the multicast lists are loaded 📋
3. finally the device is moved into the up state

...and then a NETDEV_UP message is sent to the netdev notifier chain. everyone who's anyone gets the memo, periodt 👑

here's the chill part: calling this function on an active interface is a nop. it's giving "already slaying, nothing to do" 🙈 if it fails though, you get a negative errno code back. so like, be aware 😭

⚠️ heads up bestie: failure = negative errno code. not vibes, an actual negative error number. iykyk.

---

🌈 RETURN 🌈

• 0 on success 🎉 slay
• -errno on failure 💀

---

🦋 SEE ALSO 🦋

kernel file ./net/core/dev_api.c 👀 plus the whole friend group:

• dev_change_name(9)
• dev_set_alias(9)
• dev_change_flags(9)
• dev_set_group(9)
• dev_change_net_namespace(9)
• dev_change_carrier(9)
• dev_change_tx_queue_len(9)
• dev_change_proto_down(9)
• dev_close(9)
• dev_disable_lro(9)
• dev_set_promiscuity(9)
• dev_set_allmulti(9)
• dev_set_mac_address(9)
• netdev_state_change(9)

go read them, they're iconic too 💜

---

mwah 💋 that's the whole page! brought to you by ./net/core, dated October 2026, and yes the manual name for this one is dev_open(9) — see you in the next man page, bestie 🫶✨