netdev - [PATCH net-next] net: fix net device address assign type

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Message-Id: <20230621132106.991342-1-piotrx.gardocki@intel.com>
Date: Wed, 21 Jun 2023 15:21:06 +0200
From: Piotr Gardocki <piotrx.gardocki@...el.com>
To: netdev@...r.kernel.org
Cc: piotrx.gardocki@...el.com,
	intel-wired-lan@...ts.osuosl.org,
	przemyslaw.kitszel@...el.com,
	michal.swiatkowski@...ux.intel.com,
	pmenzel@...gen.mpg.de,
	kuba@...nel.org,
	maciej.fijalkowski@...el.com,
	anthony.l.nguyen@...el.com,
	simon.horman@...igine.com,
	aleksander.lobakin@...el.com,
	gal@...dia.com
Subject: [PATCH net-next] net: fix net device address assign type

Commit ad72c4a06acc introduced optimization to return from function
quickly if the MAC address is not changing at all. It was reported
that such change causes dev->addr_assign_type to not change
to NET_ADDR_SET from _PERM or _RANDOM.
Restore the old behavior and skip only call to ndo_set_mac_address.

Fixes: ad72c4a06acc ("net: add check for current MAC address in dev_set_mac_address")
Reported-by: Gal Pressman <gal@...dia.com>
Signed-off-by: Piotr Gardocki <piotrx.gardocki@...el.com>
---
 net/core/dev.c | 10 +++++-----
 1 file changed, 5 insertions(+), 5 deletions(-)

diff --git a/net/core/dev.c b/net/core/dev.c
index e4ff0adf5523..69a3e544676c 100644
--- a/net/core/dev.c
+++ b/net/core/dev.c
@@ -8781,14 +8781,14 @@ int dev_set_mac_address(struct net_device *dev, struct sockaddr *sa,
 		return -EINVAL;
 	if (!netif_device_present(dev))
 		return -ENODEV;
-	if (!memcmp(dev->dev_addr, sa->sa_data, dev->addr_len))
-		return 0;
 	err = dev_pre_changeaddr_notify(dev, sa->sa_data, extack);
 	if (err)
 		return err;
-	err = ops->ndo_set_mac_address(dev, sa);
-	if (err)
-		return err;
+	if (memcmp(dev->dev_addr, sa->sa_data, dev->addr_len)) {
+		err = ops->ndo_set_mac_address(dev, sa);
+		if (err)
+			return err;
+	}
 	dev->addr_assign_type = NET_ADDR_SET;
 	call_netdevice_notifiers(NETDEV_CHANGEADDR, dev);
 	add_device_randomness(dev->dev_addr, dev->addr_len);
-- 
2.34.1