linux-kernel - [PATCH 5.11 035/306] ibmvnic: always store valid MAC address

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Date:   Mon, 15 Mar 2021 14:51:38 +0100
From:   gregkh@...uxfoundation.org
To:     linux-kernel@...r.kernel.org
Cc:     Greg Kroah-Hartman <gregkh@...uxfoundation.org>,
        stable@...r.kernel.org, Jiri Wiesner <jwiesner@...e.com>,
        "David S. Miller" <davem@...emloft.net>
Subject: [PATCH 5.11 035/306] ibmvnic: always store valid MAC address

From: Greg Kroah-Hartman <gregkh@...uxfoundation.org>

From: Jiri Wiesner <jwiesner@...e.com>

commit 67eb211487f0c993d9f402d1c196ef159fd6a3b5 upstream.

The last change to ibmvnic_set_mac(), 8fc3672a8ad3, meant to prevent
users from setting an invalid MAC address on an ibmvnic interface
that has not been brought up yet. The change also prevented the
requested MAC address from being stored by the adapter object for an
ibmvnic interface when the state of the ibmvnic interface is
VNIC_PROBED - that is after probing has finished but before the
ibmvnic interface is brought up. The MAC address stored by the
adapter object is used and sent to the hypervisor for checking when
an ibmvnic interface is brought up.

The ibmvnic driver ignoring the requested MAC address when in
VNIC_PROBED state caused LACP bonds (bonds in 802.3ad mode) with more
than one slave to malfunction. The bonding code must be able to
change the MAC address of its slaves before they are brought up
during enslaving. The inability of kernels with 8fc3672a8ad3 to set
the MAC addresses of bonding slaves is observable in the output of
"ip address show". The MAC addresses of the slaves are the same as
the MAC address of the bond on a working system whereas the slaves
retain their original MAC addresses on a system with a malfunctioning
LACP bond.

Fixes: 8fc3672a8ad3 ("ibmvnic: fix ibmvnic_set_mac")
Signed-off-by: Jiri Wiesner <jwiesner@...e.com>
Signed-off-by: David S. Miller <davem@...emloft.net>
Signed-off-by: Greg Kroah-Hartman <gregkh@...uxfoundation.org>
---
 drivers/net/ethernet/ibm/ibmvnic.c |    5 ++---
 1 file changed, 2 insertions(+), 3 deletions(-)

--- a/drivers/net/ethernet/ibm/ibmvnic.c
+++ b/drivers/net/ethernet/ibm/ibmvnic.c
@@ -1923,10 +1923,9 @@ static int ibmvnic_set_mac(struct net_de
 	if (!is_valid_ether_addr(addr->sa_data))
 		return -EADDRNOTAVAIL;

-	if (adapter->state != VNIC_PROBED) {
-		ether_addr_copy(adapter->mac_addr, addr->sa_data);
+	ether_addr_copy(adapter->mac_addr, addr->sa_data);
+	if (adapter->state != VNIC_PROBED)
 		rc = __ibmvnic_set_mac(netdev, addr->sa_data);
-	}

 	return rc;
 }