bonding: fix incorrect software timestamping report

JIRA: https://issues.redhat.com/browse/RHEL-42409
Upstream Status: net.git commit a95b031

commit a95b031
Author: Hangbin Liu <liuhangbin@gmail.com>
Date:   Thu Jun 20 16:56:26 2024 +0800

    bonding: fix incorrect software timestamping report

    The __ethtool_get_ts_info function returns directly if the device has a
    get_ts_info() method. For bonding with an active slave, this works correctly
    as we simply return the real device's timestamping information. However,
    when there is no active slave, we only check the slave's TX software
    timestamp information. We still need to set the phc index and RX timestamp
    information manually. Otherwise, the result will be look like:

      Time stamping parameters for bond0:
      Capabilities:
              software-transmit
      PTP Hardware Clock: 0
      Hardware Transmit Timestamp Modes: none
      Hardware Receive Filter Modes: none

    This issue does not affect VLAN or MACVLAN devices, as they only have one
    downlink and can directly use the downlink's timestamping information.

    Fixes: b8768dc ("net: ethtool: Refactor identical get_ts_info implementations.")
    Reported-by: Liang Li <liali@redhat.com>
    Closes: https://issues.redhat.com/browse/RHEL-42409
    Signed-off-by: Hangbin Liu <liuhangbin@gmail.com>
    Acked-by: Kory Maincent <kory.maincent@bootlin.com>
    Signed-off-by: David S. Miller <davem@davemloft.net>

Signed-off-by: Hangbin Liu <haliu@redhat.com>

Author: Hangbin Liu

drivers/net/bonding/bond_main.c

@@ -5778,6 +5778,9 @@ static int bond_ethtool_get_ts_info(struct net_device *bond_dev,
 	if (real_dev) {
 		ret = ethtool_get_ts_info_by_layer(real_dev, info);
 	} else {
+		info->phc_index = -1;
+		info->so_timestamping = SOF_TIMESTAMPING_RX_SOFTWARE |
+					SOF_TIMESTAMPING_SOFTWARE;
 		/* Check if all slaves support software tx timestamping */
 		rcu_read_lock();
 		bond_for_each_slave_rcu(bond, slave, iter) {