bonding: only set speed/duplex to unknown, if getting speed failed

bond_update_speed_duplex() first set speed/duplex to unknown and
then asks slave driver for current speed/duplex. Since getting
speed/duplex might take longer there is a race, where this false state
is visible by /proc/net/bonding. With commit 691b2bf14946 ("bonding:
 update port speed when getting bond speed") this race gets more visible,
if user space is calling ethtool on a regular base.

Fix this by only setting speed/duplex to unknown, if link speed is
really unknown/unusable.

Fixes: 98f41f694f46 ("bonding:update speed/duplex for NETDEV_CHANGE")
Signed-off-by: Thomas Bogendoerfer <tbogendoerfer@suse.de>
Acked-by: Jay Vosburgh <jv@jvosburgh.net>
Reviewed-by: Nikolay Aleksandrov <razor@blackwall.org>
Reviewed-by: Hangbin Liu <liuhangbin@gmail.com>
Link: https://patch.msgid.link/20260203141153.51581-1-tbogendoerfer@suse.de
Signed-off-by: Jakub Kicinski <kuba@kernel.org>

diff --git a/drivers/net/bonding/bond_main.c b/drivers/net/bonding/bond_main.c
index 45bd2bb102ffdf12cf59bb96c20f10544687ba1a..47f13d86cb7ef07327bde6b249b0ad9d3f5e5e1f 100644 (file)
--- a/drivers/net/bonding/bond_main.c
+++ b/drivers/net/bonding/bond_main.c
@@ -791,26 +791,29 @@ static int bond_update_speed_duplex(struct slave *slave)
        struct ethtool_link_ksettings ecmd;
        int res;
 
-       slave->speed = SPEED_UNKNOWN;
-       slave->duplex = DUPLEX_UNKNOWN;
-
        res = __ethtool_get_link_ksettings(slave_dev, &ecmd);
        if (res < 0)
-               return 1;
+               goto speed_duplex_unknown;
        if (ecmd.base.speed == 0 || ecmd.base.speed == ((__u32)-1))
-               return 1;
+               goto speed_duplex_unknown;
        switch (ecmd.base.duplex) {
        case DUPLEX_FULL:
        case DUPLEX_HALF:
                break;
        default:
-               return 1;
+               goto speed_duplex_unknown;
        }
 
        slave->speed = ecmd.base.speed;
        slave->duplex = ecmd.base.duplex;
 
        return 0;
+
+speed_duplex_unknown:
+       slave->speed = SPEED_UNKNOWN;
+       slave->duplex = DUPLEX_UNKNOWN;
+
+       return 1;
 }
 
 const char *bond_slave_link_status(s8 link)