From: Vladimir Oltean <vladimir.oltean@xxxxxxx> [ Upstream commit b94cbc909f1d80378a1f541968309e5c1178c98b ] DSA implements a bunch of 'standardized' ethtool statistics counters, namely tx_packets, tx_bytes, rx_packets, rx_bytes. So whatever the hardware driver returns in .get_sset_count(), we need to add 4 to that. That is ok, except that .get_sset_count() can return a negative error code, for example: b53_get_sset_count -> phy_ethtool_get_sset_count -> return -EIO -EIO is -5, and with 4 added to it, it becomes -1, aka -EPERM. One can imagine that certain error codes may even become positive, although based on code inspection I did not see instances of that. Check the error code first, if it is negative return it as-is. Based on a similar patch for dsa_master_get_strings from Dan Carpenter: https://patchwork.kernel.org/project/netdevbpf/patch/YJaSe3RPgn7gKxZv@mwanda/ Fixes: 91da11f870f0 ("net: Distributed Switch Architecture protocol support") Signed-off-by: Vladimir Oltean <vladimir.oltean@xxxxxxx> Reviewed-by: Florian Fainelli <f.fainelli@xxxxxxxxx> Reviewed-by: Andrew Lunn <andrew@xxxxxxx> Signed-off-by: David S. Miller <davem@xxxxxxxxxxxxx> Signed-off-by: Sasha Levin <sashal@xxxxxxxxxx> --- net/dsa/slave.c | 12 +++++++----- 1 file changed, 7 insertions(+), 5 deletions(-) diff --git a/net/dsa/slave.c b/net/dsa/slave.c index 06f8874d53ee..75b4cd4bcafb 100644 --- a/net/dsa/slave.c +++ b/net/dsa/slave.c @@ -692,13 +692,15 @@ static int dsa_slave_get_sset_count(struct net_device *dev, int sset) struct dsa_switch *ds = dp->ds; if (sset == ETH_SS_STATS) { - int count; + int count = 0; - count = 4; - if (ds->ops->get_sset_count) - count += ds->ops->get_sset_count(ds, dp->index, sset); + if (ds->ops->get_sset_count) { + count = ds->ops->get_sset_count(ds, dp->index, sset); + if (count < 0) + return count; + } - return count; + return count + 4; } return -EOPNOTSUPP; -- 2.30.2
