[PATCH net v2 1/3] net/ethtool/ioctl: return -EOPNOTSUPP if we have no phy stats

[Daniil Tatianin]

It's not very useful to copy back an empty ethtool_stats struct and
return 0 if we didn't actually have any stats. This also allows for
further simplification of this function in the future commits.

Signed-off-by: Daniil Tatianin <d-tatianin@xxxxxxxxxxxxxx>
Reviewed-by: Andrew Lunn <andrew@xxxxxxx>
---
 net/ethtool/ioctl.c | 3 ++-
 1 file changed, 2 insertions(+), 1 deletion(-)

diff --git a/net/ethtool/ioctl.c b/net/ethtool/ioctl.c
index 57e7238a4136..e8a294b38b7b 100644
--- a/net/ethtool/ioctl.c
+++ b/net/ethtool/ioctl.c
@@ -2093,7 +2093,8 @@ static int ethtool_get_phy_stats(struct net_device *dev, void __user *useraddr)
 		return n_stats;
 	if (n_stats > S32_MAX / sizeof(u64))
 		return -ENOMEM;
-	WARN_ON_ONCE(!n_stats);
+	if (WARN_ON_ONCE(!n_stats))
+		return -EOPNOTSUPP;
 
 	if (copy_from_user(&stats, useraddr, sizeof(stats)))
 		return -EFAULT;
-- 
2.25.1