ethtool: Provide a default implementation of ethtool_ops::get_drvinfo

The driver name and bus address for a net_device can normally be found
through the driver model now.  Instead of requiring drivers to provide
this information redundantly through the ethtool_ops::get_drvinfo
operation, use the driver model to do so if the driver does not define
the operation.  Since ETHTOOL_GDRVINFO no longer requires the driver
to implement any operations, do not require net_device::ethtool_ops to
be set either.

Remove implementations of get_drvinfo and ethtool_ops that provide
only this information.

Signed-off-by: Ben Hutchings <bhutchings@solarflare.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

1 files changed, 23 insertions, 10 deletions

diff --git a/net/core/ethtool.c b/net/core/ethtool.c
index 7a85367..d2c4da5 100644
--- a/net/core/ethtool.c
+++ b/net/core/ethtool.c
@@ -205,18 +205,24 @@ static noinline_for_stack int ethtool_get_drvinfo(struct net_device *dev,
 	struct ethtool_drvinfo info;
 	const struct ethtool_ops *ops = dev->ethtool_ops;
 
-	if (!ops->get_drvinfo)
-		return -EOPNOTSUPP;
-
 	memset(&info, 0, sizeof(info));
 	info.cmd = ETHTOOL_GDRVINFO;
-	ops->get_drvinfo(dev, &info);
+	if (ops && ops->get_drvinfo) {
+		ops->get_drvinfo(dev, &info);
+	} else if (dev->dev.parent && dev->dev.parent->driver) {
+		strlcpy(info.bus_info, dev_name(dev->dev.parent),
+			sizeof(info.bus_info));
+		strlcpy(info.driver, dev->dev.parent->driver->name,
+			sizeof(info.driver));
+	} else {
+		return -EOPNOTSUPP;
+	}
 
 	/*
 	 * this method of obtaining string set info is deprecated;
 	 * Use ETHTOOL_GSSET_INFO instead.
 	 */
-	if (ops->get_sset_count) {
+	if (ops && ops->get_sset_count) {
 		int rc;
 
 		rc = ops->get_sset_count(dev, ETH_SS_TEST);
@@ -229,9 +235,9 @@ static noinline_for_stack int ethtool_get_drvinfo(struct net_device *dev,
 		if (rc >= 0)
 			info.n_priv_flags = rc;
 	}
-	if (ops->get_regs_len)
+	if (ops && ops->get_regs_len)
 		info.regdump_len = ops->get_regs_len(dev);
-	if (ops->get_eeprom_len)
+	if (ops && ops->get_eeprom_len)
 		info.eedump_len = ops->get_eeprom_len(dev);
 
 	if (copy_to_user(useraddr, &info, sizeof(info)))
@@ -1402,12 +1408,19 @@ int dev_ethtool(struct net *net, struct ifreq *ifr)
 	if (!dev || !netif_device_present(dev))
 		return -ENODEV;
 
-	if (!dev->ethtool_ops)
-		return -EOPNOTSUPP;
-
 	if (copy_from_user(&ethcmd, useraddr, sizeof(ethcmd)))
 		return -EFAULT;
 
+	if (!dev->ethtool_ops) {
+		/* ETHTOOL_GDRVINFO does not require any driver support.
+		 * It is also unprivileged and does not change anything,
+		 * so we can take a shortcut to it. */
+		if (ethcmd == ETHTOOL_GDRVINFO)
+			return ethtool_get_drvinfo(dev, useraddr);
+		else
+			return -EOPNOTSUPP;
+	}
+
 	/* Allow some commands to be done by anyone */
 	switch (ethcmd) {
 	case ETHTOOL_GDRVINFO: