ethtool: Veto some operations during firmware flashing process

Some operations cannot be performed during the firmware flashing
process.

For example:

- Port must be down during the whole flashing process to avoid packet loss
  while committing reset for example.

- Writing to EEPROM interrupts the flashing process, so operations like
  ethtool dump, module reset, get and set power mode should be vetoed.

- Split port firmware flashing should be vetoed.

In order to veto those scenarios, add a flag in 'struct net_device' that
indicates when a firmware flash is taking place on the module and use it
to prevent interruptions during the process.
Signed-off-by: Danielle Ratson <danieller@nvidia.com>
Reviewed-by: Petr Machata <petrm@nvidia.com>
Reviewed-by: Andrew Lunn <andrew@lunn.ch>
Signed-off-by: David S. Miller <davem@davemloft.net>

include/linux/netdevice.h

@@ -1990,6 +1990,8 @@ enum netdev_reg_state {
  *
  *	@threaded:	napi threaded mode is enabled
  *
+ *	@module_fw_flash_in_progress:	Module firmware flashing is in progress.
+ *
  *	@net_notifier_list:	List of per-net netdev notifier block
  *				that follow this device when it is moved
  *				to another network namespace.
@@ -2374,7 +2376,7 @@ struct net_device {
 	bool			proto_down;
 	bool			threaded;
 	unsigned		wol_enabled:1;
-
+	unsigned		module_fw_flash_in_progress:1;
 	struct list_head	net_notifier_list;
 
 #if IS_ENABLED(CONFIG_MACSEC)

net/ethtool/eeprom.c

@@ -91,6 +91,12 @@ static int get_module_eeprom_by_page(struct net_device *dev,
 {
 	const struct ethtool_ops *ops = dev->ethtool_ops;
 
+	if (dev->module_fw_flash_in_progress) {
+		NL_SET_ERR_MSG(extack,
+			       "Module firmware flashing is in progress");
+		return -EBUSY;
+	}
+
 	if (dev->sfp_bus)
 		return sfp_get_module_eeprom_by_page(dev->sfp_bus, page_data, extack);
 

net/ethtool/ioctl.c

@@ -658,6 +658,9 @@ static int ethtool_get_settings(struct net_device *dev, void __user *useraddr)
 	if (!dev->ethtool_ops->get_link_ksettings)
 		return -EOPNOTSUPP;
 
+	if (dev->module_fw_flash_in_progress)
+		return -EBUSY;
+
 	memset(&link_ksettings, 0, sizeof(link_ksettings));
 	err = dev->ethtool_ops->get_link_ksettings(dev, &link_ksettings);
 	if (err < 0)
@@ -1449,6 +1452,9 @@ static int ethtool_reset(struct net_device *dev, char __user *useraddr)
 	if (!dev->ethtool_ops->reset)
 		return -EOPNOTSUPP;
 
+	if (dev->module_fw_flash_in_progress)
+		return -EBUSY;
+
 	if (copy_from_user(&reset, useraddr, sizeof(reset)))
 		return -EFAULT;
 
@@ -2462,6 +2468,9 @@ int ethtool_get_module_info_call(struct net_device *dev,
 	const struct ethtool_ops *ops = dev->ethtool_ops;
 	struct phy_device *phydev = dev->phydev;
 
+	if (dev->module_fw_flash_in_progress)
+		return -EBUSY;
+
 	if (dev->sfp_bus)
 		return sfp_get_module_info(dev->sfp_bus, modinfo);
 
@@ -2499,6 +2508,9 @@ int ethtool_get_module_eeprom_call(struct net_device *dev,
 	const struct ethtool_ops *ops = dev->ethtool_ops;
 	struct phy_device *phydev = dev->phydev;
 
+	if (dev->module_fw_flash_in_progress)
+		return -EBUSY;
+
 	if (dev->sfp_bus)
 		return sfp_get_module_eeprom(dev->sfp_bus, ee, data);
 

net/ethtool/netlink.c

@@ -765,10 +765,22 @@ static void ethnl_notify_features(struct netdev_notifier_info *info)
 static int ethnl_netdev_event(struct notifier_block *this, unsigned long event,
 			      void *ptr)
 {
+	struct netdev_notifier_info *info = ptr;
+	struct netlink_ext_ack *extack;
+	struct net_device *dev;
+
+	dev = netdev_notifier_info_to_dev(info);
+	extack = netdev_notifier_info_to_extack(info);
+
 	switch (event) {
 	case NETDEV_FEAT_CHANGE:
 		ethnl_notify_features(ptr);
 		break;
+	case NETDEV_PRE_UP:
+		if (dev->module_fw_flash_in_progress) {
+			NL_SET_ERR_MSG(extack, "Can't set port up while flashing module firmware");
+			return NOTIFY_BAD;
+		}
 	}
 
 	return NOTIFY_DONE;