net: ethtool: ioctl: concentrate the locking

Add another layer of helper functions to make upcoming locking
changes easier. Otherwise we'd need a pretty complex goto
structure. netdev instance lock is now taken slightly sooner
but that should not be an issue since rtnl_lock is already held,
anyway.

Reviewed-by: Eric Dumazet <edumazet@google.com>
Acked-by: Stanislav Fomichev <sdf@fomichev.me>
Reviewed-by: Jacob Keller <jacob.e.keller@intel.com>
Link: https://patch.msgid.link/20260605002912.3456868-11-kuba@kernel.org
Signed-off-by: Jakub Kicinski <kuba@kernel.org>

diff --git a/net/ethtool/ioctl.c b/net/ethtool/ioctl.c
index a4b0cbae406366d505f138bcdf24f6d1a6315706..c32c099845e3126707c46a05f22a5b8b40332faa 100644 (file)
--- a/net/ethtool/ioctl.c
+++ b/net/ethtool/ioctl.c
@@ -3258,18 +3258,14 @@ static int ethtool_set_fecparam(struct net_device *dev, void __user *useraddr)
 /* The main entry point in this file.  Called from net/core/dev_ioctl.c */
 
 static int
-__dev_ethtool(struct net *net, struct ifreq *ifr, void __user *useraddr,
-             u32 ethcmd, struct ethtool_devlink_compat *devlink_state)
+dev_ethtool_locked(struct net *net, struct net_device *dev,
+                  void __user *useraddr,
+                  u32 ethcmd, struct ethtool_devlink_compat *devlink_state)
 {
-       struct net_device *dev;
        u32 sub_cmd;
        int rc;
        netdev_features_t old_features;
 
-       dev = __dev_get_by_name(net, ifr->ifr_name);
-       if (!dev)
-               return -ENODEV;
-
        if (ethcmd == ETHTOOL_PERQUEUE) {
                if (copy_from_user(&sub_cmd, useraddr + sizeof(ethcmd), sizeof(sub_cmd)))
                        return -EFAULT;
@@ -3320,7 +3316,6 @@ __dev_ethtool(struct net *net, struct ifreq *ifr, void __user *useraddr,
                        return -EPERM;
        }
 
-       netdev_lock_ops(dev);
        if (dev->dev.parent)
                pm_runtime_get_sync(dev->dev.parent);
 
@@ -3560,7 +3555,29 @@ __dev_ethtool(struct net *net, struct ifreq *ifr, void __user *useraddr,
 out:
        if (dev->dev.parent)
                pm_runtime_put(dev->dev.parent);
+
+       return rc;
+}
+
+static int
+__dev_ethtool(struct net *net, struct ifreq *ifr, void __user *useraddr,
+             u32 ethcmd, struct ethtool_devlink_compat *devlink_state)
+{
+       struct net_device *dev;
+       int rc;
+
+       rtnl_lock();
+       dev = __dev_get_by_name(net, ifr->ifr_name);
+       if (!dev) {
+               rc = -ENODEV;
+               goto exit_rtnl_unlock;
+       }
+
+       netdev_lock_ops(dev);
+       rc = dev_ethtool_locked(net, dev, useraddr, ethcmd, devlink_state);
        netdev_unlock_ops(dev);
+exit_rtnl_unlock:
+       rtnl_unlock();
 
        return rc;
 }
@@ -3588,9 +3605,7 @@ int dev_ethtool(struct net *net, struct ifreq *ifr, void __user *useraddr)
                break;
        }
 
-       rtnl_lock();
        rc = __dev_ethtool(net, ifr, useraddr, ethcmd, state);
-       rtnl_unlock();
        if (rc)
                goto exit_free;