[PATCH, net-next, v3, 1/2] Three virtual devices (ibmveth, virtio_net, and netvsc) all have similar code to set/get link settings and validate ethtool command. To eliminate duplication of code, it is factored out into core/ethtool.c.

[Cris Forno <cforno12@linux.vnet.ibm.com>]

Signed-off-by: Cris Forno <cforno12@linux.vnet.ibm.com>
---
 include/linux/ethtool.h |  2 ++
 net/core/ethtool.c      | 58 +++++++++++++++++++++++++++++++++++++++++++++++++
 2 files changed, 60 insertions(+)

diff --git a/include/linux/ethtool.h b/include/linux/ethtool.h
index 95991e43..1b0417b 100644
--- a/include/linux/ethtool.h
+++ b/include/linux/ethtool.h
@@ -394,6 +394,8 @@ struct ethtool_ops {
 					  struct ethtool_coalesce *);
 	int	(*set_per_queue_coalesce)(struct net_device *, u32,
 					  struct ethtool_coalesce *);
+	bool    (*virtdev_validate_link_ksettings)(const struct
+						   ethtool_link_ksettings *);
 	int	(*get_link_ksettings)(struct net_device *,
 				      struct ethtool_link_ksettings *);
 	int	(*set_link_ksettings)(struct net_device *,
diff --git a/net/core/ethtool.c b/net/core/ethtool.c
index cd9bc67..4091a94 100644
--- a/net/core/ethtool.c
+++ b/net/core/ethtool.c
@@ -579,6 +579,32 @@ static int load_link_ksettings_from_user(struct ethtool_link_ksettings *to,
 	return 0;
 }
 
+/* Check if the user is trying to change anything besides speed/duplex */
+static bool
+ethtool_virtdev_validate_cmd(const struct ethtool_link_ksettings *cmd)
+{
+	struct ethtool_link_ksettings diff1 = *cmd;
+	struct ethtool_link_ksettings diff2 = {};
+
+	/* cmd is always set so we need to clear it, validate the port type
+	 * and also without autonegotiation we can ignore advertising
+	 */
+	diff1.base.speed = 0;
+	diff2.base.port = PORT_OTHER;
+	ethtool_link_ksettings_zero_link_mode(&diff1, advertising);
+	diff1.base.duplex = 0;
+	diff1.base.cmd = 0;
+	diff1.base.link_mode_masks_nwords = 0;
+
+	return !memcmp(&diff1.base, &diff2.base, sizeof(diff1.base)) &&
+		bitmap_empty(diff1.link_modes.supported,
+			     __ETHTOOL_LINK_MODE_MASK_NBITS) &&
+		bitmap_empty(diff1.link_modes.advertising,
+			     __ETHTOOL_LINK_MODE_MASK_NBITS) &&
+		bitmap_empty(diff1.link_modes.lp_advertising,
+			     __ETHTOOL_LINK_MODE_MASK_NBITS);
+}
+
 /* convert a kernel internal ethtool_link_ksettings to
  * ethtool_link_usettings in user space. return 0 on success, errno on
  * error.
@@ -660,6 +686,17 @@ static int ethtool_get_link_ksettings(struct net_device *dev,
 	return store_link_ksettings_for_user(useraddr, &link_ksettings);
 }
 
+static int
+ethtool_virtdev_get_link_ksettings(struct net_device *dev,
+				   struct ethtool_link_ksettings *cmd,
+				   u32 *speed, u8 *duplex)
+{
+	cmd->base.speed = *speed;
+	cmd->base.duplex = *duplex;
+	cmd->base.port = PORT_OTHER;
+	return 0;
+}
+
 /* Update device ethtool_link_settings. */
 static int ethtool_set_link_ksettings(struct net_device *dev,
 				      void __user *useraddr)
@@ -696,6 +733,27 @@ static int ethtool_set_link_ksettings(struct net_device *dev,
 	return dev->ethtool_ops->set_link_ksettings(dev, &link_ksettings);
 }
 
+static int
+ethtool_virtdev_set_link_ksettings(struct net_device *dev,
+				   const struct ethtool_link_ksettings *cmd,
+				   u32 *dev_speed, u8 *dev_duplex)
+{
+	u32 speed;
+	u8 duplex;
+
+	speed = cmd->base.speed;
+	duplex = cmd->base.duplex;
+	/* don't allow custom speed and duplex */
+	if (!ethtool_validate_speed(speed) ||
+	    !ethtool_validate_duplex(duplex) ||
+	    !dev->ethtool_ops->virtdev_validate_link_ksettings(cmd))
+		return -EINVAL;
+	*dev_speed = speed;
+	*dev_duplex = duplex;
+
+	return 0;
+}
+
 /* Query device for its ethtool_cmd settings.
  *
  * Backward compatibility note: for compatibility with legacy ethtool, this is
-- 
1.8.3.1