ethtool: Add and use ethnl_update_bool.

Signed-off-by: David S. Miller <davem@davemloft.net>

net/ethtool/mm.c

@@ -225,7 +225,7 @@ int ethnl_set_mm(struct sk_buff *skb, struct genl_info *info)
 	ethnl_update_u32(&cfg.verify_time, tb[ETHTOOL_A_MM_VERIFY_TIME], &mod);
 	ethnl_update_bool(&cfg.tx_enabled, tb[ETHTOOL_A_MM_TX_ENABLED], &mod);
 	ethnl_update_bool(&cfg.pmac_enabled, tb[ETHTOOL_A_MM_PMAC_ENABLED],
-			  &mod);
+			    &mod);
 	ethnl_update_u32(&cfg.tx_min_frag_size,
 			 tb[ETHTOOL_A_MM_TX_MIN_FRAG_SIZE], &mod);
 

net/ethtool/netlink.h

@@ -137,6 +137,32 @@ static inline void ethnl_update_bool32(u32 *dst, const struct nlattr *attr,
 	*mod = true;
 }
 
+/**
+ * ethnl_update_bool() - updateb bool used as bool from NLA_U8 attribute
+ * @dst:  value to update
+ * @attr: netlink attribute with new value or null
+ * @mod:  pointer to bool for modification tracking
+ *
+ * Use the bool value from NLA_U8 netlink attribute @attr to set bool variable
+ * pointed to by @dst to 0 (if zero) or 1 (if not); do nothing if @attr is
+ * null. Bool pointed to by @mod is set to true if this function changed the
+ * logical value of *dst, otherwise it is left as is.
+ */
+static inline void ethnl_update_bool(bool *dst, const struct nlattr *attr,
+				     bool *mod)
+{
+	u8 val;
+
+	if (!attr)
+		return;
+	val = !!nla_get_u8(attr);
+	if (!!*dst == val)
+		return;
+
+	*dst = val;
+	*mod = true;
+}
+
 /**
  * ethnl_update_binary() - update binary data from NLA_BINARY attribute
  * @dst:  value to update