remove mapstructure from identity,networking,objectstorage,orchestration,pagination
diff --git a/openstack/networking/v2/ports/results.go b/openstack/networking/v2/ports/results.go
index 0908fda..e757a54 100644
--- a/openstack/networking/v2/ports/results.go
+++ b/openstack/networking/v2/ports/results.go
@@ -1,7 +1,6 @@
 package ports
 
 import (
-	"github.com/mitchellh/mapstructure"
 	"github.com/gophercloud/gophercloud"
 	"github.com/gophercloud/gophercloud/pagination"
 )
@@ -12,16 +11,11 @@
 
 // Extract is a function that accepts a result and extracts a port resource.
 func (r commonResult) Extract() (*Port, error) {
-	if r.Err != nil {
-		return nil, r.Err
-	}
-
-	var res struct {
+	var s struct {
 		Port *Port `json:"port"`
 	}
-	err := mapstructure.Decode(r.Body, &res)
-
-	return res.Port, err
+	err := r.ExtractInto(&s)
+	return s.Port, err
 }
 
 // CreateResult represents the result of a create operation.
@@ -46,44 +40,45 @@
 
 // IP is a sub-struct that represents an individual IP.
 type IP struct {
-	SubnetID  string `mapstructure:"subnet_id" json:"subnet_id"`
-	IPAddress string `mapstructure:"ip_address" json:"ip_address,omitempty"`
+	SubnetID  string `json:"subnet_id"`
+	IPAddress string `json:"ip_address,omitempty"`
 }
 
+// AddressPair contains the IP Address and the MAC address.
 type AddressPair struct {
-	IPAddress  string `mapstructure:"ip_address" json:"ip_address,omitempty"`
-	MACAddress string `mapstructure:"mac_address" json:"mac_address,omitempty"`
+	IPAddress  string `json:"ip_address,omitempty"`
+	MACAddress string `json:"mac_address,omitempty"`
 }
 
 // Port represents a Neutron port. See package documentation for a top-level
 // description of what this is.
 type Port struct {
 	// UUID for the port.
-	ID string `mapstructure:"id" json:"id"`
+	ID string `json:"id"`
 	// Network that this port is associated with.
-	NetworkID string `mapstructure:"network_id" json:"network_id"`
+	NetworkID string `json:"network_id"`
 	// Human-readable name for the port. Might not be unique.
-	Name string `mapstructure:"name" json:"name"`
+	Name string `json:"name"`
 	// Administrative state of port. If false (down), port does not forward packets.
-	AdminStateUp bool `mapstructure:"admin_state_up" json:"admin_state_up"`
+	AdminStateUp bool `json:"admin_state_up"`
 	// Indicates whether network is currently operational. Possible values include
 	// `ACTIVE', `DOWN', `BUILD', or `ERROR'. Plug-ins might define additional values.
-	Status string `mapstructure:"status" json:"status"`
+	Status string `json:"status"`
 	// Mac address to use on this port.
-	MACAddress string `mapstructure:"mac_address" json:"mac_address"`
+	MACAddress string `json:"mac_address"`
 	// Specifies IP addresses for the port thus associating the port itself with
 	// the subnets where the IP addresses are picked from
-	FixedIPs []IP `mapstructure:"fixed_ips" json:"fixed_ips"`
+	FixedIPs []IP `json:"fixed_ips"`
 	// Owner of network. Only admin users can specify a tenant_id other than its own.
-	TenantID string `mapstructure:"tenant_id" json:"tenant_id"`
+	TenantID string `json:"tenant_id"`
 	// Identifies the entity (e.g.: dhcp agent) using this port.
-	DeviceOwner string `mapstructure:"device_owner" json:"device_owner"`
+	DeviceOwner string `json:"device_owner"`
 	// Specifies the IDs of any security groups associated with a port.
-	SecurityGroups []string `mapstructure:"security_groups" json:"security_groups"`
+	SecurityGroups []string `json:"security_groups"`
 	// Identifies the device (e.g., virtual server) using this port.
-	DeviceID string `mapstructure:"device_id" json:"device_id"`
+	DeviceID string `json:"device_id"`
 	// Identifies the list of IP addresses the port will recognize/accept
-	AllowedAddressPairs []AddressPair `mapstructure:"allowed_address_pairs" json:"allowed_address_pairs"`
+	AllowedAddressPairs []AddressPair `json:"allowed_address_pairs"`
 }
 
 // PortPage is the page returned by a pager when traversing over a collection
@@ -95,38 +90,31 @@
 // NextPageURL is invoked when a paginated collection of ports has reached
 // the end of a page and the pager seeks to traverse over a new one. In order
 // to do this, it needs to construct the next page's URL.
-func (p PortPage) NextPageURL() (string, error) {
-	type resp struct {
-		Links []gophercloud.Link `mapstructure:"ports_links"`
+func (page PortPage) NextPageURL() (string, error) {
+	var s struct {
+		Links []gophercloud.Link `json:"ports_links"`
 	}
-
-	var r resp
-	err := mapstructure.Decode(p.Body, &r)
+	err := page.ExtractInto(&s)
 	if err != nil {
 		return "", err
 	}
-
-	return gophercloud.ExtractNextURL(r.Links)
+	return gophercloud.ExtractNextURL(s.Links)
 }
 
 // IsEmpty checks whether a PortPage struct is empty.
-func (p PortPage) IsEmpty() (bool, error) {
-	is, err := ExtractPorts(p)
-	if err != nil {
-		return true, nil
-	}
-	return len(is) == 0, nil
+func (page PortPage) IsEmpty() (bool, error) {
+	is, err := ExtractPorts(page)
+	return len(is) == 0, err
 }
 
 // ExtractPorts accepts a Page struct, specifically a PortPage struct,
 // and extracts the elements into a slice of Port structs. In other words,
 // a generic collection is mapped into a relevant slice.
 func ExtractPorts(page pagination.Page) ([]Port, error) {
-	var resp struct {
-		Ports []Port `mapstructure:"ports" json:"ports"`
+	r := page.(PortPage)
+	var s struct {
+		Ports []Port `json:"ports"`
 	}
-
-	err := mapstructure.Decode(page.(PortPage).Body, &resp)
-
-	return resp.Ports, err
+	err := r.ExtractInto(&s)
+	return s.Ports, err
 }