diff mbox

[v3] {net,IB}/{rxe,usnic}: Utilize generic mac to eui32 function

Message ID 1488915118-23331-1-git-send-email-yuval.shaia@oracle.com
State Not Applicable, archived
Delegated to: David Miller
Headers show

Commit Message

Yuval Shaia March 7, 2017, 7:31 p.m. UTC
This logic seems to be duplicated in (at least) three separate files.
Move it to one place so code can be re-use.

Signed-off-by: Yuval Shaia <yuval.shaia@oracle.com>
---
v0 -> v1:
	* Add missing #include
	* Rename to genaddrconf_ifid_eui48
v1 -> v2:
	* Reset eui[0] to default if dev_id is used
v2 -> v3:
	* Add helper function to avoid re-setting eui[0] to default if
	  dev_id is used
---
 drivers/infiniband/hw/usnic/usnic_common_util.h | 11 +++--------
 drivers/infiniband/sw/rxe/rxe_net.c             | 11 ++---------
 include/net/addrconf.h                          | 25 +++++++++++++++++++------
 3 files changed, 24 insertions(+), 23 deletions(-)

Comments

Leon Romanovsky March 8, 2017, 7:40 a.m. UTC | #1
On Tue, Mar 07, 2017 at 09:31:58PM +0200, Yuval Shaia wrote:
> This logic seems to be duplicated in (at least) three separate files.
> Move it to one place so code can be re-use.
>
> Signed-off-by: Yuval Shaia <yuval.shaia@oracle.com>
> ---
> v0 -> v1:
> 	* Add missing #include
> 	* Rename to genaddrconf_ifid_eui48
> v1 -> v2:
> 	* Reset eui[0] to default if dev_id is used
> v2 -> v3:
> 	* Add helper function to avoid re-setting eui[0] to default if
> 	  dev_id is used
> ---
>  drivers/infiniband/hw/usnic/usnic_common_util.h | 11 +++--------
>  drivers/infiniband/sw/rxe/rxe_net.c             | 11 ++---------
>  include/net/addrconf.h                          | 25 +++++++++++++++++++------
>  3 files changed, 24 insertions(+), 23 deletions(-)

Not promising statistics :)

>
> diff --git a/drivers/infiniband/hw/usnic/usnic_common_util.h b/drivers/infiniband/hw/usnic/usnic_common_util.h
> index b54986d..d91b035 100644
> --- a/drivers/infiniband/hw/usnic/usnic_common_util.h
> +++ b/drivers/infiniband/hw/usnic/usnic_common_util.h
> @@ -34,6 +34,8 @@
>  #ifndef USNIC_CMN_UTIL_H
>  #define USNIC_CMN_UTIL_H
>
> +#include <net/addrconf.h>
> +
>  static inline void
>  usnic_mac_to_gid(const char *const mac, char *raw_gid)
>  {
> @@ -57,14 +59,7 @@ usnic_mac_ip_to_gid(const char *const mac, const __be32 inaddr, char *raw_gid)
>  	raw_gid[1] = 0x80;
>  	memset(&raw_gid[2], 0, 2);
>  	memcpy(&raw_gid[4], &inaddr, 4);
> -	raw_gid[8] = mac[0]^2;
> -	raw_gid[9] = mac[1];
> -	raw_gid[10] = mac[2];
> -	raw_gid[11] = 0xff;
> -	raw_gid[12] = 0xfe;
> -	raw_gid[13] = mac[3];
> -	raw_gid[14] = mac[4];
> -	raw_gid[15] = mac[5];
> +	addrconf_addr_eui48(&raw_gid[8], mac);
>  }
>
>  static inline void
> diff --git a/drivers/infiniband/sw/rxe/rxe_net.c b/drivers/infiniband/sw/rxe/rxe_net.c
> index d8610960..ab8ea23 100644
> --- a/drivers/infiniband/sw/rxe/rxe_net.c
> +++ b/drivers/infiniband/sw/rxe/rxe_net.c
> @@ -38,6 +38,7 @@
>  #include <linux/if_vlan.h>
>  #include <net/udp_tunnel.h>
>  #include <net/sch_generic.h>
> +#include <net/addrconf.h>
>  #include <linux/netfilter.h>
>  #include <rdma/ib_addr.h>
>
> @@ -86,18 +87,10 @@ struct rxe_recv_sockets recv_sockets;
>
>  static __be64 rxe_mac_to_eui64(struct net_device *ndev)
>  {

It is worth to drop this wrapper completely. The rxe_mac_to_eui64 is
called twice in the same file.

> -	unsigned char *mac_addr = ndev->dev_addr;
>  	__be64 eui64;
>  	unsigned char *dst = (unsigned char *)&eui64;
>
> -	dst[0] = mac_addr[0] ^ 2;
> -	dst[1] = mac_addr[1];
> -	dst[2] = mac_addr[2];
> -	dst[3] = 0xff;
> -	dst[4] = 0xfe;
> -	dst[5] = mac_addr[3];
> -	dst[6] = mac_addr[4];
> -	dst[7] = mac_addr[5];
> +	addrconf_addr_eui48(dst, ndev->dev_addr);
>
>  	return eui64;
>  }
> diff --git a/include/net/addrconf.h b/include/net/addrconf.h
> index 17c6fd8..28274ed 100644
> --- a/include/net/addrconf.h
> +++ b/include/net/addrconf.h
> @@ -103,12 +103,25 @@ int addrconf_prefix_rcv_add_addr(struct net *net, struct net_device *dev,
>  				 u32 addr_flags, bool sllao, bool tokenized,
>  				 __u32 valid_lft, u32 prefered_lft);
>
> +static inline void addrconf_addr_eui48_xor(u8 *eui, const char *const addr, bool xor)
> +{
> +	memcpy(eui, addr, 3);
> +	if (xor)
> +		eui[0] ^= 2;
> +	eui[3] = 0xFF;
> +	eui[4] = 0xFE;
> +	memcpy(eui + 5, addr + 3, 3);
> +}
> +
> +static inline void addrconf_addr_eui48(u8 *eui, const char *const addr)
> +{
> +	addrconf_addr_eui48_xor(eui, addr, true);

Just put your "eui[0] ^= 2" here and remove redundant "if (xor)".
> +}
> +
>  static inline int addrconf_ifid_eui48(u8 *eui, struct net_device *dev)
>  {
>  	if (dev->addr_len != ETH_ALEN)
>  		return -1;
> -	memcpy(eui, dev->dev_addr, 3);
> -	memcpy(eui + 5, dev->dev_addr + 3, 3);
>
>  	/*
>  	 * The zSeries OSA network cards can be shared among various
> @@ -123,14 +136,14 @@ static inline int addrconf_ifid_eui48(u8 *eui, struct net_device *dev)
>  	 * case.  Hence the resulting interface identifier has local
>  	 * scope according to RFC2373.
>  	 */
> +
> +	addrconf_addr_eui48_xor(eui, dev->dev_addr, !dev->dev_id);
> +
>  	if (dev->dev_id) {
>  		eui[3] = (dev->dev_id >> 8) & 0xFF;
>  		eui[4] = dev->dev_id & 0xFF;
> -	} else {
> -		eui[3] = 0xFF;
> -		eui[4] = 0xFE;
> -		eui[0] ^= 2;

Leave this line.
Thanks

>  	}
> +
>  	return 0;
>  }
>
> --
> 2.7.4
>
Yuval Shaia March 8, 2017, 1:48 p.m. UTC | #2
On Wed, Mar 08, 2017 at 09:40:41AM +0200, Leon Romanovsky wrote:
> On Tue, Mar 07, 2017 at 09:31:58PM +0200, Yuval Shaia wrote:
> > This logic seems to be duplicated in (at least) three separate files.
> > Move it to one place so code can be re-use.
> >
> > Signed-off-by: Yuval Shaia <yuval.shaia@oracle.com>
> > ---
> > v0 -> v1:
> > 	* Add missing #include
> > 	* Rename to genaddrconf_ifid_eui48
> > v1 -> v2:
> > 	* Reset eui[0] to default if dev_id is used
> > v2 -> v3:
> > 	* Add helper function to avoid re-setting eui[0] to default if
> > 	  dev_id is used
> > ---
> >  drivers/infiniband/hw/usnic/usnic_common_util.h | 11 +++--------
> >  drivers/infiniband/sw/rxe/rxe_net.c             | 11 ++---------
> >  include/net/addrconf.h                          | 25 +++++++++++++++++++------
> >  3 files changed, 24 insertions(+), 23 deletions(-)
> 
> Not promising statistics :)

It is not fair, i also added 4 new blank lines :)

> 
> >
> > diff --git a/drivers/infiniband/hw/usnic/usnic_common_util.h b/drivers/infiniband/hw/usnic/usnic_common_util.h
> > index b54986d..d91b035 100644
> > --- a/drivers/infiniband/hw/usnic/usnic_common_util.h
> > +++ b/drivers/infiniband/hw/usnic/usnic_common_util.h
> > @@ -34,6 +34,8 @@
> >  #ifndef USNIC_CMN_UTIL_H
> >  #define USNIC_CMN_UTIL_H
> >
> > +#include <net/addrconf.h>
> > +
> >  static inline void
> >  usnic_mac_to_gid(const char *const mac, char *raw_gid)
> >  {
> > @@ -57,14 +59,7 @@ usnic_mac_ip_to_gid(const char *const mac, const __be32 inaddr, char *raw_gid)
> >  	raw_gid[1] = 0x80;
> >  	memset(&raw_gid[2], 0, 2);
> >  	memcpy(&raw_gid[4], &inaddr, 4);
> > -	raw_gid[8] = mac[0]^2;
> > -	raw_gid[9] = mac[1];
> > -	raw_gid[10] = mac[2];
> > -	raw_gid[11] = 0xff;
> > -	raw_gid[12] = 0xfe;
> > -	raw_gid[13] = mac[3];
> > -	raw_gid[14] = mac[4];
> > -	raw_gid[15] = mac[5];
> > +	addrconf_addr_eui48(&raw_gid[8], mac);
> >  }
> >
> >  static inline void
> > diff --git a/drivers/infiniband/sw/rxe/rxe_net.c b/drivers/infiniband/sw/rxe/rxe_net.c
> > index d8610960..ab8ea23 100644
> > --- a/drivers/infiniband/sw/rxe/rxe_net.c
> > +++ b/drivers/infiniband/sw/rxe/rxe_net.c
> > @@ -38,6 +38,7 @@
> >  #include <linux/if_vlan.h>
> >  #include <net/udp_tunnel.h>
> >  #include <net/sch_generic.h>
> > +#include <net/addrconf.h>
> >  #include <linux/netfilter.h>
> >  #include <rdma/ib_addr.h>
> >
> > @@ -86,18 +87,10 @@ struct rxe_recv_sockets recv_sockets;
> >
> >  static __be64 rxe_mac_to_eui64(struct net_device *ndev)
> >  {
> 
> It is worth to drop this wrapper completely. The rxe_mac_to_eui64 is
> called twice in the same file.

hmmm, this is a classic wrapper to adapt an existing API signature to
usage. And in this case to return __be64 from existing function which
returns void.

What we can do is the opposite - get rid of rxe_node_guid and rxe_port_guid
and call directly to rxe_mac_to_eui64. This is based on the assumption that
node_guid and port_guid are the same in Soft RoCE.
What do you think?

> 
> > -	unsigned char *mac_addr = ndev->dev_addr;
> >  	__be64 eui64;
> >  	unsigned char *dst = (unsigned char *)&eui64;
> >
> > -	dst[0] = mac_addr[0] ^ 2;
> > -	dst[1] = mac_addr[1];
> > -	dst[2] = mac_addr[2];
> > -	dst[3] = 0xff;
> > -	dst[4] = 0xfe;
> > -	dst[5] = mac_addr[3];
> > -	dst[6] = mac_addr[4];
> > -	dst[7] = mac_addr[5];
> > +	addrconf_addr_eui48(dst, ndev->dev_addr);
> >
> >  	return eui64;
> >  }
> > diff --git a/include/net/addrconf.h b/include/net/addrconf.h
> > index 17c6fd8..28274ed 100644
> > --- a/include/net/addrconf.h
> > +++ b/include/net/addrconf.h
> > @@ -103,12 +103,25 @@ int addrconf_prefix_rcv_add_addr(struct net *net, struct net_device *dev,
> >  				 u32 addr_flags, bool sllao, bool tokenized,
> >  				 __u32 valid_lft, u32 prefered_lft);
> >
> > +static inline void addrconf_addr_eui48_xor(u8 *eui, const char *const addr, bool xor)
> > +{
> > +	memcpy(eui, addr, 3);
> > +	if (xor)
> > +		eui[0] ^= 2;
> > +	eui[3] = 0xFF;
> > +	eui[4] = 0xFE;
> > +	memcpy(eui + 5, addr + 3, 3);
> > +}
> > +
> > +static inline void addrconf_addr_eui48(u8 *eui, const char *const addr)
> > +{
> > +	addrconf_addr_eui48_xor(eui, addr, true);
> 
> Just put your "eui[0] ^= 2" here and remove redundant "if (xor)".
> > +}
> > +
> >  static inline int addrconf_ifid_eui48(u8 *eui, struct net_device *dev)
> >  {
> >  	if (dev->addr_len != ETH_ALEN)
> >  		return -1;
> > -	memcpy(eui, dev->dev_addr, 3);
> > -	memcpy(eui + 5, dev->dev_addr + 3, 3);
> >
> >  	/*
> >  	 * The zSeries OSA network cards can be shared among various
> > @@ -123,14 +136,14 @@ static inline int addrconf_ifid_eui48(u8 *eui, struct net_device *dev)
> >  	 * case.  Hence the resulting interface identifier has local
> >  	 * scope according to RFC2373.
> >  	 */
> > +
> > +	addrconf_addr_eui48_xor(eui, dev->dev_addr, !dev->dev_id);
> > +
> >  	if (dev->dev_id) {
> >  		eui[3] = (dev->dev_id >> 8) & 0xFF;
> >  		eui[4] = dev->dev_id & 0xFF;
> > -	} else {
> > -		eui[3] = 0xFF;
> > -		eui[4] = 0xFE;
> > -		eui[0] ^= 2;
> 
> Leave this line.

Along with the above comment - looks better, will do.

> Thanks
> 
> >  	}
> > +
> >  	return 0;
> >  }
> >
> > --
> > 2.7.4
> >
Leon Romanovsky March 10, 2017, 4:33 p.m. UTC | #3
On Wed, Mar 08, 2017 at 03:48:57PM +0200, Yuval Shaia wrote:
> On Wed, Mar 08, 2017 at 09:40:41AM +0200, Leon Romanovsky wrote:
> > On Tue, Mar 07, 2017 at 09:31:58PM +0200, Yuval Shaia wrote:
> > > This logic seems to be duplicated in (at least) three separate files.
> > > Move it to one place so code can be re-use.
> > >
> > > Signed-off-by: Yuval Shaia <yuval.shaia@oracle.com>
> > > ---
> > > v0 -> v1:
> > > 	* Add missing #include
> > > 	* Rename to genaddrconf_ifid_eui48
> > > v1 -> v2:
> > > 	* Reset eui[0] to default if dev_id is used
> > > v2 -> v3:
> > > 	* Add helper function to avoid re-setting eui[0] to default if
> > > 	  dev_id is used
> > > ---
> > >  drivers/infiniband/hw/usnic/usnic_common_util.h | 11 +++--------
> > >  drivers/infiniband/sw/rxe/rxe_net.c             | 11 ++---------
> > >  include/net/addrconf.h                          | 25 +++++++++++++++++++------
> > >  3 files changed, 24 insertions(+), 23 deletions(-)
> >
> > Not promising statistics :)
>
> It is not fair, i also added 4 new blank lines :)
>
> >
> > >
> > > diff --git a/drivers/infiniband/hw/usnic/usnic_common_util.h b/drivers/infiniband/hw/usnic/usnic_common_util.h
> > > index b54986d..d91b035 100644
> > > --- a/drivers/infiniband/hw/usnic/usnic_common_util.h
> > > +++ b/drivers/infiniband/hw/usnic/usnic_common_util.h
> > > @@ -34,6 +34,8 @@
> > >  #ifndef USNIC_CMN_UTIL_H
> > >  #define USNIC_CMN_UTIL_H
> > >
> > > +#include <net/addrconf.h>
> > > +
> > >  static inline void
> > >  usnic_mac_to_gid(const char *const mac, char *raw_gid)
> > >  {
> > > @@ -57,14 +59,7 @@ usnic_mac_ip_to_gid(const char *const mac, const __be32 inaddr, char *raw_gid)
> > >  	raw_gid[1] = 0x80;
> > >  	memset(&raw_gid[2], 0, 2);
> > >  	memcpy(&raw_gid[4], &inaddr, 4);
> > > -	raw_gid[8] = mac[0]^2;
> > > -	raw_gid[9] = mac[1];
> > > -	raw_gid[10] = mac[2];
> > > -	raw_gid[11] = 0xff;
> > > -	raw_gid[12] = 0xfe;
> > > -	raw_gid[13] = mac[3];
> > > -	raw_gid[14] = mac[4];
> > > -	raw_gid[15] = mac[5];
> > > +	addrconf_addr_eui48(&raw_gid[8], mac);
> > >  }
> > >
> > >  static inline void
> > > diff --git a/drivers/infiniband/sw/rxe/rxe_net.c b/drivers/infiniband/sw/rxe/rxe_net.c
> > > index d8610960..ab8ea23 100644
> > > --- a/drivers/infiniband/sw/rxe/rxe_net.c
> > > +++ b/drivers/infiniband/sw/rxe/rxe_net.c
> > > @@ -38,6 +38,7 @@
> > >  #include <linux/if_vlan.h>
> > >  #include <net/udp_tunnel.h>
> > >  #include <net/sch_generic.h>
> > > +#include <net/addrconf.h>
> > >  #include <linux/netfilter.h>
> > >  #include <rdma/ib_addr.h>
> > >
> > > @@ -86,18 +87,10 @@ struct rxe_recv_sockets recv_sockets;
> > >
> > >  static __be64 rxe_mac_to_eui64(struct net_device *ndev)
> > >  {
> >
> > It is worth to drop this wrapper completely. The rxe_mac_to_eui64 is
> > called twice in the same file.
>
> hmmm, this is a classic wrapper to adapt an existing API signature to
> usage. And in this case to return __be64 from existing function which
> returns void.
>
> What we can do is the opposite - get rid of rxe_node_guid and rxe_port_guid
> and call directly to rxe_mac_to_eui64. This is based on the assumption that
> node_guid and port_guid are the same in Soft RoCE.
> What do you think?

As long as you will add a meaningful comment in these places.
Right now, the knowledge of node_guid == port_guid in RXE is very clear,
it is worth to preserve it (knowledge).

>
> >
> > > -	unsigned char *mac_addr = ndev->dev_addr;
> > >  	__be64 eui64;
> > >  	unsigned char *dst = (unsigned char *)&eui64;
> > >
> > > -	dst[0] = mac_addr[0] ^ 2;
> > > -	dst[1] = mac_addr[1];
> > > -	dst[2] = mac_addr[2];
> > > -	dst[3] = 0xff;
> > > -	dst[4] = 0xfe;
> > > -	dst[5] = mac_addr[3];
> > > -	dst[6] = mac_addr[4];
> > > -	dst[7] = mac_addr[5];
> > > +	addrconf_addr_eui48(dst, ndev->dev_addr);
> > >
> > >  	return eui64;
> > >  }
> > > diff --git a/include/net/addrconf.h b/include/net/addrconf.h
> > > index 17c6fd8..28274ed 100644
> > > --- a/include/net/addrconf.h
> > > +++ b/include/net/addrconf.h
> > > @@ -103,12 +103,25 @@ int addrconf_prefix_rcv_add_addr(struct net *net, struct net_device *dev,
> > >  				 u32 addr_flags, bool sllao, bool tokenized,
> > >  				 __u32 valid_lft, u32 prefered_lft);
> > >
> > > +static inline void addrconf_addr_eui48_xor(u8 *eui, const char *const addr, bool xor)
> > > +{
> > > +	memcpy(eui, addr, 3);
> > > +	if (xor)
> > > +		eui[0] ^= 2;
> > > +	eui[3] = 0xFF;
> > > +	eui[4] = 0xFE;
> > > +	memcpy(eui + 5, addr + 3, 3);
> > > +}
> > > +
> > > +static inline void addrconf_addr_eui48(u8 *eui, const char *const addr)
> > > +{
> > > +	addrconf_addr_eui48_xor(eui, addr, true);
> >
> > Just put your "eui[0] ^= 2" here and remove redundant "if (xor)".
> > > +}
> > > +
> > >  static inline int addrconf_ifid_eui48(u8 *eui, struct net_device *dev)
> > >  {
> > >  	if (dev->addr_len != ETH_ALEN)
> > >  		return -1;
> > > -	memcpy(eui, dev->dev_addr, 3);
> > > -	memcpy(eui + 5, dev->dev_addr + 3, 3);
> > >
> > >  	/*
> > >  	 * The zSeries OSA network cards can be shared among various
> > > @@ -123,14 +136,14 @@ static inline int addrconf_ifid_eui48(u8 *eui, struct net_device *dev)
> > >  	 * case.  Hence the resulting interface identifier has local
> > >  	 * scope according to RFC2373.
> > >  	 */
> > > +
> > > +	addrconf_addr_eui48_xor(eui, dev->dev_addr, !dev->dev_id);
> > > +
> > >  	if (dev->dev_id) {
> > >  		eui[3] = (dev->dev_id >> 8) & 0xFF;
> > >  		eui[4] = dev->dev_id & 0xFF;
> > > -	} else {
> > > -		eui[3] = 0xFF;
> > > -		eui[4] = 0xFE;
> > > -		eui[0] ^= 2;
> >
> > Leave this line.
>
> Along with the above comment - looks better, will do.
>
> > Thanks
> >
> > >  	}
> > > +
> > >  	return 0;
> > >  }
> > >
> > > --
> > > 2.7.4
> > >
>
>
diff mbox

Patch

diff --git a/drivers/infiniband/hw/usnic/usnic_common_util.h b/drivers/infiniband/hw/usnic/usnic_common_util.h
index b54986d..d91b035 100644
--- a/drivers/infiniband/hw/usnic/usnic_common_util.h
+++ b/drivers/infiniband/hw/usnic/usnic_common_util.h
@@ -34,6 +34,8 @@ 
 #ifndef USNIC_CMN_UTIL_H
 #define USNIC_CMN_UTIL_H
 
+#include <net/addrconf.h>
+
 static inline void
 usnic_mac_to_gid(const char *const mac, char *raw_gid)
 {
@@ -57,14 +59,7 @@  usnic_mac_ip_to_gid(const char *const mac, const __be32 inaddr, char *raw_gid)
 	raw_gid[1] = 0x80;
 	memset(&raw_gid[2], 0, 2);
 	memcpy(&raw_gid[4], &inaddr, 4);
-	raw_gid[8] = mac[0]^2;
-	raw_gid[9] = mac[1];
-	raw_gid[10] = mac[2];
-	raw_gid[11] = 0xff;
-	raw_gid[12] = 0xfe;
-	raw_gid[13] = mac[3];
-	raw_gid[14] = mac[4];
-	raw_gid[15] = mac[5];
+	addrconf_addr_eui48(&raw_gid[8], mac);
 }
 
 static inline void
diff --git a/drivers/infiniband/sw/rxe/rxe_net.c b/drivers/infiniband/sw/rxe/rxe_net.c
index d8610960..ab8ea23 100644
--- a/drivers/infiniband/sw/rxe/rxe_net.c
+++ b/drivers/infiniband/sw/rxe/rxe_net.c
@@ -38,6 +38,7 @@ 
 #include <linux/if_vlan.h>
 #include <net/udp_tunnel.h>
 #include <net/sch_generic.h>
+#include <net/addrconf.h>
 #include <linux/netfilter.h>
 #include <rdma/ib_addr.h>
 
@@ -86,18 +87,10 @@  struct rxe_recv_sockets recv_sockets;
 
 static __be64 rxe_mac_to_eui64(struct net_device *ndev)
 {
-	unsigned char *mac_addr = ndev->dev_addr;
 	__be64 eui64;
 	unsigned char *dst = (unsigned char *)&eui64;
 
-	dst[0] = mac_addr[0] ^ 2;
-	dst[1] = mac_addr[1];
-	dst[2] = mac_addr[2];
-	dst[3] = 0xff;
-	dst[4] = 0xfe;
-	dst[5] = mac_addr[3];
-	dst[6] = mac_addr[4];
-	dst[7] = mac_addr[5];
+	addrconf_addr_eui48(dst, ndev->dev_addr);
 
 	return eui64;
 }
diff --git a/include/net/addrconf.h b/include/net/addrconf.h
index 17c6fd8..28274ed 100644
--- a/include/net/addrconf.h
+++ b/include/net/addrconf.h
@@ -103,12 +103,25 @@  int addrconf_prefix_rcv_add_addr(struct net *net, struct net_device *dev,
 				 u32 addr_flags, bool sllao, bool tokenized,
 				 __u32 valid_lft, u32 prefered_lft);
 
+static inline void addrconf_addr_eui48_xor(u8 *eui, const char *const addr, bool xor)
+{
+	memcpy(eui, addr, 3);
+	if (xor)
+		eui[0] ^= 2;
+	eui[3] = 0xFF;
+	eui[4] = 0xFE;
+	memcpy(eui + 5, addr + 3, 3);
+}
+
+static inline void addrconf_addr_eui48(u8 *eui, const char *const addr)
+{
+	addrconf_addr_eui48_xor(eui, addr, true);
+}
+
 static inline int addrconf_ifid_eui48(u8 *eui, struct net_device *dev)
 {
 	if (dev->addr_len != ETH_ALEN)
 		return -1;
-	memcpy(eui, dev->dev_addr, 3);
-	memcpy(eui + 5, dev->dev_addr + 3, 3);
 
 	/*
 	 * The zSeries OSA network cards can be shared among various
@@ -123,14 +136,14 @@  static inline int addrconf_ifid_eui48(u8 *eui, struct net_device *dev)
 	 * case.  Hence the resulting interface identifier has local
 	 * scope according to RFC2373.
 	 */
+
+	addrconf_addr_eui48_xor(eui, dev->dev_addr, !dev->dev_id);
+
 	if (dev->dev_id) {
 		eui[3] = (dev->dev_id >> 8) & 0xFF;
 		eui[4] = dev->dev_id & 0xFF;
-	} else {
-		eui[3] = 0xFF;
-		eui[4] = 0xFE;
-		eui[0] ^= 2;
 	}
+
 	return 0;
 }