All ether_addr_equal tests in i40e can use the
slightly more efficient ether_addr_equal_64bits.

All addresses passed to the various functions that
use ether_addr_equal are using structs that have 2
or more bytes of additional data after the mac addr
being tested.

struct i40e_mac_filter.macaddr[6] (followed by s16 vlan)
struct net_device.dev_addr (pointer to char array of MAX_ADDR_LEN)
struct sockaddr.sa_data (array of 14 bytes)
struct netdev_hw_addr.addr (pointer to char array of MAX_ADDR_LEN)

Signed-off-by: Joe Perches <joe@perches.com>
---

On Fri, 2013-12-27 at 12:46 -0800, Joe Perches wrote:

On Fri, 2013-12-27 at 21:12 +0100, Julia Lawall wrote:

quoted

On Fri, 27 Dec 2013, Joe Perches wrote:

quoted

On Fri, 2013-12-27 at 07:48 -0800, Eric Dumazet wrote:

quoted

On Fri, 2013-12-27 at 14:49 +0800, Ding Tianhong wrote:

quoted

Use possibly more efficient ether_addr_equal
to instead of memcmp.

[]

quoted

quoted

diff --git a/drivers/net/plip/plip.c b/drivers/net/plip/plip.c

[]

quoted

quoted

@@ -549,7 +549,7 @@ static __be16 plip_type_trans(struct sk_buff *skb, struct net_device *dev)
 
 	if(*eth->h_dest&1)
 	{
-		if(memcmp(eth->h_dest,dev->broadcast, ETH_ALEN)==0)
+		if(ether_addr_equal(eth->h_dest, dev->broadcast))
 			skb->pkt_type=PACKET_BROADCAST;
 		else
 			skb->pkt_type=PACKET_MULTICAST;

What about :

        if (is_multicast_ether_addr(eth->h_dest)) {
                if (ether_addr_equal_64bits(eth->h_dest, dev->broadcast))
                        skb->pkt_type = PACKET_BROADCAST;
                else
                        skb->pkt_type = PACKET_MULTICAST;
        }

That is better though I wonder how many systems are
still using laplink via parallel null-printer cables.

No matter, better is better.

The same optimization using ether_addr_equal_64bits
may be possible to do in other places given other
structs too.

Perhaps it's a possible spatch/coccinelle conversion,

I don't know spatch well enough to know if a
mechanism to check if structure members have other
fields that follow them in the structure or if the
structure member is an array of a minimum size.

Maybe Julia does.  (cc'd)

I'm not sure to competely understand the issues.  Could you explain more?

Hi Julia.

Maybe this explanation is helpful?

ethernet addresses are u8[6] (48 bits)

ether_addr_equal_64bits gets passed a pointer to u8[8]
and is more efficient on 64 bit architectures than
ether_addr_equal because the test can be done with a
single compare and shift.

The idea is not to access past the end of the ethernet
address as appropriate (think pointer to eeprom or other
such end-of-addressable memory conditions)

If a struct containing an ethernet address has additional
members after the ethernet address, or the u8[6] addressa
passed to ether_addr_equal is not going to access past
the end of memory or the structure, then
ether_addr_equal_64bits should be used in lieu of
ether_addr_equal.

I believe this is correct, but maybe the
conditions for using ether_addr_equal_64bits
could be documented a bit better.

Jeff/Intel folk?  What do you think?

 drivers/net/ethernet/intel/i40e/i40e_main.c | 18 +++++++++++-------
 1 file changed, 11 insertions(+), 7 deletions(-)

diff --git a/drivers/net/ethernet/intel/i40e/i40e_main.c b/drivers/net/ethernet/intel/i40e/i40e_main.c
index efdf8a2..4c1d35c 100644
--- a/drivers/net/ethernet/intel/i40e/i40e_main.c
+++ b/drivers/net/ethernet/intel/i40e/i40e_main.c

@@ -992,7 +992,7 @@ static struct i40e_mac_filter *i40e_find_filter(struct i40e_vsi *vsi,
 		return NULL;
 
 	list_for_each_entry(f, &vsi->mac_filter_list, list) {
-		if ((ether_addr_equal(macaddr, f->macaddr)) &&
+		if (ether_addr_equal_64bits(macaddr, f->macaddr) &&
 		    (vlan == f->vlan)    &&
 		    (!is_vf || f->is_vf) &&
 		    (!is_netdev || f->is_netdev))

@@ -1020,7 +1020,7 @@ struct i40e_mac_filter *i40e_find_mac(struct i40e_vsi *vsi, u8 *macaddr,
 		return NULL;
 
 	list_for_each_entry(f, &vsi->mac_filter_list, list) {
-		if ((ether_addr_equal(macaddr, f->macaddr)) &&
+		if (ether_addr_equal_64bits(macaddr, f->macaddr) &&
 		    (!is_vf || f->is_vf) &&
 		    (!is_netdev || f->is_netdev))
 			return f;

@@ -1209,7 +1209,7 @@ static int i40e_set_mac(struct net_device *netdev, void *p)
 
 	netdev_info(netdev, "set mac address=%pM\n", addr->sa_data);
 
-	if (ether_addr_equal(netdev->dev_addr, addr->sa_data))
+	if (ether_addr_equal_64bits(netdev->dev_addr, addr->sa_data))
 		return 0;
 
 	if (vsi->type == I40E_VSI_MAIN) {

@@ -1409,21 +1409,24 @@ static void i40e_set_rx_mode(struct net_device *netdev)
 
 		if (is_multicast_ether_addr(f->macaddr)) {
 			netdev_for_each_mc_addr(mca, netdev) {
-				if (ether_addr_equal(mca->addr, f->macaddr)) {
+				if (ether_addr_equal_64bits(mca->addr,
+							    f->macaddr)) {
 					found = true;
 					break;
 				}
 			}
 		} else {
 			netdev_for_each_uc_addr(uca, netdev) {
-				if (ether_addr_equal(uca->addr, f->macaddr)) {
+				if (ether_addr_equal_64bits(uca->addr,
+							    f->macaddr)) {
 					found = true;
 					break;
 				}
 			}
 
 			for_each_dev_addr(netdev, ha) {
-				if (ether_addr_equal(ha->addr, f->macaddr)) {
+				if (ether_addr_equal_64bits(ha->addr,
+							    f->macaddr)) {
 					found = true;
 					break;
 				}

@@ -1889,7 +1892,8 @@ int i40e_vsi_kill_vlan(struct i40e_vsi *vsi, s16 vid)
 	list_for_each_entry(f, &vsi->mac_filter_list, list) {
 		if (is_netdev) {
 			if (f->vlan &&
-			    ether_addr_equal(netdev->dev_addr, f->macaddr))
+			    ether_addr_equal_64bits(netdev->dev_addr,
+						    f->macaddr))
 				filter_count++;
 		}