[PATCH] ethernet: optimize memcpy and memset

[Stephen Hemminger]

The ethernet header management only needs to handle a fixed
size address (6 bytes). If the memcpy/memset are changed to
be passed a constant length, then compiler can optimize for
this case (and if it is smart eliminate string instructions).

Signed-off-by: Stephen Hemminger <[EMAIL PROTECTED]>

--- a/net/ethernet/eth.c        2007-08-17 12:08:51.000000000 -0400
+++ b/net/ethernet/eth.c        2007-08-17 12:16:33.000000000 -0400
@@ -91,10 +91,10 @@ int eth_header(struct sk_buff *skb, stru
 
        if (!saddr)
                saddr = dev->dev_addr;
-       memcpy(eth->h_source, saddr, dev->addr_len);
+       memcpy(eth->h_source, saddr, ETH_ALEN);
 
        if (daddr) {
-               memcpy(eth->h_dest, daddr, dev->addr_len);
+               memcpy(eth->h_dest, daddr, ETH_ALEN);
                return ETH_HLEN;
        }
 
@@ -103,7 +103,7 @@ int eth_header(struct sk_buff *skb, stru
         */
 
        if (dev->flags & (IFF_LOOPBACK | IFF_NOARP)) {
-               memset(eth->h_dest, 0, dev->addr_len);
+               memset(eth->h_dest, 0, ETH_ALEN);
                return ETH_HLEN;
        }
 
@@ -135,7 +135,7 @@ int eth_rebuild_header(struct sk_buff *s
                       "%s: unable to resolve type %X addresses.\n",
                       dev->name, (int)eth->h_proto);
 
-               memcpy(eth->h_source, dev->dev_addr, dev->addr_len);
+               memcpy(eth->h_source, dev->dev_addr, ETH_ALEN);
                break;
        }
 
@@ -233,8 +233,8 @@ int eth_header_cache(struct neighbour *n
                return -1;
 
        eth->h_proto = type;
-       memcpy(eth->h_source, dev->dev_addr, dev->addr_len);
-       memcpy(eth->h_dest, neigh->ha, dev->addr_len);
+       memcpy(eth->h_source, dev->dev_addr, ETH_ALEN);
+       memcpy(eth->h_dest, neigh->ha, ETH_ALEN);
        hh->hh_len = ETH_HLEN;
        return 0;
 }
@@ -251,7 +251,7 @@ void eth_header_cache_update(struct hh_c
                             unsigned char *haddr)
 {
        memcpy(((u8 *) hh->hh_data) + HH_DATA_OFF(sizeof(struct ethhdr)),
-              haddr, dev->addr_len);
+              haddr, ETH_ALEN);
 }
 
 /**
@@ -271,7 +271,7 @@ static int eth_mac_addr(struct net_devic
                return -EBUSY;
        if (!is_valid_ether_addr(addr->sa_data))
                return -EADDRNOTAVAIL;
-       memcpy(dev->dev_addr, addr->sa_data, dev->addr_len);
+       memcpy(dev->dev_addr, addr->sa_data, ETH_ALEN);
        return 0;
 }
 
-
To unsubscribe from this list: send the line "unsubscribe netdev" in
the body of a message to [EMAIL PROTECTED]
More majordomo info at  http://vger.kernel.org/majordomo-info.html