etherdev: Process is_multicast_ether_addr at same size as other opera…

…tions This change makes it so that we process the address in is_multicast_ether_addr at the same size as the other calls. This allows us to avoid duplicate reads when used with other calls such as is_zero_ether_addr or eth_addr_copy. In addition I have added a 64 bit version of the function so in eth_type_trans we can process the destination address as a 64 bit value throughout. Signed-off-by: Alexander Duyck <[email protected]> Signed-off-by: David S. Miller <[email protected]>
olifre · May 4, 2015 · d54385c · d54385c
1 parent 849b920
commit d54385c
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Showing 2 changed files with 24 additions and 2 deletions.
diff --git a/include/linux/etherdevice.h b/include/linux/etherdevice.h
@@ -110,7 +110,29 @@ static inline bool is_zero_ether_addr(const u8 *addr)
  */
 static inline bool is_multicast_ether_addr(const u8 *addr)
 {
-	return 0x01 & addr[0];
+#if defined(CONFIG_HAVE_EFFICIENT_UNALIGNED_ACCESS)
+	u32 a = *(const u32 *)addr;
+#else
+	u16 a = *(const u16 *)addr;
+#endif
+#ifdef __BIG_ENDIAN
+	return 0x01 & (a >> ((sizeof(a) * 8) - 8));
+#else
+	return 0x01 & a;
+#endif
+}
+
+static inline bool is_multicast_ether_addr_64bits(const u8 addr[6+2])
+{
+#if defined(CONFIG_HAVE_EFFICIENT_UNALIGNED_ACCESS) && BITS_PER_LONG == 64
+#ifdef __BIG_ENDIAN
+	return 0x01 & ((*(const u64 *)addr) >> 56);
+#else
+	return 0x01 & (*(const u64 *)addr);
+#endif
+#else
+	return is_multicast_ether_addr(addr);
+#endif
 }
 
 /**

diff --git a/net/ethernet/eth.c b/net/ethernet/eth.c
@@ -159,7 +159,7 @@ __be16 eth_type_trans(struct sk_buff *skb, struct net_device *dev)
 	skb_pull_inline(skb, ETH_HLEN);
 	eth = eth_hdr(skb);
 
-	if (unlikely(is_multicast_ether_addr(eth->h_dest))) {
+	if (unlikely(is_multicast_ether_addr_64bits(eth->h_dest))) {
 		if (ether_addr_equal_64bits(eth->h_dest, dev->broadcast))
 			skb->pkt_type = PACKET_BROADCAST;
 		else