From 286ab723d4b83d37deb4017008ef1444a95cfb0d Mon Sep 17 00:00:00 2001
From: Joe Perches <joe@perches.com>
Date: Tue, 14 Jan 2014 15:18:47 -0800
Subject: [PATCH] etherdevice: Use ether_addr_copy to copy an Ethernet address
Some systems can use the normally known u16 alignment of
Ethernet addresses to save some code/text bytes and cycles.
This does not change currently emitted code on x86 by gcc 4.8.
Signed-off-by: Joe Perches <joe@perches.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
---
include/linux/etherdevice.h | 24 +++++++++++++++++++++++-
1 file changed, 23 insertions(+), 1 deletion(-)
diff --git a/include/linux/etherdevice.h b/include/linux/etherdevice.h
index f344ac04f858..9c5529dc6d07 100644
--- a/include/linux/etherdevice.h
+++ b/include/linux/etherdevice.h
@@ -217,6 +217,28 @@ static inline void eth_hw_addr_random(struct net_device *dev)
eth_random_addr(dev->dev_addr);
}
+/**
+ * ether_addr_copy - Copy an Ethernet address
+ * @dst: Pointer to a six-byte array Ethernet address destination
+ * @src: Pointer to a six-byte array Ethernet address source
+ *
+ * Please note: dst & src must both be aligned to u16.
+ */
+static inline void ether_addr_copy(u8 *dst, const u8 *src)
+{
+#if defined(CONFIG_HAVE_EFFICIENT_UNALIGNED_ACCESS)
+ *(u32 *)dst = *(const u32 *)src;
+ *(u16 *)(dst + 4) = *(const u16 *)(src + 4);
+#else
+ u16 *a = (u16 *)dst;
+ const u16 *b = (const u16 *)src;
+
+ a[0] = b[0];
+ a[1] = b[1];
+ a[2] = b[2];
+#endif
+}
+
/**
* eth_hw_addr_inherit - Copy dev_addr from another net_device
* @dst: pointer to net_device to copy dev_addr to
@@ -229,7 +251,7 @@ static inline void eth_hw_addr_inherit(struct net_device *dst,
struct net_device *src)
{
dst->addr_assign_type = src->addr_assign_type;
- memcpy(dst->dev_addr, src->dev_addr, ETH_ALEN);
+ ether_addr_copy(dst->dev_addr, src->dev_addr);
}
/**
--
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