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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>
This commit is contained in:
Joe Perches 2014-01-14 15:18:47 -08:00 committed by David S. Miller
parent a53d34c346
commit 286ab723d4
1 changed files with 23 additions and 1 deletions
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24
include/linux/etherdevice.h
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@ -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);
}
/**