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etherdevice: Optimize a few is_<foo>_ether_addr functions

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If CONFIG_HAVE_EFFICIENT_UNALIGNED_ACCESS is set,
several is_<foo>_ether_addr functions can be slightly
improved by using u32 dereferences.

I believe all current uses of is_zero_ether_addr and
is_broadcast_ether_addr are u16 aligned, so always use
u16 references to improve those functions performance.

Document the u16 alignment requirements.

Signed-off-by: Joe Perches <joe@perches.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
This commit is contained in:
Joe Perches 2013-12-06 15:44:21 -08:00 committed by David S. Miller
parent d9cd4fe5ef
commit 2c722fe1c8
1 changed files with 23 additions and 2 deletions
repo.diff.show_diff_stats Download patch file Download diff file Expand all files Collapse all files

25
include/linux/etherdevice.h
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@ -61,6 +61,8 @@ static const u8 eth_reserved_addr_base[ETH_ALEN] __aligned(2) =
* *
* Return true if address is link local reserved addr (01:80:c2:00:00:0X) per * Return true if address is link local reserved addr (01:80:c2:00:00:0X) per
* IEEE 802.1Q 8.6.3 Frame filtering. * IEEE 802.1Q 8.6.3 Frame filtering.
*
* Please note: addr must be aligned to u16.
*/ */
static inline bool is_link_local_ether_addr(const u8 *addr) static inline bool is_link_local_ether_addr(const u8 *addr)
{ {
@ -68,7 +70,12 @@ static inline bool is_link_local_ether_addr(const u8 *addr)
static const __be16 *b = (const __be16 *)eth_reserved_addr_base; static const __be16 *b = (const __be16 *)eth_reserved_addr_base;
static const __be16 m = cpu_to_be16(0xfff0); static const __be16 m = cpu_to_be16(0xfff0);
#if defined(CONFIG_HAVE_EFFICIENT_UNALIGNED_ACCESS)
return (((*(const u32 *)addr) ^ (*(const u32 *)b)) |
((a[2] ^ b[2]) & m)) == 0;
#else
return ((a[0] ^ b[0]) | (a[1] ^ b[1]) | ((a[2] ^ b[2]) & m)) == 0; return ((a[0] ^ b[0]) | (a[1] ^ b[1]) | ((a[2] ^ b[2]) & m)) == 0;
#endif
} }
/** /**
@ -76,10 +83,18 @@ static inline bool is_link_local_ether_addr(const u8 *addr)
* @addr: Pointer to a six-byte array containing the Ethernet address * @addr: Pointer to a six-byte array containing the Ethernet address
* *
* Return true if the address is all zeroes. * Return true if the address is all zeroes.
*
* Please note: addr must be aligned to u16.
*/ */
static inline bool is_zero_ether_addr(const u8 *addr) static inline bool is_zero_ether_addr(const u8 *addr)
{ {
return !(addr[0] | addr[1] | addr[2] | addr[3] | addr[4] | addr[5]); #if defined(CONFIG_HAVE_EFFICIENT_UNALIGNED_ACCESS)
return ((*(const u32 *)addr) | (*(const u16 *)(addr + 4))) == 0;
#else
return (*(const u16 *)(addr + 0) |
*(const u16 *)(addr + 2) |
*(const u16 *)(addr + 4)) == 0;
#endif
} }
/** /**
@ -110,10 +125,14 @@ static inline bool is_local_ether_addr(const u8 *addr)
* @addr: Pointer to a six-byte array containing the Ethernet address * @addr: Pointer to a six-byte array containing the Ethernet address
* *
* Return true if the address is the broadcast address. * Return true if the address is the broadcast address.
*
* Please note: addr must be aligned to u16.
*/ */
static inline bool is_broadcast_ether_addr(const u8 *addr) static inline bool is_broadcast_ether_addr(const u8 *addr)
{ {
return (addr[0] & addr[1] & addr[2] & addr[3] & addr[4] & addr[5]) == 0xff; return (*(const u16 *)(addr + 0) &
*(const u16 *)(addr + 2) &
*(const u16 *)(addr + 4)) == 0xffff;
} }
/** /**
@ -135,6 +154,8 @@ static inline bool is_unicast_ether_addr(const u8 *addr)
* a multicast address, and is not FF:FF:FF:FF:FF:FF. * a multicast address, and is not FF:FF:FF:FF:FF:FF.
* *
* Return true if the address is valid. * Return true if the address is valid.
*
* Please note: addr must be aligned to u16.
*/ */
static inline bool is_valid_ether_addr(const u8 *addr) static inline bool is_valid_ether_addr(const u8 *addr)
{ {