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arp_tables: ifname_compare() can assume 16bit alignment

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Arches without efficient unaligned access can still perform a loop
assuming 16bit alignment in ifname_compare()

Signed-off-by: Eric Dumazet <dada1@cosmosbay.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
This commit is contained in:
Eric Dumazet
2009-03-24 14:15:22 -07:00
committed by David S. Miller
parent 8dd1d0471b
commit 35c7f6de73
1 changed files with 6 additions and 2 deletions
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8
net/ipv4/netfilter/arp_tables.c
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@@ -76,6 +76,7 @@ static inline int arp_devaddr_compare(const struct arpt_devaddr_info *ap,
/* /*
* Unfortunatly, _b and _mask are not aligned to an int (or long int) * Unfortunatly, _b and _mask are not aligned to an int (or long int)
* Some arches dont care, unrolling the loop is a win on them. * Some arches dont care, unrolling the loop is a win on them.
* For other arches, we only have a 16bit alignement.
*/ */
static unsigned long ifname_compare(const char *_a, const char *_b, const char *_mask) static unsigned long ifname_compare(const char *_a, const char *_b, const char *_mask)
{ {
@@ -95,10 +96,13 @@ static unsigned long ifname_compare(const char *_a, const char *_b, const char *
BUILD_BUG_ON(IFNAMSIZ > 4 * sizeof(unsigned long)); BUILD_BUG_ON(IFNAMSIZ > 4 * sizeof(unsigned long));
#else #else
unsigned long ret = 0; unsigned long ret = 0;
const u16 *a = (const u16 *)_a;
const u16 *b = (const u16 *)_b;
const u16 *mask = (const u16 *)_mask;
int i; int i;
for (i = 0; i < IFNAMSIZ; i++) for (i = 0; i < IFNAMSIZ/sizeof(u16); i++)
ret |= (_a[i] ^ _b[i]) & _mask[i]; ret |= (a[i] ^ b[i]) & mask[i];
#endif #endif
return ret; return ret;
} }