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fib: use __fls() on non null argument

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__fls(x) is a bit faster than fls(x), granted we know x is non null.

As Ben Hutchings pointed out, fls(x) = __fls(x) + 1

Signed-off-by: Eric Dumazet <edumazet@google.com>
Cc: Ben Hutchings <bhutchings@solarflare.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
This commit is contained in:
Eric Dumazet 2012-08-07 10:45:47 +00:00 committed by David S. Miller
parent 425f09ab7d
commit 79cda75a10
1 changed files with 2 additions and 1 deletions
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3
net/ipv4/fib_trie.c
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@ -1550,7 +1550,8 @@ int fib_table_lookup(struct fib_table *tb, const struct flowi4 *flp,
* state.directly.
*/
if (pref_mismatch) {
int mp = KEYLENGTH - fls(pref_mismatch);
/* fls(x) = __fls(x) + 1 */
int mp = KEYLENGTH - __fls(pref_mismatch) - 1;
if (tkey_extract_bits(cn->key, mp, cn->pos - mp) != 0)
goto backtrace;