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authorHerbert Xu <herbert@gondor.apana.org.au>2015-03-23 16:50:20 +0300
committerDavid S. Miller <davem@davemloft.net>2015-03-24 05:07:51 +0300
commitde91b25c8011089f5dd99b9d24743db1f550ca4b (patch)
treeee038e699a64ef4ee361673f7ca22619ca3b0491 /include/linux/rhashtable.h
parentd88252f9bb74d266653542b753f9ab404e8b88db (diff)
downloadlinux-de91b25c8011089f5dd99b9d24743db1f550ca4b.tar.xz
rhashtable: Eliminate unnecessary branch in rht_key_hashfn
When rht_key_hashfn is called from rhashtable itself and params is equal to ht->p, there is no point in checking params.key_len and falling back to ht->p.key_len. For some reason gcc couldn't figure out that params is the same as ht->p. So let's help it by only checking params.key_len when it's a constant. Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au> Acked-by: Thomas Graf <tgraf@suug.ch> Signed-off-by: David S. Miller <davem@davemloft.net>
Diffstat (limited to 'include/linux/rhashtable.h')
-rw-r--r--include/linux/rhashtable.h8
1 files changed, 6 insertions, 2 deletions
diff --git a/include/linux/rhashtable.h b/include/linux/rhashtable.h
index 89d102270570..3851952781d7 100644
--- a/include/linux/rhashtable.h
+++ b/include/linux/rhashtable.h
@@ -199,8 +199,12 @@ static inline unsigned int rht_key_hashfn(
struct rhashtable *ht, const struct bucket_table *tbl,
const void *key, const struct rhashtable_params params)
{
- return rht_bucket_index(tbl, params.hashfn(key, params.key_len ?:
- ht->p.key_len,
+ /* params must be equal to ht->p if it isn't constant. */
+ unsigned key_len = __builtin_constant_p(params.key_len) ?
+ (params.key_len ?: ht->p.key_len) :
+ params.key_len;
+
+ return rht_bucket_index(tbl, params.hashfn(key, key_len,
tbl->hash_rnd));
}