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authorThomas Graf <tgraf@suug.ch>2015-01-02 23:00:17 +0100
committerDavid S. Miller <davem@davemloft.net>2015-01-03 20:32:57 +0100
commitb8e1943e9f754219bcfb40bac4a605b5348acb25 (patch)
treea80b48e78a57a10ace266997f65f754034cce083 /lib/rhashtable.c
parentrhashtable: Convert bucket iterators to take table and index (diff)
downloadlinux-b8e1943e9f754219bcfb40bac4a605b5348acb25.tar.xz
linux-b8e1943e9f754219bcfb40bac4a605b5348acb25.zip
rhashtable: Factor out bucket_tail() function
Subsequent patches will require access to the bucket tail. Access to the tail is relatively cheap as the automatic resizing of the table should keep the number of entries per bucket to no more than 0.75 on average. Signed-off-by: Thomas Graf <tgraf@suug.ch> Signed-off-by: David S. Miller <davem@davemloft.net>
Diffstat (limited to '')
-rw-r--r--lib/rhashtable.c23
1 files changed, 14 insertions, 9 deletions
diff --git a/lib/rhashtable.c b/lib/rhashtable.c
index ce450d095fdf..0bd29c178910 100644
--- a/lib/rhashtable.c
+++ b/lib/rhashtable.c
@@ -83,6 +83,18 @@ static u32 head_hashfn(const struct rhashtable *ht,
return rht_bucket_index(tbl, obj_raw_hashfn(ht, rht_obj(ht, he)));
}
+static struct rhash_head __rcu **bucket_tail(struct bucket_table *tbl, u32 n)
+{
+ struct rhash_head __rcu **pprev;
+
+ for (pprev = &tbl->buckets[n];
+ rht_dereference_bucket(*pprev, tbl, n);
+ pprev = &rht_dereference_bucket(*pprev, tbl, n)->next)
+ ;
+
+ return pprev;
+}
+
static struct bucket_table *bucket_table_alloc(size_t nbuckets)
{
struct bucket_table *tbl;
@@ -266,7 +278,6 @@ EXPORT_SYMBOL_GPL(rhashtable_expand);
int rhashtable_shrink(struct rhashtable *ht)
{
struct bucket_table *ntbl, *tbl = rht_dereference(ht->tbl, ht);
- struct rhash_head __rcu **pprev;
unsigned int i;
ASSERT_RHT_MUTEX(ht);
@@ -286,15 +297,9 @@ int rhashtable_shrink(struct rhashtable *ht)
*/
for (i = 0; i < ntbl->size; i++) {
ntbl->buckets[i] = tbl->buckets[i];
+ RCU_INIT_POINTER(*bucket_tail(ntbl, i),
+ tbl->buckets[i + ntbl->size]);
- /* Link each bucket in the new table to the first bucket
- * in the old table that contains entries which will hash
- * to the new bucket.
- */
- for (pprev = &ntbl->buckets[i]; *pprev != NULL;
- pprev = &rht_dereference_bucket(*pprev, ntbl, i)->next)
- ;
- RCU_INIT_POINTER(*pprev, tbl->buckets[i + ntbl->size]);
}
/* Publish the new, valid hash table */