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-rw-r--r--lib/rhashtable.c17
1 files changed, 13 insertions, 4 deletions
diff --git a/lib/rhashtable.c b/lib/rhashtable.c
index bdb7e4cadf05..9f6890aedd1a 100644
--- a/lib/rhashtable.c
+++ b/lib/rhashtable.c
@@ -63,13 +63,22 @@ EXPORT_SYMBOL_GPL(lockdep_rht_bucket_is_held);
#define ASSERT_RHT_MUTEX(HT)
#endif
+static inline union nested_table *nested_table_top(
+ const struct bucket_table *tbl)
+{
+ /* The top-level bucket entry does not need RCU protection
+ * because it's set at the same time as tbl->nest.
+ */
+ return (void *)rcu_dereference_protected(tbl->buckets[0], 1);
+}
+
static void nested_table_free(union nested_table *ntbl, unsigned int size)
{
const unsigned int shift = PAGE_SHIFT - ilog2(sizeof(void *));
const unsigned int len = 1 << shift;
unsigned int i;
- ntbl = rcu_dereference_raw(ntbl->table);
+ ntbl = rcu_dereference_protected(ntbl->table, 1);
if (!ntbl)
return;
@@ -89,7 +98,7 @@ static void nested_bucket_table_free(const struct bucket_table *tbl)
union nested_table *ntbl;
unsigned int i;
- ntbl = (union nested_table *)rcu_dereference_raw(tbl->buckets[0]);
+ ntbl = nested_table_top(tbl);
for (i = 0; i < len; i++)
nested_table_free(ntbl + i, size);
@@ -1173,7 +1182,7 @@ struct rhash_lock_head **__rht_bucket_nested(const struct bucket_table *tbl,
unsigned int subhash = hash;
union nested_table *ntbl;
- ntbl = (union nested_table *)rcu_dereference_raw(tbl->buckets[0]);
+ ntbl = nested_table_top(tbl);
ntbl = rht_dereference_bucket_rcu(ntbl[index].table, tbl, hash);
subhash >>= tbl->nest;
@@ -1213,7 +1222,7 @@ struct rhash_lock_head **rht_bucket_nested_insert(struct rhashtable *ht,
unsigned int size = tbl->size >> tbl->nest;
union nested_table *ntbl;
- ntbl = (union nested_table *)rcu_dereference_raw(tbl->buckets[0]);
+ ntbl = nested_table_top(tbl);
hash >>= tbl->nest;
ntbl = nested_table_alloc(ht, &ntbl[index].table,
size <= (1 << shift));