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-rw-r--r--lib/rhashtable.c42
1 files changed, 40 insertions, 2 deletions
diff --git a/lib/rhashtable.c b/lib/rhashtable.c
index 8023b554905c..ed6ae1ad304c 100644
--- a/lib/rhashtable.c
+++ b/lib/rhashtable.c
@@ -727,6 +727,43 @@ EXPORT_SYMBOL_GPL(rhashtable_lookup_compare);
*/
bool rhashtable_lookup_insert(struct rhashtable *ht, struct rhash_head *obj)
{
+ struct rhashtable_compare_arg arg = {
+ .ht = ht,
+ .key = rht_obj(ht, obj) + ht->p.key_offset,
+ };
+
+ BUG_ON(!ht->p.key_len);
+
+ return rhashtable_lookup_compare_insert(ht, obj, &rhashtable_compare,
+ &arg);
+}
+EXPORT_SYMBOL_GPL(rhashtable_lookup_insert);
+
+/**
+ * rhashtable_lookup_compare_insert - search and insert object to hash table
+ * with compare function
+ * @ht: hash table
+ * @obj: pointer to hash head inside object
+ * @compare: compare function, must return true on match
+ * @arg: argument passed on to compare function
+ *
+ * Locks down the bucket chain in both the old and new table if a resize
+ * is in progress to ensure that writers can't remove from the old table
+ * and can't insert to the new table during the atomic operation of search
+ * and insertion. Searches for duplicates in both the old and new table if
+ * a resize is in progress.
+ *
+ * Lookups may occur in parallel with hashtable mutations and resizing.
+ *
+ * Will trigger an automatic deferred table resizing if the size grows
+ * beyond the watermark indicated by grow_decision() which can be passed
+ * to rhashtable_init().
+ */
+bool rhashtable_lookup_compare_insert(struct rhashtable *ht,
+ struct rhash_head *obj,
+ bool (*compare)(void *, void *),
+ void *arg)
+{
struct bucket_table *new_tbl, *old_tbl;
spinlock_t *new_bucket_lock, *old_bucket_lock;
u32 new_hash, old_hash;
@@ -747,7 +784,8 @@ bool rhashtable_lookup_insert(struct rhashtable *ht, struct rhash_head *obj)
if (unlikely(old_tbl != new_tbl))
spin_lock_bh_nested(new_bucket_lock, RHT_LOCK_NESTED);
- if (rhashtable_lookup(ht, rht_obj(ht, obj) + ht->p.key_offset)) {
+ if (rhashtable_lookup_compare(ht, rht_obj(ht, obj) + ht->p.key_offset,
+ compare, arg)) {
success = false;
goto exit;
}
@@ -763,7 +801,7 @@ exit:
return success;
}
-EXPORT_SYMBOL_GPL(rhashtable_lookup_insert);
+EXPORT_SYMBOL_GPL(rhashtable_lookup_compare_insert);
static size_t rounded_hashtable_size(struct rhashtable_params *params)
{