rhashtable: Do hashing inside of rhashtable_lookup_compare()

Hash the key inside of rhashtable_lookup_compare() like
rhashtable_lookup() does. This allows to simplify the hashing
functions and keep them private.

Signed-off-by: Thomas Graf <tgraf@suug.ch>
Cc: netfilter-devel@vger.kernel.org
Signed-off-by: David S. Miller <davem@davemloft.net>

1 files changed, 30 insertions, 61 deletions

diff --git a/lib/rhashtable.c b/lib/rhashtable.c
index 6c3c723e902b..1ee0eb636ca3 100644
--- a/lib/rhashtable.c
+++ b/lib/rhashtable.c
@@ -42,69 +42,39 @@ static void *rht_obj(const struct rhashtable *ht, const struct rhash_head *he)
 	return (void *) he - ht->p.head_offset;
 }
 
-static u32 __hashfn(const struct rhashtable *ht, const void *key,
-		      u32 len, u32 hsize)
+static u32 rht_bucket_index(const struct bucket_table *tbl, u32 hash)
 {
-	u32 h;
-
-	h = ht->p.hashfn(key, len, ht->p.hash_rnd);
-
-	return h & (hsize - 1);
-}
-
-/**
- * rhashtable_hashfn - compute hash for key of given length
- * @ht:		hash table to compute for
- * @key:	pointer to key
- * @len:	length of key
- *
- * Computes the hash value using the hash function provided in the 'hashfn'
- * of struct rhashtable_params. The returned value is guaranteed to be
- * smaller than the number of buckets in the hash table.
- */
-u32 rhashtable_hashfn(const struct rhashtable *ht, const void *key, u32 len)
-{
-	struct bucket_table *tbl = rht_dereference_rcu(ht->tbl, ht);
-
-	return __hashfn(ht, key, len, tbl->size);
+	return hash & (tbl->size - 1);
 }
-EXPORT_SYMBOL_GPL(rhashtable_hashfn);
 
-static u32 obj_hashfn(const struct rhashtable *ht, const void *ptr, u32 hsize)
+static u32 obj_raw_hashfn(const struct rhashtable *ht, const void *ptr)
 {
-	if (unlikely(!ht->p.key_len)) {
-		u32 h;
-
-		h = ht->p.obj_hashfn(ptr, ht->p.hash_rnd);
+	u32 hash;
 
-		return h & (hsize - 1);
-	}
+	if (unlikely(!ht->p.key_len))
+		hash = ht->p.obj_hashfn(ptr, ht->p.hash_rnd);
+	else
+		hash = ht->p.hashfn(ptr + ht->p.key_offset, ht->p.key_len,
+				    ht->p.hash_rnd);
 
-	return __hashfn(ht, ptr + ht->p.key_offset, ht->p.key_len, hsize);
+	return hash;
 }
 
-/**
- * rhashtable_obj_hashfn - compute hash for hashed object
- * @ht:		hash table to compute for
- * @ptr:	pointer to hashed object
- *
- * Computes the hash value using the hash function `hashfn` respectively
- * 'obj_hashfn' depending on whether the hash table is set up to work with
- * a fixed length key. The returned value is guaranteed to be smaller than
- * the number of buckets in the hash table.
- */
-u32 rhashtable_obj_hashfn(const struct rhashtable *ht, void *ptr)
+static u32 key_hashfn(const struct rhashtable *ht, const void *key, u32 len)
 {
 	struct bucket_table *tbl = rht_dereference_rcu(ht->tbl, ht);
+	u32 hash;
+
+	hash = ht->p.hashfn(key, len, ht->p.hash_rnd);
 
-	return obj_hashfn(ht, ptr, tbl->size);
+	return rht_bucket_index(tbl, hash);
 }
-EXPORT_SYMBOL_GPL(rhashtable_obj_hashfn);
 
 static u32 head_hashfn(const struct rhashtable *ht,
-		       const struct rhash_head *he, u32 hsize)
+		       const struct bucket_table *tbl,
+		       const struct rhash_head *he)
 {
-	return obj_hashfn(ht, rht_obj(ht, he), hsize);
+	return rht_bucket_index(tbl, obj_raw_hashfn(ht, rht_obj(ht, he)));
 }
 
 static struct bucket_table *bucket_table_alloc(size_t nbuckets)
@@ -170,9 +140,9 @@ static void hashtable_chain_unzip(const struct rhashtable *ht,
 	 * reaches a node that doesn't hash to the same bucket as the
 	 * previous node p. Call the previous node p;
 	 */
-	h = head_hashfn(ht, p, new_tbl->size);
+	h = head_hashfn(ht, new_tbl, p);
 	rht_for_each(he, p->next, ht) {
-		if (head_hashfn(ht, he, new_tbl->size) != h)
+		if (head_hashfn(ht, new_tbl, he) != h)
 			break;
 		p = he;
 	}
@@ -184,7 +154,7 @@ static void hashtable_chain_unzip(const struct rhashtable *ht,
 	next = NULL;
 	if (he) {
 		rht_for_each(he, he->next, ht) {
-			if (head_hashfn(ht, he, new_tbl->size) == h) {
+			if (head_hashfn(ht, new_tbl, he) == h) {
 				next = he;
 				break;
 			}
@@ -237,9 +207,9 @@ int rhashtable_expand(struct rhashtable *ht)
 	 * single imprecise chain.
 	 */
 	for (i = 0; i < new_tbl->size; i++) {
-		h = i & (old_tbl->size - 1);
+		h = rht_bucket_index(old_tbl, i);
 		rht_for_each(he, old_tbl->buckets[h], ht) {
-			if (head_hashfn(ht, he, new_tbl->size) == i) {
+			if (head_hashfn(ht, new_tbl, he) == i) {
 				RCU_INIT_POINTER(new_tbl->buckets[i], he);
 				break;
 			}
@@ -353,7 +323,7 @@ void rhashtable_insert(struct rhashtable *ht, struct rhash_head *obj)
 
 	ASSERT_RHT_MUTEX(ht);
 
-	hash = head_hashfn(ht, obj, tbl->size);
+	hash = head_hashfn(ht, tbl, obj);
 	RCU_INIT_POINTER(obj->next, tbl->buckets[hash]);
 	rcu_assign_pointer(tbl->buckets[hash], obj);
 	ht->nelems++;
@@ -413,7 +383,7 @@ bool rhashtable_remove(struct rhashtable *ht, struct rhash_head *obj)
 
 	ASSERT_RHT_MUTEX(ht);
 
-	h = head_hashfn(ht, obj, tbl->size);
+	h = head_hashfn(ht, tbl, obj);
 
 	pprev = &tbl->buckets[h];
 	rht_for_each(he, tbl->buckets[h], ht) {
@@ -452,7 +422,7 @@ void *rhashtable_lookup(const struct rhashtable *ht, const void *key)
 
 	BUG_ON(!ht->p.key_len);
 
-	h = __hashfn(ht, key, ht->p.key_len, tbl->size);
+	h = key_hashfn(ht, key, ht->p.key_len);
 	rht_for_each_rcu(he, tbl->buckets[h], ht) {
 		if (memcmp(rht_obj(ht, he) + ht->p.key_offset, key,
 			   ht->p.key_len))
@@ -467,7 +437,7 @@ EXPORT_SYMBOL_GPL(rhashtable_lookup);
 /**
  * rhashtable_lookup_compare - search hash table with compare function
  * @ht:		hash table
- * @hash:	hash value of desired entry
+ * @key:	the pointer to the key
  * @compare:	compare function, must return true on match
  * @arg:	argument passed on to compare function
  *
@@ -479,15 +449,14 @@ EXPORT_SYMBOL_GPL(rhashtable_lookup);
  *
  * Returns the first entry on which the compare function returned true.
  */
-void *rhashtable_lookup_compare(const struct rhashtable *ht, u32 hash,
+void *rhashtable_lookup_compare(const struct rhashtable *ht, const void *key,
 				bool (*compare)(void *, void *), void *arg)
 {
 	const struct bucket_table *tbl = rht_dereference_rcu(ht->tbl, ht);
 	struct rhash_head *he;
+	u32 hash;
 
-	if (unlikely(hash >= tbl->size))
-		return NULL;
-
+	hash = key_hashfn(ht, key, ht->p.key_len);
 	rht_for_each_rcu(he, tbl->buckets[hash], ht) {
 		if (!compare(rht_obj(ht, he), arg))
 			continue;