batman-adv: Use common Jenkins Hash implementation

An unoptimized version of the Jenkins one-at-a-time hash function is used
and partially copied all over the code wherever an hashtable is used.
Instead the optimized version shared between the whole kernel should be
used to reduce code duplication and use better optimized code.

Only the DAT code must use the old implementation because it is used as
distributed hash function which has to be common for all nodes.

Signed-off-by: Sven Eckelmann <sven@narfation.org>
Signed-off-by: Marek Lindner <mareklindner@neomailbox.ch>

net/batman-adv/bridge_loop_avoidance.c

@@ -42,12 +42,8 @@ static inline uint32_t batadv_choose_claim(const void *data, uint32_t size)
 	struct batadv_bla_claim *claim = (struct batadv_bla_claim *)data;
 	uint32_t hash = 0;
 
-	hash = batadv_hash_bytes(hash, &claim->addr, sizeof(claim->addr));
-	hash = batadv_hash_bytes(hash, &claim->vid, sizeof(claim->vid));
-
-	hash += (hash << 3);
-	hash ^= (hash >> 11);
-	hash += (hash << 15);
+	hash = jhash(&claim->addr, sizeof(claim->addr), hash);
+	hash = jhash(&claim->vid, sizeof(claim->vid), hash);
 
 	return hash % size;
 }
@@ -59,12 +55,8 @@ static inline uint32_t batadv_choose_backbone_gw(const void *data,
 	const struct batadv_bla_claim *claim = (struct batadv_bla_claim *)data;
 	uint32_t hash = 0;
 
-	hash = batadv_hash_bytes(hash, &claim->addr, sizeof(claim->addr));
-	hash = batadv_hash_bytes(hash, &claim->vid, sizeof(claim->vid));
-
-	hash += (hash << 3);
-	hash ^= (hash >> 11);
-	hash += (hash << 15);
+	hash = jhash(&claim->addr, sizeof(claim->addr), hash);
+	hash = jhash(&claim->vid, sizeof(claim->vid), hash);
 
 	return hash % size;
 }

net/batman-adv/distributed-arp-table.c

@@ -206,9 +206,22 @@ static uint32_t batadv_hash_dat(const void *data, uint32_t size)
 {
 	uint32_t hash = 0;
 	const struct batadv_dat_entry *dat = data;
+	const unsigned char *key;
+	uint32_t i;
+
+	key = (const unsigned char *)&dat->ip;
+	for (i = 0; i < sizeof(dat->ip); i++) {
+		hash += key[i];
+		hash += (hash << 10);
+		hash ^= (hash >> 6);
+	}
 
-	hash = batadv_hash_bytes(hash, &dat->ip, sizeof(dat->ip));
-	hash = batadv_hash_bytes(hash, &dat->vid, sizeof(dat->vid));
+	key = (const unsigned char *)&dat->vid;
+	for (i = 0; i < sizeof(dat->vid); i++) {
+		hash += key[i];
+		hash += (hash << 10);
+		hash ^= (hash >> 6);
+	}
 
 	hash += (hash << 3);
 	hash ^= (hash >> 11);

net/batman-adv/hash.h

@@ -79,28 +79,6 @@ static inline void batadv_hash_delete(struct batadv_hashtable *hash,
 	batadv_hash_destroy(hash);
 }
 
-/**
- *	batadv_hash_bytes - hash some bytes and add them to the previous hash
- *	@hash: previous hash value
- *	@data: data to be hashed
- *	@size: number of bytes to be hashed
- *
- *	Returns the new hash value.
- */
-static inline uint32_t batadv_hash_bytes(uint32_t hash, const void *data,
-					 uint32_t size)
-{
-	const unsigned char *key = data;
-	int i;
-
-	for (i = 0; i < size; i++) {
-		hash += key[i];
-		hash += (hash << 10);
-		hash ^= (hash >> 6);
-	}
-	return hash;
-}
-
 /**
  *	batadv_hash_add - adds data to the hashtable
  *	@hash: storage hash table

net/batman-adv/main.h

@@ -174,6 +174,7 @@ enum batadv_uev_type {
 #include <linux/workqueue.h>	/* workqueue */
 #include <linux/percpu.h>
 #include <linux/slab.h>
+#include <linux/jhash.h>
 #include <net/sock.h>		/* struct sock */
 #include <net/addrconf.h>	/* ipv6 address stuff */
 #include <linux/ip.h>

net/batman-adv/network-coding.c

@@ -453,14 +453,8 @@ static uint32_t batadv_nc_hash_choose(const void *data, uint32_t size)
 	const struct batadv_nc_path *nc_path = data;
 	uint32_t hash = 0;
 
-	hash = batadv_hash_bytes(hash, &nc_path->prev_hop,
-				 sizeof(nc_path->prev_hop));
-	hash = batadv_hash_bytes(hash, &nc_path->next_hop,
-				 sizeof(nc_path->next_hop));
-
-	hash += (hash << 3);
-	hash ^= (hash >> 11);
-	hash += (hash << 15);
+	hash = jhash(&nc_path->prev_hop, sizeof(nc_path->prev_hop), hash);
+	hash = jhash(&nc_path->next_hop, sizeof(nc_path->next_hop), hash);
 
 	return hash % size;
 }

net/batman-adv/originator.h

@@ -75,20 +75,9 @@ void batadv_orig_node_vlan_free_ref(struct batadv_orig_node_vlan *orig_vlan);
  */
 static inline uint32_t batadv_choose_orig(const void *data, uint32_t size)
 {
-	const unsigned char *key = data;
 	uint32_t hash = 0;
-	size_t i;
-
-	for (i = 0; i < 6; i++) {
-		hash += key[i];
-		hash += (hash << 10);
-		hash ^= (hash >> 6);
-	}
-
-	hash += (hash << 3);
-	hash ^= (hash >> 11);
-	hash += (hash << 15);
 
+	hash = jhash(data, ETH_ALEN, hash);
 	return hash % size;
 }
 

net/batman-adv/translation-table.c

@@ -67,12 +67,8 @@ static inline uint32_t batadv_choose_tt(const void *data, uint32_t size)
 	uint32_t hash = 0;
 
 	tt = (struct batadv_tt_common_entry *)data;
-	hash = batadv_hash_bytes(hash, &tt->addr, ETH_ALEN);
-	hash = batadv_hash_bytes(hash, &tt->vid, sizeof(tt->vid));
-
-	hash += (hash << 3);
-	hash ^= (hash >> 11);
-	hash += (hash << 15);
+	hash = jhash(&tt->addr, ETH_ALEN, hash);
+	hash = jhash(&tt->vid, sizeof(tt->vid), hash);
 
 	return hash % size;
 }