From: Sven Eckelmann <sven.eckelmann@gmx.de>
Date: Sun, 21 Nov 2010 23:55:57 +0000 (+0100)
Subject: Staging: batman-adv: Remove hashdata_choose_cb from hash
X-Git-Tag: v2.6.38-rc1~423^2~221
X-Git-Url: http://git.openpandora.org/cgi-bin/gitweb.cgi?a=commitdiff_plain;h=6d5e654240dc14ded3d74aa5df6857572ba9f5e3;p=pandora-kernel.git

Staging: batman-adv: Remove hashdata_choose_cb from hash

Function pointers cannot be inlined by a compiler and thus always has
the overhead of an call. hashdata_choose_cb's are one of the most often
called function pointers and its overhead must kept relative low.

As first step, every function which uses this function pointer takes it
as parameter instead of storing it inside the hash abstraction
structure.

This not generate any performance gain right now. The called functions
must also be able to be inlined by the calling functions to enable
inlining of the function pointer.

Reported-by: David S. Miller <davem@davemloft.net>
Signed-off-by: Sven Eckelmann <sven.eckelmann@gmx.de>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
---

diff --git a/drivers/staging/batman-adv/TODO b/drivers/staging/batman-adv/TODO
index a9c77d671a5a..2c02aa107de8 100644
--- a/drivers/staging/batman-adv/TODO
+++ b/drivers/staging/batman-adv/TODO
@@ -1,6 +1,5 @@
  * remove own list functionality from hash
  * use hlist_head, hlist_node in hash
- * don't use callbacks for choose in hash
  * think about more efficient ways instead of abstraction of hash
  * Request a new review
  * Process the comments from the review
diff --git a/drivers/staging/batman-adv/hash.c b/drivers/staging/batman-adv/hash.c
index a4abe140a953..6361a3175520 100644
--- a/drivers/staging/batman-adv/hash.c
+++ b/drivers/staging/batman-adv/hash.c
@@ -137,7 +137,7 @@ struct hash_it_t *hash_iterate(struct hashtable_t *hash,
 }
 
 /* allocates and clears the hash */
-struct hashtable_t *hash_new(int size, hashdata_choose_cb choose)
+struct hashtable_t *hash_new(int size)
 {
 	struct hashtable_t *hash;
 
@@ -156,13 +156,12 @@ struct hashtable_t *hash_new(int size, hashdata_choose_cb choose)
 
 	hash_init(hash);
 
-	hash->choose = choose;
-
 	return hash;
 }
 
 /* adds data to the hashtable. returns 0 on success, -1 on error */
-int hash_add(struct hashtable_t *hash, hashdata_compare_cb compare, void *data)
+int hash_add(struct hashtable_t *hash, hashdata_compare_cb compare,
+	     hashdata_choose_cb choose, void *data)
 {
 	int index;
 	struct element_t *bucket, *prev_bucket = NULL;
@@ -170,7 +169,7 @@ int hash_add(struct hashtable_t *hash, hashdata_compare_cb compare, void *data)
 	if (!hash)
 		return -1;
 
-	index = hash->choose(data, hash->size);
+	index = choose(data, hash->size);
 	bucket = hash->table[index];
 
 	while (bucket != NULL) {
@@ -203,7 +202,7 @@ int hash_add(struct hashtable_t *hash, hashdata_compare_cb compare, void *data)
 /* finds data, based on the key in keydata. returns the found data on success,
  * or NULL on error */
 void *hash_find(struct hashtable_t *hash, hashdata_compare_cb compare,
-		void *keydata)
+		hashdata_choose_cb choose, void *keydata)
 {
 	int index;
 	struct element_t *bucket;
@@ -211,7 +210,7 @@ void *hash_find(struct hashtable_t *hash, hashdata_compare_cb compare,
 	if (!hash)
 		return NULL;
 
-	index = hash->choose(keydata , hash->size);
+	index = choose(keydata , hash->size);
 	bucket = hash->table[index];
 
 	while (bucket != NULL) {
@@ -250,11 +249,11 @@ void *hash_remove_bucket(struct hashtable_t *hash, struct hash_it_t *hash_it_t)
  * structure you use with just the key filled, we just need the key for
  * comparing. */
 void *hash_remove(struct hashtable_t *hash, hashdata_compare_cb compare,
-		  void *data)
+		  hashdata_choose_cb choose, void *data)
 {
 	struct hash_it_t hash_it_t;
 
-	hash_it_t.index = hash->choose(data, hash->size);
+	hash_it_t.index = choose(data, hash->size);
 	hash_it_t.bucket = hash->table[hash_it_t.index];
 	hash_it_t.prev_bucket = NULL;
 
@@ -277,14 +276,15 @@ void *hash_remove(struct hashtable_t *hash, hashdata_compare_cb compare,
 /* resize the hash, returns the pointer to the new hash or NULL on
  * error. removes the old hash on success. */
 struct hashtable_t *hash_resize(struct hashtable_t *hash,
-				hashdata_compare_cb compare, int size)
+				hashdata_compare_cb compare,
+				hashdata_choose_cb choose, int size)
 {
 	struct hashtable_t *new_hash;
 	struct element_t *bucket;
 	int i;
 
 	/* initialize a new hash with the new size */
-	new_hash = hash_new(size, hash->choose);
+	new_hash = hash_new(size);
 
 	if (new_hash == NULL)
 		return NULL;
@@ -294,7 +294,7 @@ struct hashtable_t *hash_resize(struct hashtable_t *hash,
 		bucket = hash->table[i];
 
 		while (bucket != NULL) {
-			hash_add(new_hash, compare, bucket->data);
+			hash_add(new_hash, compare, choose, bucket->data);
 			bucket = bucket->next;
 		}
 	}
Reading git-diff-tree failed