hash: customize compare function

Give user a chance to customize the hash key compare function.
The default rte_hash_cmp_eq function is set in the rte_hash_create
function, but these builtin ones may not good enough, so the user
may call this to override the default one.

Signed-off-by: Yu Nemo Wenbin <yuwb_bjy@ctbri.com.cn>
Acked-by: Pablo de Lara <pablo.de.lara.guarch@intel.com>

lib/librte_hash/rte_cuckoo_hash.c

@@ -102,8 +102,6 @@ EAL_REGISTER_TAILQ(rte_hash_tailq)
 
 #define LCORE_CACHE_SIZE		8
 
-typedef int (*rte_hash_cmp_eq_t)(const void *key1, const void *key2, size_t key_len);
-
 struct lcore_cache {
 	unsigned len; /**< Cache len */
 	void *objs[LCORE_CACHE_SIZE]; /**< Cache objects */
@@ -187,6 +185,11 @@ rte_hash_find_existing(const char *name)
 	return h;
 }
 
+void rte_hash_set_cmp_func(struct rte_hash *h, rte_hash_cmp_eq_t func)
+{
+	h->rte_hash_cmp_eq = func;
+}
+
 struct rte_hash *
 rte_hash_create(const struct rte_hash_parameters *params)
 {

lib/librte_hash/rte_hash.h

@@ -66,6 +66,9 @@ typedef uint32_t hash_sig_t;
 typedef uint32_t (*rte_hash_function)(const void *key, uint32_t key_len,
 				      uint32_t init_val);
 
+/** Type of function used to compare the hash key. */
+typedef int (*rte_hash_cmp_eq_t)(const void *key1, const void *key2, size_t key_len);
+
 /**
  * Parameters used when creating the hash table.
  */
@@ -103,6 +106,19 @@ struct rte_hash;
 struct rte_hash *
 rte_hash_create(const struct rte_hash_parameters *params);
 
+/**
+ * Set a new hash compare function other than the default one.
+ *
+ * @note Function pointer does not work with multi-process, so do not use it
+ * in multi-process mode.
+ *
+ * @param h
+ *   Hash table to reset
+ * @param func
+ *   New compare function
+ */
+void rte_hash_set_cmp_func(struct rte_hash *h, rte_hash_cmp_eq_t func);
+
 /**
  * Find an existing hash table object and return a pointer to it.
  *

lib/librte_hash/rte_hash_version.map

@@ -31,3 +31,10 @@ DPDK_2.1 {
 	rte_hash_reset;
 
 } DPDK_2.0;
+
+DPDK_2.2 {
+	global:
+
+	rte_hash_set_cmp_func;
+
+} DPDK_2.1;