[PATCH v3 1/3] hash: add rte_hash_set_cmp_func() function.

[Yu Nemo Wenbin <yuwb_bjy@ctbri.com.cn>]

Give user a chance to costomize 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>
---
 lib/librte_hash/rte_cuckoo_hash.c    |  7 +++++--
 lib/librte_hash/rte_hash.h           | 15 +++++++++++++++
 lib/librte_hash/rte_hash_version.map |  1 +
 3 files changed, 21 insertions(+), 2 deletions(-)

diff --git a/lib/librte_hash/rte_cuckoo_hash.c b/lib/librte_hash/rte_cuckoo_hash.c
index 1e970de..71e2419 100644
--- a/lib/librte_hash/rte_cuckoo_hash.c
+++ b/lib/librte_hash/rte_cuckoo_hash.c
@@ -98,8 +98,6 @@ 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 */
@@ -183,6 +181,11 @@ 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)
 {
diff --git a/lib/librte_hash/rte_hash.h b/lib/librte_hash/rte_hash.h
index b678766..8378a42 100644
--- a/lib/librte_hash/rte_hash.h
+++ b/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 key. It works like the memcmp() */
+typedef int (*rte_hash_cmp_eq_t)(const void *key1, const void *key2, size_t key_len);
+
 /**
  * Parameters used when creating the hash table.
  */
@@ -104,6 +107,18 @@ struct rte_hash *
 rte_hash_create(const struct rte_hash_parameters *params);
 
 /**
+ * Set the rte_hash_set_cmp_func.
+ * Set the new hash compare function if the default one is not suitable enough.
+ *
+ * @note Function pointer does not work with multi-process, so don't use it
+ * in multi-process mode.
+ *
+ * @param h
+ *   Hash table to reset
+ */
+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.
  *
  * @param name
diff --git a/lib/librte_hash/rte_hash_version.map b/lib/librte_hash/rte_hash_version.map
index 906c8ad..3bc1e2c 100644
--- a/lib/librte_hash/rte_hash_version.map
+++ b/lib/librte_hash/rte_hash_version.map
@@ -30,5 +30,6 @@ DPDK_2.1 {
 	rte_hash_lookup_data;
 	rte_hash_lookup_with_hash_data;
 	rte_hash_reset;
+	rte_hash_set_cmp_func;
 
 } DPDK_2.0;
-- 
1.9.1