[PATCH] lib/hash: new feature adding existing key

["Abdullah Ömer Yamaç" <omer.yamac@ceng.metu.edu.tr>]

In some use cases inserting data with the same key shouldn't be
overwritten. We use a new flag in this patch to disable overwriting
data for the same key.

Signed-off-by: Abdullah Ömer Yamaç <omer.yamac@ceng.metu.edu.tr>

---
Cc: Yipeng Wang <yipeng1.wang@intel.com>
---
 lib/hash/rte_cuckoo_hash.c | 10 +++++++++-
 lib/hash/rte_cuckoo_hash.h |  2 ++
 lib/hash/rte_hash.h        |  4 ++++
 3 files changed, 15 insertions(+), 1 deletion(-)

diff --git a/lib/hash/rte_cuckoo_hash.c b/lib/hash/rte_cuckoo_hash.c
index 829b79c89a..cd87d6e4cd 100644
--- a/lib/hash/rte_cuckoo_hash.c
+++ b/lib/hash/rte_cuckoo_hash.c
@@ -32,7 +32,8 @@
 				   RTE_HASH_EXTRA_FLAGS_RW_CONCURRENCY | \
 				   RTE_HASH_EXTRA_FLAGS_EXT_TABLE |	\
 				   RTE_HASH_EXTRA_FLAGS_NO_FREE_ON_DEL | \
-				   RTE_HASH_EXTRA_FLAGS_RW_CONCURRENCY_LF)
+				   RTE_HASH_EXTRA_FLAGS_RW_CONCURRENCY_LF | \
+				   RTE_HASH_EXTRA_FLAGS_DISABLE_UPDATE_EXISTING_KEY)
 
 #define FOR_EACH_BUCKET(CURRENT_BKT, START_BUCKET)                            \
 	for (CURRENT_BKT = START_BUCKET;                                      \
@@ -148,6 +149,7 @@ rte_hash_create(const struct rte_hash_parameters *params)
 	unsigned int readwrite_concur_support = 0;
 	unsigned int writer_takes_lock = 0;
 	unsigned int no_free_on_del = 0;
+	unsigned int no_update_data = 0;
 	uint32_t *ext_bkt_to_free = NULL;
 	uint32_t *tbl_chng_cnt = NULL;
 	struct lcore_cache *local_free_slots = NULL;
@@ -216,6 +218,9 @@ rte_hash_create(const struct rte_hash_parameters *params)
 		no_free_on_del = 1;
 	}
 
+	if (params->extra_flag & RTE_HASH_EXTRA_FLAGS_DISABLE_UPDATE_EXISTING_KEY)
+		no_update_data = 1;
+
 	/* Store all keys and leave the first entry as a dummy entry for lookup_bulk */
 	if (use_local_cache)
 		/*
@@ -428,6 +433,7 @@ rte_hash_create(const struct rte_hash_parameters *params)
 	h->ext_table_support = ext_table_support;
 	h->writer_takes_lock = writer_takes_lock;
 	h->no_free_on_del = no_free_on_del;
+	h->no_update_data = no_update_data;
 	h->readwrite_concur_lf_support = readwrite_concur_lf_support;
 
 #if defined(RTE_ARCH_X86)
@@ -699,6 +705,8 @@ search_and_update(const struct rte_hash *h, void *data, const void *key,
 			k = (struct rte_hash_key *) ((char *)keys +
 					bkt->key_idx[i] * h->key_entry_size);
 			if (rte_hash_cmp_eq(key, k->key, h) == 0) {
+				if (h->no_update_data == 1)
+					return -EALRDY;
 				/* The store to application data at *data
 				 * should not leak after the store to pdata
 				 * in the key store. i.e. pdata is the guard
diff --git a/lib/hash/rte_cuckoo_hash.h b/lib/hash/rte_cuckoo_hash.h
index eb2644f74b..e8b7283ec2 100644
--- a/lib/hash/rte_cuckoo_hash.h
+++ b/lib/hash/rte_cuckoo_hash.h
@@ -193,6 +193,8 @@ struct rte_hash {
 	/**< If read-write concurrency support is enabled */
 	uint8_t ext_table_support;     /**< Enable extendable bucket table */
 	uint8_t no_free_on_del;
+	/**< If update is prohibited on adding same key */
+	uint8_t no_update_data;
 	/**< If key index should be freed on calling rte_hash_del_xxx APIs.
 	 * If this is set, rte_hash_free_key_with_position must be called to
 	 * free the key index associated with the deleted entry.
diff --git a/lib/hash/rte_hash.h b/lib/hash/rte_hash.h
index a399346d02..f8afb4e06d 100644
--- a/lib/hash/rte_hash.h
+++ b/lib/hash/rte_hash.h
@@ -55,6 +55,10 @@ extern "C" {
  */
 #define RTE_HASH_EXTRA_FLAGS_RW_CONCURRENCY_LF 0x20
 
+/** Flag to disable updating data of existing key
+ */
+#define RTE_HASH_EXTRA_FLAGS_DISABLE_UPDATE_EXISTING_KEY 0x40
+
 /**
  * The type of hash value of a key.
  * It should be a value of at least 32bit with fully random pattern.
-- 
2.34.1