[dpdk-dev] [PATCH v2] hash: new function to retrieve a key given its position
Yari Adan Petralanda
yari.adan.petralanda at ericsson.com
Fri Jun 17 12:59:43 CEST 2016
The function rte_hash_get_key_with_position is added in this patch.
As the position returned when adding a key is frequently used as an
offset into an array of user data, this function performs the operation
of retrieving a key given this offset.
A possible use case would be to delete a key from the hash table when
its entry in the array of data has certain value. For instance, the key
could be a flow 5-tuple, and the value stored in the array a time
stamp.
Signed-off-by: Juan Antonio Montesinos <juan.antonio.montesinos.delgado at ericsson.com>
Signed-off-by: Yari Adan Petralanda <yari.adan.petralanda at ericsson.com>
---
app/test/test_hash.c | 42 ++++++++++++++++++++++++++++++++++++
lib/librte_hash/rte_cuckoo_hash.c | 18 ++++++++++++++++
lib/librte_hash/rte_hash.h | 18 ++++++++++++++++
lib/librte_hash/rte_hash_version.map | 7 ++++++
4 files changed, 85 insertions(+)
diff --git a/app/test/test_hash.c b/app/test/test_hash.c
index 7e41725..d50afae 100644
--- a/app/test/test_hash.c
+++ b/app/test/test_hash.c
@@ -421,6 +421,46 @@ static int test_add_update_delete(void)
}
/*
+ * Sequence of operations for retrieving a key with its position
+ *
+ * - create table
+ * - add key
+ * - get the key with its position: hit
+ * - delete key
+ * - try to get the deleted key: miss
+ *
+ */
+static int test_hash_get_key_with_position(void)
+{
+ struct rte_hash *handle = NULL;
+ int pos, expectedPos, result;
+ void *key;
+
+ ut_params.name = "hash_get_key_with_position";
+ handle = rte_hash_create(&ut_params);
+ RETURN_IF_ERROR(handle == NULL, "hash creation failed");
+
+ pos = rte_hash_add_key(handle, &keys[0]);
+ print_key_info("Add", &keys[0], pos);
+ RETURN_IF_ERROR(pos < 0, "failed to add key (pos0=%d)", pos);
+ expectedPos = pos;
+
+ result = rte_hash_get_key_with_position(handle, pos, &key);
+ RETURN_IF_ERROR(result != 0, "error retrieving a key");
+
+ pos = rte_hash_del_key(handle, &keys[0]);
+ print_key_info("Del", &keys[0], pos);
+ RETURN_IF_ERROR(pos != expectedPos,
+ "failed to delete key (pos0=%d)", pos);
+
+ result = rte_hash_get_key_with_position(handle, pos, &key);
+ RETURN_IF_ERROR(result != -ENOENT, "non valid key retrieved");
+
+ rte_hash_free(handle);
+ return 0;
+}
+
+/*
* Sequence of operations for find existing hash table
*
* - create table
@@ -1442,6 +1482,8 @@ test_hash(void)
return -1;
if (test_hash_add_delete_jhash_3word() < 0)
return -1;
+ if (test_hash_get_key_with_position() < 0)
+ return -1;
if (test_hash_find_existing() < 0)
return -1;
if (test_add_update_delete() < 0)
diff --git a/lib/librte_hash/rte_cuckoo_hash.c b/lib/librte_hash/rte_cuckoo_hash.c
index 7b7d1f8..d537336 100644
--- a/lib/librte_hash/rte_cuckoo_hash.c
+++ b/lib/librte_hash/rte_cuckoo_hash.c
@@ -973,6 +973,24 @@ rte_hash_del_key(const struct rte_hash *h, const void *key)
return __rte_hash_del_key_with_hash(h, key, rte_hash_hash(h, key));
}
+int
+rte_hash_get_key_with_position(const struct rte_hash *h, const int32_t position,
+ void **key)
+{
+ RETURN_IF_TRUE(((h == NULL) || (key == NULL)), -EINVAL);
+
+ struct rte_hash_key *k, *keys = h->key_store;
+ k = (struct rte_hash_key *) ((char *) keys + (position + 1) * h->key_entry_size);
+ *key = k->key;
+
+ if (position !=
+ __rte_hash_lookup_with_hash(h, *key, rte_hash_hash(h, *key), NULL)) {
+ return -ENOENT;
+ }
+
+ return 0;
+}
+
/* Lookup bulk stage 0: Prefetch input key */
static inline void
lookup_stage0(unsigned *idx, uint64_t *lookup_mask,
diff --git a/lib/librte_hash/rte_hash.h b/lib/librte_hash/rte_hash.h
index 724315a..d1bd360 100644
--- a/lib/librte_hash/rte_hash.h
+++ b/lib/librte_hash/rte_hash.h
@@ -268,6 +268,24 @@ rte_hash_del_key(const struct rte_hash *h, const void *key);
int32_t
rte_hash_del_key_with_hash(const struct rte_hash *h, const void *key, hash_sig_t sig);
+/**
+ * Find a key in the hash table given the position.
+ * This operation is multi-thread safe.
+ *
+ * @param h
+ * Hash table to get the key from.
+ * @param position
+ * Position returned when the key was inserted.
+ * @param key
+ * Output containing a pointer to the key
+ * @return
+ * - 0 if retrieved successfully
+ * - EINVAL if the parameters are invalid.
+ * - ENOENT if no valid key is found in the given position.
+ */
+int
+rte_hash_get_key_with_position(const struct rte_hash *h, const int32_t position,
+ void **key);
/**
* Find a key-value pair in the hash table.
diff --git a/lib/librte_hash/rte_hash_version.map b/lib/librte_hash/rte_hash_version.map
index 4f25436..4237995 100644
--- a/lib/librte_hash/rte_hash_version.map
+++ b/lib/librte_hash/rte_hash_version.map
@@ -38,3 +38,10 @@ DPDK_2.2 {
rte_hash_set_cmp_func;
} DPDK_2.1;
+
+DPDK_16.07 {
+ global:
+
+ rte_hash_get_key_with_position;
+
+}; DPDK_2.2
--
2.1.4
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