From 6dc34e0afe7a7b8815c4e09ae5cc7b01486df420 Mon Sep 17 00:00:00 2001 From: Yari Adan Petralanda Date: Mon, 4 Jul 2016 10:59:52 +0200 Subject: [PATCH] hash: retrieve a key given its position 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 Signed-off-by: Yari Adan Petralanda Acked-by: Pablo de Lara --- app/test/test_hash.c | 42 ++++++++++++++++++++++++++++ lib/librte_hash/rte_cuckoo_hash.c | 20 +++++++++++++ lib/librte_hash/rte_hash.h | 18 ++++++++++++ lib/librte_hash/rte_hash_version.map | 7 +++++ 4 files changed, 87 insertions(+) diff --git a/app/test/test_hash.c b/app/test/test_hash.c index 7e41725ae9..29abcd9ea1 100644 --- a/app/test/test_hash.c +++ b/app/test/test_hash.c @@ -420,6 +420,46 @@ static int test_add_update_delete(void) return 0; } +/* + * 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_w_pos"; + 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 * @@ -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 e3cc3a7ce2..26e54f68a8 100644 --- a/lib/librte_hash/rte_cuckoo_hash.c +++ b/lib/librte_hash/rte_cuckoo_hash.c @@ -877,6 +877,26 @@ 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 c9612fbd01..622c180094 100644 --- a/lib/librte_hash/rte_hash.h +++ b/lib/librte_hash/rte_hash.h @@ -271,6 +271,24 @@ 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 4f25436e77..52a2576f92 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; -- 2.20.1