Re: [PATCH v2] lib/hash: new feature adding existing key

[Thomas Monjalon <thomas@monjalon.net>]

Any review please?
If maintainers agree with the idea, we should announce the ABI change.


23/10/2023 10:29, Abdullah Ömer Yamaç:
> From: 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>
> Cc: Sameh Gobriel <sameh.gobriel@intel.com>
> Cc: Bruce Richardson <bruce.richardson@intel.com>
> Cc: Vladimir Medvedkin <vladimir.medvedkin@intel.com>
> Cc: David Marchand <david.marchand@redhat.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 19b23f2a97..fe8f21bee4 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)
> @@ -707,6 +713,8 @@ 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 -EINVAL;
>  				/* 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 7ecc021111..ca5b4841d2 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.
>