From mboxrd@z Thu Jan  1 00:00:00 1970
From: Thomas Monjalon <thomas@monjalon.net>
Subject: Re: [PATCH] hash: validate hash bucket entries while
	compiling
Date: Thu, 12 Jul 2018 09:42:20 +0200
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References: <20180531153049.41306-1-honnappa.nagarahalli@arm.com>
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Cc: dev@dpdk.org, Honnappa Nagarahalli <honnappa.nagarahalli@arm.com>
To: bruce.richardson@intel.com, pablo.de.lara.guarch@intel.com
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Review please?

31/05/2018 17:30, Honnappa Nagarahalli:
> Validate RTE_HASH_BUCKET_ENTRIES during compilation instead of
> run time.
> 
> Signed-off-by: Honnappa Nagarahalli <honnappa.nagarahalli@arm.com>
> Reviewed-by: Gavin Hu <gavin.hu@arm.com>
> ---
>  lib/librte_eal/common/include/rte_common.h | 5 +++++
>  lib/librte_hash/rte_cuckoo_hash.c          | 1 -
>  lib/librte_hash/rte_cuckoo_hash.h          | 4 ++++
>  3 files changed, 9 insertions(+), 1 deletion(-)
> 
> diff --git a/lib/librte_eal/common/include/rte_common.h b/lib/librte_eal/common/include/rte_common.h
> index 434adfd45..a9df7c161 100644
> --- a/lib/librte_eal/common/include/rte_common.h
> +++ b/lib/librte_eal/common/include/rte_common.h
> @@ -293,6 +293,11 @@ rte_combine64ms1b(register uint64_t v)
>  
>  /*********** Macros to work with powers of 2 ********/
>  
> +/**
> + * Macro to return 1 if n is a power of 2, 0 otherwise
> + */
> +#define RTE_IS_POWER_OF_2(n) ((n) && !(((n) - 1) & (n)))
> +
>  /**
>   * Returns true if n is a power of 2
>   * @param n
> diff --git a/lib/librte_hash/rte_cuckoo_hash.c b/lib/librte_hash/rte_cuckoo_hash.c
> index a07543a29..375e7d208 100644
> --- a/lib/librte_hash/rte_cuckoo_hash.c
> +++ b/lib/librte_hash/rte_cuckoo_hash.c
> @@ -107,7 +107,6 @@ rte_hash_create(const struct rte_hash_parameters *params)
>  	/* Check for valid parameters */
>  	if ((params->entries > RTE_HASH_ENTRIES_MAX) ||
>  			(params->entries < RTE_HASH_BUCKET_ENTRIES) ||
> -			!rte_is_power_of_2(RTE_HASH_BUCKET_ENTRIES) ||
>  			(params->key_len == 0)) {
>  		rte_errno = EINVAL;
>  		RTE_LOG(ERR, HASH, "rte_hash_create has invalid parameters\n");
> diff --git a/lib/librte_hash/rte_cuckoo_hash.h b/lib/librte_hash/rte_cuckoo_hash.h
> index 7a54e5557..bd6ad1bd6 100644
> --- a/lib/librte_hash/rte_cuckoo_hash.h
> +++ b/lib/librte_hash/rte_cuckoo_hash.h
> @@ -97,6 +97,10 @@ enum add_key_case {
>  /** Number of items per bucket. */
>  #define RTE_HASH_BUCKET_ENTRIES		8
>  
> +#if !RTE_IS_POWER_OF_2(RTE_HASH_BUCKET_ENTRIES)
> +#error RTE_HASH_BUCKET_ENTRIES must be a power of 2
> +#endif
> +
>  #define NULL_SIGNATURE			0
>  
>  #define EMPTY_SLOT			0
>