Re: [PATCH v10 21/21] hash: remove use of VLAs by using standard arrays

["Medvedkin, Vladimir" <vladimir.medvedkin@intel.com>]

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Hi Andre,

On 20/11/2024 03:13, Andre Muezerie wrote:
> MSVC does not support VLAs, replace VLAs with standard C arrays.
>
> Signed-off-by: Andre Muezerie<andremue@linux.microsoft.com>
> ---
>   lib/hash/rte_thash_gf2_poly_math.c | 7 ++++---
>   1 file changed, 4 insertions(+), 3 deletions(-)
>
> diff --git a/lib/hash/rte_thash_gf2_poly_math.c b/lib/hash/rte_thash_gf2_poly_math.c
> index 1c62974e71..cf7c7d396c 100644
> --- a/lib/hash/rte_thash_gf2_poly_math.c
> +++ b/lib/hash/rte_thash_gf2_poly_math.c
> @@ -8,6 +8,7 @@
>   #include <rte_thash.h>
>   #include <rte_log.h>
>   
> +#define MAX_POLY_DEGREE 32
>   #define MAX_TOEPLITZ_KEY_LENGTH 64
>   RTE_LOG_REGISTER_SUFFIX(thash_poly_logtype, thash_poly, INFO);
>   #define RTE_LOGTYPE_HASH thash_poly_logtype
> @@ -149,7 +150,7 @@ gf2_pow(uint32_t a, uint32_t pow, uint32_t r, int degree)
>   static uint32_t
>   __thash_get_rand_poly(int poly_degree)
>   {
> -	uint32_t roots[poly_degree];
> +	uint32_t roots[MAX_POLY_DEGREE];
>   	uint32_t rnd;
>   	uint32_t ret_poly = 0;
>   	int i, j;
> @@ -194,7 +195,7 @@ __thash_get_rand_poly(int poly_degree)
>   	 * Get coefficients of the polynomial for
>   	 * (x - roots[0])(x - roots[1])...(x - roots[n])
>   	 */
> -	uint32_t poly_coefficients[poly_degree + 1];
> +	uint32_t poly_coefficients[MAX_POLY_DEGREE + 1];
>   	for (i = 0; i <= poly_degree; i++)
>   		poly_coefficients[i] = 0;
Since poly_coefficients is not a VLA anymore you can initializeit with 
zeros and get rid of the loop
>   
> @@ -247,7 +248,7 @@ thash_get_rand_poly(uint32_t poly_degree)
>   {
>   	uint32_t ret_poly;
>   
> -	if (poly_degree > 32) {
> +	if (poly_degree > MAX_POLY_DEGREE) {
>   		HASH_LOG(ERR, "Wrong polynomial degree %d, must be in range [1, 32]", poly_degree);
>   		return 0;
>   	}

-- 
Regards,
Vladimir

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