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

[Medvedkin, Vladimir]

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<andre...@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