Re: [PATCH v2 2/5] test_hash.c: split test_int_hash into arch-specific functions

[David Gow]

On Mon, Sep 27, 2021 at 6:33 AM Isabella Basso <isabellabdoamaral@xxxxxx> wrote:
>
> Split the test_int_hash function to keep its mainloop separate from
> arch-specific chunks, which are only compiled as needed. This aims at
> improving readability.
>
> Tested-by: David Gow <davidgow@xxxxxxxxxx>
> Signed-off-by: Isabella Basso <isabellabdoamaral@xxxxxx>
> ---

This looks good to me. It's possibly worth fixing up the changelog
mixup between this and patch 3 if you send out a v3.

A minor suggestion re: commenting below, otherwise this is:

Reviewed-by: David Gow <davidgow@xxxxxxxxxx>

-- David

>  lib/test_hash.c | 86 ++++++++++++++++++++++++++++++++-----------------
>  1 file changed, 57 insertions(+), 29 deletions(-)
>
> diff --git a/lib/test_hash.c b/lib/test_hash.c
> index d4b0cfdb0377..08fe63776c4f 100644
> --- a/lib/test_hash.c
> +++ b/lib/test_hash.c
> @@ -56,6 +56,53 @@ fill_buf(char *buf, size_t len, u32 seed)
>         }
>  }
>
> +/* Holds most testing variables for the int test */

It might be worth commenting what these variables actually are here,
as it's pretty confusing on a quick read through.

Maybe something like:

> +struct test_hash_params {
> +       unsigned long long *h64;

/* Pointer to integer to be hashed. */

> +       u32 h0;

/* Low 32-bits of integer to be hashed. */

> +       u32 h1;

/* Arch-specific hash result. */

> +       u32 h2;

/* Generic hash result. */

> +       u32 (*hash_or)[33];

/* ORed hashes of given size (in bits) */


> +};
> +
> +#ifdef HAVE_ARCH__HASH_32
> +static bool __init
> +test_int__hash_32(struct test_hash_params *params)
> +{
> +       params->hash_or[1][0] |= params->h2 = __hash_32_generic(params->h0);
> +#if HAVE_ARCH__HASH_32 == 1
> +       if (params->h1 != params->h2) {
> +               pr_err("__hash_32(%#x) = %#x != __hash_32_generic() = %#x",
> +                      params->h0, params->h1, params->h2);
> +               return false;
> +       }
> +#endif
> +       return true;
> +}
> +#endif
> +
> +#ifdef HAVE_ARCH_HASH_64
> +static bool __init
> +test_int_hash_64(struct test_hash_params *params, u32 const *m, int *k)
> +{
> +       params->h2 = hash_64_generic(*params->h64, *k);
> +#if HAVE_ARCH_HASH_64 == 1
> +       if (params->h1 != params->h2) {
> +               pr_err("hash_64(%#llx, %d) = %#x != hash_64_generic() = %#x",
> +                      *params->h64, *k, params->h1, params->h2);
> +               return false;
> +       }
> +#else
> +       if (params->h2 > *m) {
> +               pr_err("hash_64_generic(%#llx, %d) = %#x > %#x",
> +                      *params->h64, *k, params->h1, *m);
> +               return false;
> +       }
> +#endif
> +       return true;
> +}
> +#endif
> +
>  /*
>   * Test the various integer hash functions.  h64 (or its low-order bits)
>   * is the integer to hash.  hash_or accumulates the OR of the hash values,
> @@ -69,19 +116,13 @@ static bool __init
>  test_int_hash(unsigned long long h64, u32 hash_or[2][33])
>  {
>         int k;
> -       u32 h0 = (u32)h64, h1, h2;
> +       struct test_hash_params params = { &h64, (u32)h64, 0, 0, hash_or };
>
>         /* Test __hash32 */
> -       hash_or[0][0] |= h1 = __hash_32(h0);
> +       hash_or[0][0] |= params.h1 = __hash_32(params.h0);
>  #ifdef HAVE_ARCH__HASH_32
> -       hash_or[1][0] |= h2 = __hash_32_generic(h0);
> -#if HAVE_ARCH__HASH_32 == 1
> -       if (h1 != h2) {
> -               pr_err("__hash_32(%#x) = %#x != __hash_32_generic() = %#x",
> -                       h0, h1, h2);
> +       if (!test_int__hash_32(&params))
>                 return false;
> -       }
> -#endif
>  #endif
>
>         /* Test k = 1..32 bits */
> @@ -89,37 +130,24 @@ test_int_hash(unsigned long long h64, u32 hash_or[2][33])
>                 u32 const m = ((u32)2 << (k-1)) - 1;    /* Low k bits set */
>
>                 /* Test hash_32 */
> -               hash_or[0][k] |= h1 = hash_32(h0, k);
> -               if (h1 > m) {
> -                       pr_err("hash_32(%#x, %d) = %#x > %#x", h0, k, h1, m);
> +               hash_or[0][k] |= params.h1 = hash_32(params.h0, k);
> +               if (params.h1 > m) {
> +                       pr_err("hash_32(%#x, %d) = %#x > %#x", params.h0, k, params.h1, m);
>                         return false;
>                 }
>
>                 /* Test hash_64 */
> -               hash_or[1][k] |= h1 = hash_64(h64, k);
> -               if (h1 > m) {
> -                       pr_err("hash_64(%#llx, %d) = %#x > %#x", h64, k, h1, m);
> +               hash_or[1][k] |= params.h1 = hash_64(h64, k);
> +               if (params.h1 > m) {
> +                       pr_err("hash_64(%#llx, %d) = %#x > %#x", h64, k, params.h1, m);
>                         return false;
>                 }
>  #ifdef HAVE_ARCH_HASH_64
> -               h2 = hash_64_generic(h64, k);
> -#if HAVE_ARCH_HASH_64 == 1
> -               if (h1 != h2) {
> -                       pr_err("hash_64(%#llx, %d) = %#x != hash_64_generic() "
> -                               "= %#x", h64, k, h1, h2);
> +               if (!test_int_hash_64(&params, &m, &k))
>                         return false;
> -               }
> -#else
> -               if (h2 > m) {
> -                       pr_err("hash_64_generic(%#llx, %d) = %#x > %#x",
> -                               h64, k, h1, m);
> -                       return false;
> -               }
> -#endif
>  #endif
>         }
>
> -       (void)h2;       /* Suppress unused variable warning */
>         return true;
>  }
>
> --
> 2.33.0
>