[PATCH v3] String: Ensure 'MIN_PAGE_SIZE' is multiple of 'getpagesize'

[Matheus Castanho]

Noah Goldstein via Libc-alpha <libc-alpha@sourceware.org> writes:

> When 'TEST_LEN' was defined as (4096 * 3) the allocation size Would
> not be a multiple of system page size if system page size > 4096.
> ---
>  string/test-strcmp.c  | 14 +++++++-------
>  string/test-strncmp.c | 18 +++++++++---------
>  2 files changed, 16 insertions(+), 16 deletions(-)
>
> diff --git a/string/test-strcmp.c b/string/test-strcmp.c
> index eacbdc8857..0abce769d0 100644
> --- a/string/test-strcmp.c
> +++ b/string/test-strcmp.c
> @@ -16,7 +16,7 @@
>     License along with the GNU C Library; if not, see
>     <https://www.gnu.org/licenses/>.  */
>
> -#define TEST_LEN (4096 * 3)
> +#define TEST_LEN (getpagesize () * 3)
>  #define MIN_PAGE_SIZE (TEST_LEN + 2 * getpagesize ())
>
>  #define TEST_MAIN
> @@ -393,7 +393,7 @@ int
>  test_main (void)
>  {
>    size_t i, j;
> -
> +  const size_t test_len = MIN(TEST_LEN, 3 * 4096);
>    test_init ();
>    check();
>    check2 ();
> @@ -435,7 +435,7 @@ test_main (void)
>
>    for (j = 0; j < 160; ++j)
>      {
> -      for (i = 0; i < TEST_LEN;)
> +      for (i = 0; i < test_len;)
>          {
>            do_test (getpagesize () - j - 1, 0, i, 127, 0);
>            do_test (getpagesize () - j - 1, 0, i, 127, 1);
> @@ -461,17 +461,17 @@ test_main (void)
>              {
>                i += 7;
>              }
> -          else if (i + 161 < TEST_LEN)
> +          else if (i + 161 < test_len)
>              {
>                i += 31;
>                i *= 17;
>                i /= 16;
> -              if (i + 161 > TEST_LEN)
> +              if (i + 161 > test_len)
>                  {
> -                  i = TEST_LEN - 160;
> +                  i = test_len - 160;
>                  }
>              }
> -          else if (i + 32 < TEST_LEN)
> +          else if (i + 32 < test_len)
>              {
>                i += 7;
>              }
> diff --git a/string/test-strncmp.c b/string/test-strncmp.c
> index 1a3cee1792..831cb77893 100644
> --- a/string/test-strncmp.c
> +++ b/string/test-strncmp.c
> @@ -16,7 +16,7 @@
>     License along with the GNU C Library; if not, see
>     <https://www.gnu.org/licenses/>.  */
>
> -#define TEST_LEN (4096 * 3)
> +#define TEST_LEN (getpagesize () * 3)
>  #define MIN_PAGE_SIZE (TEST_LEN + 2 * getpagesize ())
>
>  #define TEST_MAIN
> @@ -430,7 +430,7 @@ check_overflow (void)
>    const size_t of_masks[]
>        = { ULONG_MAX, LONG_MIN, ULONG_MAX - (ULONG_MAX >> 2),
>            ((size_t)LONG_MAX) >> 1 };
> -
> +  const size_t test_len = MIN(TEST_LEN, 3 * 4096);
>    for (of_idx = 0; of_idx < sizeof (of_masks) / sizeof (of_masks[0]); ++of_idx)
>      {
>        of_mask = of_masks[of_idx];
> @@ -484,7 +484,7 @@ check_overflow (void)
>                           of_mask - j * 2, 0, 127, -1);
>              }
>
> -          for (i = 1; i < TEST_LEN; i += i)
> +          for (i = 1; i < test_len; i += i)
>              {
>                do_test_n (j, 0, i - 1, of_mask, 0, 127, 0);
>                do_test_n (j, 0, i - 1, of_mask, 0, 127, 1);
> @@ -540,7 +540,7 @@ int
>  test_main (void)
>  {
>    size_t i, j;
> -
> +  const size_t test_len = MIN(TEST_LEN, 3 * 4096);
>    test_init ();
>
>    check1 ();
> @@ -608,7 +608,7 @@ test_main (void)
>
>    for (j = 0; j < 160; ++j)
>      {
> -      for (i = 0; i < TEST_LEN;)
> +      for (i = 0; i < test_len;)
>          {
>            do_test_n (getpagesize () - j - 1, 0, i, i + 1, 0, 127, 0);
>            do_test_n (getpagesize () - j - 1, 0, i, i + 1, 0, 127, 1);
> @@ -677,17 +677,17 @@ test_main (void)
>              {
>                i += 7;
>              }
> -          else if (i + 161 < TEST_LEN)
> +          else if (i + 161 < test_len)
>              {
>                i += 31;
>                i *= 17;
>                i /= 16;
> -              if (i + 161 > TEST_LEN)
> +              if (i + 161 > test_len)
>                  {
> -                  i = TEST_LEN - 160;
> +                  i = test_len - 160;
>                  }
>              }
> -          else if (i + 32 < TEST_LEN)
> +          else if (i + 32 < test_len)
>              {
>                i += 7;
>              }

This version builds fine and passes all tests.
Tested on powerpc, powerpc64, and powerpc64le.

Thanks,
Matheus Castanho