linux-kernel - Re: [PATCH 3/8] lib: bitmap: fold nbits into region struct

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Date:   Tue, 26 Jan 2021 19:08:05 -0800
From:   Yury Norov <yury.norov@...il.com>
To:     Paul Gortmaker <paul.gortmaker@...driver.com>
Cc:     Linux Kernel Mailing List <linux-kernel@...r.kernel.org>,
        lizefan@...wei.com, Ingo Molnar <mingo@...nel.org>,
        Thomas Gleixner <tglx@...utronix.de>, josh@...htriplett.org,
        Peter Zijlstra <peterz@...radead.org>,
        "Paul E. McKenney" <paulmck@...nel.org>, fweisbec@...il.com,
        Rasmus Villemoes <linux@...musvillemoes.dk>,
        Andy Shevchenko <andriy.shevchenko@...ux.intel.com>
Subject: Re: [PATCH 3/8] lib: bitmap: fold nbits into region struct

On Tue, Jan 26, 2021 at 9:12 AM Paul Gortmaker
<paul.gortmaker@...driver.com> wrote:
>
> This will reduce parameter passing and enable using nbits as part
> of future dynamic region parameter parsing.
>
> Cc: Yury Norov <yury.norov@...il.com>
> Cc: Rasmus Villemoes <linux@...musvillemoes.dk>
> Cc: Andy Shevchenko <andriy.shevchenko@...ux.intel.com>
> Suggested-by: Yury Norov <yury.norov@...il.com>
> Signed-off-by: Paul Gortmaker <paul.gortmaker@...driver.com>
> ---
>  lib/bitmap.c | 19 ++++++++++---------
>  1 file changed, 10 insertions(+), 9 deletions(-)
>
> diff --git a/lib/bitmap.c b/lib/bitmap.c
> index 75006c4036e9..162e2850c622 100644
> --- a/lib/bitmap.c
> +++ b/lib/bitmap.c
> @@ -487,24 +487,24 @@ EXPORT_SYMBOL(bitmap_print_to_pagebuf);
>
>  /*
>   * Region 9-38:4/10 describes the following bitmap structure:
> - * 0      9  12    18                  38
> - * .........****......****......****......
> - *         ^  ^     ^                   ^
> - *      start  off   group_len        end
> + * 0      9  12    18                  38           N
> + * .........****......****......****..................
> + *         ^  ^     ^                   ^           ^
> + *      start  off   group_len        end       nbits
>   */
>  struct region {
>         unsigned int start;
>         unsigned int off;
>         unsigned int group_len;
>         unsigned int end;
> +       unsigned int nbits;
>  };
>
> -static int bitmap_set_region(const struct region *r,
> -                               unsigned long *bitmap, int nbits)
> +static int bitmap_set_region(const struct region *r, unsigned long *bitmap)
>  {
>         unsigned int start;
>
> -       if (r->end >= nbits)
> +       if (r->end >= r->nbits)
>                 return -ERANGE;
>
>         for (start = r->start; start <= r->end; start += r->group_len)
> @@ -640,7 +640,8 @@ int bitmap_parselist(const char *buf, unsigned long *maskp, int nmaskbits)
>         struct region r;
>         long ret;
>
> -       bitmap_zero(maskp, nmaskbits);
> +       r.nbits = nmaskbits;
> +       bitmap_zero(maskp, r.nbits);
>
>         while (buf) {
>                 buf = bitmap_find_region(buf);
> @@ -655,7 +656,7 @@ int bitmap_parselist(const char *buf, unsigned long *maskp, int nmaskbits)
>                 if (ret)
>                         return ret;
>
> -               ret = bitmap_set_region(&r, maskp, nmaskbits);
> +               ret = bitmap_set_region(&r, maskp);
>                 if (ret)
>                         return ret;
>         }
> --
> 2.17.1

Acked-by: Yury Norov <yury.norov@...il.com>