Re: [PATCH 4/8] lib: bitmap: move ERANGE check from set_region to check_region
From: Andy Shevchenko
Date: Wed Feb 10 2021 - 11:34:01 EST
On Tue, Feb 09, 2021 at 05:59:03PM -0500, Paul Gortmaker wrote:
> It makes sense to do all the checks in check_region() and not 1/2
> in check_region and 1/2 in set_region.
>
> Since set_region is called immediately after check_region, the net
> effect on runtime is zero, but it gets rid of an if (...) return...
Reviewed-by: Andy Shevchenko <andriy.shevchenko@xxxxxxxxxxxxxxx>
> Cc: Yury Norov <yury.norov@xxxxxxxxx>
> Cc: Rasmus Villemoes <linux@xxxxxxxxxxxxxxxxxx>
> Cc: Andy Shevchenko <andriy.shevchenko@xxxxxxxxxxxxxxx>
> Acked-by: Yury Norov <yury.norov@xxxxxxxxx>
> Signed-off-by: Paul Gortmaker <paul.gortmaker@xxxxxxxxxxxxx>
> ---
> lib/bitmap.c | 19 +++++++------------
> 1 file changed, 7 insertions(+), 12 deletions(-)
>
> diff --git a/lib/bitmap.c b/lib/bitmap.c
> index 75006c4036e9..9596ba53c36b 100644
> --- a/lib/bitmap.c
> +++ b/lib/bitmap.c
> @@ -499,25 +499,22 @@ struct region {
> unsigned int end;
> };
>
> -static int bitmap_set_region(const struct region *r,
> - unsigned long *bitmap, int nbits)
> +static void bitmap_set_region(const struct region *r, unsigned long *bitmap)
> {
> unsigned int start;
>
> - if (r->end >= nbits)
> - return -ERANGE;
> -
> for (start = r->start; start <= r->end; start += r->group_len)
> bitmap_set(bitmap, start, min(r->end - start + 1, r->off));
> -
> - return 0;
> }
>
> -static int bitmap_check_region(const struct region *r)
> +static int bitmap_check_region(const struct region *r, int nbits)
> {
> if (r->start > r->end || r->group_len == 0 || r->off > r->group_len)
> return -EINVAL;
>
> + if (r->end >= nbits)
> + return -ERANGE;
> +
> return 0;
> }
>
> @@ -651,13 +648,11 @@ int bitmap_parselist(const char *buf, unsigned long *maskp, int nmaskbits)
> if (IS_ERR(buf))
> return PTR_ERR(buf);
>
> - ret = bitmap_check_region(&r);
> + ret = bitmap_check_region(&r, nmaskbits);
> if (ret)
> return ret;
>
> - ret = bitmap_set_region(&r, maskp, nmaskbits);
> - if (ret)
> - return ret;
> + bitmap_set_region(&r, maskp);
> }
>
> return 0;
> --
> 2.17.1
>
--
With Best Regards,
Andy Shevchenko