Re: [Qemu-devel] [RESEND][PATCH] bitmap: get last word mask from nr directly

[Peter Xu]

On Wed, Jul 17, 2019 at 09:29:02AM +0800, Wei Yang wrote:
> The value left in nr is the number of bits for the last word, which
> could be calculate the last word mask directly.

Is it true even if start does not align to BITS_PER_LONG?

> 
> Remove the unnecessary size.
> 
> Signed-off-by: Wei Yang <address@hidden>
> ---
> resend with wider audience
> ---
>  util/bitmap.c | 6 ++----
>  1 file changed, 2 insertions(+), 4 deletions(-)
> 
> diff --git a/util/bitmap.c b/util/bitmap.c
> index cb618c65a5..5aa60b8717 100644
> --- a/util/bitmap.c
> +++ b/util/bitmap.c
> @@ -160,7 +160,6 @@ int slow_bitmap_andnot(unsigned long *dst, const unsigned 
> long *bitmap1,
>  void bitmap_set(unsigned long *map, long start, long nr)
>  {
>      unsigned long *p = map + BIT_WORD(start);
> -    const long size = start + nr;
>      int bits_to_set = BITS_PER_LONG - (start % BITS_PER_LONG);
>      unsigned long mask_to_set = BITMAP_FIRST_WORD_MASK(start);
>  
> @@ -174,7 +173,7 @@ void bitmap_set(unsigned long *map, long start, long nr)
>          p++;
>      }
>      if (nr) {
> -        mask_to_set &= BITMAP_LAST_WORD_MASK(size);
> +        mask_to_set &= BITMAP_LAST_WORD_MASK(nr);
>          *p |= mask_to_set;
>      }
>  }
> @@ -221,7 +220,6 @@ void bitmap_set_atomic(unsigned long *map, long start, 
> long nr)
>  void bitmap_clear(unsigned long *map, long start, long nr)
>  {
>      unsigned long *p = map + BIT_WORD(start);
> -    const long size = start + nr;
>      int bits_to_clear = BITS_PER_LONG - (start % BITS_PER_LONG);
>      unsigned long mask_to_clear = BITMAP_FIRST_WORD_MASK(start);
>  
> @@ -235,7 +233,7 @@ void bitmap_clear(unsigned long *map, long start, long nr)
>          p++;
>      }
>      if (nr) {
> -        mask_to_clear &= BITMAP_LAST_WORD_MASK(size);
> +        mask_to_clear &= BITMAP_LAST_WORD_MASK(nr);
>          *p &= ~mask_to_clear;
>      }
>  }
> -- 
> 2.17.1
> 

Regards,

-- 
Peter Xu