Re: [Qemu-block] [PATCH v3 09/20] mirror: Update signature of mirror_clip_sectors()

[Jeff Cody]

On Tue, Jun 27, 2017 at 02:24:47PM -0500, Eric Blake wrote:
> Rather than having a void function that modifies its input
> in-place as the output, change the signature to reduce a layer
> of indirection and return the result.
> 
> Suggested-by: John Snow <address@hidden>
> Signed-off-by: Eric Blake <address@hidden>
> Reviewed-by: John Snow <address@hidden>
> 

Reviewed-by: Jeff Cody <address@hidden>

> ---
> v2: new patch
> ---
>  block/mirror.c | 15 ++++++++-------
>  1 file changed, 8 insertions(+), 7 deletions(-)
> 
> diff --git a/block/mirror.c b/block/mirror.c
> index af27bcc..1a43304 100644
> --- a/block/mirror.c
> +++ b/block/mirror.c
> @@ -176,12 +176,12 @@ static void mirror_read_complete(void *opaque, int ret)
>      aio_context_release(blk_get_aio_context(s->common.blk));
>  }
> 
> -static inline void mirror_clip_sectors(MirrorBlockJob *s,
> -                                       int64_t sector_num,
> -                                       int *nb_sectors)
> +static inline int mirror_clip_sectors(MirrorBlockJob *s,
> +                                      int64_t sector_num,
> +                                      int nb_sectors)
>  {
> -    *nb_sectors = MIN(*nb_sectors,
> -                      s->bdev_length / BDRV_SECTOR_SIZE - sector_num);
> +    return MIN(nb_sectors,
> +               s->bdev_length / BDRV_SECTOR_SIZE - sector_num);
>  }
> 
>  /* Round sector_num and/or nb_sectors to target cluster if COW is needed, and
> @@ -216,7 +216,8 @@ static int mirror_cow_align(MirrorBlockJob *s,
>      }
>      /* Clipping may result in align_nb_sectors unaligned to chunk boundary, 
> but
>       * that doesn't matter because it's already the end of source image. */
> -    mirror_clip_sectors(s, align_sector_num, &align_nb_sectors);
> +    align_nb_sectors = mirror_clip_sectors(s, align_sector_num,
> +                                           align_nb_sectors);
> 
>      ret = align_sector_num + align_nb_sectors - (*sector_num + *nb_sectors);
>      *sector_num = align_sector_num;
> @@ -445,7 +446,7 @@ static uint64_t coroutine_fn 
> mirror_iteration(MirrorBlockJob *s)
>              return 0;
>          }
> 
> -        mirror_clip_sectors(s, sector_num, &io_sectors);
> +        io_sectors = mirror_clip_sectors(s, sector_num, io_sectors);
>          switch (mirror_method) {
>          case MIRROR_METHOD_COPY:
>              io_sectors = mirror_do_read(s, sector_num, io_sectors);
> -- 
> 2.9.4
>