Re: [Xen-devel] [PATCH] drivers/block/xen-blkback/common.h: use DIV_ROUND_UP instead of reimplementing its function

[Jan Beulich]

>>> On 12.09.18 at 07:45, <zhongjiang@xxxxxxxxxx> wrote:
> --- a/drivers/block/xen-blkback/common.h
> +++ b/drivers/block/xen-blkback/common.h
> @@ -65,7 +65,7 @@
>  	(XEN_PAGES_PER_INDIRECT_FRAME / XEN_PAGES_PER_SEGMENT)
>  
>  #define MAX_INDIRECT_PAGES \
> -	((MAX_INDIRECT_SEGMENTS + SEGS_PER_INDIRECT_FRAME - 1)/SEGS_PER_INDIRECT_FRAME)
> +		DIV_ROUND_UP(MAX_INDIRECT_SEGMENTS, SEGS_PER_INDIRECT_FRAME)
>  #define INDIRECT_PAGES(_segs) DIV_ROUND_UP(_segs, XEN_PAGES_PER_INDIRECT_FRAME)

My first reaction was to suggest

#define MAX_INDIRECT_PAGES INDIRECT_PAGES(MAX_INDIRECT_SEGMENTS)

but that wouldn't match what's there currently (note the two different
divisors). I can't really decide whether that's just unfortunate naming
of the two macros, or an actual bug.

Jan