Re: [PATCH] erofs-utils: use cmpsgn(x, y) for standardized large value comparsion

[Gao Xiang via Linux-erofs <linux-erofs@lists.ozlabs.org>]

On Mon, Oct 14, 2019 at 07:30:48PM +0800, Gao Xiang wrote:
> Previously, roundup(bb->buffers.off % EROFS_BLKSIZ, alignsize)
> + incr + extrasize is a unsigned 64bit value and sgn(x) didn't
> work properly. Fix it.

Update commit message:

erofs-utils: use cmpsgn(x, y) for standardized large value comparsion
    
Previously, roundup(bb->buffers.off % EROFS_BLKSIZ, alignsize)
+ incr + extrasize is an unsigned 64bit value and sgn(x) didn't
work properly. Fix it.
    
Fixes: b0ca535297b6 ("erofs-utils: support 64-bit internal buffer cache")

Guifu, do you have time reviewing and testing those patches?
I'd like to release erofs-utils 1.0 for upstreaming AOSP these days...

Thanks,
Gao Xiang

> 
> Signed-off-by: Gao Xiang <hsiangkao@aol.com>
> ---
>  include/erofs/defs.h | 5 +++--
>  lib/cache.c          | 6 +++---
>  2 files changed, 6 insertions(+), 5 deletions(-)
> 
> diff --git a/include/erofs/defs.h b/include/erofs/defs.h
> index 15db4e3..db51350 100644
> --- a/include/erofs/defs.h
> +++ b/include/erofs/defs.h
> @@ -136,9 +136,10 @@ typedef int64_t         s64;
>  	type __max2 = (y);			\
>  	__max1 > __max2 ? __max1: __max2; })
>  
> -#define sgn(x) ({		\
> +#define cmpsgn(x, y) ({		\
>  	typeof(x) _x = (x);	\
> -(_x > 0) - (_x < 0); })
> +	typeof(y) _y = (y);	\
> +(_x > _y) - (_x < _y); })
>  
>  #define ARRAY_SIZE(arr)	(sizeof(arr) / sizeof((arr)[0]))
>  
> diff --git a/lib/cache.c b/lib/cache.c
> index 41d2d5d..e61b201 100644
> --- a/lib/cache.c
> +++ b/lib/cache.c
> @@ -80,9 +80,9 @@ static int __erofs_battach(struct erofs_buffer_block *bb,
>  			   bool dryrun)
>  {
>  	const erofs_off_t alignedoffset = roundup(bb->buffers.off, alignsize);
> -	const int oob = sgn(roundup(bb->buffers.off % EROFS_BLKSIZ,
> -				    alignsize) + incr + extrasize -
> -			    EROFS_BLKSIZ);
> +	const int oob = cmpsgn(roundup(bb->buffers.off % EROFS_BLKSIZ,
> +				       alignsize) + incr + extrasize,
> +			       EROFS_BLKSIZ);
>  	bool tailupdate = false;
>  	erofs_blk_t blkaddr;
>  
> -- 
> 2.17.1
>