Re: [PATCH 1/2] inflate_fast: sout is already a short so ptr arith was off by one.

[Andrew Morton <akpm@linux-foundation.org>]

On Sun, 28 Feb 2010 17:06:02 +0100
Joakim Tjernlund <Joakim.Tjernlund@transmode.se> wrote:

> This won't change anything for current code, but post increment
> will break without this fix, should anyone want to try that.
> 

The description is a bit cryptic.  Hopefully you understand what you
mean, but does anyone else?

> diff --git a/lib/zlib_inflate/inffast.c b/lib/zlib_inflate/inffast.c
> index fa62fc7..2c13ecc 100644
> --- a/lib/zlib_inflate/inffast.c
> +++ b/lib/zlib_inflate/inffast.c
> @@ -286,7 +286,7 @@ void inflate_fast(z_streamp strm, unsigned start)
>  		    } else { /* dist == 1 or dist == 2 */
>  			unsigned short pat16;
>  
> -			pat16 = *(sout-2+2*OFF);
> +			pat16 = *(sout-1+OFF);
>  			if (dist == 1) {
>  				union uu mm;
>  				/* copy one char pattern to both bytes */

The code you're altering was changed two months ago by, err, you.  I
don't know if the patch still makes sense in current kernels.

Please don't raise patches against old kernels.  Please check that,
redo the patch, add a changelog which helps non-inffast.c people
understand what it does, then resend?