fix ngx_reset_pool

[Maxim Dounin]

Hello!

On Tue, Jul 19, 2016 at 12:38:58AM +0800, 梁思健 wrote:

> # HG changeset patch
> # User Liang Sijian <liangsijian at foxmail.com>
> # Date 1468859189 -28800
> #      Tue Jul 19 00:26:29 2016 +0800
> # Node ID 45ef1e0a48a82b2a81db6bc447aaeb16a10056f9
> # Parent  6acaa638fa074dada02ad4544a299584da9abc85
> fix ngx_reset_pool
> 
> diff --git a/src/core/ngx_palloc.c b/src/core/ngx_palloc.c
> --- a/src/core/ngx_palloc.c
> +++ b/src/core/ngx_palloc.c
> @@ -109,7 +109,8 @@ ngx_reset_pool(ngx_pool_t *pool)
>      }
>  
>      for (p = pool; p; p = p->d.next) {
> -        p->d.last = (u_char *) p + sizeof(ngx_pool_t);
> +        p->d.last = (u_char *) p +
> +            (p == pool ? sizeof(ngx_pool_t ) : sizeof(ngx_pool_data_t));
>          p->d.failed = 0;
>      }

A previous attempt to "fix" this can be found here, it looks 
slightly better from my point of view:

http://mailman.nginx.org/pipermail/nginx-devel/2010-June/000351.html

Though we are quite happy with the current code, while it is not 
optimal - it is simple and good enough from practical point of 
view.

-- 
Maxim Dounin
http://nginx.org/