Re: [dpdk-dev] [PATCH 1/2] mempool: fix returned value on 64 bit after counting objects

["Ananyev, Konstantin" <konstantin.ananyev@intel.com>]

> -----Original Message-----
> From: dev [mailto:dev-bounces@dpdk.org] On Behalf Of Adrien Mazarguil
> Sent: Monday, May 25, 2015 5:28 PM
> To: dev@dpdk.org
> Subject: [dpdk-dev] [PATCH 1/2] mempool: fix returned value on 64 bit after counting objects
> 
> rte_mempool_xmem_usage()'s return type is ssize_t which has the same
> architecture-dependent width as size_t but is signed.
> 
> On 64-bit architectures, returning a negative uint32_t value without casting
> to ssize_t first does not work as intended, the sign bit is lost and the
> returned value is garbage.
> 
> This commit fixes an assertion failure in testpmd on 64 bit architectures
> when combining --no-huge and --mp-anon outside of Xen Dom0:
> 
>  PANIC in mempool_anon_create():
>  line 170        assert "elt_num == mp->size" failed
> 
> Fixes: 148f963fb532 ("xen: core library changes")
> 
> Signed-off-by: Adrien Mazarguil <adrien.mazarguil@6wind.com>
> ---
>  lib/librte_mempool/rte_mempool.c | 2 +-
>  1 file changed, 1 insertion(+), 1 deletion(-)
> 
> diff --git a/lib/librte_mempool/rte_mempool.c b/lib/librte_mempool/rte_mempool.c
> index 01972ba..d1a02a2 100644
> --- a/lib/librte_mempool/rte_mempool.c
> +++ b/lib/librte_mempool/rte_mempool.c
> @@ -361,7 +361,7 @@ rte_mempool_xmem_usage(void *vaddr, uint32_t elt_num, size_t elt_sz,
>  	if ((n = rte_mempool_obj_iter(vaddr, elt_num, elt_sz, 1,
>  			paddr, pg_num, pg_shift, mempool_lelem_iter,
>  			&uv)) != elt_num) {
> -		return (-n);
> +		return (-(ssize_t)n);
>  	}
> 
>  	uv = RTE_ALIGN_CEIL(uv, pg_sz);
> --

Acked-by: Konstantin Ananyev <konstantin.ananyev@intel.com>

> 2.1.0