Re: [dpdk-dev] [PATCH] mbuf: remove unused next member

[Olivier Matz <olivier.matz@6wind.com>]

Hi Xialong,

On Tue, Jun 09, 2020 at 01:29:55PM +0800, Xiaolong Ye wrote:
> TAILQ_ENTRY next is not needed in struct mbuf_dynfield_elt and
> mbuf_dynflag_elt, since they are actually chained by rte_tailq_entry's
> next field when calling TAILQ_INSERT_TAIL(mbuf_dynfield/dynflag_list, te,
> next).
> 
> Fixes: 4958ca3a443a ("mbuf: support dynamic fields and flags")
> Cc: stable@dpdk.org
> 
> Signed-off-by: Xiaolong Ye <xiaolong.ye@intel.com>

Good catch, I forgot to remove this field which was used in former
implementations. Thanks!

I suggest to update the title to highlight it's about dynamic mbuf:
  mbuf: remove unused next member in dyn flag/field

Apart from this:
Acked-by: Olivier Matz <olivier.matz@6wind.com>

> ---
> 
> I found this issue when reading the mbuf dynfiled/dynflag feature code,
> mbuf_autotest is passed with this change, though I may miss something or
> this filed has some special design purpose, please correct me if I am
> wrong.
> 
>  lib/librte_mbuf/rte_mbuf_dyn.c | 2 --
>  1 file changed, 2 deletions(-)
> 
> diff --git a/lib/librte_mbuf/rte_mbuf_dyn.c b/lib/librte_mbuf/rte_mbuf_dyn.c
> index d6931f847..953e3ec31 100644
> --- a/lib/librte_mbuf/rte_mbuf_dyn.c
> +++ b/lib/librte_mbuf/rte_mbuf_dyn.c
> @@ -19,7 +19,6 @@
>  #define RTE_MBUF_DYN_MZNAME "rte_mbuf_dyn"
>  
>  struct mbuf_dynfield_elt {
> -	TAILQ_ENTRY(mbuf_dynfield_elt) next;
>  	struct rte_mbuf_dynfield params;
>  	size_t offset;
>  };
> @@ -31,7 +30,6 @@ static struct rte_tailq_elem mbuf_dynfield_tailq = {
>  EAL_REGISTER_TAILQ(mbuf_dynfield_tailq);
>  
>  struct mbuf_dynflag_elt {
> -	TAILQ_ENTRY(mbuf_dynflag_elt) next;
>  	struct rte_mbuf_dynflag params;
>  	unsigned int bitnum;
>  };
> -- 
> 2.17.1
>