Re: [dpdk-dev] [PATCH v3 1/4] ring: future proof flag settings

[Honnappa Nagarahalli <Honnappa.Nagarahalli@arm.com>]

<snip>

> 
> All API's should check that they support the flag values passed.
> These checks ensure that the extra bits can safely be used without risk of ABI
> breakage.
> 
> Signed-off-by: Stephen Hemminger <stephen@networkplumber.org>
Reviewed-by: Honnappa Nagarahalli <honnappa.nagarahalli@arm.com>

> ---
>  lib/librte_ring/rte_ring.c | 12 ++++++++++++
>  1 file changed, 12 insertions(+)
> 
> diff --git a/lib/librte_ring/rte_ring.c b/lib/librte_ring/rte_ring.c index
> ebe5ccf0de68..e16dd45a82de 100644
> --- a/lib/librte_ring/rte_ring.c
> +++ b/lib/librte_ring/rte_ring.c
> @@ -42,6 +42,11 @@ static struct rte_tailq_elem rte_ring_tailq = {  };
>  EAL_REGISTER_TAILQ(rte_ring_tailq)
> 
> +/* mask of all valid flag values to ring_create() */ #define
> +RING_F_MASK (RING_F_SP_ENQ | RING_F_SC_DEQ | RING_F_EXACT_SZ | \
> +		     RING_F_MP_RTS_ENQ | RING_F_MC_RTS_DEQ |	       \
> +		     RING_F_MP_HTS_ENQ | RING_F_MC_HTS_DEQ )
> +
>  /* true if x is a power of 2 */
>  #define POWEROF2(x) ((((x)-1) & (x)) == 0)
> 
> @@ -197,6 +202,13 @@ rte_ring_init(struct rte_ring *r, const char *name,
> unsigned count,
>  	RTE_BUILD_BUG_ON(offsetof(struct rte_ring_headtail, tail) !=
>  		offsetof(struct rte_ring_rts_headtail, tail.val.pos));
> 
> +	/* future proof flags, only allow supported values */
> +	if (flags & ~RING_F_MASK) {
> +		RTE_LOG(ERR, RING,
> +			"Unsupported flags requested %#x\n", flags);
> +		return -EINVAL;
> +	}
> +
>  	/* init the ring structure */
>  	memset(r, 0, sizeof(*r));
>  	ret = strlcpy(r->name, name, sizeof(r->name));
> --
> 2.20.1