Re: [dpdk-dev] [PATCH v2 04/13] ethdev: support of multiple sizes of redirection table

["Richardson, Bruce" <bruce.richardson@intel.com>]

> -----Original Message-----
> From: dev [mailto:dev-bounces@dpdk.org] On Behalf Of Thomas Monjalon
> Sent: Tuesday, October 28, 2014 10:10 AM
> To: Zhang, Helin
> Cc: dev@dpdk.org
> Subject: Re: [dpdk-dev] [PATCH v2 04/13] ethdev: support of multiple sizes of
> redirection table
> 
> 2014-10-28 00:33, Zhang, Helin:
> > From: Thomas Monjalon [mailto:thomas.monjalon@6wind.com]
> > > 2014-09-25 16:40, Helin Zhang:
> > > >  /* Definitions used for redirection table entry size */
> > > > -#define ETH_RSS_RETA_NUM_ENTRIES 128
> > > > -#define ETH_RSS_RETA_MAX_QUEUE   16
> > > > +#define ETH_RSS_RETA_SIZE_64  64
> > > > +#define ETH_RSS_RETA_SIZE_128 128
> > > > +#define ETH_RSS_RETA_SIZE_512 512
> > > > +
> > > > +#define RTE_BIT_WIDTH_64 (CHAR_BIT * sizeof(uint64_t))
> > >
> > > Are these constants really needed?
> >
> > These constants were defined for the third input parameter of
> > rte_eth_dev_rss_reta_update() and rte_eth_dev_rss_reta_query(). End users
> need
> > to give the correct reta size listed as above, as other values is not valid. So it
> would be
> > better to list the valid reta sizes in macros here.
> 
If only limited range of values are allowed, would an enum work better than a set of macros? 

> OK, so you should explain that only these values are allowed.
> In general, it's something we explain in the comment of the function.
> 
> By the way, why only these values are allowed?