Re: [dpdk-dev] [PATCH v5 1/5] mbuf: introduce routine to get private mbuf pool flags

[Slava Ovsiienko <viacheslavo@mellanox.com>]

> -----Original Message-----
> From: Stephen Hemminger <stephen@networkplumber.org>
> Sent: Monday, January 20, 2020 22:44
> To: Slava Ovsiienko <viacheslavo@mellanox.com>
> Cc: dev@dpdk.org; Matan Azrad <matan@mellanox.com>; Raslan Darawsheh
> <rasland@mellanox.com>; Ori Kam <orika@mellanox.com>; Shahaf Shuler
> <shahafs@mellanox.com>; olivier.matz@6wind.com; thomas@mellanox.net
> Subject: Re: [PATCH v5 1/5] mbuf: introduce routine to get private mbuf pool
> flags
> 
> On Mon, 20 Jan 2020 17:23:19 +0000
> Viacheslav Ovsiienko <viacheslavo@mellanox.com> wrote:
> 
> > The routine rte_pktmbuf_priv_flags is introduced to fetch the flags
> > from the mbuf memory pool private structure in unified fashion.
> >
> > Signed-off-by: Viacheslav Ovsiienko <viacheslavo@mellanox.com>
> > Acked-by: Olivier Matz <olivier.matz@6wind.com>
> > ---
> >  lib/librte_mbuf/rte_mbuf.h | 17 +++++++++++++++++
> >  1 file changed, 17 insertions(+)
> >
> > diff --git a/lib/librte_mbuf/rte_mbuf.h b/lib/librte_mbuf/rte_mbuf.h
> > index 2d4bda2..9b0691d 100644
> > --- a/lib/librte_mbuf/rte_mbuf.h
> > +++ b/lib/librte_mbuf/rte_mbuf.h
> > @@ -306,6 +306,23 @@ struct rte_pktmbuf_pool_private {
> >  	uint32_t flags; /**< reserved for future use. */  };
> >
> > +/**
> > + * Return the flags from private data in an mempool structure.
> > + *
> > + * @param mp
> > + *   A pointer to the mempool structure.
> > + * @return
> > + *   The flags from the private data structure.
> > + */
> > +static inline uint32_t
> > +rte_pktmbuf_priv_flags(struct rte_mempool *mp) {
> > +	struct rte_pktmbuf_pool_private *mbp_priv;
> > +
> > +	mbp_priv = (struct rte_pktmbuf_pool_private
> *)rte_mempool_get_priv(mp);
> > +	return mbp_priv->flags;
> > +}
> > +
> >  #ifdef RTE_LIBRTE_MBUF_DEBUG
> >
> >  /**  check mbuf type in debug mode */
> 
> Looks fine, but a couple of minor suggestions.
> 
> 
> Since this doesn't modify the mbuf, the arguments should be const.
> Since rte_mempool_get_priv returns void *, the cast is unnecessary.

rte_mempool_get_priv() does not expect "const", so adding "const" is a bit problematic,
and we should not change the rte_mempool_get_priv() prototype.
Do you think we should take private structure pointer directly from the pool
structure instead of calling rte_mempool_get_priv() ?

With best regards, Slava