diff mbox series

[v5,1/5] mbuf: introduce routine to get private mbuf pool flags

Message ID 1579541003-2399-2-git-send-email-viacheslavo@mellanox.com (mailing list archive)
State Superseded, archived
Delegated to: Thomas Monjalon
Headers
Series mbuf: detach mbuf with pinned external buffer |

Checks

Context Check Description
ci/checkpatch success coding style OK
ci/Intel-compilation success Compilation OK

Commit Message

Slava Ovsiienko Jan. 20, 2020, 5:23 p.m. UTC 
  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(+)

Comments

Stephen Hemminger Jan. 20, 2020, 8:43 p.m. UTC | #1 
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.
Thomas Monjalon Jan. 20, 2020, 10:52 p.m. UTC | #2 
20/01/2020 21:43, Stephen Hemminger:
> 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>
> > ---
> > --- a/lib/librte_mbuf/rte_mbuf.h
> > +++ b/lib/librte_mbuf/rte_mbuf.h
> > +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;
> > +}
> 
> 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.

It makes sense.
Please let's make these minor changes in a separate patch
as I am closing -rc1 with the v6 of this series included.
Thanks
Slava Ovsiienko Jan. 21, 2020, 6:48 a.m. UTC | #3 
Hi, Stephen

I'm appreciated for the for reviewing.

> -----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.

Agree, will prepare the dedicated patch.

With best regards, Slava
Slava Ovsiienko Jan. 21, 2020, 8 a.m. UTC | #4 
> -----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
Olivier Matz Jan. 21, 2020, 8:14 a.m. UTC | #5 
On Tue, Jan 21, 2020 at 08:00:17AM +0000, Slava Ovsiienko wrote:
> > -----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() ?

I'm not sure it would work. The problem is that to get the priv,
we do pool_ptr + offset. So if we want to remove the const, we'll
have to do a cast to "unconst". Not sure it is worth doing it.

Thanks
Olivier
Slava Ovsiienko Jan. 21, 2020, 8:23 a.m. UTC | #6 
> -----Original Message-----
> From: Olivier Matz <olivier.matz@6wind.com>
> Sent: Tuesday, January 21, 2020 10:14
> To: Slava Ovsiienko <viacheslavo@mellanox.com>
> Cc: Stephen Hemminger <stephen@networkplumber.org>; dev@dpdk.org;
> Matan Azrad <matan@mellanox.com>; Raslan Darawsheh
> <rasland@mellanox.com>; Ori Kam <orika@mellanox.com>; Shahaf Shuler
> <shahafs@mellanox.com>; thomas@mellanox.net
> Subject: Re: [PATCH v5 1/5] mbuf: introduce routine to get private mbuf pool
> flags
> 
> On Tue, Jan 21, 2020 at 08:00:17AM +0000, Slava Ovsiienko wrote:
> > > -----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() ?
> 
> I'm not sure it would work. The problem is that to get the priv, we do
> pool_ptr + offset. So if we want to remove the const, we'll have to do a cast to
> "unconst". Not sure it is worth doing it.
> 
> Thanks
> Olivier
OK, I'll just remove not necessary (struct rte_pktmbuf_pool_private*) cast and
will not introduce const qualifier for the parameter.

With best regards, Slava
Slava Ovsiienko Jan. 21, 2020, 9:13 a.m. UTC | #7 
> -----Original Message-----
> From: dev <dev-bounces@dpdk.org> On Behalf Of Slava Ovsiienko
> Sent: Tuesday, January 21, 2020 10:24
> To: Olivier Matz <olivier.matz@6wind.com>
> Cc: Stephen Hemminger <stephen@networkplumber.org>; dev@dpdk.org;
> Matan Azrad <matan@mellanox.com>; Raslan Darawsheh
> <rasland@mellanox.com>; Ori Kam <orika@mellanox.com>; Shahaf Shuler
> <shahafs@mellanox.com>; thomas@mellanox.net
> Subject: Re: [dpdk-dev] [PATCH v5 1/5] mbuf: introduce routine to get private
> mbuf pool flags
> 
> > -----Original Message-----
> > From: Olivier Matz <olivier.matz@6wind.com>
> > Sent: Tuesday, January 21, 2020 10:14
> > To: Slava Ovsiienko <viacheslavo@mellanox.com>
> > Cc: Stephen Hemminger <stephen@networkplumber.org>; dev@dpdk.org;
> > Matan Azrad <matan@mellanox.com>; Raslan Darawsheh
> > <rasland@mellanox.com>; Ori Kam <orika@mellanox.com>; Shahaf Shuler
> > <shahafs@mellanox.com>; thomas@mellanox.net
> > Subject: Re: [PATCH v5 1/5] mbuf: introduce routine to get private
> > mbuf pool flags
> >
> > On Tue, Jan 21, 2020 at 08:00:17AM +0000, Slava Ovsiienko wrote:
> > > > -----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() ?
> >
> > I'm not sure it would work. The problem is that to get the priv, we do
> > pool_ptr + offset. So if we want to remove the const, we'll have to do
> > a cast to "unconst". Not sure it is worth doing it.
> >
> > Thanks
> > Olivier
> OK, I'll just remove not necessary (struct rte_pktmbuf_pool_private*) cast and
> will not introduce const qualifier for the parameter.
> 
> With best regards, Slava
I've checked the rte_mempool_get_priv() usage - in all header files there
are the type casts. The "rte_mbuf.h" contains the rte_pktmbuf_priv_size() and
rte_pktmbuf_data_room_size(), both provide the cast.  What is the reason?
C++ compatibility? Should we remove the cast in rte_pktmbuf_priv_flags()?

With best regards,
Slava
Olivier Matz Jan. 21, 2020, 2:01 p.m. UTC | #8 
On Tue, Jan 21, 2020 at 09:13:48AM +0000, Slava Ovsiienko wrote:
> > -----Original Message-----
> > From: dev <dev-bounces@dpdk.org> On Behalf Of Slava Ovsiienko
> > Sent: Tuesday, January 21, 2020 10:24
> > To: Olivier Matz <olivier.matz@6wind.com>
> > Cc: Stephen Hemminger <stephen@networkplumber.org>; dev@dpdk.org;
> > Matan Azrad <matan@mellanox.com>; Raslan Darawsheh
> > <rasland@mellanox.com>; Ori Kam <orika@mellanox.com>; Shahaf Shuler
> > <shahafs@mellanox.com>; thomas@mellanox.net
> > Subject: Re: [dpdk-dev] [PATCH v5 1/5] mbuf: introduce routine to get private
> > mbuf pool flags
> > 
> > > -----Original Message-----
> > > From: Olivier Matz <olivier.matz@6wind.com>
> > > Sent: Tuesday, January 21, 2020 10:14
> > > To: Slava Ovsiienko <viacheslavo@mellanox.com>
> > > Cc: Stephen Hemminger <stephen@networkplumber.org>; dev@dpdk.org;
> > > Matan Azrad <matan@mellanox.com>; Raslan Darawsheh
> > > <rasland@mellanox.com>; Ori Kam <orika@mellanox.com>; Shahaf Shuler
> > > <shahafs@mellanox.com>; thomas@mellanox.net
> > > Subject: Re: [PATCH v5 1/5] mbuf: introduce routine to get private
> > > mbuf pool flags
> > >
> > > On Tue, Jan 21, 2020 at 08:00:17AM +0000, Slava Ovsiienko wrote:
> > > > > -----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() ?
> > >
> > > I'm not sure it would work. The problem is that to get the priv, we do
> > > pool_ptr + offset. So if we want to remove the const, we'll have to do
> > > a cast to "unconst". Not sure it is worth doing it.
> > >
> > > Thanks
> > > Olivier
> > OK, I'll just remove not necessary (struct rte_pktmbuf_pool_private*) cast and
> > will not introduce const qualifier for the parameter.
> > 
> > With best regards, Slava
> I've checked the rte_mempool_get_priv() usage - in all header files there
> are the type casts. The "rte_mbuf.h" contains the rte_pktmbuf_priv_size() and
> rte_pktmbuf_data_room_size(), both provide the cast.  What is the reason?
> C++ compatibility? Should we remove the cast in rte_pktmbuf_priv_flags()?

Removing the cast will certainly break C++ code using this header.
There is a similar case in commit a2ff2827dc84 ("mbuf: fix C++ build on
void pointer cast")

In my opinion it can stay as it is now.
Stephen Hemminger Jan. 21, 2020, 4:21 p.m. UTC | #9 
On Tue, 21 Jan 2020 15:01:57 +0100
Olivier Matz <olivier.matz@6wind.com> wrote:

> > I've checked the rte_mempool_get_priv() usage - in all header files there
> > are the type casts. The "rte_mbuf.h" contains the rte_pktmbuf_priv_size() and
> > rte_pktmbuf_data_room_size(), both provide the cast.  What is the reason?
> > C++ compatibility? Should we remove the cast in rte_pktmbuf_priv_flags()?  
> 
> Removing the cast will certainly break C++ code using this header.
> There is a similar case in commit a2ff2827dc84 ("mbuf: fix C++ build on
> void pointer cast")
> 
> In my opinion it can stay as it is now.

Agreed. Thanks for trying.
diff mbox series

Patch

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 */