[dpdk-dev] [PATCH v4 03/24] ethdev: add function to release port in local process

[Zhang, Qi Z]

> -----Original Message-----
> From: Zhang, Qi Z
> Sent: Tuesday, June 26, 2018 9:29 PM
> To: 'Matan Azrad' <matan at mellanox.com>; Thomas Monjalon
> <thomas at monjalon.net>; Burakov, Anatoly <anatoly.burakov at intel.com>
> Cc: Ananyev, Konstantin <konstantin.ananyev at intel.com>; dev at dpdk.org;
> Richardson, Bruce <bruce.richardson at intel.com>; Yigit, Ferruh
> <ferruh.yigit at intel.com>; Shelton, Benjamin H
> <benjamin.h.shelton at intel.com>; Vangati, Narender
> <narender.vangati at intel.com>
> Subject: RE: [dpdk-dev] [PATCH v4 03/24] ethdev: add function to release port
> in local process
> 
> Hi Matan:
> 
> > -----Original Message-----
> > From: Matan Azrad [mailto:matan at mellanox.com]
> > Sent: Tuesday, June 26, 2018 7:50 PM
> > To: Zhang, Qi Z <qi.z.zhang at intel.com>; Thomas Monjalon
> > <thomas at monjalon.net>; Burakov, Anatoly <anatoly.burakov at intel.com>
> > Cc: Ananyev, Konstantin <konstantin.ananyev at intel.com>; dev at dpdk.org;
> > Richardson, Bruce <bruce.richardson at intel.com>; Yigit, Ferruh
> > <ferruh.yigit at intel.com>; Shelton, Benjamin H
> > <benjamin.h.shelton at intel.com>; Vangati, Narender
> > <narender.vangati at intel.com>
> > Subject: RE: [dpdk-dev] [PATCH v4 03/24] ethdev: add function to
> > release port in local process
> >
> > Hi Qi
> >
> > Please see comments\questions..
> >
> > From: Qi Zhang
> > > Add driver API rte_eth_release_port_private to support the
> > > requirement that an ethdev only be released on secondary process, so
> > > only local state be set to unused , share data will not be reset so
> > > primary process can
> > still use it.
> > >
> > > Signed-off-by: Qi Zhang <qi.z.zhang at intel.com>
> > > ---
> > >
> > >  lib/librte_ethdev/rte_ethdev.c        | 24 +++++++++++++++++++++---
> > >  lib/librte_ethdev/rte_ethdev_driver.h | 13 +++++++++++++
> > >  2 files changed, 34 insertions(+), 3 deletions(-)
> > >
> > > diff --git a/lib/librte_ethdev/rte_ethdev.c
> > > b/lib/librte_ethdev/rte_ethdev.c index a9977df97..205b2ee33 100644
> > > --- a/lib/librte_ethdev/rte_ethdev.c
> > > +++ b/lib/librte_ethdev/rte_ethdev.c
> > > @@ -359,6 +359,23 @@ rte_eth_dev_attach_secondary(const char
> > *name)  }
> > >
> > >  int
> > > +rte_eth_dev_release_port_private(struct rte_eth_dev *eth_dev) {
> > > +	if (eth_dev == NULL)
> > > +		return -EINVAL;
> > > +
> > > +	_rte_eth_dev_callback_process(eth_dev, RTE_ETH_EVENT_DESTROY,
> > > NULL);
> > > +
> > > +	rte_spinlock_lock(&rte_eth_dev_shared_data->ownership_lock);
> >
> > I don't think you need the lock here because there is not shared data to
> reset.
> 
> OK, will remove this.
> 
> >
> > > +	eth_dev->state = RTE_ETH_DEV_UNUSED;
> > > +
> > > +	rte_spinlock_unlock(&rte_eth_dev_shared_data->ownership_lock);
> > > +
> > > +	return 0;
> > > +}
> > > +
> > > +int
> > >  rte_eth_dev_release_port(struct rte_eth_dev *eth_dev)  {
> > >  	if (eth_dev == NULL)
> > > @@ -370,9 +387,10 @@ rte_eth_dev_release_port(struct rte_eth_dev
> > > *eth_dev)
> > >
> > >  	rte_spinlock_lock(&rte_eth_dev_shared_data->ownership_lock);
> > >
> > > -	eth_dev->state = RTE_ETH_DEV_UNUSED;
> > > -
> > > -	memset(eth_dev->data, 0, sizeof(struct rte_eth_dev_data));
> > > +	if (eth_dev->state != RTE_ETH_DEV_UNUSED) {
> >
> > Can you explain why not to release the shared data in case of locally
> > unused port?
> 
> Now, we have rte_eth_dev_release_port be called in rte_eth_dev_detach, its
> redundant for some driver, because they already will release port in
> dev->remove, but I'm not sure if it is true for all drivers.
> 
> On secondary process, when detach a device, it is possible that
> rte_eth_dev_release_port be called after rte_eth_dev_release_port_local , so
> it will reset share data which is not expected, since the primary process will fail
> on detach it because  rte_eth_dev_allocated will return NULL.
> 
> There could be other way, but current implementation help to reuse exist
> code., I can't add more comment on this change in v5

I can add more comment

> 
> Regards
> Qi
> 
> >
> > > +		eth_dev->state = RTE_ETH_DEV_UNUSED;
> > > +		memset(eth_dev->data, 0, sizeof(struct rte_eth_dev_data));
> > > +	}
> > >
> > >  	rte_spinlock_unlock(&rte_eth_dev_shared_data->ownership_lock);
> > >
> > > diff --git a/lib/librte_ethdev/rte_ethdev_driver.h
> > > b/lib/librte_ethdev/rte_ethdev_driver.h
> > > index c9c825e3f..49c27223d 100644
> > > --- a/lib/librte_ethdev/rte_ethdev_driver.h
> > > +++ b/lib/librte_ethdev/rte_ethdev_driver.h
> > > @@ -70,6 +70,19 @@ int rte_eth_dev_release_port(struct rte_eth_dev
> > > *eth_dev);
> > >
> > >  /**
> > >   * @internal
> > > + * Release the specified ethdev port in local process, only set to
> > > +ethdev
> > > + * state to unused, but not reset share data since it assume other
> > > +process
> > > + * is still using it, typically it is called by secondary process.
> > > + *
> > > + * @param eth_dev
> > > + * The *eth_dev* pointer is the address of the *rte_eth_dev* structure.
> > > + * @return
> > > + *   - 0 on success, negative on error
> > > + */
> > > +int rte_eth_dev_release_port_private(struct rte_eth_dev *eth_dev);
> > > +
> > > +/**
> > > + * @internal
> > >   * Release device queues and clear its configuration to force the user
> > >   * application to reconfigure it. It is for internal use only.
> > >   *
> > > --
> > > 2.13.6