Re: [dpdk-dev] [PATCH v2 2/2] net/failsafe: support multicast address list set

["Gaëtan Rivet" <gaetan.rivet@6wind.com>]

On Wed, Sep 19, 2018 at 04:50:57PM +0200, Gaëtan Rivet wrote:
> Hi,
> 
> Sorry about the delay on this, overall it looks ok;
> I have an issue however, see inline.
> 
> On Mon, Sep 03, 2018 at 07:55:22AM +0100, Andrew Rybchenko wrote:
> > From: Evgeny Im <Evgeny.Im@oktetlabs.com>
> > 
> > Signed-off-by: Evgeny Im <Evgeny.Im@oktetlabs.com>
> > Signed-off-by: Andrew Rybchenko <arybchenko@solarflare.com>
> > ---
> >  doc/guides/nics/features/failsafe.ini   |  1 +
> >  doc/guides/rel_notes/release_18_11.rst  |  6 ++++
> >  drivers/net/failsafe/failsafe.c         |  1 +
> >  drivers/net/failsafe/failsafe_ether.c   | 17 +++++++++
> >  drivers/net/failsafe/failsafe_ops.c     | 48 +++++++++++++++++++++++++
> >  drivers/net/failsafe/failsafe_private.h |  2 ++
> >  6 files changed, 75 insertions(+)
> > 
> > diff --git a/doc/guides/nics/features/failsafe.ini b/doc/guides/nics/features/failsafe.ini
> > index 83cc99d19..39ee57965 100644
> > --- a/doc/guides/nics/features/failsafe.ini
> > +++ b/doc/guides/nics/features/failsafe.ini
> > @@ -12,6 +12,7 @@ Jumbo frame          = Y
> >  Promiscuous mode     = Y
> >  Allmulticast mode    = Y
> >  Unicast MAC filter   = Y
> > +Multicast MAC filter = Y
> >  VLAN filter          = Y
> >  Flow control         = Y
> >  Flow API             = Y
> > diff --git a/doc/guides/rel_notes/release_18_11.rst b/doc/guides/rel_notes/release_18_11.rst
> > index 24204e67b..54e0e4ee4 100644
> > --- a/doc/guides/rel_notes/release_18_11.rst
> > +++ b/doc/guides/rel_notes/release_18_11.rst
> > @@ -54,6 +54,12 @@ New Features
> >       Also, make sure to start the actual text at the margin.
> >       =========================================================
> >  
> > +* **Updated failsafe driver.**
> > +
> > +  Updated the failsafe driver including the following changes:
> > +
> > +  * Support multicast MAC address set.
> > +
> >  
> >  API Changes
> >  -----------
> > diff --git a/drivers/net/failsafe/failsafe.c b/drivers/net/failsafe/failsafe.c
> > index 657919f93..c3999f026 100644
> > --- a/drivers/net/failsafe/failsafe.c
> > +++ b/drivers/net/failsafe/failsafe.c
> > @@ -304,6 +304,7 @@ fs_rte_eth_free(const char *name)
> >  	ret = pthread_mutex_destroy(&PRIV(dev)->hotplug_mutex);
> >  	if (ret)
> >  		ERROR("Error while destroying hotplug mutex");
> > +	rte_free(PRIV(dev)->mcast_addrs);
> >  	rte_free(PRIV(dev));
> >  	rte_eth_dev_release_port(dev);
> >  	return ret;
> > diff --git a/drivers/net/failsafe/failsafe_ether.c b/drivers/net/failsafe/failsafe_ether.c
> > index 5b5cb3b49..5078feabe 100644
> > --- a/drivers/net/failsafe/failsafe_ether.c
> > +++ b/drivers/net/failsafe/failsafe_ether.c
> > @@ -424,6 +424,23 @@ failsafe_eth_dev_state_sync(struct rte_eth_dev *dev)
> >  	ret = dev->dev_ops->dev_start(dev);
> >  	if (ret)
> >  		goto err_remove;
> > +	/*
> > +	 * Propagate multicast MAC addresses to sub-devices,
> > +	 * if non zero number of addresses is set.
> > +	 * The condition is required to avoid breakage of failsafe
> > +	 * for sub-devices which do not support the operation
> > +	 * if the feature is really not used.
> > +	 */
> > +	if (PRIV(dev)->nb_mcast_addr > 0) {
> > +		ret = dev->dev_ops->set_mc_addr_list(dev,
> > +						     PRIV(dev)->mcast_addrs,
> > +						     PRIV(dev)->nb_mcast_addr);
> > +		if (ret) {
> > +			ERROR("Could not set list of multicast addresses to sub_device %d",
> > +			      i);
> > +			goto err_remove;
> > +		}
> > +	}
> 
> Using here the dev-ops instead of calling the rte_eth_* API as is done for the
> other configuration items, is unorthodox and I believe could lead to
> issues.

Sorry I forgot the mention it, but it seems that this could be done
in fs_eth_dev_conf_apply() instead, which explains why I would consider
using the dev-ops being unorthodox.

> 
> Why didn't you call rte_eth_dev_set_mc_addr_list on the new port only instead,
> the same way it is done for the other configuration item?
> 
> Using the dev-ops, you are making the other sub-device re-apply the
> same configuration periodically (in case of repeated hotplug error),
> twice per sub-device upkeep cycle. This is unnecessary and seems to
> foster instability for no clear benefit. Can you justify it?
> 

If it was necessary to call this after the dev_start, I think it
would be better to restrict the configuration to inactive sub-devices,
in any case.

-- 
Gaëtan Rivet
6WIND