[dpdk-dev] [dpdk-stable] [PATCH v3 1/7] ethdev: fix port data reset timing

[Matan Azrad]

Hi Ferruh

From: Ferruh Yigit, Sent: Monday, March 5, 2018 5:07 PM
> On 3/5/2018 2:52 PM, Matan Azrad wrote:
> > HI
> >
> > From: Ferruh Yigit, Sent: Monday, March 5, 2018 1:24 PM
> >> On 1/18/2018 4:35 PM, Matan Azrad wrote:
> >>> rte_eth_dev_data structure is allocated per ethdev port and can be
> >>> used to get a data of the port internally.
> >>>
> >>> rte_eth_dev_attach_secondary tries to find the port identifier using
> >>> rte_eth_dev_data name field comparison and may get an identifier of
> >>> invalid port in case of this port was released by the primary
> >>> process because the port release API doesn't reset the port data.
> >>>
> >>> So, it will be better to reset the port data in release time instead
> >>> of allocation time.
> >>>
> >>> Move the port data reset to the port release API.
> >>>
> >>> Fixes: d948f596fee2 ("ethdev: fix port data mismatched in multiple
> >>> process model")
> >>> Cc: stable at dpdk.org
> >>>
> >>> Signed-off-by: Matan Azrad <matan at mellanox.com>
> >>> ---
> >>>  lib/librte_ether/rte_ethdev.c | 2 +-
> >>>  1 file changed, 1 insertion(+), 1 deletion(-)
> >>>
> >>> diff --git a/lib/librte_ether/rte_ethdev.c
> >>> b/lib/librte_ether/rte_ethdev.c index 7044159..156231c 100644
> >>> --- a/lib/librte_ether/rte_ethdev.c
> >>> +++ b/lib/librte_ether/rte_ethdev.c
> >>> @@ -204,7 +204,6 @@ struct rte_eth_dev *
> >>>  		return NULL;
> >>>  	}
> >>>
> >>> -	memset(&rte_eth_dev_data[port_id], 0, sizeof(struct
> >> rte_eth_dev_data));
> >>>  	eth_dev = eth_dev_get(port_id);
> >>>  	snprintf(eth_dev->data->name, sizeof(eth_dev->data->name),
> >> "%s", name);
> >>>  	eth_dev->data->port_id = port_id;
> >>> @@ -252,6 +251,7 @@ struct rte_eth_dev *
> >>>  	if (eth_dev == NULL)
> >>>  		return -EINVAL;
> >>>
> >>> +	memset(eth_dev->data, 0, sizeof(struct rte_eth_dev_data));
> >>
> >> Hi Matan,
> >>
> >> What most of the vdev release path does is:
> >>
> >> eth_dev = rte_eth_dev_allocated(...)
> >> rte_free(eth_dev->data->dev_private);
> >> rte_free(eth_dev->data);
> >> rte_eth_dev_release_port(eth_dev);
> >>
> >> Since eth_dev->data freed, memset() it in rte_eth_dev_release_port()
> >> will be problem.
> >>
> >> We don't run remove path that is why we didn't hit the issue but this
> >> seems problem for all virtual PMDs.
> >
> > Yes, it is a problem and should be fixed:
> > For vdevs which use private rte_eth_dev_data the remove order can be:
> > 	private_data = eth_dev->data;
> > 	rte_free(eth_dev->data->dev_private);
> > 	rte_eth_dev_release_port(eth_dev); /* The last operation working
> on ethdev structure. */
> > 	rte_free(private_data);
> 
> Do we need to save "private_data"?

Just to emphasis that eth_dev structure should not more be available after rte_eth_dev_release_port().
Maybe in the future rte_eth_dev_release_port() will zero eth_dev structure too :)

> >
> >
> >> Also rte_eth_dev_pci_release() looks problematic now.
> >
> > Yes, again, the last operation working on ethdev structure should be
> rte_eth_dev_release_port().
> >
> > So need to fix all vdevs and the rte_eth_dev_pci_release() function.
> >
> > Any comments?
> >