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

[Matan Azrad]

Hi Ferruh

> From: Ferruh Yigit, Wednesday, March 28, 2018 1:38 AM
> On 3/5/2018 3:12 PM, Matan Azrad wrote:
> > 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 :)
> 
> Hi Matan,
> 
> Reminder of this issue, it would be nice to fix in this release.
> 

Regarding the private rte_eth_dev_data, it should be fixed in the next thread:
https://dpdk.org/dev/patchwork/patch/35632/

Regarding the rte_eth_dev_pci_release() function: I'm going to send a fix.

> >
> >>>
> >>>
> >>>> 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?
> >>>
> >