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

Ferruh Yigit ferruh.yigit at intel.com
Wed Mar 28 00:37:52 CEST 2018


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.

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



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