Re: [dpdk-dev] [PATCH 2/2] net/vhost: prevent multiple setup on reconfig

[Maxime Coquelin <maxime.coquelin@redhat.com>]

Hi Tiwei,

On 2/19/20 4:44 AM, Tiwei Bie wrote:
> On Tue, Feb 18, 2020 at 06:22:40PM +0100, Maxime Coquelin wrote:
>> Ethdev's .dev_configure callback can be called multiple
>> time during a device life-time, but Vhost makes the
>> wrong assumption that it is not the case and try to
>> setup again the device on reconfiguration.
>>
>> This patch ensures the device hasn't been already setup
>> before proceeding.
>>
>> Fixes: 3d01b759d267 ("net/vhost: delay driver setup")
>>
>> Reported-by: Yinan Wang <yinan.wang@intel.com>
>> Signed-off-by: Maxime Coquelin <maxime.coquelin@redhat.com>
>> Tested-by: Yinan Wang <yinan.wang@intel.com>
>> Reviewed-by: David Marchand <david.marchand@redhat.com>
>> ---
>>  drivers/net/vhost/rte_eth_vhost.c | 5 +++++
>>  1 file changed, 5 insertions(+)
>>
>> diff --git a/drivers/net/vhost/rte_eth_vhost.c b/drivers/net/vhost/rte_eth_vhost.c
>> index 4a7b1b608c..458ed58f5f 100644
>> --- a/drivers/net/vhost/rte_eth_vhost.c
>> +++ b/drivers/net/vhost/rte_eth_vhost.c
>> @@ -876,6 +876,11 @@ vhost_driver_setup(struct rte_eth_dev *eth_dev)
>>  	unsigned int numa_node = eth_dev->device->numa_node;
>>  	const char *name = eth_dev->device->name;
>>  
>> +	/* Don't try to setup again if it has already been done. */
>> +	list = find_internal_resource(internal->iface_name);
>> +	if (list)
>> +		return 0;
>> +
>>  	list = rte_zmalloc_socket(name, sizeof(*list), 0, numa_node);
>>  	if (list == NULL)
>>  		return -1;
>> -- 
>> 2.24.1
> 
> Thanks Maxime for the fix!
> 
> Reviewed-by: Tiwei Bie <tiwei.bie@intel.com>
> 
> Not related to this fix, it seems there is a potential leak after
> delaying the driver setup to _configure, as the list won't be
> registered until users configure the device. So internal->iface_name
> allocated in _create will leak if the device is released without
> doing _configure first.
> 
> https://github.com/DPDK/dpdk/blob/e6c78e736d77/drivers/net/vhost/rte_eth_vhost.c#L1058
> https://github.com/DPDK/dpdk/blob/e6c78e736d77/drivers/net/vhost/rte_eth_vhost.c#L1075
> 
> It's not a common case and it's quite late in this release,
> probably it's fine to fix it later.

That's a valid point, and I also agree there is no urgency for v20.02.
Itsuro, would you take care of fixing it for v20.05?

Thanks,
Maxime
> Thanks,
> Tiwei
>