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

[Tiwei Bie <tiwei.bie@intel.com>]

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.

Thanks,
Tiwei