Re: [PATCH net 1/3] net/mlx5e: Harden uplink netdev access against device unbind

[Jianbo Liu]

On 9/11/2025 8:45 AM, Jakub Kicinski wrote:
> On Wed, 10 Sep 2025 11:23:09 +0800 Jianbo Liu wrote:
> > On 9/10/2025 9:23 AM, Jakub Kicinski wrote:
> > > On Mon, 8 Sep 2025 13:07:04 +0300 Tariq Toukan wrote:
> > > > +	struct net_device *netdev = mlx5_uplink_netdev_get(dev);
> > > > +	struct mlx5e_priv *priv;
> > > > +	int err;
> > > > +
> > > > +	if (!netdev)
> > > > +		return 0;
> > >
> > > Please don't call in variable init functions which require cleanup
> > > or error checking.
> >
> > But in this function, a NULL return from mlx5_uplink_netdev_get is a
> > valid condition where it should simply return 0. No cleanup or error
> > check is needed.
>
> You have to check if it succeeded, and if so, you need to clean up
> later. Do no hide meaningful code in variable init.

My focus was on the NULL case, but I see now that the real issue is 
ensuring the corresponding cleanup (_put) happens on the successful 
path. Hiding the _get call in the initializer makes that less clear.

I will refactor the code to follow the correct pattern, like this:

struct net_device *netdev;

netdev = mlx5_uplink_netdev_get(dev);
if (!netdev)
	return 0;

Thank you for the explanation.