Re: [PATCH net-next 02/11] net: Introduce new api for walking upper and lower devices

Stephen Hemminger
2016-10-17T12:21:21Z

On Fri, 14 Oct 2016 18:28:42 -0700
David Ahern <dsa-qUQiAmfTcIp+XZJcv9eMoEEOCMrvLtNR@public.gmane.org> wrote:

>
> /**
> + * netdev_has_upper_dev_all - Check if device is linked to an upper device
> + * @dev: device
> + * @upper_dev: upper device to check
> + *
> + * Find out if a device is linked to specified upper device and return true
> + * in case it is. Note that this checks the entire upper device chain.
> + * The caller must hold rcu lock.
> + */
> +
> +static int __netdev_has_upper_dev(struct net_device *upper_dev, void *data)
> +{
> + struct net_device *dev = (struct net_device *)data;
> +
> + if (upper_dev == dev)
> + return 1;
> +
> + return 0;
> +}
> +
> +bool netdev_has_upper_dev_all_rcu(struct net_device *dev,
> + struct net_device *upper_dev)
> +{
> + if (netdev_walk_all_upper_dev_rcu(dev, __netdev_has_upper_dev,
> + upper_dev))
> + return true;
> +
> + return false;
> +}
> +EXPORT_SYMBOL(netdev_has_upper_dev_all_rcu);

You should write this more succinctly as:

static bool __netdev_has_upper_dev(struct net_device *upper_dev, void *data)
{
struct net_device *dev = data;

return upper_dev == dev;
}

bool netdev_has_upper_dev_all_rcu(struct net_device *dev,
struct net_device *upper_dev)
{
return netdev_walk_all_upper_dev_rcu(dev,
__netdev_has_upper_dev, upper_dev);
}

No if/else needed. No cast of void * ptr need. Use const if possible?