On Tue, Feb 23, 2016 at 04:51:26PM +0100, Jiri Pirko wrote:
> From: Jiri Pirko <j...@mellanox.com>
>
> Introduce devlink infrastructure for drivers to register and expose to
> userspace via generic Netlink interface.
>
> There are two basic objects defined:
> devlink - one instance for every "parent device", for example switch ASIC
> devlink port - one instance for every physical port of the device.
>
> This initial portion implements basic get/dump of objects to userspace.
> Also, port splitter and port type setting is implemented.
...
> +/**
> + * devlink_alloc - Allocate new devlink instance resources
> + *
> + * @ops: ops
> + * @priv_size: size of user private data
> + *
> + * Allocate new devlink instance resources, including devlink index
> + * and name.
> + */
> +struct devlink *devlink_alloc(const struct devlink_ops *ops, size_t
> priv_size)
> +{
> + static atomic_t dev_counter = ATOMIC_INIT(0);
> + struct devlink *devlink;
> +
> + devlink = kzalloc(sizeof(*devlink) + priv_size, GFP_KERNEL);
> + if (!devlink)
> + return NULL;
> + devlink->ops = ops;
> + devlink_net_set(devlink, &init_net);
> +
> +different_name:
> + devlink->index = atomic_inc_return(&dev_counter);
> + if (devlink->index < 0) {
> + /* wrapped */
> + atomic_dec(&dev_counter);
> + kfree(devlink);
> + return NULL;
> + }
> + /* atomic_inc_return makes it start at 1, make it start at 0 */
> + devlink->index--;
> +
> + dev_set_name(&devlink->dev, DEVLINK_GENL_NAME "%d", devlink->index);
> + if (devlink_name_exists(devlink_net(devlink), devlink_name(devlink)))
> + goto different_name;
> +
> + INIT_LIST_HEAD(&devlink->port_list);
> + device_initialize(&devlink->dev);
> + devlink->dev.class = &devlink_class;
> + devlink->dev.platform_data = devlink;
> + return devlink;
> +}
> +EXPORT_SYMBOL_GPL(devlink_alloc);
The increment then decrement bit feels... Clunky and a little confusing.
Why not just atomic_read(&dev_counter) before different_name:, then an
atomic_inc_return(&dev_counter) under the if clause before the goto, and
eliminate the devlink->index-- bit?
--
Jarod Wilson
ja...@redhat.com
