On Fri, 31 Jan 2014, Dan Williams wrote:
> For example:
Topic sentence? A reader seeing this could be forgiven for wondering
"Example of what?".
> usb2/2-1/2-1:1.0/port1/peer => ../../../../usb3/3-1/3-1:1.0/port1
> usb2/2-1/2-1:1.0/port2/peer => ../../../../usb3/3-1/3-1:1.0/port2
> usb2/2-1/2-1:1.0/port3/peer => ../../../../usb3/3-1/3-1:1.0/port3
> usb2/2-1/2-1:1.0/port4/peer => ../../../../usb3/3-1/3-1:1.0/port4
> usb2/2-0:1.0/port1/peer => ../../../usb3/3-0:1.0/port1
> usb2/2-0:1.0/port2/peer => ../../../usb3/3-0:1.0/port2
> usb2/2-0:1.0/port3/peer => ../../../usb3/3-0:1.0/port3
> usb2/2-0:1.0/port4/peer => ../../../usb3/3-0:1.0/port4
>
> usb3/3-1/3-1:1.0/port1/peer => ../../../../usb2/2-1/2-1:1.0/port1
> usb3/3-1/3-1:1.0/port2/peer => ../../../../usb2/2-1/2-1:1.0/port2
> usb3/3-1/3-1:1.0/port3/peer => ../../../../usb2/2-1/2-1:1.0/port3
> usb3/3-1/3-1:1.0/port4/peer => ../../../../usb2/2-1/2-1:1.0/port4
> usb3/3-0:1.0/port1/peer => ../../../usb2/2-0:1.0/port1
> usb3/3-0:1.0/port2/peer => ../../../usb2/2-0:1.0/port2
> usb3/3-0:1.0/port3/peer => ../../../usb2/2-0:1.0/port3
> usb3/3-0:1.0/port4/peer => ../../../usb2/2-0:1.0/port4
> + mutex_lock(&peer_lock);
> + peer = port_dev->peer;
> + do if (peer) {
> + retval = sysfs_create_link(&port_dev->dev.kobj,
> + &peer->dev.kobj, "peer");
> + if (retval)
> + break;
> + retval = sysfs_create_link(&peer->dev.kobj,
> + &port_dev->dev.kobj, "peer");
> + } while (0);
This is an unusual idiom; I don't recall seeing it before. How about
writing this in a more conventional fashion? It would require one
less line of code...
> + mutex_unlock(&peer_lock);
> + if (retval)
> + goto error_links;
> +
> pm_runtime_set_active(&port_dev->dev);
>
> /* It would be dangerous if user space couldn't
> @@ -339,6 +357,8 @@ int usb_hub_create_port_device(struct usb_hub *hub, int port1)
>
> error_register:
> put_device(&port_dev->dev);
> +error_links:
> + device_unregister(&port_dev->dev);
You don't explicitly remove the first link if the second link fails. I
guess sysfs is smart enough to do this for you, right?
Alan Stern
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