Re: [PATCH 1/5] um: port: Move an assignment for the variable "fd" in port_wait()

Jeff Dike
2017-01-19T00:03:30Z

On Wed, Jan 18, 2017 at 10:56:17PM +0100, SF Markus Elfring wrote:
> diff --git a/arch/um/drivers/port_kern.c b/arch/um/drivers/port_kern.c
> index 40ca5cc275e9..b2bbda21c5f3 100644
> --- a/arch/um/drivers/port_kern.c
> +++ b/arch/um/drivers/port_kern.c
> @@ -230,10 +230,10 @@ int port_wait(void *data)
>
> atomic_inc(&port->wait_count);
> while (1) {
> - fd = -ERESTARTSYS;
> - if (wait_for_completion_interruptible(&port->done))
> + if (wait_for_completion_interruptible(&port->done)) {
> + fd = -ERESTARTSYS;
> goto out;
> -
> + }
> spin_lock(&port->lock);
>
> conn = list_entry(port->connections.next, struct connection,
> --
> 2.11.0
>

The current code is pretty standard kernel coding style. The inline
fd = -ERESTARTSYS;
is likely free, or close to it, and I believe that having anything
besides a goto inside the if could make it significantly more
expensive.

Jeff

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Jeff Dike
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