Re: [PATCH] xen: check return value of xenbus_printf

David Vrabel
2015-10-15T16:41:04Z

On 15/10/15 17:25, Insu Yun wrote:
> Internally, xenbus_printf uses memory allocation, so it can be failed in
> memory pressure.Therefore, xenbus_printf's return should be checked
> and properly handled.
[...]
> --- a/drivers/input/misc/xen-kbdfront.c
> +++ b/drivers/input/misc/xen-kbdfront.c
> @@ -129,8 +129,11 @@ static int xenkbd_probe(struct xenbus_device *dev,
>
> if (xenbus_scanf(XBT_NIL, dev->otherend, "feature-abs-pointer", "%d", &abs) < 0)
> abs = 0;
> - if (abs)
> - xenbus_printf(XBT_NIL, dev->nodename, "request-abs-pointer", "1");
> + if (abs) {
> + ret = xenbus_printf(XBT_NIL, dev->nodename, "request-abs-pointer", "1");
> + if (ret)
> + pr_warning("xenkbd: can't request abs-pointer");

I think you want abs = 0 here or input device will be configured as
absolute but the backend will supply relative coordinates.

David