[PATCH 3.2 015/115] watchdog: rc32434_wdt: fix ioctl error handling

[Ben Hutchings]

3.2.80-rc1 review patch.  If anyone has any objections, please let me know.

------------------

From: "Michael S. Tsirkin" <mst@xxxxxxxxxx>

commit 10e7ac22cdd4d211cef99afcb9371b70cb175be6 upstream.

Calling return copy_to_user(...) in an ioctl will not do the right thing
if there's a pagefault: copy_to_user returns the number of bytes not
copied in this case.

Fix up watchdog/rc32434_wdt to do
	return copy_to_user(...)) ?  -EFAULT : 0;

instead.

Signed-off-by: Michael S. Tsirkin <mst@xxxxxxxxxx>
Signed-off-by: Guenter Roeck <linux@xxxxxxxxxxxx>
Signed-off-by: Wim Van Sebroeck <wim@xxxxxxxxx>
Signed-off-by: Ben Hutchings <ben@xxxxxxxxxxxxxxx>
---
 drivers/watchdog/rc32434_wdt.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

--- a/drivers/watchdog/rc32434_wdt.c
+++ b/drivers/watchdog/rc32434_wdt.c
@@ -239,7 +239,7 @@ static long rc32434_wdt_ioctl(struct fil
 			return -EINVAL;
 		/* Fall through */
 	case WDIOC_GETTIMEOUT:
-		return copy_to_user(argp, &timeout, sizeof(int));
+		return copy_to_user(argp, &timeout, sizeof(int)) ? -EFAULT : 0;
 	default:
 		return -ENOTTY;
 	}