diff --git a/drivers/uio/uio.c b/drivers/uio/uio.c
index 144cf736528812eb13a802bf0c1b9c623ed8bf6b..3f76e38e6f303179ab81e371c9d6f6e11286fb0a 100644
--- a/drivers/uio/uio.c
+++ b/drivers/uio/uio.c
@@ -624,6 +624,12 @@ static ssize_t uio_write(struct file *filep, const char __user *buf,
 	ssize_t retval;
 	s32 irq_on;
 
+	if (count != sizeof(s32))
+		return -EINVAL;
+
+	if (copy_from_user(&irq_on, buf, count))
+		return -EFAULT;
+
 	mutex_lock(&idev->info_lock);
 	if (!idev->info) {
 		retval = -EINVAL;
@@ -635,21 +641,11 @@ static ssize_t uio_write(struct file *filep, const char __user *buf,
 		goto out;
 	}
 
-	if (count != sizeof(s32)) {
-		retval = -EINVAL;
-		goto out;
-	}
-
 	if (!idev->info->irqcontrol) {
 		retval = -ENOSYS;
 		goto out;
 	}
 
-	if (copy_from_user(&irq_on, buf, count)) {
-		retval = -EFAULT;
-		goto out;
-	}
-
 	retval = idev->info->irqcontrol(idev->info, irq_on);
 
 out: