pvcalls-front: don't return error when the ring is full

sstabellini · Boris Ostrovsky · commit d90a1ca60a1e · 2019-01-02T11:00:31.000-05:00
When the ring is full, size == array_size. It is not an error condition,
so simply return 0 instead of an error.

Signed-off-by: Stefano Stabellini &lt;stefanos@xilinx.com&gt;
Reviewed-by: Boris Ostrovsky &lt;boris.ostrovsky@oracle.com&gt;
Signed-off-by: Boris Ostrovsky &lt;boris.ostrovsky@oracle.com&gt;
diff --git a/drivers/xen/pvcalls-front.c b/drivers/xen/pvcalls-front.c
@@ -475,8 +475,10 @@ static int __write_ring(struct pvcalls_data_intf *intf,
 	virt_mb();
 
 	size = pvcalls_queued(prod, cons, array_size);
-	if (size >= array_size)
+	if (size > array_size)
 		return -EINVAL;
+	if (size == array_size)
+		return 0;
 	if (len > array_size - size)
 		len = array_size - size;
 
