xen: use struct_size() helper in kzalloc()

Andrea Righi · jgross1 · commit ad94dc3a7eb5 · 2019-04-05T08:42:41.000+02:00
struct privcmd_buf_vma_private has a zero-sized array at the end
(pages), use the new struct_size() helper to determine the proper
allocation size and avoid potential type mistakes.

Signed-off-by: Andrea Righi &lt;andrea.righi@canonical.com&gt;
Reviewed-by: Juergen Gross &lt;jgross@suse.com&gt;
Signed-off-by: Juergen Gross &lt;jgross@suse.com&gt;
diff --git a/drivers/xen/privcmd-buf.c b/drivers/xen/privcmd-buf.c
@@ -140,8 +140,7 @@ static int privcmd_buf_mmap(struct file *file, struct vm_area_struct *vma)
 	if (!(vma->vm_flags & VM_SHARED))
 		return -EINVAL;
 
-	vma_priv = kzalloc(sizeof(*vma_priv) + count * sizeof(void *),
-			   GFP_KERNEL);
+	vma_priv = kzalloc(struct_size(vma_priv, pages, count), GFP_KERNEL);
 	if (!vma_priv)
 		return -ENOMEM;
 
