// this detects cases where a value compared to NULL is subsequently passed
// to PTR_ERR
//
// Confidence: High
// Copyright: (C) Gilles Muller, Julia Lawall, EMN, INRIA, DIKU.  GPLv2.
// URL: http://coccinelle.lip6.fr/rules/ptr.html
// Options:

@@
expression E,E1;
@@

if (
-   E == NULL
+   IS_ERR(E)
   ) { <+... when != E = E1
        PTR_ERR(E)
       ...+> }