Coccinelle: Add null/eno.cocci

The various basic memory allocation functions don't return ERR_PTR
Signed-off-by: NNicolas Palix <npalix@diku.dk>
Signed-off-by: NJulia Lawall <julia@diku.dk>
Signed-off-by: NMichal Marek <mmarek@suse.cz>

scripts/coccinelle/null/eno.cocci

+/// The various basic memory allocation functions don't return ERR_PTR
+///
+// Confidence: High
+// Copyright: (C) 2010 Nicolas Palix, DIKU.  GPLv2.
+// Copyright: (C) 2010 Julia Lawall, DIKU.  GPLv2.
+// Copyright: (C) 2010 Gilles Muller, INRIA/LiP6.  GPLv2.
+// URL: http://coccinelle.lip6.fr/
+// Comments:
+// Options: -no_includes -include_headers
+
+virtual patch
+
+@@
+expression x,E;
+@@
+
+x = \(kmalloc\|kzalloc\|kcalloc\|kmem_cache_alloc\|kmem_cache_zalloc\|kmem_cache_alloc_node\|kmalloc_node\|kzalloc_node\)(...)
+... when != x = E
+- IS_ERR(x)
++ !x