Add scripts/coccinelle/alloc/kzalloc-simple.cocci

This semantic patch replaces a pair of calls to kmalloc and memset
by a single call to kzalloc.

It only looks for simple cases to avoid false positives.
Signed-off-by: Nicolas Palix <npalix@diku.dk>
Signed-off-by: Julia Lawall <julia@diku.dk>
Signed-off-by: Michal Marek <mmarek@suse.cz>

scripts/coccinelle/alloc/kzalloc-simple.cocci

+///
+/// kzalloc should be used rather than kmalloc followed by memset 0
+///
+// Confidence: High
+// Copyright: (C) 2009-2010 Julia Lawall, Nicolas Palix, DIKU.  GPLv2.
+// Copyright: (C) 2009-2010 Gilles Muller, INRIA/LiP6.  GPLv2.
+// URL: http://coccinelle.lip6.fr/rules/kzalloc.html
+// Options: -no_includes -include_headers
+//
+// Keywords: kmalloc, kzalloc
+// Version min: < 2.6.12 kmalloc
+// Version min:   2.6.14 kzalloc
+//
+
+virtual context
+virtual patch
+virtual org
+virtual report
+
+//----------------------------------------------------------
+//  For context mode
+//----------------------------------------------------------
+
+@depends on context@
+type T, T2;
+expression x;
+expression E1,E2;
+statement S;
+@@
+
+* x = (T)kmalloc(E1,E2);
+  if ((x==NULL) || ...) S
+* memset((T2)x,0,E1);
+
+//----------------------------------------------------------
+//  For patch mode
+//----------------------------------------------------------
+
+@depends on patch@
+type T, T2;
+expression x;
+expression E1,E2;
+statement S;
+@@
+
+- x = (T)kmalloc(E1,E2);
++ x = kzalloc(E1,E2);
+  if ((x==NULL) || ...) S
+- memset((T2)x,0,E1);
+
+//----------------------------------------------------------
+//  For org mode
+//----------------------------------------------------------
+
+@r depends on org || report@
+type T, T2;
+expression x;
+expression E1,E2;
+statement S;
+position p;
+@@
+
+ x = (T)kmalloc@p(E1,E2);
+ if ((x==NULL) || ...) S
+ memset((T2)x,0,E1);
+
+@script:python depends on org@
+p << r.p;
+x << r.x;
+@@
+
+msg="%s" % (x)
+msg_safe=msg.replace("[","@(").replace("]",")")
+coccilib.org.print_todo(p[0], msg_safe)
+
+@script:python depends on report@
+p << r.p;
+x << r.x;
+@@
+
+msg="WARNING: kzalloc should be used for %s, instead of kmalloc/memset" % (x)
+coccilib.report.print_report(p[0], msg)