Coccinelle: Script to detect cast after memory allocation

This script detects cases of use of cast for the value returned by
kmalloc, kzalloc, kcalloc, kmem_cache_alloc, kmem_cache_zalloc,
kmem_cache_alloc_node, kmalloc_node and kzalloc_node and removes
the cast as it is not useful. This Coccinelle script replaces
drop_kmalloc_cast.cocci as it removes the casting in more limited
cases of kmalloc, kzalloc and kcalloc.

Signed-off-by: Himangi Saraogi <himangi774@gmail.com>
Acked-by: Julia Lawall <julia.lawall@lip6.fr>
Signed-off-by: Michal Marek <mmarek@suse.cz>

scripts/coccinelle/api/alloc/alloc_cast.cocci

@@ -0,0 +1,72 @@
+/// Remove casting the values returned by memory allocation functions
+/// like kmalloc, kzalloc, kmem_cache_alloc, kmem_cache_zalloc etc.
+///
+//# This makes an effort to find cases of casting of values returned by
+//# kmalloc, kzalloc, kcalloc, kmem_cache_alloc, kmem_cache_zalloc,
+//# kmem_cache_alloc_node, kmalloc_node and kzalloc_node and removes
+//# the casting as it is not required. The result in the patch case may
+//#need some reformatting.
+//
+// Confidence: High
+// Copyright: 2014, Himangi Saraogi  GPLv2.
+// Comments:
+// Options: --no-includes --include-headers
+//
+
+virtual context
+virtual patch
+virtual org
+virtual report
+
+//----------------------------------------------------------
+//  For context mode
+//----------------------------------------------------------
+
+@depends on context@
+type T;
+@@
+
+* (T *)
+  \(kmalloc\|kzalloc\|kcalloc\|kmem_cache_alloc\|kmem_cache_zalloc\|
+   kmem_cache_alloc_node\|kmalloc_node\|kzalloc_node\)(...)
+
+//----------------------------------------------------------
+//  For patch mode
+//----------------------------------------------------------
+
+@depends on patch@
+type T;
+@@
+
+- (T *)
+  (\(kmalloc\|kzalloc\|kcalloc\|kmem_cache_alloc\|kmem_cache_zalloc\|
+   kmem_cache_alloc_node\|kmalloc_node\|kzalloc_node\)(...))
+
+//----------------------------------------------------------
+//  For org and report mode
+//----------------------------------------------------------
+
+@r depends on org || report@
+type T;
+position p;
+@@
+
+ (T@p *)\(kmalloc\|kzalloc\|kcalloc\|kmem_cache_alloc\|kmem_cache_zalloc\|
+   kmem_cache_alloc_node\|kmalloc_node\|kzalloc_node\)(...)
+
+@script:python depends on org@
+p << r.p;
+t << r.T;
+@@
+
+coccilib.org.print_safe_todo(p[0], t)
+
+@script:python depends on report@
+p << r.p;
+t << r.T;
+@@
+
+msg="WARNING: casting value returned by memory allocation function to (%s *) is useless." % (t)
+coccilib.report.print_report(p[0], msg)
+
+