perf tools: Use __maybe_used for unused variables

perf defines both __used and __unused variables to use for marking
unused variables. The variable __used is defined to
__attribute__((__unused__)), which contradicts the kernel definition to
__attribute__((__used__)) for new gcc versions. On Android, __used is
also defined in system headers and this leads to warnings like: warning:
'__used__' attribute ignored

__unused is not defined in the kernel and is not a standard definition.
If __unused is included everywhere instead of __used, this leads to
conflicts with glibc headers, since glibc has a variables with this name
in its headers.

The best approach is to use __maybe_unused, the definition used in the
kernel for __attribute__((unused)). In this way there is only one
definition in perf sources (instead of 2 definitions that point to the
same thing: __used and __unused) and it works on both Linux and Android.
This patch simply replaces all instances of __used and __unused with
__maybe_unused.

Signed-off-by: Irina Tirdea <[email protected]>
Acked-by: Pekka Enberg <[email protected]>
Cc: David Ahern <[email protected]>
Cc: Ingo Molnar <[email protected]>
Cc: Namhyung Kim <[email protected]>
Cc: Paul Mackerras <[email protected]>
Cc: Peter Zijlstra <[email protected]>
Cc: Steven Rostedt <[email protected]>
Link: http://lkml.kernel.org/r/[email protected]
[ committer note: fixed up conflict with a116e05 in builtin-sched.c ]
Signed-off-by: Arnaldo Carvalho de Melo <[email protected]>

1 files changed, 5 insertions, 3 deletions

diff --git a/tools/perf/util/python.c b/tools/perf/util/python.c
index 27187f0b71f0..ca85444bcfbf 100644
--- a/tools/perf/util/python.c
+++ b/tools/perf/util/python.c
@@ -672,7 +672,7 @@ struct pyrf_evlist {
 };
 
 static int pyrf_evlist__init(struct pyrf_evlist *pevlist,
-			     PyObject *args, PyObject *kwargs __used)
+			     PyObject *args, PyObject *kwargs __maybe_unused)
 {
 	PyObject *pcpus = NULL, *pthreads = NULL;
 	struct cpu_map *cpus;
@@ -733,7 +733,8 @@ static PyObject *pyrf_evlist__poll(struct pyrf_evlist *pevlist,
 }
 
 static PyObject *pyrf_evlist__get_pollfd(struct pyrf_evlist *pevlist,
-					 PyObject *args __used, PyObject *kwargs __used)
+					 PyObject *args __maybe_unused,
+					 PyObject *kwargs __maybe_unused)
 {
 	struct perf_evlist *evlist = &pevlist->evlist;
         PyObject *list = PyList_New(0);
@@ -765,7 +766,8 @@ free_list:
 
 
 static PyObject *pyrf_evlist__add(struct pyrf_evlist *pevlist,
-				  PyObject *args, PyObject *kwargs __used)
+				  PyObject *args,
+				  PyObject *kwargs __maybe_unused)
 {
 	struct perf_evlist *evlist = &pevlist->evlist;
 	PyObject *pevsel;