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 <irina.tirdea@intel.com>
Acked-by: Pekka Enberg <penberg@kernel.org>
Cc: David Ahern <dsahern@gmail.com>
Cc: Ingo Molnar <mingo@redhat.com>
Cc: Namhyung Kim <namhyung.kim@lge.com>
Cc: Paul Mackerras <paulus@samba.org>
Cc: Peter Zijlstra <a.p.zijlstra@chello.nl>
Cc: Steven Rostedt <rostedt@goodmis.org>
Link: http://lkml.kernel.org/r/1347315303-29906-7-git-send-email-irina.tirdea@intel.com
[ committer note: fixed up conflict with a116e05 in builtin-sched.c ]
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>

3 files changed, 6 insertions, 5 deletions

diff --git a/tools/perf/ui/gtk/browser.c b/tools/perf/ui/gtk/browser.c
index 3c16ab5..55acba6 100644
--- a/tools/perf/ui/gtk/browser.c
+++ b/tools/perf/ui/gtk/browser.c
@@ -237,8 +237,9 @@ static GtkWidget *perf_gtk__setup_statusbar(void)
 
 int perf_evlist__gtk_browse_hists(struct perf_evlist *evlist,
 				  const char *help,
-				  void (*timer) (void *arg)__used,
-				  void *arg __used, int delay_secs __used)
+				  void (*timer) (void *arg)__maybe_unused,
+				  void *arg __maybe_unused,
+				  int delay_secs __maybe_unused)
 {
 	struct perf_evsel *pos;
 	GtkWidget *vbox;
diff --git a/tools/perf/ui/gtk/setup.c b/tools/perf/ui/gtk/setup.c
index 2642943..3c4c6ef 100644
--- a/tools/perf/ui/gtk/setup.c
+++ b/tools/perf/ui/gtk/setup.c
@@ -12,7 +12,7 @@ int perf_gtk__init(void)
 	return gtk_init_check(NULL, NULL) ? 0 : -1;
 }
 
-void perf_gtk__exit(bool wait_for_ok __used)
+void perf_gtk__exit(bool wait_for_ok __maybe_unused)
 {
 	if (!perf_gtk__is_active_context(pgctx))
 		return;
diff --git a/tools/perf/ui/gtk/util.c b/tools/perf/ui/gtk/util.c
index b8efb96..8aada5b 100644
--- a/tools/perf/ui/gtk/util.c
+++ b/tools/perf/ui/gtk/util.c
@@ -117,8 +117,8 @@ struct perf_error_ops perf_gtk_eops = {
  *        For now, just add stubs for NO_NEWT=1 build.
  */
 #ifdef NO_NEWT_SUPPORT
-void ui_progress__update(u64 curr __used, u64 total __used,
-			 const char *title __used)
+void ui_progress__update(u64 curr __maybe_unused, u64 total __maybe_unused,
+			 const char *title __maybe_unused)
 {
 }
 #endif