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>

1 files changed, 16 insertions, 14 deletions

diff --git a/tools/perf/builtin-timechart.c b/tools/perf/builtin-timechart.c
index 3b75b2e21ea5..55a3a6c6b9e7 100644
--- a/tools/perf/builtin-timechart.c
+++ b/tools/perf/builtin-timechart.c
@@ -275,28 +275,28 @@ static int cpus_cstate_state[MAX_CPUS];
 static u64 cpus_pstate_start_times[MAX_CPUS];
 static u64 cpus_pstate_state[MAX_CPUS];
 
-static int process_comm_event(struct perf_tool *tool __used,
+static int process_comm_event(struct perf_tool *tool __maybe_unused,
 			      union perf_event *event,
-			      struct perf_sample *sample __used,
-			      struct machine *machine __used)
+			      struct perf_sample *sample __maybe_unused,
+			      struct machine *machine __maybe_unused)
 {
 	pid_set_comm(event->comm.tid, event->comm.comm);
 	return 0;
 }
 
-static int process_fork_event(struct perf_tool *tool __used,
+static int process_fork_event(struct perf_tool *tool __maybe_unused,
 			      union perf_event *event,
-			      struct perf_sample *sample __used,
-			      struct machine *machine __used)
+			      struct perf_sample *sample __maybe_unused,
+			      struct machine *machine __maybe_unused)
 {
 	pid_fork(event->fork.pid, event->fork.ppid, event->fork.time);
 	return 0;
 }
 
-static int process_exit_event(struct perf_tool *tool __used,
+static int process_exit_event(struct perf_tool *tool __maybe_unused,
 			      union perf_event *event,
-			      struct perf_sample *sample __used,
-			      struct machine *machine __used)
+			      struct perf_sample *sample __maybe_unused,
+			      struct machine *machine __maybe_unused)
 {
 	pid_exit(event->fork.pid, event->fork.time);
 	return 0;
@@ -491,11 +491,11 @@ static void sched_switch(int cpu, u64 timestamp, struct trace_entry *te)
 }
 
 
-static int process_sample_event(struct perf_tool *tool __used,
-				union perf_event *event __used,
+static int process_sample_event(struct perf_tool *tool __maybe_unused,
+				union perf_event *event __maybe_unused,
 				struct perf_sample *sample,
 				struct perf_evsel *evsel,
-				struct machine *machine __used)
+				struct machine *machine __maybe_unused)
 {
 	struct trace_entry *te;
 
@@ -1081,7 +1081,8 @@ static int __cmd_record(int argc, const char **argv)
 }
 
 static int
-parse_process(const struct option *opt __used, const char *arg, int __used unset)
+parse_process(const struct option *opt __maybe_unused, const char *arg,
+	      int __maybe_unused unset)
 {
 	if (arg)
 		add_process_filter(arg);
@@ -1106,7 +1107,8 @@ static const struct option options[] = {
 };
 
 
-int cmd_timechart(int argc, const char **argv, const char *prefix __used)
+int cmd_timechart(int argc, const char **argv,
+		  const char *prefix __maybe_unused)
 {
 	argc = parse_options(argc, argv, options, timechart_usage,
 			PARSE_OPT_STOP_AT_NON_OPTION);