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, 5 insertions, 5 deletions

diff --git a/tools/perf/builtin-record.c b/tools/perf/builtin-record.c
index 7b8b891d4d56..c643ed669ef9 100644
--- a/tools/perf/builtin-record.c
+++ b/tools/perf/builtin-record.c
@@ -92,8 +92,8 @@ static int write_output(struct perf_record *rec, void *buf, size_t size)
 
 static int process_synthesized_event(struct perf_tool *tool,
                                      union perf_event *event,
-                                     struct perf_sample *sample __used,
-                                     struct machine *machine __used)
+                                     struct perf_sample *sample __maybe_unused,
+                                     struct machine *machine __maybe_unused)
 {
         struct perf_record *rec = container_of(tool, struct perf_record, tool);
         if (write_output(rec, event, event->header.size) < 0)
@@ -159,7 +159,7 @@ static void sig_handler(int sig)
         signr = sig;
 }
 
-static void perf_record__sig_exit(int exit_status __used, void *arg)
+static void perf_record__sig_exit(int exit_status __maybe_unused, void *arg)
 {
         struct perf_record *rec = arg;
         int status;
@@ -827,7 +827,7 @@ static int get_stack_size(char *str, unsigned long *_size)
 #endif /* !NO_LIBUNWIND_SUPPORT */
 
 static int
-parse_callchain_opt(const struct option *opt __used, const char *arg,
+parse_callchain_opt(const struct option *opt __maybe_unused, const char *arg,
                     int unset)
 {
         struct perf_record *rec = (struct perf_record *)opt->value;
@@ -1003,7 +1003,7 @@ const struct option record_options[] = {
         OPT_END()
 };
 
-int cmd_record(int argc, const char **argv, const char *prefix __used)
+int cmd_record(int argc, const char **argv, const char *prefix __maybe_unused)
 {
         int err = -ENOMEM;
         struct perf_evsel *pos;