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, 11 insertions, 10 deletions

diff --git a/tools/perf/util/probe-event.c b/tools/perf/util/probe-event.c
index e8c72de0f70c..4ce04c2281d3 100644
--- a/tools/perf/util/probe-event.c
+++ b/tools/perf/util/probe-event.c
@@ -41,7 +41,7 @@
 #include "symbol.h"
 #include "thread.h"
 #include "debugfs.h"
-#include "trace-event.h"        /* For __unused */
+#include "trace-event.h"        /* For __maybe_unused */
 #include "probe-event.h"
 #include "probe-finder.h"
 #include "session.h"
@@ -647,8 +647,8 @@ static int kprobe_convert_to_perf_probe(struct probe_trace_point *tp,
 }
 
 static int try_to_find_probe_trace_events(struct perf_probe_event *pev,
-                                struct probe_trace_event **tevs __unused,
-                                int max_tevs __unused, const char *target)
+                                struct probe_trace_event **tevs __maybe_unused,
+                                int max_tevs __maybe_unused, const char *target)
 {
         if (perf_probe_event_need_dwarf(pev)) {
                 pr_warning("Debuginfo-analysis is not supported.\n");
@@ -661,17 +661,18 @@ static int try_to_find_probe_trace_events(struct perf_probe_event *pev,
         return 0;
 }
 
-int show_line_range(struct line_range *lr __unused, const char *module __unused)
+int show_line_range(struct line_range *lr __maybe_unused,
+                    const char *module __maybe_unused)
 {
         pr_warning("Debuginfo-analysis is not supported.\n");
         return -ENOSYS;
 }
 
-int show_available_vars(struct perf_probe_event *pevs __unused,
-                        int npevs __unused, int max_vls __unused,
-                        const char *module __unused,
-                        struct strfilter *filter __unused,
-                        bool externs __unused)
+int show_available_vars(struct perf_probe_event *pevs __maybe_unused,
+                        int npevs __maybe_unused, int max_vls __maybe_unused,
+                        const char *module __maybe_unused,
+                        struct strfilter *filter __maybe_unused,
+                        bool externs __maybe_unused)
 {
         pr_warning("Debuginfo-analysis is not supported.\n");
         return -ENOSYS;
@@ -2183,7 +2184,7 @@ static struct strfilter *available_func_filter;
  * If a symbol corresponds to a function with global binding and
  * matches filter return 0. For all others return 1.
  */
-static int filter_available_functions(struct map *map __unused,
+static int filter_available_functions(struct map *map __maybe_unused,
                                       struct symbol *sym)
 {
         if (sym->binding == STB_GLOBAL &&