[PATCH 5.14 087/151] tracing: Fix missing osnoise tracer on max_latency

Greg Kroah-Hartman
2021-10-18T13:56:49Z

From: Jackie Liu <liuyun01@kylinos.cn>

commit 424b650f35c77defbb3cbd6e5221d3697af42250 upstream.

The compiler warns when the data are actually unused:

kernel/trace/trace.c:1712:13: error: ‘trace_create_maxlat_file’ defined but not used [-Werror=unused-function]
1712 | static void trace_create_maxlat_file(struct trace_array *tr,
| ^~~~~~~~~~~~~~~~~~~~~~~~

[Why]
CONFIG_HWLAT_TRACER=n, CONFIG_TRACER_MAX_TRACE=n, CONFIG_OSNOISE_TRACER=y
gcc report warns.

[How]
Now trace_create_maxlat_file will only take effect when
CONFIG_HWLAT_TRACER=y or CONFIG_TRACER_MAX_TRACE=y. In fact, after
adding osnoise trace, it also needs to take effect.

Link: https://lore.kernel.org/all/c1d9e328-ad7c-920b-6c24-9e1598a6421c@infradead.org/
Link: https://lkml.kernel.org/r/20210922025122.3268022-1-liu.yun@linux.dev

Fixes: bce29ac9ce0b ("trace: Add osnoise tracer")
Cc: Daniel Bristot de Oliveira <bristot@redhat.com>
Suggested-by: Steven Rostedt <rostedt@goodmis.org>
Reviewed-by: Daniel Bristot de Oliveira <bristot@kernel.org>
Tested-by: Randy Dunlap <rdunlap@infradead.org> # build-tested
Signed-off-by: Jackie Liu <liuyun01@kylinos.cn>
Signed-off-by: Steven Rostedt (VMware) <rostedt@goodmis.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
---
kernel/trace/trace.c | 11 ++++-------
1 file changed, 4 insertions(+), 7 deletions(-)

--- a/kernel/trace/trace.c
+++ b/kernel/trace/trace.c
@@ -1744,16 +1744,15 @@ void latency_fsnotify(struct trace_array
irq_work_queue(&tr->fsnotify_irqwork);
}

-/*
- * (defined(CONFIG_TRACER_MAX_TRACE) || defined(CONFIG_HWLAT_TRACER)) && \
- * defined(CONFIG_FSNOTIFY)
- */
-#else
+#elif defined(CONFIG_TRACER_MAX_TRACE) || defined(CONFIG_HWLAT_TRACER) \
+ || defined(CONFIG_OSNOISE_TRACER)

#define trace_create_maxlat_file(tr, d_tracer) \
trace_create_file("tracing_max_latency", 0644, d_tracer, \
&tr->max_latency, &tracing_max_lat_fops)

+#else
+#define trace_create_maxlat_file(tr, d_tracer) do { } while (0)
#endif

#ifdef CONFIG_TRACER_MAX_TRACE
@@ -9457,9 +9456,7 @@ init_tracer_tracefs(struct trace_array *

create_trace_options_dir(tr);

-#if defined(CONFIG_TRACER_MAX_TRACE) || defined(CONFIG_HWLAT_TRACER)
trace_create_maxlat_file(tr, d_tracer);
-#endif

if (ftrace_create_function_files(tr, d_tracer))
MEM_FAIL(1, "Could not allocate function filter files");