[PATCH] tracing: fix missing osnoise tracer on max_latency

From: Jackie Liu
Date: Sat Sep 18 2021 - 01:11:41 EST


From: Jackie Liu <liuyun01@xxxxxxxxxx>

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.

BTW, Fixed the conflicting defined comment information.

Fixes: bce29ac9ce0b ("trace: Add osnoise tracer")
Cc: Daniel Bristot de Oliveira <bristot@xxxxxxxxxx>
Signed-off-by: Jackie Liu <liuyun01@xxxxxxxxxx>
---
kernel/trace/trace.c | 9 +++------
1 file changed, 3 insertions(+), 6 deletions(-)

diff --git a/kernel/trace/trace.c b/kernel/trace/trace.c
index 7896d30d90f7..d7e3ed82fafd 100644
--- a/kernel/trace/trace.c
+++ b/kernel/trace/trace.c
@@ -1744,11 +1744,7 @@ void latency_fsnotify(struct trace_array *tr)
irq_work_queue(&tr->fsnotify_irqwork);
}

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

#define trace_create_maxlat_file(tr, d_tracer) \
trace_create_file("tracing_max_latency", 0644, d_tracer, \
@@ -9473,7 +9469,8 @@ init_tracer_tracefs(struct trace_array *tr, struct dentry *d_tracer)

create_trace_options_dir(tr);

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

--
2.25.1