From: Jackie Liu <liuyun01@xxxxxxxxxx> 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@xxxxxxxxxxxxx/ Link: https://lkml.kernel.org/r/20210922025122.3268022-1-liu.yun@xxxxxxxxx Fixes: bce29ac9ce0b ("trace: Add osnoise tracer") Cc: Daniel Bristot de Oliveira <bristot@xxxxxxxxxx> Suggested-by: Steven Rostedt <rostedt@xxxxxxxxxxx> Reviewed-by: Daniel Bristot de Oliveira <bristot@xxxxxxxxxx> Tested-by: Randy Dunlap <rdunlap@xxxxxxxxxxxxx> # build-tested Signed-off-by: Jackie Liu <liuyun01@xxxxxxxxxx> Signed-off-by: Steven Rostedt (VMware) <rostedt@xxxxxxxxxxx> Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx> --- 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");