Commit ba73713d authored by Steven Rostedt's avatar Steven Rostedt Committed by Steven Rostedt (Google)
Browse files

tracing: Clean up use of trace_create_maxlat_file() 



In trace.c, the function trace_create_maxlat_file() is defined behind the
 #ifdef CONFIG_TRACER_MAX_TRACE block. The #else part defines it as:

 #define trace_create_maxlat_file(tr, d_tracer)				\
	trace_create_file("tracing_max_latency", TRACE_MODE_WRITE,	\
			  d_tracer, tr, &tracing_max_lat_fops)

But the one place that it it used has:

 #ifdef CONFIG_TRACER_MAX_TRACE
	trace_create_maxlat_file(tr, d_tracer);
 #endif

Which is pointless and also wrong!

It only gets created when both CONFIG_TRACE_MAX_TRACE and CONFIG_FS_NOTIFY
is defined, but the file itself should not be dependent on
CONFIG_FS_NOTIFY. Always create that file when TRACE_MAX_TRACE is defined
regardless if FS_NOTIFY is or is not.

Cc: Mathieu Desnoyers <mathieu.desnoyers@efficios.com>
Acked-by: default avatarMasami Hiramatsu (Google) <mhiramat@kernel.org>
Link: https://patch.msgid.link/20260207191101.0e014abd@robin


Signed-off-by: default avatarSteven Rostedt (Google) <rostedt@goodmis.org>
parent 326669fa

kernel/trace/trace.c

+16 −22
Original line number Diff line number Diff line
@@ -1912,10 +1912,7 @@ static ssize_t trace_seq_to_buffer(struct trace_seq *s, void *buf, size_t cnt) 
unsigned long __read_mostly	tracing_thresh;



#ifdef CONFIG_TRACER_MAX_TRACE

static const struct file_operations tracing_max_lat_fops;



#ifdef LATENCY_FS_NOTIFY



static struct workqueue_struct *fsnotify_wq;



static void latency_fsnotify_workfn(struct work_struct *work)
@@ -1932,17 +1929,6 @@ static void latency_fsnotify_workfn_irq(struct irq_work *iwork) 
	queue_work(fsnotify_wq, &tr->fsnotify_work);

}



static void trace_create_maxlat_file(struct trace_array *tr,

				     struct dentry *d_tracer)

{

	INIT_WORK(&tr->fsnotify_work, latency_fsnotify_workfn);

	init_irq_work(&tr->fsnotify_irqwork, latency_fsnotify_workfn_irq);

	tr->d_max_latency = trace_create_file("tracing_max_latency",

					      TRACE_MODE_WRITE,

					      d_tracer, tr,

					      &tracing_max_lat_fops);

}



__init static int latency_fsnotify_init(void)

{

	fsnotify_wq = alloc_workqueue("tr_max_lat_wq",
@@ -1967,14 +1953,22 @@ void latency_fsnotify(struct trace_array *tr) 
	 */

	irq_work_queue(&tr->fsnotify_irqwork);

}

#endif /* !LATENCY_FS_NOTIFY */



#else /* !LATENCY_FS_NOTIFY */



#define trace_create_maxlat_file(tr, d_tracer)				\

	trace_create_file("tracing_max_latency", TRACE_MODE_WRITE,	\

			  d_tracer, tr, &tracing_max_lat_fops)

static const struct file_operations tracing_max_lat_fops;



static void trace_create_maxlat_file(struct trace_array *tr,

				     struct dentry *d_tracer)

{

#ifdef LATENCY_FS_NOTIFY

	INIT_WORK(&tr->fsnotify_work, latency_fsnotify_workfn);

	init_irq_work(&tr->fsnotify_irqwork, latency_fsnotify_workfn_irq);

#endif

	tr->d_max_latency = trace_create_file("tracing_max_latency",

					      TRACE_MODE_WRITE,

					      d_tracer, tr,

					      &tracing_max_lat_fops);

}



/*

 * Copy the new maximum trace into the separate maximum-trace
@@ -2109,7 +2103,9 @@ update_max_tr_single(struct trace_array *tr, struct task_struct *tsk, int cpu) 
	__update_max_tr(tr, tsk, cpu);

	arch_spin_unlock(&tr->max_lock);

}



#else /* !CONFIG_TRACER_MAX_TRACE */

static inline void trace_create_maxlat_file(struct trace_array *tr,

					    struct dentry *d_tracer) { }

#endif /* CONFIG_TRACER_MAX_TRACE */



struct pipe_wait {
@@ -10664,9 +10660,7 @@ init_tracer_tracefs(struct trace_array *tr, struct dentry *d_tracer) 


	create_trace_options_dir(tr);



#ifdef CONFIG_TRACER_MAX_TRACE

	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");