From: Steven Rostedt <[email protected]>
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.
Signed-off-by: Steven Rostedt (Google) <[email protected]>
---
Changes since v2: https://patch.msgid.link/20260206230410.4ed96e9f@robin
- On further inspection, tracing_max_latency should always be created if
CONFIG_TRACER_MAX_TRACE is defined regardless if CONFIG_FS_NOTIFY is.
kernel/trace/trace.c | 38 ++++++++++++++++----------------------
1 file changed, 16 insertions(+), 22 deletions(-)
diff --git a/kernel/trace/trace.c b/kernel/trace/trace.c
index 702ef851db45..d02c4004c718 100644
--- a/kernel/trace/trace.c
+++ b/kernel/trace/trace.c
@@ -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");
--
2.51.0
