ftrace: add trace_function api for other tracers to use

A new check was added in the ftrace function that wont trace if the CPU
trace buffer is disabled.  Unfortunately, other tracers used ftrace() to
write to the buffer after they disabled it. The new disable check makes
these calls into a nop.

This patch changes the __ftrace that is called without the check into a
new api for the other tracers to use, called "trace_function". The other
tracers use this interface instead when the trace CPU buffer is already
disabled.

Signed-off-by: Steven Rostedt <srostedt@redhat.com>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>

1 files changed, 5 insertions, 5 deletions

diff --git a/kernel/trace/trace_irqsoff.c b/kernel/trace/trace_irqsoff.c
index d2a6e6f1ad2d..3269f4ff5172 100644
--- a/kernel/trace/trace_irqsoff.c
+++ b/kernel/trace/trace_irqsoff.c
@@ -95,7 +95,7 @@ irqsoff_tracer_call(unsigned long ip, unsigned long parent_ip)
         disabled = atomic_inc_return(&data->disabled);
 
         if (likely(disabled == 1))
-                ftrace(tr, data, ip, parent_ip, flags);
+                trace_function(tr, data, ip, parent_ip, flags);
 
         atomic_dec(&data->disabled);
 }
@@ -150,7 +150,7 @@ check_critical_timing(struct trace_array *tr,
         if (!report_latency(delta))
                 goto out_unlock;
 
-        ftrace(tr, data, CALLER_ADDR0, parent_ip, flags);
+        trace_function(tr, data, CALLER_ADDR0, parent_ip, flags);
 
         latency = nsecs_to_usecs(delta);
 
@@ -188,7 +188,7 @@ out:
         data->critical_sequence = max_sequence;
         data->preempt_timestamp = ftrace_now(cpu);
         tracing_reset(data);
-        ftrace(tr, data, CALLER_ADDR0, parent_ip, flags);
+        trace_function(tr, data, CALLER_ADDR0, parent_ip, flags);
 }
 
 static inline void notrace
@@ -221,7 +221,7 @@ start_critical_timing(unsigned long ip, unsigned long parent_ip)
 
         local_save_flags(flags);
 
-        ftrace(tr, data, ip, parent_ip, flags);
+        trace_function(tr, data, ip, parent_ip, flags);
 
         __get_cpu_var(tracing_cpu) = 1;
 
@@ -254,7 +254,7 @@ stop_critical_timing(unsigned long ip, unsigned long parent_ip)
 
         atomic_inc(&data->disabled);
         local_save_flags(flags);
-        ftrace(tr, data, ip, parent_ip, flags);
+        trace_function(tr, data, ip, parent_ip, flags);
         check_critical_timing(tr, data, parent_ip ? : ip, cpu);
         data->critical_start = 0;
         atomic_dec(&data->disabled);