1 files changed, 50 insertions, 52 deletions

diff --git a/kernel/trace/trace_sched_wakeup.c b/kernel/trace/trace_sched_wakeup.c
index 033510dbb322..31689d2df7f3 100644
--- a/kernel/trace/trace_sched_wakeup.c
+++ b/kernel/trace/trace_sched_wakeup.c
@@ -56,43 +56,73 @@ static struct tracer_flags tracer_flags = {
 #define is_graph() (tracer_flags.val & TRACE_DISPLAY_GRAPH)
 
 #ifdef CONFIG_FUNCTION_TRACER
+
 /*
- * wakeup uses its own tracer function to keep the overhead down:
+ * Prologue for the wakeup function tracers.
+ *
+ * Returns 1 if it is OK to continue, and preemption
+ *            is disabled and data->disabled is incremented.
+ *         0 if the trace is to be ignored, and preemption
+ *            is not disabled and data->disabled is
+ *            kept the same.
+ *
+ * Note, this function is also used outside this ifdef but
+ *  inside the #ifdef of the function graph tracer below.
+ *  This is OK, since the function graph tracer is
+ *  dependent on the function tracer.
  */
-static void
-wakeup_tracer_call(unsigned long ip, unsigned long parent_ip)
+static int
+func_prolog_preempt_disable(struct trace_array *tr,
+                            struct trace_array_cpu **data,
+                            int *pc)
 {
-        struct trace_array *tr = wakeup_trace;
-        struct trace_array_cpu *data;
-        unsigned long flags;
         long disabled;
         int cpu;
-        int pc;
 
         if (likely(!wakeup_task))
-                return;
+                return 0;
 
-        pc = preempt_count();
+        *pc = preempt_count();
         preempt_disable_notrace();
 
         cpu = raw_smp_processor_id();
         if (cpu != wakeup_current_cpu)
                 goto out_enable;
 
-        data = tr->data[cpu];
-        disabled = atomic_inc_return(&data->disabled);
+        *data = tr->data[cpu];
+        disabled = atomic_inc_return(&(*data)->disabled);
         if (unlikely(disabled != 1))
                 goto out;
 
-        local_irq_save(flags);
+        return 1;
 
-        trace_function(tr, ip, parent_ip, flags, pc);
+out:
+        atomic_dec(&(*data)->disabled);
+
+out_enable:
+        preempt_enable_notrace();
+        return 0;
+}
+
+/*
+ * wakeup uses its own tracer function to keep the overhead down:
+ */
+static void
+wakeup_tracer_call(unsigned long ip, unsigned long parent_ip)
+{
+        struct trace_array *tr = wakeup_trace;
+        struct trace_array_cpu *data;
+        unsigned long flags;
+        int pc;
+
+        if (!func_prolog_preempt_disable(tr, &data, &pc))
+                return;
 
+        local_irq_save(flags);
+        trace_function(tr, ip, parent_ip, flags, pc);
         local_irq_restore(flags);
 
- out:
         atomic_dec(&data->disabled);
- out_enable:
         preempt_enable_notrace();
 }
 
@@ -154,32 +184,16 @@ static int wakeup_graph_entry(struct ftrace_graph_ent *trace)
         struct trace_array *tr = wakeup_trace;
         struct trace_array_cpu *data;
         unsigned long flags;
-        long disabled;
-        int cpu, pc, ret = 0;
+        int pc, ret = 0;
 
-        if (likely(!wakeup_task))
+        if (!func_prolog_preempt_disable(tr, &data, &pc))
                 return 0;
 
-        pc = preempt_count();
-        preempt_disable_notrace();
-
-        cpu = raw_smp_processor_id();
-        if (cpu != wakeup_current_cpu)
-                goto out_enable;
-
-        data = tr->data[cpu];
-        disabled = atomic_inc_return(&data->disabled);
-        if (unlikely(disabled != 1))
-                goto out;
-
         local_save_flags(flags);
         ret = __trace_graph_entry(tr, trace, flags, pc);
-
-out:
         atomic_dec(&data->disabled);
-
-out_enable:
         preempt_enable_notrace();
+
         return ret;
 }
 
@@ -188,31 +202,15 @@ static void wakeup_graph_return(struct ftrace_graph_ret *trace)
         struct trace_array *tr = wakeup_trace;
         struct trace_array_cpu *data;
         unsigned long flags;
-        long disabled;
-        int cpu, pc;
+        int pc;
 
-        if (likely(!wakeup_task))
+        if (!func_prolog_preempt_disable(tr, &data, &pc))
                 return;
 
-        pc = preempt_count();
-        preempt_disable_notrace();
-
-        cpu = raw_smp_processor_id();
-        if (cpu != wakeup_current_cpu)
-                goto out_enable;
-
-        data = tr->data[cpu];
-        disabled = atomic_inc_return(&data->disabled);
-        if (unlikely(disabled != 1))
-                goto out;
-
         local_save_flags(flags);
         __trace_graph_return(tr, trace, flags, pc);
-
-out:
         atomic_dec(&data->disabled);
 
-out_enable:
         preempt_enable_notrace();
         return;
 }