tracing: Use flag buffer_disabled for irqsoff tracer

[~andy/linux] / kernel / trace / trace_irqsoff.c

diff --git a/kernel/trace/trace_irqsoff.c b/kernel/trace/trace_irqsoff.c
index 443b25b43b4f60f3b58102daab06c6150f01ad64..2aefbee93a6d574a0ea082632788a1d5c7791474 100644 (file)
--- a/kernel/trace/trace_irqsoff.c
+++ b/kernel/trace/trace_irqsoff.c
@@ -33,6 +33,7 @@ enum {
 static int trace_type __read_mostly;
 
 static int save_flags;
+static bool function_enabled;
 
 static void stop_irqsoff_tracer(struct trace_array *tr, int graph);
 static int start_irqsoff_tracer(struct trace_array *tr, int graph);
@@ -121,7 +122,7 @@ static int func_prolog_dec(struct trace_array *tr,
        if (!irqs_disabled_flags(*flags))
                return 0;
 
-       *data = tr->data[cpu];
+       *data = per_cpu_ptr(tr->trace_buffer.data, cpu);
        disabled = atomic_inc_return(&(*data)->disabled);
 
        if (likely(disabled == 1))
@@ -175,7 +176,7 @@ static int irqsoff_set_flag(u32 old_flags, u32 bit, int set)
                per_cpu(tracing_cpu, cpu) = 0;
 
        tracing_max_latency = 0;
-       tracing_reset_online_cpus(irqsoff_trace);
+       tracing_reset_online_cpus(&irqsoff_trace->trace_buffer);
 
        return start_irqsoff_tracer(irqsoff_trace, set);
 }
@@ -372,7 +373,7 @@ start_critical_timing(unsigned long ip, unsigned long parent_ip)
        struct trace_array_cpu *data;
        unsigned long flags;
 
-       if (likely(!tracer_enabled))
+       if (!tracer_enabled || !tracing_is_enabled())
                return;
 
        cpu = raw_smp_processor_id();
@@ -380,7 +381,7 @@ start_critical_timing(unsigned long ip, unsigned long parent_ip)
        if (per_cpu(tracing_cpu, cpu))
                return;
 
-       data = tr->data[cpu];
+       data = per_cpu_ptr(tr->trace_buffer.data, cpu);
 
        if (unlikely(!data) || atomic_read(&data->disabled))
                return;
@@ -415,10 +416,10 @@ stop_critical_timing(unsigned long ip, unsigned long parent_ip)
        else
                return;
 
-       if (!tracer_enabled)
+       if (!tracer_enabled || !tracing_is_enabled())
                return;
 
-       data = tr->data[cpu];
+       data = per_cpu_ptr(tr->trace_buffer.data, cpu);
 
        if (unlikely(!data) ||
            !data->critical_start || atomic_read(&data->disabled))
@@ -528,15 +529,60 @@ void trace_preempt_off(unsigned long a0, unsigned long a1)
 }
 #endif /* CONFIG_PREEMPT_TRACER */
 
-static int start_irqsoff_tracer(struct trace_array *tr, int graph)
+static int register_irqsoff_function(int graph, int set)
 {
-       int ret = 0;
+       int ret;
 
-       if (!graph)
-               ret = register_ftrace_function(&trace_ops);
-       else
+       /* 'set' is set if TRACE_ITER_FUNCTION is about to be set */
+       if (function_enabled || (!set && !(trace_flags & TRACE_ITER_FUNCTION)))
+               return 0;
+
+       if (graph)
                ret = register_ftrace_graph(&irqsoff_graph_return,
                                            &irqsoff_graph_entry);
+       else
+               ret = register_ftrace_function(&trace_ops);
+
+       if (!ret)
+               function_enabled = true;
+
+       return ret;
+}
+
+static void unregister_irqsoff_function(int graph)
+{
+       if (!function_enabled)
+               return;
+
+       if (graph)
+               unregister_ftrace_graph();
+       else
+               unregister_ftrace_function(&trace_ops);
+
+       function_enabled = false;
+}
+
+static void irqsoff_function_set(int set)
+{
+       if (set)
+               register_irqsoff_function(is_graph(), 1);
+       else
+               unregister_irqsoff_function(is_graph());
+}
+
+static int irqsoff_flag_changed(struct tracer *tracer, u32 mask, int set)
+{
+       if (mask & TRACE_ITER_FUNCTION)
+               irqsoff_function_set(set);
+
+       return trace_keep_overwrite(tracer, mask, set);
+}
+
+static int start_irqsoff_tracer(struct trace_array *tr, int graph)
+{
+       int ret;
+
+       ret = register_irqsoff_function(graph, 0);
 
        if (!ret && tracing_is_enabled())
                tracer_enabled = 1;
@@ -550,10 +596,7 @@ static void stop_irqsoff_tracer(struct trace_array *tr, int graph)
 {
        tracer_enabled = 0;
 
-       if (!graph)
-               unregister_ftrace_function(&trace_ops);
-       else
-               unregister_ftrace_graph();
+       unregister_irqsoff_function(graph);
 }
 
 static void __irqsoff_tracer_init(struct trace_array *tr)
@@ -561,14 +604,14 @@ static void __irqsoff_tracer_init(struct trace_array *tr)
        save_flags = trace_flags;
 
        /* non overwrite screws up the latency tracers */
-       set_tracer_flag(TRACE_ITER_OVERWRITE, 1);
-       set_tracer_flag(TRACE_ITER_LATENCY_FMT, 1);
+       set_tracer_flag(tr, TRACE_ITER_OVERWRITE, 1);
+       set_tracer_flag(tr, TRACE_ITER_LATENCY_FMT, 1);
 
        tracing_max_latency = 0;
        irqsoff_trace = tr;
        /* make sure that the tracer is visible */
        smp_wmb();
-       tracing_reset_online_cpus(tr);
+       tracing_reset_online_cpus(&tr->trace_buffer);
 
        if (start_irqsoff_tracer(tr, is_graph()))
                printk(KERN_ERR "failed to start irqsoff tracer\n");
@@ -581,8 +624,8 @@ static void irqsoff_tracer_reset(struct trace_array *tr)
 
        stop_irqsoff_tracer(tr, is_graph());
 
-       set_tracer_flag(TRACE_ITER_LATENCY_FMT, lat_flag);
-       set_tracer_flag(TRACE_ITER_OVERWRITE, overwrite_flag);
+       set_tracer_flag(tr, TRACE_ITER_LATENCY_FMT, lat_flag);
+       set_tracer_flag(tr, TRACE_ITER_OVERWRITE, overwrite_flag);
 }
 
 static void irqsoff_tracer_start(struct trace_array *tr)
@@ -615,7 +658,7 @@ static struct tracer irqsoff_tracer __read_mostly =
        .print_line     = irqsoff_print_line,
        .flags          = &tracer_flags,
        .set_flag       = irqsoff_set_flag,
-       .flag_changed   = trace_keep_overwrite,
+       .flag_changed   = irqsoff_flag_changed,
 #ifdef CONFIG_FTRACE_SELFTEST
        .selftest    = trace_selftest_startup_irqsoff,
 #endif
@@ -649,7 +692,7 @@ static struct tracer preemptoff_tracer __read_mostly =
        .print_line     = irqsoff_print_line,
        .flags          = &tracer_flags,
        .set_flag       = irqsoff_set_flag,
-       .flag_changed   = trace_keep_overwrite,
+       .flag_changed   = irqsoff_flag_changed,
 #ifdef CONFIG_FTRACE_SELFTEST
        .selftest    = trace_selftest_startup_preemptoff,
 #endif
@@ -685,7 +728,7 @@ static struct tracer preemptirqsoff_tracer __read_mostly =
        .print_line     = irqsoff_print_line,
        .flags          = &tracer_flags,
        .set_flag       = irqsoff_set_flag,
-       .flag_changed   = trace_keep_overwrite,
+       .flag_changed   = irqsoff_flag_changed,
 #ifdef CONFIG_FTRACE_SELFTEST
        .selftest    = trace_selftest_startup_preemptirqsoff,
 #endif