ftrace: remove trace array ctrl

Impact: remove obsolete variable in trace_array structure

With the new start / stop method of ftrace, the ctrl variable
in the trace_array structure is now obsolete. Remove it.

Signed-off-by: Steven Rostedt <srostedt@redhat.com>
Signed-off-by: Ingo Molnar <mingo@elte.hu>

10 files changed, 24 insertions, 59 deletions

diff --git a/kernel/trace/trace.c b/kernel/trace/trace.c
index 9e83188172a1..58435415b366 100644
--- a/kernel/trace/trace.c
+++ b/kernel/trace/trace.c
@@ -537,7 +537,6 @@ int register_tracer(struct tracer *type)
         if (type->selftest) {
                 struct tracer *saved_tracer = current_trace;
                 struct trace_array *tr = &global_trace;
-                int saved_ctrl = tr->ctrl;
                 int i;
                 /*
                  * Run a selftest on this tracer.
@@ -550,13 +549,11 @@ int register_tracer(struct tracer *type)
                         tracing_reset(tr, i);
                 }
                 current_trace = type;
-                tr->ctrl = 0;
                 /* the test is responsible for initializing and enabling */
                 pr_info("Testing tracer %s: ", type->name);
                 ret = type->selftest(type, tr);
                 /* the test is responsible for resetting too */
                 current_trace = saved_tracer;
-                tr->ctrl = saved_ctrl;
                 if (ret) {
                         printk(KERN_CONT "FAILED!\n");
                         goto out;
@@ -966,7 +963,7 @@ ftrace_special(unsigned long arg1, unsigned long arg2, unsigned long arg3)
         int cpu;
         int pc;
 
-        if (tracing_disabled || !tr->ctrl)
+        if (tracing_disabled)
                 return;
 
         pc = preempt_count();
@@ -2820,7 +2817,6 @@ tracing_entries_write(struct file *filp, const char __user *ubuf,
         unsigned long val;
         char buf[64];
         int ret;
-        struct trace_array *tr = filp->private_data;
 
         if (cnt >= sizeof(buf))
                 return -EINVAL;
@@ -2840,12 +2836,7 @@ tracing_entries_write(struct file *filp, const char __user *ubuf,
 
         mutex_lock(&trace_types_lock);
 
-        if (tr->ctrl) {
-                cnt = -EBUSY;
-                pr_info("ftrace: please disable tracing"
-                        " before modifying buffer size\n");
-                goto out;
-        }
+        tracing_stop();
 
         if (val != global_trace.entries) {
                 ret = ring_buffer_resize(global_trace.buffer, val);
@@ -2878,6 +2869,7 @@ tracing_entries_write(struct file *filp, const char __user *ubuf,
         if (tracing_disabled)
                 cnt = -ENOMEM;
  out:
+        tracing_start();
         max_tr.entries = global_trace.entries;
         mutex_unlock(&trace_types_lock);
 
@@ -2900,9 +2892,8 @@ tracing_mark_write(struct file *filp, const char __user *ubuf,
 {
         char *buf;
         char *end;
-        struct trace_array *tr = &global_trace;
 
-        if (!tr->ctrl || tracing_disabled)
+        if (tracing_disabled)
                 return -EINVAL;
 
         if (cnt > TRACE_BUF_SIZE)
@@ -3131,7 +3122,7 @@ int trace_vprintk(unsigned long ip, const char *fmt, va_list args)
         unsigned long flags, irq_flags;
         int cpu, len = 0, size, pc;
 
-        if (!tr->ctrl || tracing_disabled)
+        if (tracing_disabled)
                 return 0;
 
         pc = preempt_count();
@@ -3365,7 +3356,6 @@ __init static int tracer_alloc_buffers(void)
 #endif
 
         /* All seems OK, enable tracing */
-        global_trace.ctrl = 1;
         tracing_disabled = 0;
 
         atomic_notifier_chain_register(&panic_notifier_list,
diff --git a/kernel/trace/trace.h b/kernel/trace/trace.h
index e481edaae1c4..cfda9d219e66 100644
--- a/kernel/trace/trace.h
+++ b/kernel/trace/trace.h
@@ -172,7 +172,6 @@ struct trace_iterator;
 struct trace_array {
         struct ring_buffer      *buffer;
         unsigned long           entries;
-        long                    ctrl;
         int                     cpu;
         cycle_t                 time_start;
         struct task_struct      *waiter;
diff --git a/kernel/trace/trace_functions.c b/kernel/trace/trace_functions.c
index e980b872bef5..8693b7a0a5b2 100644
--- a/kernel/trace/trace_functions.c
+++ b/kernel/trace/trace_functions.c
@@ -44,14 +44,12 @@ static void stop_function_trace(struct trace_array *tr)
 
 static void function_trace_init(struct trace_array *tr)
 {
-        if (tr->ctrl)
-                start_function_trace(tr);
+        start_function_trace(tr);
 }
 
 static void function_trace_reset(struct trace_array *tr)
 {
-        if (tr->ctrl)
-                stop_function_trace(tr);
+        stop_function_trace(tr);
 }
 
 static void function_trace_start(struct trace_array *tr)
diff --git a/kernel/trace/trace_irqsoff.c b/kernel/trace/trace_irqsoff.c
index ffdf592a54e3..d919d4eaa7cc 100644
--- a/kernel/trace/trace_irqsoff.c
+++ b/kernel/trace/trace_irqsoff.c
@@ -383,15 +383,12 @@ static void __irqsoff_tracer_init(struct trace_array *tr)
         irqsoff_trace = tr;
         /* make sure that the tracer is visible */
         smp_wmb();
-
-        if (tr->ctrl)
-                start_irqsoff_tracer(tr);
+        start_irqsoff_tracer(tr);
 }
 
 static void irqsoff_tracer_reset(struct trace_array *tr)
 {
-        if (tr->ctrl)
-                stop_irqsoff_tracer(tr);
+        stop_irqsoff_tracer(tr);
 }
 
 static void irqsoff_tracer_start(struct trace_array *tr)
diff --git a/kernel/trace/trace_mmiotrace.c b/kernel/trace/trace_mmiotrace.c
index fa9354e78b57..51bcf370215e 100644
--- a/kernel/trace/trace_mmiotrace.c
+++ b/kernel/trace/trace_mmiotrace.c
@@ -34,17 +34,16 @@ static void mmio_trace_init(struct trace_array *tr)
 {
         pr_debug("in %s\n", __func__);
         mmio_trace_array = tr;
-        if (tr->ctrl) {
-                mmio_reset_data(tr);
-                enable_mmiotrace();
-        }
+
+        mmio_reset_data(tr);
+        enable_mmiotrace();
 }
 
 static void mmio_trace_reset(struct trace_array *tr)
 {
         pr_debug("in %s\n", __func__);
-        if (tr->ctrl)
-                disable_mmiotrace();
+
+        disable_mmiotrace();
         mmio_reset_data(tr);
         mmio_trace_array = NULL;
 }
diff --git a/kernel/trace/trace_nop.c b/kernel/trace/trace_nop.c
index e3c5fbfcdd36..2ef1d227e7d8 100644
--- a/kernel/trace/trace_nop.c
+++ b/kernel/trace/trace_nop.c
@@ -32,14 +32,12 @@ static void nop_trace_init(struct trace_array *tr)
         for_each_online_cpu(cpu)
                 tracing_reset(tr, cpu);
 
-        if (tr->ctrl)
-                start_nop_trace(tr);
+        start_nop_trace(tr);
 }
 
 static void nop_trace_reset(struct trace_array *tr)
 {
-        if (tr->ctrl)
-                stop_nop_trace(tr);
+        stop_nop_trace(tr);
 }
 
 struct tracer nop_trace __read_mostly =
diff --git a/kernel/trace/trace_sched_switch.c b/kernel/trace/trace_sched_switch.c
index 7b73fd11e4aa..be35bdfe2e38 100644
--- a/kernel/trace/trace_sched_switch.c
+++ b/kernel/trace/trace_sched_switch.c
@@ -209,14 +209,12 @@ static void stop_sched_trace(struct trace_array *tr)
 static void sched_switch_trace_init(struct trace_array *tr)
 {
         ctx_trace = tr;
-
-        if (tr->ctrl)
-                start_sched_trace(tr);
+        start_sched_trace(tr);
 }
 
 static void sched_switch_trace_reset(struct trace_array *tr)
 {
-        if (tr->ctrl && sched_ref)
+        if (sched_ref)
                 stop_sched_trace(tr);
 }
 
diff --git a/kernel/trace/trace_sched_wakeup.c b/kernel/trace/trace_sched_wakeup.c
index 23e54d4e4d92..983f2b1478c9 100644
--- a/kernel/trace/trace_sched_wakeup.c
+++ b/kernel/trace/trace_sched_wakeup.c
@@ -334,18 +334,14 @@ static void stop_wakeup_tracer(struct trace_array *tr)
 static void wakeup_tracer_init(struct trace_array *tr)
 {
         wakeup_trace = tr;
-
-        if (tr->ctrl)
-                start_wakeup_tracer(tr);
+        start_wakeup_tracer(tr);
 }
 
 static void wakeup_tracer_reset(struct trace_array *tr)
 {
-        if (tr->ctrl) {
-                stop_wakeup_tracer(tr);
-                /* make sure we put back any tasks we are tracing */
-                wakeup_reset(tr);
-        }
+        stop_wakeup_tracer(tr);
+        /* make sure we put back any tasks we are tracing */
+        wakeup_reset(tr);
 }
 
 static void wakeup_tracer_start(struct trace_array *tr)
diff --git a/kernel/trace/trace_selftest.c b/kernel/trace/trace_selftest.c
index 746934340474..ea4e5d3b15df 100644
--- a/kernel/trace/trace_selftest.c
+++ b/kernel/trace/trace_selftest.c
@@ -110,7 +110,6 @@ int trace_selftest_startup_dynamic_tracing(struct tracer *trace,
         ftrace_set_filter(func_name, strlen(func_name), 1);
 
         /* enable tracing */
-        tr->ctrl = 1;
         trace->init(tr);
 
         /* Sleep for a 1/10 of a second */
@@ -181,7 +180,6 @@ trace_selftest_startup_function(struct tracer *trace, struct trace_array *tr)
         ftrace_enabled = 1;
         tracer_enabled = 1;
 
-        tr->ctrl = 1;
         trace->init(tr);
         /* Sleep for a 1/10 of a second */
         msleep(100);
@@ -224,7 +222,6 @@ trace_selftest_startup_irqsoff(struct tracer *trace, struct trace_array *tr)
         int ret;
 
         /* start the tracing */
-        tr->ctrl = 1;
         trace->init(tr);
         /* reset the max latency */
         tracing_max_latency = 0;
@@ -261,7 +258,6 @@ trace_selftest_startup_preemptoff(struct tracer *trace, struct trace_array *tr)
         int ret;
 
         /* start the tracing */
-        tr->ctrl = 1;
         trace->init(tr);
         /* reset the max latency */
         tracing_max_latency = 0;
@@ -298,7 +294,6 @@ trace_selftest_startup_preemptirqsoff(struct tracer *trace, struct trace_array *
         int ret;
 
         /* start the tracing */
-        tr->ctrl = 1;
         trace->init(tr);
 
         /* reset the max latency */
@@ -427,7 +422,6 @@ trace_selftest_startup_wakeup(struct tracer *trace, struct trace_array *tr)
         wait_for_completion(&isrt);
 
         /* start the tracing */
-        tr->ctrl = 1;
         trace->init(tr);
         /* reset the max latency */
         tracing_max_latency = 0;
@@ -484,7 +478,6 @@ trace_selftest_startup_sched_switch(struct tracer *trace, struct trace_array *tr
         int ret;
 
         /* start the tracing */
-        tr->ctrl = 1;
         trace->init(tr);
         /* Sleep for a 1/10 of a second */
         msleep(100);
@@ -512,7 +505,6 @@ trace_selftest_startup_sysprof(struct tracer *trace, struct trace_array *tr)
         int ret;
 
         /* start the tracing */
-        tr->ctrl = 1;
         trace->init(tr);
         /* Sleep for a 1/10 of a second */
         msleep(100);
diff --git a/kernel/trace/trace_sysprof.c b/kernel/trace/trace_sysprof.c
index 8097430edff9..05f753422aea 100644
--- a/kernel/trace/trace_sysprof.c
+++ b/kernel/trace/trace_sysprof.c
@@ -265,14 +265,12 @@ static void stack_trace_init(struct trace_array *tr)
 {
         sysprof_trace = tr;
 
-        if (tr->ctrl)
-                start_stack_trace(tr);
+        start_stack_trace(tr);
 }
 
 static void stack_trace_reset(struct trace_array *tr)
 {
-        if (tr->ctrl)
-                stop_stack_trace(tr);
+        stop_stack_trace(tr);
 }
 
 static struct tracer stack_trace __read_mostly =