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Subject[PATCH 1/5] tracing/ftrace: Types and naming corrections for sched tracer
This patch applies some corrections suggested by Steven Rostedt.

Change the type of shed_ref into int since it is used
into a Mutex, we don't need it anymore as an atomic
variable in the sched_switch tracer.
Also change the name of the register mutex.


Signed-off-by: Frederic Weisbecker <fweisbec@gmail.com>
Cc: Steven Rostedt <rostedt@goodmis.org>
---
kernel/trace/trace_sched_switch.c | 30 +++++++++++++-----------------
1 files changed, 13 insertions(+), 17 deletions(-)

diff --git a/kernel/trace/trace_sched_switch.c
b/kernel/trace/trace_sched_switch.c
index 9d7bdac..969953b 100644
--- a/kernel/trace/trace_sched_switch.c
+++ b/kernel/trace/trace_sched_switch.c
@@ -16,8 +16,8 @@

static struct trace_array *ctx_trace;
static int __read_mostly tracer_enabled;
-static atomic_t sched_ref;
-static DEFINE_MUTEX(tracepoint_mutex);
+static int sched_ref;
+static DEFINE_MUTEX(sched_register_mutex);

static void
probe_sched_switch(struct rq *__rq, struct task_struct *prev,
@@ -28,7 +28,7 @@ probe_sched_switch(struct rq *__rq, struct task_struct *prev,
int cpu;
int pc;

- if (!atomic_read(&sched_ref))
+ if (!sched_ref)
return;

tracing_record_cmdline(prev);
@@ -124,26 +124,22 @@ static void tracing_sched_unregister(void)

static void tracing_start_sched_switch(void)
{
- long ref;
-
- mutex_lock(&tracepoint_mutex);
- tracer_enabled = 1;
- ref = atomic_inc_return(&sched_ref);
- if (ref == 1)
+ mutex_lock(&sched_register_mutex);
+ if (!(sched_ref++)) {
+ tracer_enabled = 1;
tracing_sched_register();
- mutex_unlock(&tracepoint_mutex);
+ }
+ mutex_unlock(&sched_register_mutex);
}

static void tracing_stop_sched_switch(void)
{
- long ref;
-
- mutex_lock(&tracepoint_mutex);
- tracer_enabled = 0;
- ref = atomic_dec_and_test(&sched_ref);
- if (ref)
+ mutex_lock(&sched_register_mutex);
+ if (!(--sched_ref)) {
tracing_sched_unregister();
- mutex_unlock(&tracepoint_mutex);
+ tracer_enabled = 0;
+ }
+ mutex_unlock(&sched_register_mutex);
}

void tracing_start_cmdline_record(void)

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