tracing/ftrace: replace none tracer by nop tracer
Replace "none" tracer by the recently created "nop" tracer.
Both are pretty similar except that nop accepts TRACE_PRINT
or TRACE_SPECIAL entries.
And as a consequence, changing the size of the ring buffer now
requires that tracing has already been disabled.
Signed-off-by: Frederic Weisbecker <fweisbec@gmail.com>
Cc: Steven Rostedt <rostedt@goodmis.org>
Cc: Steven Noonan <steven@uplinklabs.net>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
diff --git a/kernel/trace/trace.c b/kernel/trace/trace.c
index eee1fd9..f2ef72f 100644
--- a/kernel/trace/trace.c
+++ b/kernel/trace/trace.c
@@ -142,24 +142,6 @@
/* trace_flags holds iter_ctrl options */
unsigned long trace_flags = TRACE_ITER_PRINT_PARENT;
-static notrace void no_trace_init(struct trace_array *tr)
-{
- int cpu;
-
- ftrace_function_enabled = 0;
- if(tr->ctrl)
- for_each_online_cpu(cpu)
- tracing_reset(tr->data[cpu]);
- tracer_enabled = 0;
-}
-
-/* dummy trace to disable tracing */
-static struct tracer no_tracer __read_mostly = {
- .name = "none",
- .init = no_trace_init
-};
-
-
/**
* trace_wake_up - wake up tasks waiting for trace input
*
@@ -962,7 +944,7 @@
long disabled;
int cpu;
- if (tracing_disabled || current_trace == &no_tracer || !tr->ctrl)
+ if (tracing_disabled || !tr->ctrl)
return;
local_irq_save(flags);
@@ -2795,6 +2777,7 @@
unsigned long val;
char buf[64];
int i, ret;
+ struct trace_array *tr = filp->private_data;
if (cnt >= sizeof(buf))
return -EINVAL;
@@ -2814,9 +2797,9 @@
mutex_lock(&trace_types_lock);
- if (current_trace != &no_tracer) {
+ if (tr->ctrl) {
cnt = -EBUSY;
- pr_info("ftrace: set current_tracer to none"
+ pr_info("ftrace: please disable tracing"
" before modifying buffer size\n");
goto out;
}
@@ -2879,20 +2862,6 @@
return cnt;
}
-static int tracing_open_mark(struct inode *inode, struct file *filp)
-{
- int ret;
-
- ret = tracing_open_generic(inode, filp);
- if (ret)
- return ret;
-
- if (current_trace == &no_tracer)
- return -ENODEV;
-
- return 0;
-}
-
static int mark_printk(const char *fmt, ...)
{
int ret;
@@ -2911,7 +2880,7 @@
char *end;
struct trace_array *tr = &global_trace;
- if (current_trace == &no_tracer || !tr->ctrl || tracing_disabled)
+ if (!tr->ctrl || tracing_disabled)
return -EINVAL;
if (cnt > TRACE_BUF_SIZE)
@@ -2971,7 +2940,7 @@
};
static struct file_operations tracing_mark_fops = {
- .open = tracing_open_mark,
+ .open = tracing_open_generic,
.write = tracing_mark_write,
};
@@ -3123,7 +3092,7 @@
long disabled;
int cpu, len = 0, write, written = 0;
- if (current_trace == &no_tracer || !tr->ctrl || tracing_disabled)
+ if (!tr->ctrl || tracing_disabled)
return 0;
local_irq_save(flags);
@@ -3539,8 +3508,8 @@
trace_init_cmdlines();
- register_tracer(&no_tracer);
- current_trace = &no_tracer;
+ register_tracer(&nop_trace);
+ current_trace = &nop_trace;
/* All seems OK, enable tracing */
global_trace.ctrl = tracer_enabled;