tracing: Move a printk out of ftrace_raw_reg_event_foo()

Move the printk from each ftrace_raw_reg_event_foo() to
its caller ftrace_event_enable_disable(). This avoids each
regfunc trace event callbacks to handle a same error report
that can be carried from the caller.

See how much space this saves:

   text    data     bss     dec     hex filename
5345151 1961864 7103260 14410275         dbe223 vmlinux.o.old
5331487 1961864 7103260 14396611         dbacc3 vmlinux.o

Signed-off-by: Li Zefan <lizf@cn.fujitsu.com>
Acked-by: Steven Rostedt <rostedt@goodmis.org>
Cc: Jason Baron <jbaron@redhat.com>
LKML-Reference: <4B1DC4AC.802@cn.fujitsu.com>
[start cmdline record before calling regfunc to avoid lost
window of pid to comm resolution]
Signed-off-by: Frederic Weisbecker <fweisbec@gmail.com>

1 files changed, 15 insertions, 5 deletions

diff --git a/kernel/trace/trace_events.c b/kernel/trace/trace_events.c
index 97b0b3aa166d..189b09baf4fb 100644
--- a/kernel/trace/trace_events.c
+++ b/kernel/trace/trace_events.c
@@ -118,9 +118,11 @@ int trace_event_raw_init(struct ftrace_event_call *call)
 }
 EXPORT_SYMBOL_GPL(trace_event_raw_init);
 
-static void ftrace_event_enable_disable(struct ftrace_event_call *call,
+static int ftrace_event_enable_disable(struct ftrace_event_call *call,
                                         int enable)
 {
+        int ret = 0;
+
         switch (enable) {
         case 0:
                 if (call->enabled) {
@@ -131,12 +133,20 @@ static void ftrace_event_enable_disable(struct ftrace_event_call *call,
                 break;
         case 1:
                 if (!call->enabled) {
-                        call->enabled = 1;
                         tracing_start_cmdline_record();
-                        call->regfunc(call);
+                        ret = call->regfunc(call);
+                        if (ret) {
+                                tracing_stop_cmdline_record();
+                                pr_info("event trace: Could not enable event "
+                                        "%s\n", call->name);
+                                break;
+                        }
+                        call->enabled = 1;
                 }
                 break;
         }
+
+        return ret;
 }
 
 static void ftrace_clear_events(void)
@@ -415,7 +425,7 @@ event_enable_write(struct file *filp, const char __user *ubuf, size_t cnt,
         case 0:
         case 1:
                 mutex_lock(&event_mutex);
-                ftrace_event_enable_disable(call, val);
+                ret = ftrace_event_enable_disable(call, val);
                 mutex_unlock(&event_mutex);
                 break;
 
@@ -425,7 +435,7 @@ event_enable_write(struct file *filp, const char __user *ubuf, size_t cnt,
 
         *ppos += cnt;
 
-        return cnt;
+        return ret ? ret : cnt;
 }
 
 static ssize_t