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>

diff --git a/include/trace/ftrace.h b/include/trace/ftrace.h
index 2af2f7a2c1bd85d66ce113662ea608deec7aa587..0c21af85211c79e8a356fbdf00a3bb24a493b68e 100644 (file)
--- a/include/trace/ftrace.h
+++ b/include/trace/ftrace.h
@@ -555,13 +555,7 @@ static void ftrace_profile_disable_##name(struct ftrace_event_call *unused)\
  *
  * static int ftrace_reg_event_<call>(struct ftrace_event_call *unused)
  * {
- *     int ret;
- *
- *     ret = register_trace_<call>(ftrace_event_<call>);
- *     if (!ret)
- *             pr_info("event trace: Could not activate trace point "
- *                     "probe to  <call>");
- *     return ret;
+ *     return register_trace_<call>(ftrace_event_<call>);
  * }
  *
  * static void ftrace_unreg_event_<call>(struct ftrace_event_call *unused)
@@ -710,13 +704,7 @@ static void ftrace_raw_event_##call(proto)                         \
                                                                        \
 static int ftrace_raw_reg_event_##call(struct ftrace_event_call *unused)\
 {                                                                      \
-       int ret;                                                        \
-                                                                       \
-       ret = register_trace_##call(ftrace_raw_event_##call);           \
-       if (ret)                                                        \
-               pr_info("event trace: Could not activate trace point "  \
-                       "probe to %s\n", #call);                        \
-       return ret;                                                     \
+       return register_trace_##call(ftrace_raw_event_##call);          \
 }                                                                      \
                                                                        \
 static void ftrace_raw_unreg_event_##call(struct ftrace_event_call *unused)\

diff --git a/kernel/trace/trace_events.c b/kernel/trace/trace_events.c
index 97b0b3aa166da670aa91a44193c63a1ab8458064..189b09baf4fbfd1bb6a2340897c477d83d6de800 100644 (file)
--- 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

diff --git a/kernel/trace/trace_syscalls.c b/kernel/trace/trace_syscalls.c
index b957edd0ca3b35750b93e6968ad1f6e09d073239..75289f372dd270816742e7dd94c1d5c2474442d8 100644 (file)
--- a/kernel/trace/trace_syscalls.c
+++ b/kernel/trace/trace_syscalls.c
@@ -325,10 +325,7 @@ int reg_event_syscall_enter(struct ftrace_event_call *call)
        mutex_lock(&syscall_trace_lock);
        if (!sys_refcount_enter)
                ret = register_trace_sys_enter(ftrace_syscall_enter);
-       if (ret) {
-               pr_info("event trace: Could not activate"
-                               "syscall entry trace point");
-       } else {
+       if (!ret) {
                set_bit(num, enabled_enter_syscalls);
                sys_refcount_enter++;
        }
@@ -362,10 +359,7 @@ int reg_event_syscall_exit(struct ftrace_event_call *call)
        mutex_lock(&syscall_trace_lock);
        if (!sys_refcount_exit)
                ret = register_trace_sys_exit(ftrace_syscall_exit);
-       if (ret) {
-               pr_info("event trace: Could not activate"
-                               "syscall exit trace point");
-       } else {
+       if (!ret) {
                set_bit(num, enabled_exit_syscalls);
                sys_refcount_exit++;
        }