tracing: Pushdown the bkl tracepoints calls

Currently we are calling the bkl tracepoint callbacks just before the
bkl lock/unlock operations, ie the tracepoint call is not inside a
lock_kernel() function but inside a lock_kernel() macro. Hence the
bkl trace event header must be included from smp_lock.h. This raises
some nasty circular header dependencies:

linux/smp_lock.h -> trace/events/bkl.h -> trace/define_trace.h
-> trace/ftrace.h -> linux/ftrace_event.h -> linux/hardirq.h
-> linux/smp_lock.h

This results in incomplete event declarations, spurious event
definitions and other kind of funny behaviours.

This is hardly fixable without ugly workarounds. So instead, we push
the file name, line number and function name as lock_kernel()
parameters, so that we only deal with the trace event header from
lib/kernel_lock.c

This adds two parameters to lock_kernel() and unlock_kernel() but
it should be fine wrt to performances because this pair dos not seem
to be called in fast paths.

Signed-off-by: Frederic Weisbecker <fweisbec@gmail.com>
Cc: Steven Rostedt <rostedt@goodmis.org>
Cc: Ingo Molnar <mingo@elte.hu>
Cc: Li Zefan <lizf@cn.fujitsu.com>

1 files changed, 11 insertions, 4 deletions

diff --git a/lib/kernel_lock.c b/lib/kernel_lock.c
index 5c10b2e1fd08..4ebfa5a164d7 100644
--- a/lib/kernel_lock.c
+++ b/lib/kernel_lock.c
@@ -8,9 +8,11 @@
 #include <linux/module.h>
 #include <linux/kallsyms.h>
 #include <linux/semaphore.h>
-#define CREATE_TRACE_POINTS
 #include <linux/smp_lock.h>
 
+#define CREATE_TRACE_POINTS
+#include <trace/events/bkl.h>
+
 /*
  * The 'big kernel lock'
  *
@@ -114,19 +116,24 @@ static inline void __unlock_kernel(void)
  * This cannot happen asynchronously, so we only need to
  * worry about other CPU's.
  */
-void __lockfunc _lock_kernel(void)
+void __lockfunc _lock_kernel(const char *func, const char *file, int line)
 {
-	int depth = current->lock_depth+1;
+	int depth = current->lock_depth + 1;
+
+	trace_lock_kernel(func, file, line);
+
 	if (likely(!depth))
 		__lock_kernel();
 	current->lock_depth = depth;
 }
 
-void __lockfunc _unlock_kernel(void)
+void __lockfunc _unlock_kernel(const char *func, const char *file, int line)
 {
 	BUG_ON(current->lock_depth < 0);
 	if (likely(--current->lock_depth < 0))
 		__unlock_kernel();
+
+	trace_unlock_kernel(func, file, line);
 }
 
 EXPORT_SYMBOL(_lock_kernel);