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tracing: Only process module tracepoints once 

The commit:

 9f987b3141f086de27832514aad9f50a53f754
 tracing: Include module.h in define_trace.h

only solved half the problem. If the trace/events/module.h header is
included at the time of define_trace.h (or in ftrace.h within it),
the module.h TRACE_SYSTEM will override the current TRACE_SYSTEM
macro.

Since define_trace.h is included when CREATE_TRACE_POINTS is set,
and the first thing it does is to #undef CREATE_TRACE_POINTS,
by placing the module.h TRACE_SYSTEM inside a
 #ifdef CREATE_TRACE_POINTS
we can prevent it from overriding the TRACE_SYSTEM that is
being processed, and still process the module.h tracepoints
when the module code defines CREATE_TRACE_POINTS and includes
the trace/events/module.h header.

As with commit 9f987b3141, this is only an issue if module.h
is not included before the trace/events/<event>.h file is
included, which (luckily) has not happened yet.

Reported-by: Peter Zijlstra <a.p.zijlstra@chello.nl>
Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
This commit is contained in:
Steven Rostedt 2011-01-14 11:25:58 -05:00 committed by Steven Rostedt
parent 4ad9f594d7
commit c94fbe1d9e
1 changed files with 10 additions and 0 deletions
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10
include/trace/events/module.h
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@ -1,5 +1,15 @@
/*
* Because linux/module.h has tracepoints in the header, and ftrace.h
* eventually includes this file, define_trace.h includes linux/module.h
* But we do not want the module.h to override the TRACE_SYSTEM macro
* variable that define_trace.h is processing, so we only set it
* when module events are being processed, which would happen when
* CREATE_TRACE_POINTS is defined.
*/
#ifdef CREATE_TRACE_POINTS
#undef TRACE_SYSTEM
#define TRACE_SYSTEM module
#endif
#if !defined(_TRACE_MODULE_H) || defined(TRACE_HEADER_MULTI_READ)
#define _TRACE_MODULE_H