From 7cb2e3ee2aeec5b83ecadba929a2dc575dd4008f Mon Sep 17 00:00:00 2001 From: Steven Rostedt Date: Wed, 26 Aug 2009 00:32:37 -0400 Subject: tracing: add comments to explain TRACE_EVENT out of protection The commit: commit 5ac35daa9343936038a3c9c4f4d6d3fe6a2a7bd8 Author: Xiao Guangrong tracing/events: fix the include file dependencies Moved the TRACE_EVENT out of the ifdef protection of tracepoints.h but uses the define of TRACE_EVENT itself as protection. This patch adds comments to explain why. Signed-off-by: Steven Rostedt --- include/linux/tracepoint.h | 13 +++++++++++-- 1 file changed, 11 insertions(+), 2 deletions(-) (limited to 'include/linux/tracepoint.h') diff --git a/include/linux/tracepoint.h b/include/linux/tracepoint.h index 81709854f7ab..0341f2e2698a 100644 --- a/include/linux/tracepoint.h +++ b/include/linux/tracepoint.h @@ -180,7 +180,15 @@ static inline void tracepoint_synchronize_unregister(void) } #define PARAMS(args...) args -#endif + +#endif /* _LINUX_TRACEPOINT_H */ + +/* + * Note: we keep the TRACE_EVENT outside the include file ifdef protection. + * This is due to the way trace events work. If a file includes two + * trace event headers under one "CREATE_TRACE_POINTS" the first include + * will override the TRACE_EVENT and break the second include. + */ #ifndef TRACE_EVENT /* @@ -287,4 +295,5 @@ static inline void tracepoint_synchronize_unregister(void) #define TRACE_EVENT(name, proto, args, struct, assign, print) \ DECLARE_TRACE(name, PARAMS(proto), PARAMS(args)) -#endif + +#endif /* ifdef TRACE_EVENT (see note above) */ -- cgit v1.2.1