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authorSteven Rostedt <srostedt@redhat.com>2009-08-26 00:32:37 -0400
committerSteven Rostedt <rostedt@goodmis.org>2009-08-26 00:32:37 -0400
commit7cb2e3ee2aeec5b83ecadba929a2dc575dd4008f (patch)
tree8918c12cac3cd816bf3dfaafc3fac46e36f4a73d /include/linux/tracepoint.h
parent5ac35daa9343936038a3c9c4f4d6d3fe6a2a7bd8 (diff)
downloadlinux-linaro-stable-7cb2e3ee2aeec5b83ecadba929a2dc575dd4008f.tar.gz
tracing: add comments to explain TRACE_EVENT out of protection
The commit: commit 5ac35daa9343936038a3c9c4f4d6d3fe6a2a7bd8 Author: Xiao Guangrong <xiaoguangrong@cn.fujitsu.com> 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 <rostedt@goodmis.org>
Diffstat (limited to 'include/linux/tracepoint.h')
-rw-r--r--include/linux/tracepoint.h13
1 files changed, 11 insertions, 2 deletions
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) */