1 files changed, 18 insertions, 1 deletions

diff --git a/kernel/trace/trace.h b/kernel/trace/trace.h
index 1974ce818ddb..005f08629b8b 100644
--- a/kernel/trace/trace.h
+++ b/kernel/trace/trace.h
@@ -15,7 +15,6 @@
 #include <linux/trace_seq.h>
 #include <linux/trace_events.h>
 #include <linux/compiler.h>
-#include <linux/trace_seq.h>
 #include <linux/glob.h>
 
 #ifdef CONFIG_FTRACE_SYSCALLS
@@ -1967,4 +1966,22 @@ static inline void tracer_hardirqs_off(unsigned long a0, unsigned long a1) { }
 
 extern struct trace_iterator *tracepoint_print_iter;
 
+/*
+ * Reset the state of the trace_iterator so that it can read consumed data.
+ * Normally, the trace_iterator is used for reading the data when it is not
+ * consumed, and must retain state.
+ */
+static __always_inline void trace_iterator_reset(struct trace_iterator *iter)
+{
+        const size_t offset = offsetof(struct trace_iterator, seq);
+
+        /*
+         * Keep gcc from complaining about overwriting more than just one
+         * member in the structure.
+         */
+        memset((char *)iter + offset, 0, sizeof(struct trace_iterator) - offset);
+
+        iter->pos = -1;
+}
+
 #endif /* _LINUX_KERNEL_TRACE_H */