include/linux/trace.h

#ifndef _LINUX_TRACE_H
#define _LINUX_TRACE_H

#ifdef CONFIG_TRACING
/*
 * The trace export - an export of Ftrace output. The trace_export
 * can process traces and export them to a registered destination as
 * an addition to the current only output of Ftrace - i.e. ring buffer.
 *
 * If you want traces to be sent to some other place rather than ring
 * buffer only, just need to register a new trace_export and implement
 * its own .write() function for writing traces to the storage.
 *
 * next		- pointer to the next trace_export
 * write	- copy traces which have been delt with ->commit() to
 *		  the destination
 */
struct trace_export {
	struct trace_export __rcu	*next;
	void (*write)(const void *, unsigned int);
};

int register_ftrace_export(struct trace_export *export);
int unregister_ftrace_export(struct trace_export *export);

#endif	/* CONFIG_TRACING */

#endif	/* _LINUX_TRACE_H */