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Commit c521efd1 authored Dec 07, 2009 by Steven Rostedt Committed by Steven Rostedt Dec 07, 2009

tracing: Add pipe_close interface

An ftrace plugin can add a pipe_open interface when the user opens
trace_pipe. But if the plugin allocates something within the pipe_open
it can not free it because there exists no pipe_close. The hook to
the trace file open has a corresponding close. The closing of the
trace_pipe file should also have a corresponding close.

Signed-off-by: Steven Rostedt <rostedt@goodmis.org>

parent 6ec22f9b

kernel/trace/trace.c

+4 −0

Original line number	Original line	Diff line number	Diff line
	@@ -2898,6 +2898,10 @@ static int tracing_release_pipe(struct inode inode, struct file file)
	else		else
	cpumask_clear_cpu(iter->cpu_file, tracing_reader_cpumask);		cpumask_clear_cpu(iter->cpu_file, tracing_reader_cpumask);


			if (iter->trace->pipe_open)
			iter->trace->pipe_close(iter);

	mutex_unlock(&trace_types_lock);		mutex_unlock(&trace_types_lock);

	free_cpumask_var(iter->started);		free_cpumask_var(iter->started);

kernel/trace/trace.h

+2 −0

Original line number	Original line	Diff line number	Diff line
	@@ -272,6 +272,7 @@ struct tracer_flags {
	* @pipe_open: called when the trace_pipe file is opened		* @pipe_open: called when the trace_pipe file is opened
	* @wait_pipe: override how the user waits for traces on trace_pipe		* @wait_pipe: override how the user waits for traces on trace_pipe
	* @close: called when the trace file is released		* @close: called when the trace file is released
			* @pipe_close: called when the trace_pipe file is released
	* @read: override the default read callback on trace_pipe		* @read: override the default read callback on trace_pipe
	* @splice_read: override the default splice_read callback on trace_pipe		* @splice_read: override the default splice_read callback on trace_pipe
	* @selftest: selftest to run on boot (see trace_selftest.c)		* @selftest: selftest to run on boot (see trace_selftest.c)
	@@ -290,6 +291,7 @@ struct tracer {
	void (pipe_open)(struct trace_iterator iter);		void (pipe_open)(struct trace_iterator iter);
	void (wait_pipe)(struct trace_iterator iter);		void (wait_pipe)(struct trace_iterator iter);
	void (close)(struct trace_iterator iter);		void (close)(struct trace_iterator iter);
			void (pipe_close)(struct trace_iterator iter);
	ssize_t (read)(struct trace_iterator iter,		ssize_t (read)(struct trace_iterator iter,
	struct file filp, char __user ubuf,		struct file filp, char __user ubuf,
	size_t cnt, loff_t *ppos);		size_t cnt, loff_t *ppos);