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Commit 107bad8b authored by Steven Rostedt's avatar Steven Rostedt Committed by Thomas Gleixner
Browse files

ftrace: add trace pipe header pluggin 



This patch adds a method for open_pipe and open_read to the pluggins
so that they can add a header to the trace pipe call.

Signed-off-by: default avatarSteven Rostedt <srostedt@redhat.com>
Signed-off-by: default avatarIngo Molnar <mingo@elte.hu>
Signed-off-by: default avatarThomas Gleixner <tglx@linutronix.de>
parent 53d0aa77

kernel/trace/trace.c

+31 −7
Original line number Diff line number Diff line
@@ -2307,11 +2307,15 @@ static int tracing_open_pipe(struct inode *inode, struct file *filp) 
	if (!iter)

		return -ENOMEM;



	mutex_lock(&trace_types_lock);

	iter->tr = &global_trace;

	iter->trace = current_trace;



	filp->private_data = iter;



	if (iter->trace->pipe_open)

		iter->trace->pipe_open(iter);

	mutex_unlock(&trace_types_lock);



	return 0;

}
@@ -2380,13 +2384,24 @@ tracing_read_pipe(struct file *filp, char __user *ubuf, 
		return cnt;

	}



	mutex_lock(&trace_types_lock);

	if (iter->trace->read) {

		ret = iter->trace->read(iter, filp, ubuf, cnt, ppos);

		if (ret) {

			read = ret;

			goto out;

		}

	}



	trace_seq_reset(&iter->seq);

	start = 0;



	while (trace_empty(iter)) {



		if ((filp->f_flags & O_NONBLOCK))

			return -EAGAIN;

		if ((filp->f_flags & O_NONBLOCK)) {

			read = -EAGAIN;

			goto out;

		}



		/*

		 * This is a make-shift waitqueue. The reason we don't use
@@ -2400,16 +2415,22 @@ tracing_read_pipe(struct file *filp, char __user *ubuf, 
		set_current_state(TASK_INTERRUPTIBLE);

		iter->tr->waiter = current;



		mutex_unlock(&trace_types_lock);



		/* sleep for one second, and try again. */

		schedule_timeout(HZ);



		mutex_lock(&trace_types_lock);



		iter->tr->waiter = NULL;



		if (signal_pending(current))

			return -EINTR;

		if (signal_pending(current)) {

			read = -EINTR;

			goto out;

		}



		if (iter->trace != current_trace)

			return 0;

			goto out;



		/*

		 * We block until we read something and tracing is disabled.
@@ -2428,7 +2449,7 @@ tracing_read_pipe(struct file *filp, char __user *ubuf, 


	/* stop when tracing is finished */

	if (trace_empty(iter))

		return 0;

		goto out;



	if (cnt >= PAGE_SIZE)

		cnt = PAGE_SIZE - 1;
@@ -2518,6 +2539,9 @@ tracing_read_pipe(struct file *filp, char __user *ubuf, 
	if (ret)

		read = -EFAULT;



out:

	mutex_unlock(&trace_types_lock);



	return read;

}

kernel/trace/trace.h

+5 −0
Original line number Diff line number Diff line
@@ -135,9 +135,13 @@ struct tracer { 
	void			(*init)(struct trace_array *tr);

	void			(*reset)(struct trace_array *tr);

	void			(*open)(struct trace_iterator *iter);

	void			(*pipe_open)(struct trace_iterator *iter);

	void			(*close)(struct trace_iterator *iter);

	void			(*start)(struct trace_iterator *iter);

	void			(*stop)(struct trace_iterator *iter);

	ssize_t			(*read)(struct trace_iterator *iter,

					struct file *filp, char __user *ubuf,

					size_t cnt, loff_t *ppos);

	void			(*ctrl_update)(struct trace_array *tr);

#ifdef CONFIG_FTRACE_STARTUP_TEST

	int			(*selftest)(struct tracer *trace,
@@ -160,6 +164,7 @@ struct trace_seq { 
struct trace_iterator {

	struct trace_array	*tr;

	struct tracer		*trace;

	void			*private;

	long			last_overrun[NR_CPUS];

	long			overrun[NR_CPUS];