tracing: Fix hwlat kthread migration

The hwlat tracer creates a kernel thread at start of the tracer. It is
pinned to a single CPU and will move to the next CPU after each period of
running. If the user modifies the migration thread's affinity, it will not
change after that happens.

The original code created the thread at the first instance it was called,
but later was changed to destroy the thread after the tracer was finished,
and would not be created until the next instance of the tracer was
established. The code that initialized the affinity was only called on the
initial instantiation of the tracer. After that, it was not initialized, and
the previous affinity did not match the current newly created one, making
it appear that the user modified the thread's affinity when it did not, and
the thread failed to migrate again.

Cc: stable@vger.kernel.org
Fixes: 0330f7aa8ee6 ("tracing: Have hwlat trace migrate across tracing_cpumask CPUs")
Signed-off-by: Steven Rostedt (VMware) <rostedt@goodmis.org>

path: root/sound/usb/line6/capture.h

/*
 * Line 6 Linux USB driver
 *
 * Copyright (C) 2004-2010 Markus Grabner (grabner@icg.tugraz.at)
 *
 *	This program is free software; you can redistribute it and/or
 *	modify it under the terms of the GNU General Public License as
 *	published by the Free Software Foundation, version 2.
 *
 */

#ifndef CAPTURE_H
#define CAPTURE_H

#include <sound/pcm.h>

#include "driver.h"
#include "pcm.h"

extern struct snd_pcm_ops snd_line6_capture_ops;

extern void line6_capture_copy(struct snd_line6_pcm *line6pcm, char *fbuf,
			       int fsize);
extern void line6_capture_check_period(struct snd_line6_pcm *line6pcm,
				       int length);
extern int line6_create_audio_in_urbs(struct snd_line6_pcm *line6pcm);
extern int line6_submit_audio_in_all_urbs(struct snd_line6_pcm *line6pcm);

#endif