Re: [RFC][PATCH 2/2] [PATCH 2/2] tracing: Make event based trace_printk()

[Steven Rostedt <rostedt@goodmis.org>]

On Wed, 2010-11-17 at 22:58 -0500, Steven Rostedt wrote:

> +static __init int event_printk_init(void)
> +{
> +	struct event_printk_struct *print;
> +	struct dentry *d_events;
> +	char *topdir;
> +	char *p;
> +	int len;
> +	int ret = -1;
> +
> +	/*
> +	 * Do nothing if we have no trace printks.
> +	 * May change in the future when we support modules.
> +	 */
> +	if (__start_trace_printk == __stop_trace_printk)
> +		return 0;
> +
> +	/*
> +	 * Use this file to find the path for other
> +	 * files. That is, __FILE__ returns the full path,
> +	 * but we don't want the top dir path, so we must
> +	 * chop it off. We know the path of this file as it
> +	 * is (kernel/trace/event_printk.c), so we simply
> +	 * cut that off and then we have the path to cut
> +	 * off of other files.
> +	 */
> +	topdir = kstrdup(__FILE__, GFP_KERNEL);
> +	if (WARN(!topdir, "failed to allocate printk info"))
> +		return -1;
> +
> +	p = strstr(topdir, "kernel/trace/event_printk.c");
> +	if (WARN(!p, "event_printk.c not found. Did the file move?"))
> +		goto out;
> +	*p = '\0';
> +
> +	d_events = event_trace_events_dir();
> +
> +	printk_root = debugfs_create_dir("printk", d_events);
> +	if (WARN(!printk_root, "Could not create printk entry"))
> +		goto out;
> +
> +	trace_create_file("enable", 0644, printk_root,
> +			  NULL, &trace_printk_enable_fops);
> +
> +	len = strlen(topdir);
> +	for_each_printk(print, __start_trace_printk, __stop_trace_printk)
> +		add_event_printk(topdir, len, print);

Oops, I'm missing a:

	ret = 0;

here.

-- Steve

> +
> + out:
> +	kfree(topdir);
> +	return ret;
> +}