Re: [PATCH 3/3] tracing: Apply tracer specific options from kernel command line.

[Steven Rostedt]

On Sun, 18 Oct 2015 19:58:10 +0800
Jiaxing Wang <hello.wjx@xxxxxxxxx> wrote:


> +static int __init apply_trace_boot_options(void)
> +{
> +	char *option;
> +	char *buf;
> +	char *str;
> +	size_t len;
> +
> +	if (trace_boot_options) {
> +		len = strlen(trace_boot_options);
> +
> +		buf = str = kmalloc(len + 1, GFP_KERNEL);
> +		if (!buf)
> +			return -ENOMEM;
> +
> +		memcpy(buf, trace_boot_options, len + 1);
> +
> +		while (str) {
> +			option = strsep(&str, ",");
> +			trace_set_options(&global_trace, option);
> +		}
> +
> +		kfree(buf);

Instead of allocating a buffer, do what I do in early_enable_events()
(see trace_events.c), where I put back the ',' after processing.

-- Steve

> +	}
> +
> +	return 0;
> +}
> +
>  static ssize_t
>  tracing_trace_options_write(struct file *filp, const char __user *ubuf,
>  			size_t cnt, loff_t *ppos)
> @@ -7153,12 +7185,7 @@ __init static int tracer_alloc_buffers(void)
>  	INIT_LIST_HEAD(&global_trace.events);
>  	list_add(&global_trace.list, &ftrace_trace_arrays);
>  
> -	while (trace_boot_options) {
> -		char *option;
> -
> -		option = strsep(&trace_boot_options, ",");
> -		trace_set_options(&global_trace, option);
> -	}
> +	apply_trace_boot_options();
>  
>  	register_snapshot_cmd();
>  

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