Re: [PATCH 1/2 v3] tracing/uprobes: Support ftrace_event_file base multibuffer

[Oleg Nesterov <oleg@redhat.com>]

Sorry again, didn't have time to review, will try tomorrow.

Looks good but a couple of minor nits, and perhaps we should
fix the bugs with unregister_trace_uprobe first... in kprobes
too _if_ I am right. I'll return tomorrow.

On 06/25, zhangwei(Jovi) wrote:
>
> -probe_event_enable(struct trace_uprobe *tu, int flag, filter_func_t filter)
> +probe_event_enable(struct trace_uprobe *tu, struct ftrace_event_file *file,
> +		   filter_func_t filter)
>  {
> +	int enabled = 0;
>  	int ret = 0;
> 
> +	/* we cannot call uprobe_register twice for same tu */
>  	if (is_trace_uprobe_enabled(tu))
> -		return -EINTR;
> +		enabled = 1;

Cosmetic again, "int enabled = 0" and then "if (is_trace_uprobe_enabled)"
looks a bit strange,

	enabled = is_trace_uprobe_enabled();

looks a bit more clean.

> +	if (file) {
> +		struct event_file_link *link;
> +
> +		if (tu->flags & TP_FLAG_PROFILE)
> +			return -EINTR;
> +
> +		link = kmalloc(sizeof(*link), GFP_KERNEL);
> +		if (!link)
> +			return -ENOMEM;
> +
> +		link->file = file;
> +		list_add_rcu(&link->list, &tu->files);

I agree with Masami, list_add_rcu_tail() looks better even if this
doesn't really matter.

Oleg.