Hi Jovi,
I'll try to read this patch carefully tomorrow.
Looks fine at first glance, but some nits below.
On 06/24, zhangwei(Jovi) wrote:
>
> static int uprobe_trace_func(struct trace_uprobe *tu, struct pt_regs *regs)
> {
> - if (!is_ret_probe(tu))
> - uprobe_trace_print(tu, 0, regs);
> + struct event_file_link *link;
> +
> + if (is_ret_probe(tu))
> + return 0;
> +
> + rcu_read_lock();
> +
> + list_for_each_entry(link, &tu->files, list)
> + uprobe_trace_print(tu, 0, regs, link->file);
> +
> + rcu_read_unlock();
Purely cosmetic and I won't argue, but why the empty lines around
list_for_each_entry() ?
> static int
> -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;
>
> - if (is_trace_uprobe_enabled(tu))
> + /*
> + * Currently TP_FLAG_TRACE/TP_FLAG_PROFILE are mutually exclusive
> + * for uprobe(filter argument issue), this need to fix in future.
> + */
> + if ((file && (tu->flags & TP_FLAG_PROFILE)) ||
> + (!file && (tu->flags & TP_FLAG_TRACE)))
> return -EINTR;
Well, this looks confusing and overcomplicated, see below.
> + /* Currently we cannot call uprobe_register twice for same tu */
> + if (is_trace_uprobe_enabled(tu))
> + enabled = 1;
The comment is wrong. It is not that we can't do this "Currently".
We must not do uprobe_register(..., consumer) twice, consumer/uprobe
are linked together.
> + if (file) {
> + struct event_file_link *link;
> +
Just add
if (TP_FLAG_PROFILE)
return -EINTR;
here and kill the complicated check below. Same for the "else" branch.
> +static void
> +probe_event_disable(struct trace_uprobe *tu, struct ftrace_event_file *file)
> +{
> + if (file) {
> + struct event_file_link *link;
> +
> + link = find_event_file_link(tu, file);
> + if (!link)
> + return;
> +
> + list_del_rcu(&link->list);
> + /* synchronize with uprobe_trace_func/uretprobe_trace_func */
> + synchronize_sched();
> + kfree(link);
> +
> + if (!list_empty(&tu->files))
> + return;
> +
> + tu->flags &= ~TP_FLAG_TRACE;
> + } else
> + tu->flags &= ~TP_FLAG_PROFILE;
> +
>
> WARN_ON(!uprobe_filter_is_empty(&tu->filter));
>
> - uprobe_unregister(tu->inode, tu->offset, &tu->consumer);
> - tu->flags &= ~flag;
> + if (!is_trace_uprobe_enabled(tu))
> + uprobe_unregister(tu->inode, tu->offset, &tu->consumer);
Well, this is not exactly right... Currently this is fine, but still.
It would be better to clear TP_FLAG_TRACE/TP_FLAG_PROFILE after
uprobe_unregister(), when we can't race with the running handler
which can check ->flags.
And I'd suggest you to send the soft-enable/disable change in a
separate (and trivial) patch.
Oleg.
--
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majord...@vger.kernel.org
More majordomo info at http://vger.kernel.org/majordomo-info.html
Please read the FAQ at http://www.tux.org/lkml/
