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SubjectRe: [PATCH 08/10] trace_kprobe: init print_fmt
Lai Jiangshan wrote:
> Init print_fmt for trace_kprobe.
> It will be used for replacing ->show_format().
>
> Signed-off-by: Lai Jiangshan<laijs@cn.fujitsu.com>

Looks good to me.

Acked-by: Masami Hiramatsu <mhiramat@redhat.com>

> ---
> diff --git a/kernel/trace/trace_kprobe.c b/kernel/trace/trace_kprobe.c
> index 3ef66d4..a12d39b 100644
> --- a/kernel/trace/trace_kprobe.c
> +++ b/kernel/trace/trace_kprobe.c
> @@ -1212,6 +1212,55 @@ static int kretprobe_event_show_format(struct ftrace_event_call *call,
> ", REC->" FIELD_STRING_RETIP);
> }
>
> +static int __set_print_fmt(struct trace_probe *tp, char *buf, int len)
> +{
> + int i;
> + int pos = 0;
> +
> + const char *fmt, *arg;
> +
> + if (!probe_is_return(tp)) {
> + fmt = "(%lx)";
> + arg = "REC->" FIELD_STRING_IP;
> + } else {
> + fmt = "(%lx<- %lx)";
> + arg = "REC->" FIELD_STRING_FUNC ", REC->" FIELD_STRING_RETIP;
> + }
> +
> + pos += snprintf(buf + pos, len> pos ? len - pos : 0, "\"%s", fmt);
> +
> + for (i = 0; i< tp->nr_args; i++) {
> + pos += snprintf(buf + pos, len> pos ? len - pos : 0,
> + " %s=%%lx", tp->args[i].name);
> + }
> +
> + pos += snprintf(buf + pos, len> pos ? len - pos : 0, "\", %s", arg);
> +
> + for (i = 0; i< tp->nr_args; i++) {
> + pos += snprintf(buf + pos, len> pos ? len - pos : 0,
> + ", REC->%s", tp->args[i].name);
> + }
> +
> + /* return the length of print_fmt */
> + return pos;
> +}
> +
> +static int set_print_fmt(struct trace_probe *tp)
> +{
> + int len;
> + char *print_fmt;
> +
> + len = __set_print_fmt(tp, NULL, 0);
> + print_fmt = kmalloc(len + 1, GFP_KERNEL);
> + if (!print_fmt)
> + return -ENOMEM;
> +
> + __set_print_fmt(tp, print_fmt, len + 1);
> + tp->call.print_fmt = print_fmt;
> +
> + return 0;
> +}
> +
> #ifdef CONFIG_EVENT_PROFILE
>
> /* Kprobe profile handler */
> @@ -1418,10 +1467,14 @@ static int register_probe_event(struct trace_probe *tp)
> call->show_format = kprobe_event_show_format;
> call->define_fields = kprobe_event_define_fields;
> }
> + if (set_print_fmt(tp)< 0)
> + return -ENOMEM;
> call->event =&tp->event;
> call->id = register_ftrace_event(&tp->event);
> - if (!call->id)
> + if (!call->id) {
> + kfree(call->print_fmt);
> return -ENODEV;
> + }
> call->enabled = 0;
> call->regfunc = probe_event_enable;
> call->unregfunc = probe_event_disable;
> @@ -1435,6 +1488,7 @@ static int register_probe_event(struct trace_probe *tp)
> ret = trace_add_event_call(call);
> if (ret) {
> pr_info("Failed to register kprobe event: %s\n", call->name);
> + kfree(call->print_fmt);
> unregister_ftrace_event(&tp->event);
> }
> return ret;
> @@ -1444,6 +1498,7 @@ static void unregister_probe_event(struct trace_probe *tp)
> {
> /* tp->event is unregistered in trace_remove_event_call() */
> trace_remove_event_call(&tp->call);
> + kfree(tp->call.print_fmt);
> }
>
> /* Make a debugfs interface for controling probe points */
>
> --
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--
Masami Hiramatsu

Software Engineer
Hitachi Computer Products (America), Inc.
Software Solutions Division

e-mail: mhiramat@redhat.com



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