From 23725aeeab10ba02bcf10ec49ad73146b54cb52f Mon Sep 17 00:00:00 2001 From: Peter Zijlstra Date: Thu, 19 Mar 2009 20:26:13 +0100 Subject: [PATCH] ftrace: provide an id file for each event Since not every event has a format file to read the id from, expose it explicitly in a separate file. Signed-off-by: Peter Zijlstra Cc: Paul Mackerras Cc: Steven Rostedt LKML-Reference: <20090319194233.372534033@chello.nl> Signed-off-by: Ingo Molnar --- kernel/trace/trace_events.c | 36 ++++++++++++++++++++++++++++++++++++ 1 file changed, 36 insertions(+) diff --git a/kernel/trace/trace_events.c b/kernel/trace/trace_events.c index c88227b3b9db..7763db8fd0b3 100644 --- a/kernel/trace/trace_events.c +++ b/kernel/trace/trace_events.c @@ -412,6 +412,29 @@ event_format_read(struct file *filp, char __user *ubuf, size_t cnt, return r; } +static ssize_t +event_id_read(struct file *filp, char __user *ubuf, size_t cnt, loff_t *ppos) +{ + struct ftrace_event_call *call = filp->private_data; + struct trace_seq *s; + int r; + + if (*ppos) + return 0; + + s = kmalloc(sizeof(*s), GFP_KERNEL); + if (!s) + return -ENOMEM; + + trace_seq_init(s); + trace_seq_printf(s, "%d\n", call->id); + + r = simple_read_from_buffer(ubuf, cnt, ppos, + s->buffer, s->len); + kfree(s); + return r; +} + static const struct seq_operations show_event_seq_ops = { .start = t_start, .next = t_next, @@ -452,6 +475,11 @@ static const struct file_operations ftrace_event_format_fops = { .read = event_format_read, }; +static const struct file_operations ftrace_event_id_fops = { + .open = tracing_open_generic, + .read = event_id_read, +}; + static struct dentry *event_trace_events_dir(void) { static struct dentry *d_tracer; @@ -550,6 +578,14 @@ event_create_dir(struct ftrace_event_call *call, struct dentry *d_events) "'%s/enable' entry\n", call->name); } + if (call->id) { + entry = debugfs_create_file("id", 0444, call->dir, call, + &ftrace_event_id_fops); + if (!entry) + pr_warning("Could not create debugfs '%s/id' entry\n", + call->name); + } + /* A trace may not want to export its format */ if (!call->show_format) return 0; -- 2.20.1