ftrace: Clean up function probe methods (e67efb93) · Commits · 戴 / test

When a function probe is created, each function that the probe is attached to, a "callback" method is called. On release of the probe, each function entry calls the "free" method. First, "callback" is a confusing name and does not really match what it does. Callback sounds like it will be called when the probe triggers. But that's not the case. This is really an "init" function, so lets rename it as such. Secondly, both "init" and "free" do not pass enough information back to the handlers. Pass back the ops, ip and data for each time the method is called. We have the information, might as well use it. Signed-off-by:

Steven Rostedt <rostedt@goodmis.org>

include/linux/ftrace.h

+4 −2

Original line number	Diff line number	Diff line
		@@ -259,8 +259,10 @@ struct ftrace_probe_ops {
		void (*func)(unsigned long ip,
		unsigned long parent_ip,
		void **data);
		int (callback)(unsigned long ip, void *data);
		void (free)(void *data);
		int (init)(struct ftrace_probe_ops ops,
		unsigned long ip, void **data);
		void (free)(struct ftrace_probe_ops ops,
		unsigned long ip, void **data);
		int (print)(struct seq_file m,
		unsigned long ip,
		struct ftrace_probe_ops *ops,

kernel/trace/ftrace.c

+3 −3

Original line number	Diff line number	Diff line
		@@ -2984,7 +2984,7 @@ static void ftrace_free_entry_rcu(struct rcu_head *rhp)
		container_of(rhp, struct ftrace_func_probe, rcu);

		if (entry->ops->free)
		entry->ops->free(&entry->data);
		entry->ops->free(entry->ops, entry->ip, &entry->data);
		kfree(entry);
		}

		@@ -3045,8 +3045,8 @@ register_ftrace_function_probe(char glob, struct ftrace_probe_ops ops,
		* for each function we find. We call the callback
		* to give the caller an opportunity to do so.
		*/
		if (ops->callback) {
		if (ops->callback(rec->ip, &entry->data) < 0) {
		if (ops->init) {
		if (ops->init(ops, rec->ip, &entry->data) < 0) {
		/* caller does not like this func */
		kfree(entry);
		continue;

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