[PATCH v3 2/5] tracepoint: Support tterating tracepoints in a loading module

[Masami Hiramatsu (Google)]

From: Masami Hiramatsu (Google) <mhira...@kernel.org>

Add for_each_tracepoint_in_module() function to iterate tracepoints in
a module. This API is needed for handling tracepoints in a loading
module from tracepoint_module_notifier callback function.
This also update for_each_module_tracepoint() to pass the module to
callback function so that it can find module easily.

Signed-off-by: Masami Hiramatsu (Google) <mhira...@kernel.org>
---
 Changes in v3:
  - Newly added.
---
 include/linux/tracepoint.h |   17 +++++++++++++++--
 kernel/tracepoint.c        |   37 +++++++++++++++++++++++++++++--------
 2 files changed, 44 insertions(+), 10 deletions(-)

diff --git a/include/linux/tracepoint.h b/include/linux/tracepoint.h
index 837fcf8ec0d5..93a9f3070b48 100644
--- a/include/linux/tracepoint.h
+++ b/include/linux/tracepoint.h
@@ -64,8 +64,13 @@ struct tp_module {
 bool trace_module_has_bad_taint(struct module *mod);
 extern int register_tracepoint_module_notifier(struct notifier_block *nb);
 extern int unregister_tracepoint_module_notifier(struct notifier_block *nb);
-void for_each_module_tracepoint(void (*fct)(struct tracepoint *, void *),
+void for_each_module_tracepoint(void (*fct)(struct tracepoint *,
+                                       struct module *, void *),
                                void *priv);
+void for_each_tracepoint_in_module(struct module *,
+                                  void (*fct)(struct tracepoint *,
+                                       struct module *, void *),
+                                  void *priv);
 #else
 static inline bool trace_module_has_bad_taint(struct module *mod)
 {
@@ -82,10 +87,18 @@ int unregister_tracepoint_module_notifier(struct 
notifier_block *nb)
        return 0;
 }
 static inline
-void for_each_module_tracepoint(void (*fct)(struct tracepoint *, void *),
+void for_each_module_tracepoint(void (*fct)(struct tracepoint *,
+                                       struct module *, void *),
                                void *priv)
 {
 }
+static inline
+void for_each_tracepoint_in_module(struct module *mod,
+                                  void (*fct)(struct tracepoint *,
+                                       struct module *, void *),
+                                  void *priv)
+{
+}
 #endif /* CONFIG_MODULES */
 
 /*
diff --git a/kernel/tracepoint.c b/kernel/tracepoint.c
index bed4aad36d92..8879da16ef4d 100644
--- a/kernel/tracepoint.c
+++ b/kernel/tracepoint.c
@@ -736,24 +736,45 @@ static __init int init_tracepoints(void)
 }
 __initcall(init_tracepoints);
 
+/**
+ * for_each_tracepoint_in_module - iteration on all tracepoints in a module
+ * @mod: module
+ * @fct: callback
+ * @priv: private data
+ */
+void for_each_tracepoint_in_module(struct module *mod,
+                                  void (*fct)(struct tracepoint *tp,
+                                   struct module *mod, void *priv),
+                                  void *priv)
+{
+       tracepoint_ptr_t *begin, *end, *iter;
+
+       lockdep_assert_held(&tracepoint_module_list_mutex);
+
+       if (!mod)
+               return;
+
+       begin = mod->tracepoints_ptrs;
+       end = mod->tracepoints_ptrs + mod->num_tracepoints;
+
+       for (iter = begin; iter < end; iter++)
+               fct(tracepoint_ptr_deref(iter), mod, priv);
+}
+
 /**
  * for_each_module_tracepoint - iteration on all tracepoints in all modules
  * @fct: callback
  * @priv: private data
  */
-void for_each_module_tracepoint(void (*fct)(struct tracepoint *tp, void *priv),
+void for_each_module_tracepoint(void (*fct)(struct tracepoint *tp,
+                                struct module *mod, void *priv),
                                void *priv)
 {
        struct tp_module *tp_mod;
-       struct module *mod;
 
        mutex_lock(&tracepoint_module_list_mutex);
-       list_for_each_entry(tp_mod, &tracepoint_module_list, list) {
-               mod = tp_mod->mod;
-               for_each_tracepoint_range(mod->tracepoints_ptrs,
-                       mod->tracepoints_ptrs + mod->num_tracepoints,
-                       fct, priv);
-       }
+       list_for_each_entry(tp_mod, &tracepoint_module_list, list)
+               for_each_tracepoint_in_module(tp_mod->mod, fct, priv);
        mutex_unlock(&tracepoint_module_list_mutex);
 }
 #endif /* CONFIG_MODULES */