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

From: Masami Hiramatsu (Google)
Date: Sun Aug 18 2024 - 06:43:20 EST


From: Masami Hiramatsu (Google) <mhiramat@xxxxxxxxxx>

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) <mhiramat@xxxxxxxxxx>
---
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 */