[PATCH] tracepoints: Use new static branch API

[PATCH] tracepoints: Use new static branch API

[Josh Poimboeuf]

The old static key API based on 'struct static_key' is deprecated.
Convert tracepoints to use the new API.

Signed-off-by: Josh Poimboeuf <jpoimboe@kernel.org>
---
 include/linux/tracepoint-defs.h | 4 ++--
 include/linux/tracepoint.h      | 8 ++++----
 kernel/tracepoint.c             | 4 ++--
 3 files changed, 8 insertions(+), 8 deletions(-)

diff --git a/include/linux/tracepoint-defs.h b/include/linux/tracepoint-defs.h
index 4dc4955f0fbf..60a6e8314d4c 100644
--- a/include/linux/tracepoint-defs.h
+++ b/include/linux/tracepoint-defs.h
@@ -31,7 +31,7 @@ struct tracepoint_func {
 
 struct tracepoint {
 	const char *name;		/* Tracepoint name */
-	struct static_key key;
+	struct static_key_false key;
 	struct static_call_key *static_call_key;
 	void *static_call_tramp;
 	void *iterator;
@@ -83,7 +83,7 @@ struct bpf_raw_event_map {
 
 #ifdef CONFIG_TRACEPOINTS
 # define tracepoint_enabled(tp) \
-	static_key_false(&(__tracepoint_##tp).key)
+	static_branch_unlikely(&(__tracepoint_##tp).key)
 #else
 # define tracepoint_enabled(tracepoint) false
 #endif
diff --git a/include/linux/tracepoint.h b/include/linux/tracepoint.h
index 6be396bb4297..ab5162fc3e4a 100644
--- a/include/linux/tracepoint.h
+++ b/include/linux/tracepoint.h
@@ -228,7 +228,7 @@ static inline struct tracepoint *tracepoint_ptr_deref(tracepoint_ptr_t *p)
 #define __DECLARE_TRACE_RCU(name, proto, args, cond)			\
 	static inline void trace_##name##_rcuidle(proto)		\
 	{								\
-		if (static_key_false(&__tracepoint_##name.key))		\
+		if (static_branch_unlikely(&__tracepoint_##name.key))	\
 			__DO_TRACE(name,				\
 				TP_ARGS(args),				\
 				TP_CONDITION(cond), 1);			\
@@ -254,7 +254,7 @@ static inline struct tracepoint *tracepoint_ptr_deref(tracepoint_ptr_t *p)
 	extern struct tracepoint __tracepoint_##name;			\
 	static inline void trace_##name(proto)				\
 	{								\
-		if (static_key_false(&__tracepoint_##name.key))		\
+		if (static_branch_unlikely(&__tracepoint_##name.key))	\
 			__DO_TRACE(name,				\
 				TP_ARGS(args),				\
 				TP_CONDITION(cond), 0);			\
@@ -291,7 +291,7 @@ static inline struct tracepoint *tracepoint_ptr_deref(tracepoint_ptr_t *p)
 	static inline bool						\
 	trace_##name##_enabled(void)					\
 	{								\
-		return static_key_false(&__tracepoint_##name.key);	\
+		return static_branch_unlikely(&__tracepoint_##name.key);\
 	}
 
 /*
@@ -308,7 +308,7 @@ static inline struct tracepoint *tracepoint_ptr_deref(tracepoint_ptr_t *p)
 	struct tracepoint __tracepoint_##_name	__used			\
 	__section("__tracepoints") = {					\
 		.name = __tpstrtab_##_name,				\
-		.key = STATIC_KEY_INIT_FALSE,				\
+		.key = STATIC_KEY_FALSE_INIT,				\
 		.static_call_key = &STATIC_CALL_KEY(tp_func_##_name),	\
 		.static_call_tramp = STATIC_CALL_TRAMP_ADDR(tp_func_##_name), \
 		.iterator = &__traceiter_##_name,			\
diff --git a/kernel/tracepoint.c b/kernel/tracepoint.c
index 8d1507dd0724..dc160cc0b616 100644
--- a/kernel/tracepoint.c
+++ b/kernel/tracepoint.c
@@ -358,7 +358,7 @@ static int tracepoint_add_func(struct tracepoint *tp,
 		tracepoint_update_call(tp, tp_funcs);
 		/* Both iterator and static call handle NULL tp->funcs */
 		rcu_assign_pointer(tp->funcs, tp_funcs);
-		static_key_enable(&tp->key);
+		static_branch_enable(&tp->key);
 		break;
 	case TP_FUNC_2:		/* 1->2 */
 		/* Set iterator static call */
@@ -414,7 +414,7 @@ static int tracepoint_remove_func(struct tracepoint *tp,
 		if (tp->unregfunc && static_key_enabled(&tp->key))
 			tp->unregfunc();
 
-		static_key_disable(&tp->key);
+		static_branch_disable(&tp->key);
 		/* Set iterator static call */
 		tracepoint_update_call(tp, tp_funcs);
 		/* Both iterator and static call handle NULL tp->funcs */
-- 
2.46.0

Re: [PATCH] tracepoints: Use new static branch API

[Josh Poimboeuf]

On Tue, Oct 01, 2024 at 03:24:01PM -0700, Josh Poimboeuf wrote:
> The old static key API based on 'struct static_key' is deprecated.
> Convert tracepoints to use the new API.
> 
> Signed-off-by: Josh Poimboeuf <jpoimboe@kernel.org>

Steven,

The kernel test robot found this patch breaks the build with
CONFIG_HIST_TRIGGERS:

  https://lore.kernel.org/202410040333.vJSL1NXx-lkp@intel.com

Here's the fix, do you want to squash it in or should I post a v2?

diff --git a/kernel/trace/trace_events_hist.c b/kernel/trace/trace_events_hist.c
index 5f9119eb7c67..cc2924ad32a3 100644
--- a/kernel/trace/trace_events_hist.c
+++ b/kernel/trace/trace_events_hist.c
@@ -822,7 +822,7 @@ static inline void trace_synth(struct synth_event *event, u64 *var_ref_vals,
 {
 	struct tracepoint *tp = event->tp;
 
-	if (unlikely(atomic_read(&tp->key.enabled) > 0)) {
+	if (unlikely(static_key_enabled(&tp->key))) {
 		struct tracepoint_func *probe_func_ptr;
 		synth_probe_func_t probe_func;
 		void *__data;

Re: [PATCH] tracepoints: Use new static branch API

[Steven Rostedt]

On Mon, 7 Oct 2024 11:25:21 -0700
Josh Poimboeuf <jpoimboe@kernel.org> wrote:

> On Tue, Oct 01, 2024 at 03:24:01PM -0700, Josh Poimboeuf wrote:
> > The old static key API based on 'struct static_key' is deprecated.
> > Convert tracepoints to use the new API.
> > 
> > Signed-off-by: Josh Poimboeuf <jpoimboe@kernel.org>  
> 
> Steven,
> 
> The kernel test robot found this patch breaks the build with
> CONFIG_HIST_TRIGGERS:
> 
>   https://lore.kernel.org/202410040333.vJSL1NXx-lkp@intel.com
> 
> Here's the fix, do you want to squash it in or should I post a v2?

Please post a v2. My workflow relies on patchwork, as it will automatically
update the status of the patch as it goes through git trees and my
"for-next/linus" postings.

If I modify the patch, then I need to do it manually.

-- Steve


> 
> diff --git a/kernel/trace/trace_events_hist.c b/kernel/trace/trace_events_hist.c
> index 5f9119eb7c67..cc2924ad32a3 100644
> --- a/kernel/trace/trace_events_hist.c
> +++ b/kernel/trace/trace_events_hist.c
> @@ -822,7 +822,7 @@ static inline void trace_synth(struct synth_event *event, u64 *var_ref_vals,
>  {
>  	struct tracepoint *tp = event->tp;
>  
> -	if (unlikely(atomic_read(&tp->key.enabled) > 0)) {
> +	if (unlikely(static_key_enabled(&tp->key))) {
>  		struct tracepoint_func *probe_func_ptr;
>  		synth_probe_func_t probe_func;
>  		void *__data;