On Tue, 1 Oct 2024 14:15:43 -0700
Josh Poimboeuf <jpoim...@kernel.org> wrote:
> On Tue, Oct 01, 2024 at 01:29:58PM +0000, Alice Ryhl wrote:
> > Add just enough support for static key so that we can use it from
> > tracepoints. Tracepoints rely on `static_key_false` even though it is
> > deprecated, so we add the same functionality to Rust.
>
> Instead of extending the old deprecated static key interface into Rust,
> can we just change tracepoints to use the new one?
Sure, care to send the patch properly, and I can add it to my queue.
-- Steve
>
> /me makes a note to go convert the other users...
>
> From: Josh Poimboeuf <jpoim...@kernel.org>
> Subject: [PATCH] tracepoints: Use new static branch API
>
> The old static key API based on 'struct static_key' is deprecated.
> Convert tracepoints to use the new API.
>
> Signed-off-by: Josh Poimboeuf <jpoim...@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 */
