Re: [PATCH v6 bpf-next 07/11] tracepoint: introduce kernel_tracepoint_find_by_name
From: Steven Rostedt <rostedt@goodmis.org>
Date: 2018-03-27 14:07:14
Also in:
netdev
On Mon, 26 Mar 2018 19:47:02 -0700 Alexei Starovoitov [off-list ref] wrote:
From: Alexei Starovoitov <ast@kernel.org> introduce kernel_tracepoint_find_by_name() helper to let bpf core find tracepoint by name and later attach bpf probe to a tracepoint Signed-off-by: Alexei Starovoitov <ast@kernel.org>
Reviewed-by: Steven Rostedt (VMware) <rostedt@goodmis.org> Thanks for doing this Alexei! One nit below.
quoted hunk ↗ jump to hunk
--- include/linux/tracepoint.h | 6 ++++++ kernel/tracepoint.c | 9 +++++++++ 2 files changed, 15 insertions(+)diff --git a/include/linux/tracepoint.h b/include/linux/tracepoint.h index c92f4adbc0d7..a00b84473211 100644 --- a/include/linux/tracepoint.h +++ b/include/linux/tracepoint.h@@ -43,6 +43,12 @@ tracepoint_probe_unregister(struct tracepoint *tp, void *probe, void *data); extern void for_each_kernel_tracepoint(void (*fct)(struct tracepoint *tp, void *priv), void *priv); +#ifdef CONFIG_TRACEPOINTS +struct tracepoint *kernel_tracepoint_find_by_name(const char *name); +#else +static inline struct tracepoint * +kernel_tracepoint_find_by_name(const char *name) { return NULL; } +#endif #ifdef CONFIG_MODULES struct tp_module {diff --git a/kernel/tracepoint.c b/kernel/tracepoint.c index 671b13457387..e2a9a0391ae2 100644 --- a/kernel/tracepoint.c +++ b/kernel/tracepoint.c@@ -528,6 +528,15 @@ void for_each_kernel_tracepoint(void (*fct)(struct tracepoint *tp, void *priv), } EXPORT_SYMBOL_GPL(for_each_kernel_tracepoint); +struct tracepoint *kernel_tracepoint_find_by_name(const char *name) +{ + struct tracepoint * const *tp = __start___tracepoints_ptrs; + + for (; tp < __stop___tracepoints_ptrs; tp++) + if (!strcmp((*tp)->name, name)) + return *tp;
Usually for cases like this, we prefer to add brackets for the for
block, as it's not a single line below it.
for (; tp < __stop__tracepoints_ptrs; tp++) {
if (!strcmp((*tp)->name, name))
return *tp;
}
-- Steve
+ return NULL; +} #ifdef CONFIG_HAVE_SYSCALL_TRACEPOINTS /* NB: reg/unreg are called while guarded with the tracepoints_mutex */