On Mon, 26 Mar 2018 19:47:02 -0700
Alexei Starovoitov <ast@xxxxxx> wrote:
> From: Alexei Starovoitov <ast@xxxxxxxxxx>
>
> 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@xxxxxxxxxx>
Reviewed-by: Steven Rostedt (VMware) <rostedt@xxxxxxxxxxx>
Thanks for doing this Alexei!
One nit below.
> ---
> 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 */
--
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