----- On Mar 27, 2018, at 10:07 AM, rostedt rostedt@xxxxxxxxxxx wrote:
> 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>
Steven showed preference for tracepoint_kernel_find_by_name() at some
point (starting with a tracepoint_ prefix). I'm find with either of
the names.
Reviewed-by: Mathieu Desnoyers <mathieu.desnoyers@xxxxxxxxxxxx>
Thanks,
Mathieu
>
> 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 */
--
Mathieu Desnoyers
EfficiOS Inc.
http://www.efficios.com
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