From mboxrd@z Thu Jan 1 00:00:00 1970 From: Steven Rostedt Subject: Re: [PATCH v6 bpf-next 07/11] tracepoint: introduce kernel_tracepoint_find_by_name Date: Tue, 27 Mar 2018 10:07:11 -0400 Message-ID: <20180327100711.0ec7aafb@gandalf.local.home> References: <20180327024706.2064725-1-ast@fb.com> <20180327024706.2064725-8-ast@fb.com> Mime-Version: 1.0 Content-Type: text/plain; charset=US-ASCII Content-Transfer-Encoding: 7bit Cc: , , , , , , , Mathieu Desnoyers To: Alexei Starovoitov Return-path: Received: from mail.kernel.org ([198.145.29.99]:41750 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1750944AbeC0OHO (ORCPT ); Tue, 27 Mar 2018 10:07:14 -0400 In-Reply-To: <20180327024706.2064725-8-ast@fb.com> Sender: netdev-owner@vger.kernel.org List-ID: On Mon, 26 Mar 2018 19:47:02 -0700 Alexei Starovoitov wrote: > From: Alexei Starovoitov > > 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 Reviewed-by: Steven Rostedt (VMware) 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 */ From mboxrd@z Thu Jan 1 00:00:00 1970 From: Steven Rostedt Subject: Re: [PATCH v6 bpf-next 07/11] tracepoint: introduce kernel_tracepoint_find_by_name Date: Tue, 27 Mar 2018 10:07:11 -0400 Message-ID: <20180327100711.0ec7aafb@gandalf.local.home> References: <20180327024706.2064725-1-ast@fb.com> <20180327024706.2064725-8-ast@fb.com> Mime-Version: 1.0 Content-Type: text/plain; charset=US-ASCII Content-Transfer-Encoding: 7bit Return-path: In-Reply-To: <20180327024706.2064725-8-ast@fb.com> Sender: netdev-owner@vger.kernel.org To: Alexei Starovoitov Cc: davem@davemloft.net, daniel@iogearbox.net, torvalds@linux-foundation.org, peterz@infradead.org, netdev@vger.kernel.org, kernel-team@fb.com, linux-api@vger.kernel.org, Mathieu Desnoyers List-Id: linux-api@vger.kernel.org On Mon, 26 Mar 2018 19:47:02 -0700 Alexei Starovoitov wrote: > From: Alexei Starovoitov > > 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 Reviewed-by: Steven Rostedt (VMware) 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 */