[PATCH v6 perf/core 0/2] perf: stop using deprecated bpf APIs

[PATCH v6 perf/core 0/2] perf: stop using deprecated bpf APIs

[Andrii Nakryiko]

libbpf's bpf_prog_load() and bpf__object_next() APIs are deprecated.
remove perf's usage of these deprecated functions. After this patch
set, the only remaining libbpf deprecated APIs in perf would be
bpf_program__set_prep() and bpf_program__nth_fd().

v5 -> v6:
  - rebase onto perf/core tree (Arnaldo);
v4 -> v5:
  - add bpf_perf_object__add() and use it where appropriate (Jiri);
  - use __maybe_unused in first patch;
v3 -> v4:
  - Fixed commit title
  - Added weak definition for deprecated function
v2 -> v3:
  - Fixed commit message to use upstream perf
v1 -> v2:
  - Added missing commit message
  - Added more details to commit message and added steps to reproduce
    original test case.

Christy Lee (2):
  perf: Stop using deprecated bpf_load_program() API
  perf: Stop using deprecated bpf_object__next() API

 tools/perf/tests/bpf.c       | 14 ++----
 tools/perf/util/bpf-event.c  | 13 +++++
 tools/perf/util/bpf-loader.c | 98 +++++++++++++++++++++++++++++-------
 3 files changed, 96 insertions(+), 29 deletions(-)

-- 
2.30.2

[PATCH v6 perf/core 1/2] perf: Stop using deprecated bpf_load_program() API

[Andrii Nakryiko]

From: Christy Lee <christylee@fb.com>

bpf_load_program() API is deprecated, remove perf's usage of the
deprecated function. Add a __weak function declaration for libbpf
version compatibility.

Signed-off-by: Christy Lee <christylee@fb.com>
Signed-off-by: Andrii Nakryiko <andrii@kernel.org>
---
 tools/perf/tests/bpf.c      | 14 ++++----------
 tools/perf/util/bpf-event.c | 13 +++++++++++++
 2 files changed, 17 insertions(+), 10 deletions(-)

diff --git a/tools/perf/tests/bpf.c b/tools/perf/tests/bpf.c
index 573490530194..57b9591f7cbb 100644
--- a/tools/perf/tests/bpf.c
+++ b/tools/perf/tests/bpf.c
@@ -281,8 +281,8 @@ static int __test__bpf(int idx)
 
 static int check_env(void)
 {
+	LIBBPF_OPTS(bpf_prog_load_opts, opts);
 	int err;
-	unsigned int kver_int;
 	char license[] = "GPL";
 
 	struct bpf_insn insns[] = {
@@ -290,19 +290,13 @@ static int check_env(void)
 		BPF_EXIT_INSN(),
 	};
 
-	err = fetch_kernel_version(&kver_int, NULL, 0);
+	err = fetch_kernel_version(&opts.kern_version, NULL, 0);
 	if (err) {
 		pr_debug("Unable to get kernel version\n");
 		return err;
 	}
-
-/* temporarily disable libbpf deprecation warnings */
-#pragma GCC diagnostic push
-#pragma GCC diagnostic ignored "-Wdeprecated-declarations"
-	err = bpf_load_program(BPF_PROG_TYPE_KPROBE, insns,
-			       ARRAY_SIZE(insns),
-			       license, kver_int, NULL, 0);
-#pragma GCC diagnostic pop
+	err = bpf_prog_load(BPF_PROG_TYPE_KPROBE, NULL, license, insns,
+			    ARRAY_SIZE(insns), &opts);
 	if (err < 0) {
 		pr_err("Missing basic BPF support, skip this test: %s\n",
 		       strerror(errno));
diff --git a/tools/perf/util/bpf-event.c b/tools/perf/util/bpf-event.c
index a517eaa51eb3..bd1bc3c86cac 100644
--- a/tools/perf/util/bpf-event.c
+++ b/tools/perf/util/bpf-event.c
@@ -33,6 +33,19 @@ struct btf * __weak btf__load_from_kernel_by_id(__u32 id)
        return err ? ERR_PTR(err) : btf;
 }
 
+int __weak bpf_prog_load(enum bpf_prog_type prog_type,
+			 const char *prog_name __maybe_unused,
+			 const char *license,
+			 const struct bpf_insn *insns, size_t insn_cnt,
+			 const struct bpf_prog_load_opts *opts)
+{
+#pragma GCC diagnostic push
+#pragma GCC diagnostic ignored "-Wdeprecated-declarations"
+	return bpf_load_program(prog_type, insns, insn_cnt, license,
+				opts->kern_version, opts->log_buf, opts->log_size);
+#pragma GCC diagnostic pop
+}
+
 struct bpf_program * __weak
 bpf_object__next_program(const struct bpf_object *obj, struct bpf_program *prev)
 {
-- 
2.30.2

[PATCH v6 perf/core 2/2] perf: Stop using deprecated bpf_object__next() API

[Andrii Nakryiko]

From: Christy Lee <christylee@fb.com>

Libbpf has deprecated the ability to keep track of object list inside
libbpf, it now requires applications to track usage multiple bpf
objects directly. Remove usage of bpf_object__next() API and hoist the
tracking logic to perf.

Acked-by: Song Liu <songliubraving@fb.com>
Signed-off-by: Christy Lee <christylee@fb.com>
Signed-off-by: Jiri Olsa <jolsa@redhat.com>
Signed-off-by: Andrii Nakryiko <andrii@kernel.org>
---
 tools/perf/util/bpf-loader.c | 98 +++++++++++++++++++++++++++++-------
 1 file changed, 79 insertions(+), 19 deletions(-)

diff --git a/tools/perf/util/bpf-loader.c b/tools/perf/util/bpf-loader.c
index 7ecfaac7536a..db61e09be585 100644
--- a/tools/perf/util/bpf-loader.c
+++ b/tools/perf/util/bpf-loader.c
@@ -49,8 +49,52 @@ struct bpf_prog_priv {
 	int *type_mapping;
 };
 
+struct bpf_perf_object {
+	struct list_head list;
+	struct bpf_object *obj;
+};
+
+static LIST_HEAD(bpf_objects_list);
+
+static struct bpf_perf_object *
+bpf_perf_object__next(struct bpf_perf_object *prev)
+{
+	struct bpf_perf_object *next;
+
+	if (!prev)
+		next = list_first_entry(&bpf_objects_list,
+					struct bpf_perf_object,
+					list);
+	else
+		next = list_next_entry(prev, list);
+
+	/* Empty list is noticed here so don't need checking on entry. */
+	if (&next->list == &bpf_objects_list)
+		return NULL;
+
+	return next;
+}
+
+#define bpf_perf_object__for_each(perf_obj, tmp)	\
+	for ((perf_obj) = bpf_perf_object__next(NULL),	\
+	     (tmp) = bpf_perf_object__next(perf_obj);	\
+	     (perf_obj) != NULL;			\
+	     (perf_obj) = (tmp), (tmp) = bpf_perf_object__next(tmp))
+
 static bool libbpf_initialized;
 
+static int bpf_perf_object__add(struct bpf_object *obj)
+{
+	struct bpf_perf_object *perf_obj = zalloc(sizeof(*perf_obj));
+
+	if (perf_obj) {
+		INIT_LIST_HEAD(&perf_obj->list);
+		perf_obj->obj = obj;
+		list_add_tail(&perf_obj->list, &bpf_objects_list);
+	}
+	return perf_obj ? 0 : -ENOMEM;
+}
+
 struct bpf_object *
 bpf__prepare_load_buffer(void *obj_buf, size_t obj_buf_sz, const char *name)
 {
@@ -67,9 +111,21 @@ bpf__prepare_load_buffer(void *obj_buf, size_t obj_buf_sz, const char *name)
 		return ERR_PTR(-EINVAL);
 	}
 
+	if (bpf_perf_object__add(obj)) {
+		bpf_object__close(obj);
+		return ERR_PTR(-ENOMEM);
+	}
+
 	return obj;
 }
 
+static void bpf_perf_object__close(struct bpf_perf_object *perf_obj)
+{
+	list_del(&perf_obj->list);
+	bpf_object__close(perf_obj->obj);
+	free(perf_obj);
+}
+
 struct bpf_object *bpf__prepare_load(const char *filename, bool source)
 {
 	struct bpf_object *obj;
@@ -100,24 +156,30 @@ struct bpf_object *bpf__prepare_load(const char *filename, bool source)
 			llvm__dump_obj(filename, obj_buf, obj_buf_sz);
 
 		free(obj_buf);
-	} else
+	} else {
 		obj = bpf_object__open(filename);
+	}
 
 	if (IS_ERR_OR_NULL(obj)) {
 		pr_debug("bpf: failed to load %s\n", filename);
 		return obj;
 	}
 
+	if (bpf_perf_object__add(obj)) {
+		bpf_object__close(obj);
+		return ERR_PTR(-BPF_LOADER_ERRNO__COMPILE);
+	}
+
 	return obj;
 }
 
 void bpf__clear(void)
 {
-	struct bpf_object *obj, *tmp;
+	struct bpf_perf_object *perf_obj, *tmp;
 
-	bpf_object__for_each_safe(obj, tmp) {
-		bpf__unprobe(obj);
-		bpf_object__close(obj);
+	bpf_perf_object__for_each(perf_obj, tmp) {
+		bpf__unprobe(perf_obj->obj);
+		bpf_perf_object__close(perf_obj);
 	}
 }
 
@@ -1501,11 +1563,11 @@ apply_obj_config_object(struct bpf_object *obj)
 
 int bpf__apply_obj_config(void)
 {
-	struct bpf_object *obj, *tmp;
+	struct bpf_perf_object *perf_obj, *tmp;
 	int err;
 
-	bpf_object__for_each_safe(obj, tmp) {
-		err = apply_obj_config_object(obj);
+	bpf_perf_object__for_each(perf_obj, tmp) {
+		err = apply_obj_config_object(perf_obj->obj);
 		if (err)
 			return err;
 	}
@@ -1513,26 +1575,24 @@ int bpf__apply_obj_config(void)
 	return 0;
 }
 
-#define bpf__for_each_map(pos, obj, objtmp)	\
-	bpf_object__for_each_safe(obj, objtmp)	\
-		bpf_object__for_each_map(pos, obj)
+#define bpf__perf_for_each_map(map, pobj, tmp)			\
+	bpf_perf_object__for_each(pobj, tmp)			\
+		bpf_object__for_each_map(map, pobj->obj)
 
-#define bpf__for_each_map_named(pos, obj, objtmp, name)	\
-	bpf__for_each_map(pos, obj, objtmp) 		\
-		if (bpf_map__name(pos) && 		\
-			(strcmp(name, 			\
-				bpf_map__name(pos)) == 0))
+#define bpf__perf_for_each_map_named(map, pobj, pobjtmp, name)	\
+	bpf__perf_for_each_map(map, pobj, pobjtmp)		\
+		if (bpf_map__name(map) && (strcmp(name, bpf_map__name(map)) == 0))
 
 struct evsel *bpf__setup_output_event(struct evlist *evlist, const char *name)
 {
 	struct bpf_map_priv *tmpl_priv = NULL;
-	struct bpf_object *obj, *tmp;
+	struct bpf_perf_object *perf_obj, *tmp;
 	struct evsel *evsel = NULL;
 	struct bpf_map *map;
 	int err;
 	bool need_init = false;
 
-	bpf__for_each_map_named(map, obj, tmp, name) {
+	bpf__perf_for_each_map_named(map, perf_obj, tmp, name) {
 		struct bpf_map_priv *priv = bpf_map__priv(map);
 
 		if (IS_ERR(priv))
@@ -1568,7 +1628,7 @@ struct evsel *bpf__setup_output_event(struct evlist *evlist, const char *name)
 		evsel = evlist__last(evlist);
 	}
 
-	bpf__for_each_map_named(map, obj, tmp, name) {
+	bpf__perf_for_each_map_named(map, perf_obj, tmp, name) {
 		struct bpf_map_priv *priv = bpf_map__priv(map);
 
 		if (IS_ERR(priv))
-- 
2.30.2

Re: [PATCH v6 perf/core 0/2] perf: stop using deprecated bpf APIs

[Jiri Olsa]

On Sat, Feb 12, 2022 at 07:51:23AM -0800, Andrii Nakryiko wrote:
> libbpf's bpf_prog_load() and bpf__object_next() APIs are deprecated.
> remove perf's usage of these deprecated functions. After this patch
> set, the only remaining libbpf deprecated APIs in perf would be
> bpf_program__set_prep() and bpf_program__nth_fd().
> 
> v5 -> v6:
>   - rebase onto perf/core tree (Arnaldo);

looks good, tests are passing for me

jirka

> v4 -> v5:
>   - add bpf_perf_object__add() and use it where appropriate (Jiri);
>   - use __maybe_unused in first patch;
> v3 -> v4:
>   - Fixed commit title
>   - Added weak definition for deprecated function
> v2 -> v3:
>   - Fixed commit message to use upstream perf
> v1 -> v2:
>   - Added missing commit message
>   - Added more details to commit message and added steps to reproduce
>     original test case.
> 
> Christy Lee (2):
>   perf: Stop using deprecated bpf_load_program() API
>   perf: Stop using deprecated bpf_object__next() API
> 
>  tools/perf/tests/bpf.c       | 14 ++----
>  tools/perf/util/bpf-event.c  | 13 +++++
>  tools/perf/util/bpf-loader.c | 98 +++++++++++++++++++++++++++++-------
>  3 files changed, 96 insertions(+), 29 deletions(-)
> 
> -- 
> 2.30.2
> 

Re: [PATCH v6 perf/core 0/2] perf: stop using deprecated bpf APIs

[Andrii Nakryiko]

On Sat, Feb 12, 2022 at 10:18 AM Jiri Olsa <olsajiri@gmail.com> wrote:
>
> On Sat, Feb 12, 2022 at 07:51:23AM -0800, Andrii Nakryiko wrote:
> > libbpf's bpf_prog_load() and bpf__object_next() APIs are deprecated.
> > remove perf's usage of these deprecated functions. After this patch
> > set, the only remaining libbpf deprecated APIs in perf would be
> > bpf_program__set_prep() and bpf_program__nth_fd().
> >
> > v5 -> v6:
> >   - rebase onto perf/core tree (Arnaldo);
>
> looks good, tests are passing for me

great, thanks for checking!

>
> jirka
>
> > v4 -> v5:
> >   - add bpf_perf_object__add() and use it where appropriate (Jiri);
> >   - use __maybe_unused in first patch;
> > v3 -> v4:
> >   - Fixed commit title
> >   - Added weak definition for deprecated function
> > v2 -> v3:
> >   - Fixed commit message to use upstream perf
> > v1 -> v2:
> >   - Added missing commit message
> >   - Added more details to commit message and added steps to reproduce
> >     original test case.
> >
> > Christy Lee (2):
> >   perf: Stop using deprecated bpf_load_program() API
> >   perf: Stop using deprecated bpf_object__next() API
> >
> >  tools/perf/tests/bpf.c       | 14 ++----
> >  tools/perf/util/bpf-event.c  | 13 +++++
> >  tools/perf/util/bpf-loader.c | 98 +++++++++++++++++++++++++++++-------
> >  3 files changed, 96 insertions(+), 29 deletions(-)
> >
> > --
> > 2.30.2
> >

Re: [PATCH v6 perf/core 0/2] perf: stop using deprecated bpf APIs

[Arnaldo Carvalho de Melo]

Em Sat, Feb 12, 2022 at 05:47:25PM -0800, Andrii Nakryiko escreveu:
> On Sat, Feb 12, 2022 at 10:18 AM Jiri Olsa <olsajiri@gmail.com> wrote:
> >
> > On Sat, Feb 12, 2022 at 07:51:23AM -0800, Andrii Nakryiko wrote:
> > > libbpf's bpf_prog_load() and bpf__object_next() APIs are deprecated.
> > > remove perf's usage of these deprecated functions. After this patch
> > > set, the only remaining libbpf deprecated APIs in perf would be
> > > bpf_program__set_prep() and bpf_program__nth_fd().
> > >
> > > v5 -> v6:
> > >   - rebase onto perf/core tree (Arnaldo);
> >
> > looks good, tests are passing for me
> 
> great, thanks for checking!

All tests passed, patches merged and pushed out to perf/core, thanks!

- Arnaldo
 
> >
> > jirka
> >
> > > v4 -> v5:
> > >   - add bpf_perf_object__add() and use it where appropriate (Jiri);
> > >   - use __maybe_unused in first patch;
> > > v3 -> v4:
> > >   - Fixed commit title
> > >   - Added weak definition for deprecated function
> > > v2 -> v3:
> > >   - Fixed commit message to use upstream perf
> > > v1 -> v2:
> > >   - Added missing commit message
> > >   - Added more details to commit message and added steps to reproduce
> > >     original test case.
> > >
> > > Christy Lee (2):
> > >   perf: Stop using deprecated bpf_load_program() API
> > >   perf: Stop using deprecated bpf_object__next() API
> > >
> > >  tools/perf/tests/bpf.c       | 14 ++----
> > >  tools/perf/util/bpf-event.c  | 13 +++++
> > >  tools/perf/util/bpf-loader.c | 98 +++++++++++++++++++++++++++++-------
> > >  3 files changed, 96 insertions(+), 29 deletions(-)
> > >
> > > --
> > > 2.30.2
> > >

-- 

- Arnaldo