[tip:perf/urgent] perf bpf: Make bpf__setup_output_event() return the bpf-output event

From: tip-bot for Arnaldo Carvalho de Melo
Date: Sat Aug 18 2018 - 07:40:31 EST


Commit-ID: 78e890ea8683f7d570f911637b23b23d27be4aed
Gitweb: https://git.kernel.org/tip/78e890ea8683f7d570f911637b23b23d27be4aed
Author: Arnaldo Carvalho de Melo <acme@xxxxxxxxxx>
AuthorDate: Tue, 7 Aug 2018 16:19:05 -0300
Committer: Arnaldo Carvalho de Melo <acme@xxxxxxxxxx>
CommitDate: Wed, 8 Aug 2018 15:55:58 -0300

perf bpf: Make bpf__setup_output_event() return the bpf-output event

We're calling it to setup that event, and we'll need it later to decide
if the bpf-output event we're handling is the one setup for a specific
purpose, return it using ERR_PTR, etc.

Cc: Adrian Hunter <adrian.hunter@xxxxxxxxx>
Cc: David Ahern <dsahern@xxxxxxxxx>
Cc: Jiri Olsa <jolsa@xxxxxxxxxx>
Cc: Namhyung Kim <namhyung@xxxxxxxxxx>
Cc: Wang Nan <wangnan0@xxxxxxxxxx>
Link: https://lkml.kernel.org/n/tip-zhachv7il2n1lopt9aonwhu7@xxxxxxxxxxxxxx
Signed-off-by: Arnaldo Carvalho de Melo <acme@xxxxxxxxxx>
---
tools/perf/builtin-trace.c | 9 +++++----
tools/perf/util/bpf-loader.c | 23 ++++++++++++-----------
tools/perf/util/bpf-loader.h | 7 ++++---
3 files changed, 21 insertions(+), 18 deletions(-)

diff --git a/tools/perf/builtin-trace.c b/tools/perf/builtin-trace.c
index 9b4e24217c46..43a699cfcadf 100644
--- a/tools/perf/builtin-trace.c
+++ b/tools/perf/builtin-trace.c
@@ -3216,8 +3216,9 @@ int cmd_trace(int argc, const char **argv)
};
bool __maybe_unused max_stack_user_set = true;
bool mmap_pages_user_set = true;
+ struct perf_evsel *evsel;
const char * const trace_subcommands[] = { "record", NULL };
- int err;
+ int err = -1;
char bf[BUFSIZ];

signal(SIGSEGV, sighandler_dump_stack);
@@ -3240,9 +3241,9 @@ int cmd_trace(int argc, const char **argv)
"cgroup monitoring only available in system-wide mode");
}

- err = bpf__setup_output_event(trace.evlist, "__augmented_syscalls__");
- if (err) {
- bpf__strerror_setup_output_event(trace.evlist, err, bf, sizeof(bf));
+ evsel = bpf__setup_output_event(trace.evlist, "__augmented_syscalls__");
+ if (IS_ERR(evsel)) {
+ bpf__strerror_setup_output_event(trace.evlist, PTR_ERR(evsel), bf, sizeof(bf));
pr_err("ERROR: Setup trace syscalls enter failed: %s\n", bf);
goto out;
}
diff --git a/tools/perf/util/bpf-loader.c b/tools/perf/util/bpf-loader.c
index 80dead642719..47aac41349a2 100644
--- a/tools/perf/util/bpf-loader.c
+++ b/tools/perf/util/bpf-loader.c
@@ -1535,7 +1535,7 @@ int bpf__apply_obj_config(void)
(strcmp(name, \
bpf_map__name(pos)) == 0))

-int bpf__setup_output_event(struct perf_evlist *evlist, const char *name)
+struct perf_evsel *bpf__setup_output_event(struct perf_evlist *evlist, const char *name)
{
struct bpf_map_priv *tmpl_priv = NULL;
struct bpf_object *obj, *tmp;
@@ -1548,7 +1548,7 @@ int bpf__setup_output_event(struct perf_evlist *evlist, const char *name)
struct bpf_map_priv *priv = bpf_map__priv(map);

if (IS_ERR(priv))
- return -BPF_LOADER_ERRNO__INTERNAL;
+ return ERR_PTR(-BPF_LOADER_ERRNO__INTERNAL);

/*
* No need to check map type: type should have been
@@ -1561,20 +1561,20 @@ int bpf__setup_output_event(struct perf_evlist *evlist, const char *name)
}

if (!need_init)
- return 0;
+ return NULL;

if (!tmpl_priv) {
char *event_definition = NULL;

if (asprintf(&event_definition, "bpf-output/no-inherit=1,name=%s/", name) < 0)
- return -ENOMEM;
+ return ERR_PTR(-ENOMEM);

err = parse_events(evlist, event_definition, NULL);
free(event_definition);

if (err) {
pr_debug("ERROR: failed to create the \"%s\" bpf-output event\n", name);
- return -err;
+ return ERR_PTR(-err);
}

evsel = perf_evlist__last(evlist);
@@ -1584,37 +1584,38 @@ int bpf__setup_output_event(struct perf_evlist *evlist, const char *name)
struct bpf_map_priv *priv = bpf_map__priv(map);

if (IS_ERR(priv))
- return -BPF_LOADER_ERRNO__INTERNAL;
+ return ERR_PTR(-BPF_LOADER_ERRNO__INTERNAL);
if (priv)
continue;

if (tmpl_priv) {
priv = bpf_map_priv__clone(tmpl_priv);
if (!priv)
- return -ENOMEM;
+ return ERR_PTR(-ENOMEM);

err = bpf_map__set_priv(map, priv, bpf_map_priv__clear);
if (err) {
bpf_map_priv__clear(map, priv);
- return err;
+ return ERR_PTR(err);
}
} else if (evsel) {
struct bpf_map_op *op;

op = bpf_map__add_newop(map, NULL);
if (IS_ERR(op))
- return PTR_ERR(op);
+ return ERR_PTR(PTR_ERR(op));
op->op_type = BPF_MAP_OP_SET_EVSEL;
op->v.evsel = evsel;
}
}

- return 0;
+ return evsel;
}

int bpf__setup_stdout(struct perf_evlist *evlist)
{
- return bpf__setup_output_event(evlist, "__bpf_stdout__");
+ struct perf_evsel *evsel = bpf__setup_output_event(evlist, "__bpf_stdout__");
+ return IS_ERR(evsel) ? PTR_ERR(evsel) : 0;
}

#define ERRNO_OFFSET(e) ((e) - __BPF_LOADER_ERRNO__START)
diff --git a/tools/perf/util/bpf-loader.h b/tools/perf/util/bpf-loader.h
index 8eca75145ac2..62d245a90e1d 100644
--- a/tools/perf/util/bpf-loader.h
+++ b/tools/perf/util/bpf-loader.h
@@ -43,6 +43,7 @@ enum bpf_loader_errno {
__BPF_LOADER_ERRNO__END,
};

+struct perf_evsel;
struct bpf_object;
struct parse_events_term;
#define PERF_BPF_PROBE_GROUP "perf_bpf_probe"
@@ -82,7 +83,7 @@ int bpf__apply_obj_config(void);
int bpf__strerror_apply_obj_config(int err, char *buf, size_t size);

int bpf__setup_stdout(struct perf_evlist *evlist);
-int bpf__setup_output_event(struct perf_evlist *evlist, const char *name);
+struct perf_evsel *bpf__setup_output_event(struct perf_evlist *evlist, const char *name);
int bpf__strerror_setup_output_event(struct perf_evlist *evlist, int err, char *buf, size_t size);
#else
#include <errno.h>
@@ -137,10 +138,10 @@ bpf__setup_stdout(struct perf_evlist *evlist __maybe_unused)
return 0;
}

-static inline int
+static inline struct perf_evsel *
bpf__setup_output_event(struct perf_evlist *evlist __maybe_unused, const char *name __maybe_unused)
{
- return 0;
+ return NULL;
}

static inline int