[RFC PATCH v8 43/49] perf tools: Iterater over tev instead of pev in bpf__for_each_program

[Wang Nan <wangnan0@huawei.com>]

This patch renames bpf__for_each_program() to bpf__for_each_tev() and
makes it iterate over 'struct probe_trace_event' instead of
'struct probe_trace_event' during the loop. The callback (add_bpf_event())
now get rid of the iteration.

This is preparation for further patches, which will allow generating
multiple instances form one BPF program and install then onto different
'struct probe_trace_event'.

Signed-off-by: Wang Nan <wangnan0@huawei.com>
---
 tools/perf/util/bpf-loader.c | 31 +++++++++++++++++++------------
 tools/perf/util/bpf-loader.h |  8 ++++----
 tools/perf/util/evlist.c     | 42 ++++++++++++++++--------------------------
 3 files changed, 39 insertions(+), 42 deletions(-)

diff --git a/tools/perf/util/bpf-loader.c b/tools/perf/util/bpf-loader.c
index 2936adf..8812e24 100644
--- a/tools/perf/util/bpf-loader.c
+++ b/tools/perf/util/bpf-loader.c
@@ -266,8 +266,7 @@ errout:
 }
 
 int
-bpf__for_each_program(bpf_prog_iter_callback_t func,
-		      void *arg)
+bpf__for_each_tev(bpf_prog_iter_callback_t func, void *arg)
 {
 	struct bpf_object *obj, *tmp;
 	struct bpf_program *prog;
@@ -275,8 +274,10 @@ bpf__for_each_program(bpf_prog_iter_callback_t func,
 
 	bpf_object__for_each(obj, tmp) {
 		bpf_object__for_each_program(prog, obj) {
+			struct probe_trace_event *tev;
+			struct perf_probe_event *pev;
 			struct bpf_prog_priv *priv;
-			int fd;
+			int i, fd;
 
 			err = bpf_program__get_private(prog,
 						       (void **)&priv);
@@ -284,16 +285,22 @@ bpf__for_each_program(bpf_prog_iter_callback_t func,
 				pr_err("bpf: failed to get private field\n");
 				return -EINVAL;
 			}
-			err = bpf_program__get_fd(prog, &fd);
-			if (err || fd < 0) {
-				pr_err("bpf: failed to get file descriptor\n");
-				return -EINVAL;
-			}
 
-			err = func(priv->pev, fd, arg);
-			if (err) {
-				pr_err("bpf: call back failed, stop iterate\n");
-				return err;
+			pev = priv->pev;
+			for (i = 0; i < pev->ntevs; i++) {
+				tev = &pev->tevs[i];
+
+				err = bpf_program__get_fd(prog, &fd);
+
+				if (err || fd < 0) {
+					pr_err("bpf: failed to get file descriptor\n");
+					return -EINVAL;
+				}
+				err = func(tev, fd, arg);
+				if (err) {
+					pr_err("bpf: call back failed, stop iterate\n");
+					return err;
+				}
 			}
 		}
 	}
diff --git a/tools/perf/util/bpf-loader.h b/tools/perf/util/bpf-loader.h
index da03e12..83697e0 100644
--- a/tools/perf/util/bpf-loader.h
+++ b/tools/perf/util/bpf-loader.h
@@ -11,7 +11,7 @@
 
 #define PERF_BPF_PROBE_GROUP "perf_bpf_probe"
 
-typedef int (*bpf_prog_iter_callback_t)(struct perf_probe_event *pev,
+typedef int (*bpf_prog_iter_callback_t)(struct probe_trace_event *tev,
 					int fd, void *arg);
 
 #ifdef HAVE_LIBBPF_SUPPORT
@@ -22,7 +22,7 @@ int bpf__load(void);
 
 void bpf__clear(void);
 
-int bpf__for_each_program(bpf_prog_iter_callback_t func, void *arg);
+int bpf__for_each_tev(bpf_prog_iter_callback_t func, void *arg);
 #else
 static inline int bpf__prepare_load(const char *filename __maybe_unused,
 				    bool source __maybe_unused)
@@ -37,8 +37,8 @@ static inline int bpf__load(void) { return 0; }
 static inline void bpf__clear(void) { }
 
 static inline int
-bpf__for_each_program(bpf_prog_iter_callback_t func __maybe_unused,
-		      void *arg __maybe_unused)
+bpf__for_each_tev(bpf_prog_iter_callback_t func __maybe_unused,
+		  void *arg __maybe_unused)
 {
 	return 0;
 }
diff --git a/tools/perf/util/evlist.c b/tools/perf/util/evlist.c
index 4022bd1..e50aed3 100644
--- a/tools/perf/util/evlist.c
+++ b/tools/perf/util/evlist.c
@@ -195,42 +195,32 @@ error:
 	return -ENOMEM;
 }
 
-static int add_bpf_event(struct perf_probe_event *pev, int fd,
+static int add_bpf_event(struct probe_trace_event *tev, int fd,
 			 void *arg)
 {
 	struct perf_evlist *evlist = arg;
 	struct perf_evsel *pos;
 	struct list_head list;
-	int err, idx, entries, i;
-
-	if (!pev || !pev->ntevs) {
-		pr_err("Internal error: add bpf event before probing\n");
-		return -EINVAL;
-	}
+	int err, idx, entries;
 
 	pr_debug("add bpf event %s:%s and attach bpf program %d\n",
-		 pev->group, pev->event, fd);
+			tev->group, tev->event, fd);
 	INIT_LIST_HEAD(&list);
 	idx = evlist->nr_entries;
 
-	for (i = 0; i < pev->ntevs; i++) {
-		struct probe_trace_event *tev = &pev->tevs[i];
-
-		pr_debug("adding %s:%s\n", tev->group, tev->event);
-		err = parse_events_add_tracepoint(&list, &idx,
-						  tev->group,
-						  tev->event);
-		if (err) {
-			struct perf_evsel *evsel, *tmp;
-
-			pr_err("Failed to add BPF event %s:%s\n",
-			       tev->group, tev->event);
-			list_for_each_entry_safe(evsel, tmp, &list, node) {
-				list_del(&evsel->node);
-				perf_evsel__delete(evsel);
-			}
-			return -EINVAL;
+	pr_debug("adding %s:%s\n", tev->group, tev->event);
+	err = parse_events_add_tracepoint(&list, &idx, tev->group,
+					  tev->event);
+	if (err) {
+		struct perf_evsel *evsel, *tmp;
+
+		pr_err("Failed to add BPF event %s:%s\n",
+				tev->group, tev->event);
+		list_for_each_entry_safe(evsel, tmp, &list, node) {
+			list_del(&evsel->node);
+			perf_evsel__delete(evsel);
 		}
+		return -EINVAL;
 	}
 
 	list_for_each_entry(pos, &list, node)
@@ -242,7 +232,7 @@ static int add_bpf_event(struct perf_probe_event *pev, int fd,
 
 int perf_evlist__add_bpf(struct perf_evlist *evlist)
 {
-	return bpf__for_each_program(add_bpf_event, evlist);
+	return bpf__for_each_tev(add_bpf_event, evlist);
 }
 
 static int perf_evlist__add_attrs(struct perf_evlist *evlist,
-- 
1.8.3.4