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tools lib bpf: Use IS_ERR() reporting macros with bpf_map__get_private()

tip:perf/core tip-bot for Arnaldo Carvalho de Melo 1 participant 1 message Jun 8, 2016

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Commit-ID:  b4cbfa5670414a567a8a3b368047538f522eff6a
Gitweb:     http://git.kernel.org/tip/b4cbfa5670414a567a8a3b368047538f522eff6a
Author:     Arnaldo Carvalho de Melo <[email protected]>
AuthorDate: Thu, 2 Jun 2016 10:51:59 -0300
Committer:  Arnaldo Carvalho de Melo <[email protected]>
CommitDate: Mon, 6 Jun 2016 18:18:30 -0300

tools lib bpf: Use IS_ERR() reporting macros with bpf_map__get_private()

To try to, over time, consistently use the IS_ERR() interface instead of using two return values, i.e. the integer return value for an error and the pointer address to return the bpf_map->priv pointer.

Also rename it to bpf__priv(), to leave the "get" term for reference counting.

Noticed while working on using BPF for collecting non-integer syscall argument payloads (struct sockaddr in calls such as connect(), for instance), where we need to use BPF maps and thus generalise bpf__setup_stdout() to connect bpf_output events with maps in a bpf proggie.

Acked-by Wang Nan <[email protected]>
Cc Adrian Hunter <[email protected]>
Cc David Ahern <[email protected]>
Cc Jiri Olsa <[email protected]>
Cc Milian Wolff <[email protected]>
Cc Namhyung Kim <[email protected]>
Link http://lkml.kernel.org/n/[email protected] open here
Signed-off-by Arnaldo Carvalho de Melo <[email protected]>
---
 tools/lib/bpf/libbpf.c       |  9 ++-------
 tools/lib/bpf/libbpf.h       |  2 +-
 tools/perf/util/bpf-loader.c | 23 +++++++++--------------
 3 files changed, 12 insertions(+), 22 deletions(-)
tools/lib/bpf/libbpf.c +2 -7
index 7e543c3..9bba1a9 100644
@@ -1351,14 +1351,9 @@ int bpf_map__set_private(struct bpf_map *map, void *priv,
 	return 0;
 }
 
-int bpf_map__get_private(struct bpf_map *map, void **ppriv)
+void *bpf_map__priv(struct bpf_map *map)
 {
-	if (!map)
-		return -EINVAL;
-
-	if (ppriv)
-		*ppriv = map->priv;
-	return 0;
+	return map ? map->priv : ERR_PTR(-EINVAL);
 }
 
 struct bpf_map *
tools/lib/bpf/libbpf.h +1 -1
index a51594c..916abf9 100644
@@ -187,6 +187,6 @@ const char *bpf_map__get_name(struct bpf_map *map);
 typedef void (*bpf_map_clear_priv_t)(struct bpf_map *, void *);
 int bpf_map__set_private(struct bpf_map *map, void *priv,
 			 bpf_map_clear_priv_t clear_priv);
-int bpf_map__get_private(struct bpf_map *map, void **ppriv);
+void *bpf_map__priv(struct bpf_map *map);
 
 #endif
tools/perf/util/bpf-loader.c +9 -14
index 493307d..e9a034e 100644
@@ -897,15 +897,13 @@ bpf_map_priv__clone(struct bpf_map_priv *priv)
 static int
 bpf_map__add_op(struct bpf_map *map, struct bpf_map_op *op)
 {
-	struct bpf_map_priv *priv;
+	struct bpf_map_priv *priv = bpf_map__priv(map);
 	const char *map_name;
-	int err;
 
 	map_name = bpf_map__get_name(map);
-	err = bpf_map__get_private(map, (void **)&priv);
-	if (err) {
+	if (IS_ERR(priv)) {
 		pr_debug("Failed to get private from map %s\n", map_name);
-		return err;
+		return PTR_ERR(priv);
 	}
 
 	if (!priv) {

@@ -1264,12 +1262,11 @@ bpf_map_config_foreach_key(struct bpf_map *map,
 	const char *name;
 	struct bpf_map_op *op;
 	struct bpf_map_def def;
-	struct bpf_map_priv *priv;
+	struct bpf_map_priv *priv = bpf_map__priv(map);
 
 	name = bpf_map__get_name(map);
 
-	err = bpf_map__get_private(map, (void **)&priv);
-	if (err) {
+	if (IS_ERR(priv)) {
 		pr_debug("ERROR: failed to get private from map %s\n", name);
 		return -BPF_LOADER_ERRNO__INTERNAL;
 	}

@@ -1489,10 +1486,9 @@ int bpf__setup_stdout(struct perf_evlist *evlist __maybe_unused)
 	bool need_init = false;
 
 	bpf__for_each_stdout_map(map, obj, tmp) {
-		struct bpf_map_priv *priv;
+		struct bpf_map_priv *priv = bpf_map__priv(map);
 
-		err = bpf_map__get_private(map, (void **)&priv);
-		if (err)
+		if (IS_ERR(priv))
 			return -BPF_LOADER_ERRNO__INTERNAL;
 
 		/*

@@ -1520,10 +1516,9 @@ int bpf__setup_stdout(struct perf_evlist *evlist __maybe_unused)
 	}
 
 	bpf__for_each_stdout_map(map, obj, tmp) {
-		struct bpf_map_priv *priv;
+		struct bpf_map_priv *priv = bpf_map__priv(map);
 
-		err = bpf_map__get_private(map, (void **)&priv);
-		if (err)
+		if (IS_ERR(priv))
 			return -BPF_LOADER_ERRNO__INTERNAL;
 		if (priv)
 			continue;