[tip:perf/core] perf bpf: Add simple pid_filter class accessible to BPF proggies

[tip-bot for Arnaldo Carvalho de Melo]

Commit-ID:  8008aab0962ea68cc00d15e8d7b0637b48837a40
Gitweb:     https://git.kernel.org/tip/8008aab0962ea68cc00d15e8d7b0637b48837a40
Author:     Arnaldo Carvalho de Melo <acme@xxxxxxxxxx>
AuthorDate: Tue, 6 Nov 2018 15:50:36 -0300
Committer:  Arnaldo Carvalho de Melo <acme@xxxxxxxxxx>
CommitDate: Wed, 21 Nov 2018 12:00:31 -0300

perf bpf: Add simple pid_filter class accessible to BPF proggies

Will be used in the augmented_raw_syscalls.c to implement 'perf trace
--filter-pids'.

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-9sybmz4vchlbpqwx2am13h9e@xxxxxxxxxxxxxx
Signed-off-by: Arnaldo Carvalho de Melo <acme@xxxxxxxxxx>
---
 tools/perf/include/bpf/pid_filter.h | 21 +++++++++++++++++++++
 1 file changed, 21 insertions(+)

diff --git a/tools/perf/include/bpf/pid_filter.h b/tools/perf/include/bpf/pid_filter.h
new file mode 100644
index 000000000000..6e61c4bdf548
--- /dev/null
+++ b/tools/perf/include/bpf/pid_filter.h
@@ -0,0 +1,21 @@
+// SPDX-License-Identifier: LGPL-2.1
+
+#ifndef _PERF_BPF_PID_FILTER_
+#define _PERF_BPF_PID_FILTER_
+
+#include <bpf.h>
+
+#define pid_filter(name) pid_map(name, bool)
+
+static int pid_filter__add(struct bpf_map *pids, pid_t pid)
+{
+	bool value = true;
+	return bpf_map_update_elem(pids, &pid, &value, BPF_NOEXIST);
+}
+
+static bool pid_filter__has(struct bpf_map *pids, pid_t pid)
+{
+	return bpf_map_lookup_elem(pids, &pid) != NULL;
+}
+
+#endif // _PERF_BPF_PID_FILTER_