Re: [PATCH v6 2/4] bpf: Add new bpf map type to store the pointer to struct perf_event

From: Alexei Starovoitov
Date: Tue Aug 04 2015 - 13:43:43 EST


On 8/4/15 1:58 AM, Kaixu Xia wrote:
diff --git a/kernel/bpf/arraymap.c b/kernel/bpf/arraymap.c
index 45df657..b1e98ff 100644
--- a/kernel/bpf/arraymap.c
+++ b/kernel/bpf/arraymap.c
@@ -273,3 +273,60 @@ static int __init register_prog_array_map(void)
return 0;
}
late_initcall(register_prog_array_map);
+
+static void perf_event_array_map_free(struct bpf_map *map)
+{
+ bpf_fd_array_map_clear(map);
+ fd_array_map_free(map);
+}
+
+static void *perf_event_fd_array_get_ptr(struct bpf_map *map, int fd)
+{
+ struct perf_event *event;
+ struct perf_event_attr *attr;
+
+ event = perf_event_get(fd);
+ if (IS_ERR(event))
+ return event;
+
+ attr = perf_event_attrs(event);
+ if (IS_ERR(attr))
+ return attr;
+
+ if (attr->type != PERF_TYPE_RAW &&
+ attr->type != PERF_TYPE_HARDWARE) {
+ perf_event_release_kernel(event);
+ return ERR_PTR(-EINVAL);
+ }
+ return event;
+}

I'm not sure whether Peter wanted to see the above function to be
in events/core.c or not.
imo it's fine here, since perf_event_attr is an uapi struct.

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