1 files changed, 63 insertions, 0 deletions

diff --git a/kernel/bpf/arraymap.c b/kernel/bpf/arraymap.c
index 4d7d5d0ed76a..bc9da93db403 100644
--- a/kernel/bpf/arraymap.c
+++ b/kernel/bpf/arraymap.c
@@ -17,6 +17,8 @@
 #include <linux/filter.h>
 #include <linux/perf_event.h>
 
+#include "map_in_map.h"
+
 static void bpf_array_free_percpu(struct bpf_array *array)
 {
         int i;
@@ -602,3 +604,64 @@ static int __init register_cgroup_array_map(void)
 }
 late_initcall(register_cgroup_array_map);
 #endif
+
+static struct bpf_map *array_of_map_alloc(union bpf_attr *attr)
+{
+        struct bpf_map *map, *inner_map_meta;
+
+        inner_map_meta = bpf_map_meta_alloc(attr->inner_map_fd);
+        if (IS_ERR(inner_map_meta))
+                return inner_map_meta;
+
+        map = fd_array_map_alloc(attr);
+        if (IS_ERR(map)) {
+                bpf_map_meta_free(inner_map_meta);
+                return map;
+        }
+
+        map->inner_map_meta = inner_map_meta;
+
+        return map;
+}
+
+static void array_of_map_free(struct bpf_map *map)
+{
+        /* map->inner_map_meta is only accessed by syscall which
+         * is protected by fdget/fdput.
+         */
+        bpf_map_meta_free(map->inner_map_meta);
+        bpf_fd_array_map_clear(map);
+        fd_array_map_free(map);
+}
+
+static void *array_of_map_lookup_elem(struct bpf_map *map, void *key)
+{
+        struct bpf_map **inner_map = array_map_lookup_elem(map, key);
+
+        if (!inner_map)
+                return NULL;
+
+        return READ_ONCE(*inner_map);
+}
+
+static const struct bpf_map_ops array_of_map_ops = {
+        .map_alloc = array_of_map_alloc,
+        .map_free = array_of_map_free,
+        .map_get_next_key = array_map_get_next_key,
+        .map_lookup_elem = array_of_map_lookup_elem,
+        .map_delete_elem = fd_array_map_delete_elem,
+        .map_fd_get_ptr = bpf_map_fd_get_ptr,
+        .map_fd_put_ptr = bpf_map_fd_put_ptr,
+};
+
+static struct bpf_map_type_list array_of_map_type __ro_after_init = {
+        .ops = &array_of_map_ops,
+        .type = BPF_MAP_TYPE_ARRAY_OF_MAPS,
+};
+
+static int __init register_array_of_map(void)
+{
+        bpf_register_map_type(&array_of_map_type);
+        return 0;
+}
+late_initcall(register_array_of_map);