bpf: remove struct bpf_map_type_list

There's no need to have struct bpf_map_type_list since
it just contains a list_head, the type, and the ops
pointer. Since the types are densely packed and not
actually dynamically registered, it's much easier and
smaller to have an array of type->ops pointer. Also
initialize this array statically to remove code needed
to initialize it.

In order to save duplicating the list, move it to the
types header file added by the previous patch and
include it in the same fashion.

Signed-off-by: Johannes Berg <johannes.berg@intel.com>
Acked-by: Alexei Starovoitov <ast@kernel.org>
Acked-by: Daniel Borkmann <daniel@iogearbox.net>
Signed-off-by: David S. Miller <davem@davemloft.net>

1 files changed, 19 insertions, 18 deletions

diff --git a/kernel/bpf/syscall.c b/kernel/bpf/syscall.c
index ea55691cbf5e..b89288e2b589 100644
--- a/kernel/bpf/syscall.c
+++ b/kernel/bpf/syscall.c
@@ -27,30 +27,29 @@ DEFINE_PER_CPU(int, bpf_prog_active);
 
 int sysctl_unprivileged_bpf_disabled __read_mostly;
 
-static LIST_HEAD(bpf_map_types);
+static const struct bpf_map_ops * const bpf_map_types[] = {
+#define BPF_PROG_TYPE(_id, _ops)
+#define BPF_MAP_TYPE(_id, _ops) \
+	[_id] = &_ops,
+#include <linux/bpf_types.h>
+#undef BPF_PROG_TYPE
+#undef BPF_MAP_TYPE
+};
 
 static struct bpf_map *find_and_alloc_map(union bpf_attr *attr)
 {
-	struct bpf_map_type_list *tl;
 	struct bpf_map *map;
 
-	list_for_each_entry(tl, &bpf_map_types, list_node) {
-		if (tl->type == attr->map_type) {
-			map = tl->ops->map_alloc(attr);
-			if (IS_ERR(map))
-				return map;
-			map->ops = tl->ops;
-			map->map_type = attr->map_type;
-			return map;
-		}
-	}
-	return ERR_PTR(-EINVAL);
-}
+	if (attr->map_type >= ARRAY_SIZE(bpf_map_types) ||
+	    !bpf_map_types[attr->map_type])
+		return ERR_PTR(-EINVAL);
 
-/* boot time registration of different map implementations */
-void bpf_register_map_type(struct bpf_map_type_list *tl)
-{
-	list_add(&tl->list_node, &bpf_map_types);
+	map = bpf_map_types[attr->map_type]->map_alloc(attr);
+	if (IS_ERR(map))
+		return map;
+	map->ops = bpf_map_types[attr->map_type];
+	map->map_type = attr->map_type;
+	return map;
 }
 
 void *bpf_map_area_alloc(size_t size)
@@ -576,8 +575,10 @@ err_put:
 static const struct bpf_verifier_ops * const bpf_prog_types[] = {
 #define BPF_PROG_TYPE(_id, _ops) \
 	[_id] = &_ops,
+#define BPF_MAP_TYPE(_id, _ops)
 #include <linux/bpf_types.h>
 #undef BPF_PROG_TYPE
+#undef BPF_MAP_TYPE
 };
 
 static int find_prog_type(enum bpf_prog_type type, struct bpf_prog *prog)