bpf: add support for bpf_spin_lock to cgroup local storage

Allow 'struct bpf_spin_lock' to reside inside cgroup local storage.

Signed-off-by: Alexei Starovoitov <ast@kernel.org>
Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>

kernel/bpf/local_storage.c

@@ -147,6 +147,7 @@ static int cgroup_storage_update_elem(struct bpf_map *map, void *_key,
 		return -ENOMEM;
 
 	memcpy(&new->data[0], value, map->value_size);
+	check_and_init_map_lock(map, new->data);
 
 	new = xchg(&storage->buf, new);
 	kfree_rcu(new, rcu);
@@ -483,6 +484,7 @@ struct bpf_cgroup_storage *bpf_cgroup_storage_alloc(struct bpf_prog *prog,
 		storage->buf = kmalloc_node(size, flags, map->numa_node);
 		if (!storage->buf)
 			goto enomem;
+		check_and_init_map_lock(map, storage->buf->data);
 	} else {
 		storage->percpu_buf = __alloc_percpu_gfp(size, 8, flags);
 		if (!storage->percpu_buf)

kernel/bpf/syscall.c

@@ -482,7 +482,8 @@ static int map_check_btf(struct bpf_map *map, const struct btf *btf,
 
 	if (map_value_has_spin_lock(map)) {
 		if (map->map_type != BPF_MAP_TYPE_HASH &&
-		    map->map_type != BPF_MAP_TYPE_ARRAY)
+		    map->map_type != BPF_MAP_TYPE_ARRAY &&
+		    map->map_type != BPF_MAP_TYPE_CGROUP_STORAGE)
 			return -ENOTSUPP;
 		if (map->spin_lock_off + sizeof(struct bpf_spin_lock) >
 		    map->value_size) {

kernel/bpf/verifier.c

@@ -3089,6 +3089,8 @@ static int check_helper_call(struct bpf_verifier_env *env, int func_id, int insn
 		regs[BPF_REG_0].map_ptr = meta.map_ptr;
 		if (fn->ret_type == RET_PTR_TO_MAP_VALUE) {
 			regs[BPF_REG_0].type = PTR_TO_MAP_VALUE;
+			if (map_value_has_spin_lock(meta.map_ptr))
+				regs[BPF_REG_0].id = ++env->id_gen;
 		} else {
 			regs[BPF_REG_0].type = PTR_TO_MAP_VALUE_OR_NULL;
 			regs[BPF_REG_0].id = ++env->id_gen;