// SPDX-License-Identifier: GPL-2.0 // Copyright (c) 2019 Facebook #include <linux/bpf.h> #include <linux/version.h> #include "bpf_helpers.h" #define VAR_NUM 16 struct hmap_elem { struct bpf_spin_lock lock; int var[VAR_NUM]; }; struct bpf_map_def SEC("maps") hash_map = { .type = BPF_MAP_TYPE_HASH, .key_size = sizeof(int), .value_size = sizeof(struct hmap_elem), .max_entries = 1, }; BPF_ANNOTATE_KV_PAIR(hash_map, int, struct hmap_elem); struct array_elem { struct bpf_spin_lock lock; int var[VAR_NUM]; }; struct bpf_map_def SEC("maps") array_map = { .type = BPF_MAP_TYPE_ARRAY, .key_size = sizeof(int), .value_size = sizeof(struct array_elem), .max_entries = 1, }; BPF_ANNOTATE_KV_PAIR(array_map, int, struct array_elem); SEC("map_lock_demo") int bpf_map_lock_test(struct __sk_buff *skb) { struct hmap_elem zero = {}, *val; int rnd = bpf_get_prandom_u32(); int key = 0, err = 1, i; struct array_elem *q; val = bpf_map_lookup_elem(&hash_map, &key); if (!val) goto err; /* spin_lock in hash map */ bpf_spin_lock(&val->lock); for (i = 0; i < VAR_NUM; i++) val->var[i] = rnd; bpf_spin_unlock(&val->lock); /* spin_lock in array */ q = bpf_map_lookup_elem(&array_map, &key); if (!q) goto err; bpf_spin_lock(&q->lock); for (i = 0; i < VAR_NUM; i++) q->var[i] = rnd; bpf_spin_unlock(&q->lock); err = 0; err: return err; } char _license[] SEC("license") = "GPL";