63 lines
		
	
	
		
			1.2 KiB
		
	
	
	
		
			C
		
	
	
	
	
	
			
		
		
	
	
			63 lines
		
	
	
		
			1.2 KiB
		
	
	
	
		
			C
		
	
	
	
	
	
| // SPDX-License-Identifier: GPL-2.0
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| // Copyright (c) 2019 Facebook
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| #include <linux/bpf.h>
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| #include <linux/version.h>
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| #include <bpf/bpf_helpers.h>
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| 
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| #define VAR_NUM 16
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| 
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| struct hmap_elem {
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| 	struct bpf_spin_lock lock;
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| 	int var[VAR_NUM];
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| };
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| 
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| struct {
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| 	__uint(type, BPF_MAP_TYPE_HASH);
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| 	__uint(max_entries, 1);
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| 	__type(key, __u32);
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| 	__type(value, struct hmap_elem);
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| } hash_map SEC(".maps");
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| 
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| struct array_elem {
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| 	struct bpf_spin_lock lock;
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| 	int var[VAR_NUM];
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| };
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| 
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| struct {
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| 	__uint(type, BPF_MAP_TYPE_ARRAY);
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| 	__uint(max_entries, 1);
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| 	__type(key, int);
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| 	__type(value, struct array_elem);
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| } array_map SEC(".maps");
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| 
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| SEC("map_lock_demo")
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| int bpf_map_lock_test(struct __sk_buff *skb)
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| {
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| 	struct hmap_elem zero = {}, *val;
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| 	int rnd = bpf_get_prandom_u32();
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| 	int key = 0, err = 1, i;
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| 	struct array_elem *q;
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| 
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| 	val = bpf_map_lookup_elem(&hash_map, &key);
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| 	if (!val)
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| 		goto err;
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| 	/* spin_lock in hash map */
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| 	bpf_spin_lock(&val->lock);
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| 	for (i = 0; i < VAR_NUM; i++)
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| 		val->var[i] = rnd;
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| 	bpf_spin_unlock(&val->lock);
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| 
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| 	/* spin_lock in array */
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| 	q = bpf_map_lookup_elem(&array_map, &key);
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| 	if (!q)
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| 		goto err;
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| 	bpf_spin_lock(&q->lock);
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| 	for (i = 0; i < VAR_NUM; i++)
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| 		q->var[i] = rnd;
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| 	bpf_spin_unlock(&q->lock);
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| 	err = 0;
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| err:
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| 	return err;
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| }
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| char _license[] SEC("license") = "GPL";
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