Support spin locks in maps about ebpf

[mehrdadrad]

The kernel space already works for sure but I just sent a pull request to support bpf_spin_lock from user space #473

[ti-mo]

The library should support this today, but this feature requires BTF map definitions to be used, with __type() macros for key and value types. A snippet from the kernel's selftests for posterity:

# tools/testing/selftests/bpf/progs/test_spin_lock.c
struct bpf_vqueue {
	struct bpf_spin_lock lock;
...
};

struct {
	__uint(type, BPF_MAP_TYPE_ARRAY);
	__uint(max_entries, 1);
	__type(key, int);
	__type(value, struct bpf_vqueue);
} vqueue SEC(".maps");

int bpf_sping_lock_test(struct __sk_buff *skb) {
...
	q = bpf_map_lookup_elem(&vqueue, &key);
...
	bpf_spin_lock(&q->lock);
...
	bpf_spin_unlock(&q->lock);

[mehrdadrad]

Added with eced84a