Re: [PATCH bpf-next 4/5] selftests/bpf: Add tests for fd_array_cnt

[Eduard Zingerman <eddyz87@gmail.com>]

On Fri, 2024-11-15 at 00:46 +0000, Anton Protopopov wrote:

[...]

> @@ -0,0 +1,374 @@
> +// SPDX-License-Identifier: GPL-2.0
> +
> +#include <test_progs.h>
> +
> +#include <linux/btf.h>
> +#include <sys/syscall.h>
> +#include <bpf/bpf.h>
> +
> +static inline int _bpf_map_create(void)
> +{
> +	static union bpf_attr attr = {
> +		.map_type = BPF_MAP_TYPE_ARRAY,
> +		.key_size = 4,
> +		.value_size = 8,
> +		.max_entries = 1,
> +	};
> +
> +	return syscall(__NR_bpf, BPF_MAP_CREATE, &attr, sizeof(attr));
> +}
> +
> +#define BTF_INFO_ENC(kind, kind_flag, vlen) \
> +	((!!(kind_flag) << 31) | ((kind) << 24) | ((vlen) & BTF_MAX_VLEN))
> +#define BTF_TYPE_ENC(name, info, size_or_type) (name), (info), (size_or_type)
> +#define BTF_INT_ENC(encoding, bits_offset, nr_bits) \
> +	((encoding) << 24 | (bits_offset) << 16 | (nr_bits))
> +#define BTF_TYPE_INT_ENC(name, encoding, bits_offset, bits, sz) \
> +	BTF_TYPE_ENC(name, BTF_INFO_ENC(BTF_KIND_INT, 0, 0), sz), \
> +	BTF_INT_ENC(encoding, bits_offset, bits)

Nit: these macro are already defined in tools/testing/selftests/bpf/test_btf.h .

> +
> +static int _btf_create(void)
> +{
> +	struct btf_blob {
> +		struct btf_header btf_hdr;
> +		__u32 types[8];
> +		__u32 str;
> +	} raw_btf = {
> +		.btf_hdr = {
> +			.magic = BTF_MAGIC,
> +			.version = BTF_VERSION,
> +			.hdr_len = sizeof(struct btf_header),
> +			.type_len = sizeof(__u32) * 8,
> +			.str_off = sizeof(__u32) * 8,
> +			.str_len = sizeof(__u32),

Nit: offsetof(struct btf_blob, str), sizeof(raw_btf.str), sizeof(raw_btf.types)
     are legal in this position.

> +		},
> +		.types = {
> +			/* long */
> +			BTF_TYPE_INT_ENC(0, BTF_INT_SIGNED, 0, 64, 8),  /* [1] */
> +			/* unsigned long */
> +			BTF_TYPE_INT_ENC(0, 0, 0, 64, 8),  /* [2] */
> +		},
> +	};
> +	static union bpf_attr attr = {
> +		.btf_size = sizeof(raw_btf),
> +	};
> +
> +	attr.btf = (long)&raw_btf;
> +
> +	return syscall(__NR_bpf, BPF_BTF_LOAD, &attr, sizeof(attr));
> +}

[...]

> +static void check_fd_array_cnt__fd_array_ok(void)
> +{
> +	int extra_fds[128];
> +	__u32 map_ids[16];
> +	__u32 nr_map_ids;
> +	int prog_fd;
> +
> +	extra_fds[0] = _bpf_map_create();
> +	if (!ASSERT_GE(extra_fds[0], 0, "_bpf_map_create"))
> +		return;
> +	extra_fds[1] = _bpf_map_create();
> +	if (!ASSERT_GE(extra_fds[1], 0, "_bpf_map_create"))
> +		return;
> +	prog_fd = load_test_prog(extra_fds, 2);
> +	if (!ASSERT_GE(prog_fd, 0, "BPF_PROG_LOAD"))
> +		return;
> +	nr_map_ids = ARRAY_SIZE(map_ids);
> +	if (!check_expected_map_ids(prog_fd, 3, map_ids, &nr_map_ids))

Nit: should probably close prog_fd and extra_fds (and in tests below).

> +		return;
> +
> +	/* maps should still exist when original file descriptors are closed */
> +	close(extra_fds[0]);
> +	close(extra_fds[1]);
> +	if (!ASSERT_EQ(map_exists(map_ids[0]), true, "map_ids[0] should exist"))
> +		return;
> +	if (!ASSERT_EQ(map_exists(map_ids[1]), true, "map_ids[1] should exist"))
> +		return;
> +
> +	close(prog_fd);
> +}

[...]