Commit 7594dcb7 authored by T.J. Mercier's avatar T.J. Mercier Committed by Alexei Starovoitov
Browse files

selftests/bpf: Add test for open coded dmabuf_iter 



Use the same test buffers as the traditional iterator and a new BPF map
to verify the test buffers can be found with the open coded dmabuf
iterator.

Signed-off-by: default avatarT.J. Mercier <tjmercier@google.com>
Acked-by: default avatarChristian König <christian.koenig@amd.com>
Acked-by: default avatarSong Liu <song@kernel.org>
Link: https://lore.kernel.org/r/20250522230429.941193-6-tjmercier@google.com


Signed-off-by: default avatarAlexei Starovoitov <ast@kernel.org>
parent ae5d2c59

tools/testing/selftests/bpf/bpf_experimental.h

+5 −0
Original line number Diff line number Diff line
@@ -591,4 +591,9 @@ extern int bpf_iter_kmem_cache_new(struct bpf_iter_kmem_cache *it) __weak __ksym 
extern struct kmem_cache *bpf_iter_kmem_cache_next(struct bpf_iter_kmem_cache *it) __weak __ksym;

extern void bpf_iter_kmem_cache_destroy(struct bpf_iter_kmem_cache *it) __weak __ksym;



struct bpf_iter_dmabuf;

extern int bpf_iter_dmabuf_new(struct bpf_iter_dmabuf *it) __weak __ksym;

extern struct dma_buf *bpf_iter_dmabuf_next(struct bpf_iter_dmabuf *it) __weak __ksym;

extern void bpf_iter_dmabuf_destroy(struct bpf_iter_dmabuf *it) __weak __ksym;



#endif

tools/testing/selftests/bpf/prog_tests/dmabuf_iter.c

+41 −0
Original line number Diff line number Diff line
@@ -219,14 +219,52 @@ static void subtest_dmabuf_iter_check_default_iter(struct dmabuf_iter *skel) 
	close(iter_fd);

}



static void subtest_dmabuf_iter_check_open_coded(struct dmabuf_iter *skel, int map_fd)

{

	LIBBPF_OPTS(bpf_test_run_opts, topts);

	char key[DMA_BUF_NAME_LEN];

	int err, fd;

	bool found;



	/* No need to attach it, just run it directly */

	fd = bpf_program__fd(skel->progs.iter_dmabuf_for_each);



	err = bpf_prog_test_run_opts(fd, &topts);

	if (!ASSERT_OK(err, "test_run_opts err"))

		return;

	if (!ASSERT_OK(topts.retval, "test_run_opts retval"))

		return;



	if (!ASSERT_OK(bpf_map_get_next_key(map_fd, NULL, key), "get next key"))

		return;



	do {

		ASSERT_OK(bpf_map_lookup_elem(map_fd, key, &found), "lookup");

		ASSERT_TRUE(found, "found test buffer");

	} while (bpf_map_get_next_key(map_fd, key, key));

}



void test_dmabuf_iter(void)

{

	struct dmabuf_iter *skel = NULL;

	int map_fd;

	const bool f = false;



	skel = dmabuf_iter__open_and_load();

	if (!ASSERT_OK_PTR(skel, "dmabuf_iter__open_and_load"))

		return;



	map_fd = bpf_map__fd(skel->maps.testbuf_hash);

	if (!ASSERT_OK_FD(map_fd, "map_fd"))

		goto destroy_skel;



	if (!ASSERT_OK(bpf_map_update_elem(map_fd, udmabuf_test_buffer_name, &f, BPF_ANY),

		       "insert udmabuf"))

		goto destroy_skel;

	if (!ASSERT_OK(bpf_map_update_elem(map_fd, sysheap_test_buffer_name, &f, BPF_ANY),

		       "insert sysheap buffer"))

		goto destroy_skel;



	if (!ASSERT_OK(create_test_buffers(), "create_test_buffers"))

		goto destroy;
@@ -237,8 +275,11 @@ void test_dmabuf_iter(void) 
		subtest_dmabuf_iter_check_no_infinite_reads(skel);

	if (test__start_subtest("default_iter"))

		subtest_dmabuf_iter_check_default_iter(skel);

	if (test__start_subtest("open_coded"))

		subtest_dmabuf_iter_check_open_coded(skel, map_fd);



destroy:

	destroy_test_buffers();

destroy_skel:

	dmabuf_iter__destroy(skel);

}

tools/testing/selftests/bpf/progs/dmabuf_iter.c

+48 −0
Original line number Diff line number Diff line
@@ -9,6 +9,13 @@ 


char _license[] SEC("license") = "GPL";



struct {

	__uint(type, BPF_MAP_TYPE_HASH);

	__uint(key_size, DMA_BUF_NAME_LEN);

	__type(value, bool);

	__uint(max_entries, 5);

} testbuf_hash SEC(".maps");



/*

 * Fields output by this iterator are delimited by newlines. Convert any

 * newlines in user-provided printed strings to spaces.
@@ -51,3 +58,44 @@ int dmabuf_collector(struct bpf_iter__dmabuf *ctx) 
	BPF_SEQ_PRINTF(seq, "%lu\n%llu\n%s\n%s\n", inode, size, name, exporter);

	return 0;

}



SEC("syscall")

int iter_dmabuf_for_each(const void *ctx)

{

	struct dma_buf *d;



	bpf_for_each(dmabuf, d) {

		char name[DMA_BUF_NAME_LEN];

		const char *pname;

		bool *found;

		long len;

		int i;



		if (bpf_core_read(&pname, sizeof(pname), &d->name))

			return 1;



		/* Buffers are not required to be named */

		if (!pname)

			continue;



		len = bpf_probe_read_kernel_str(name, sizeof(name), pname);

		if (len < 0)

			return 1;



		/*

		 * The entire name buffer is used as a map key.

		 * Zeroize any uninitialized trailing bytes after the NUL.

		 */

		bpf_for(i, len, DMA_BUF_NAME_LEN)

			name[i] = 0;



		found = bpf_map_lookup_elem(&testbuf_hash, name);

		if (found) {

			bool t = true;



			bpf_map_update_elem(&testbuf_hash, name, &t, BPF_EXIST);

		}

	}



	return 0;

}