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Message-ID: <20250522230429.941193-6-tjmercier@google.com>
Date: Thu, 22 May 2025 23:04:29 +0000
From: "T.J. Mercier" <tjmercier@...gle.com>
To: sumit.semwal@...aro.org, christian.koenig@....com, ast@...nel.org,
daniel@...earbox.net, andrii@...nel.org, martin.lau@...ux.dev,
skhan@...uxfoundation.org, alexei.starovoitov@...il.com
Cc: linux-kernel@...r.kernel.org, linux-media@...r.kernel.org,
dri-devel@...ts.freedesktop.org, linaro-mm-sig@...ts.linaro.org,
bpf@...r.kernel.org, linux-kselftest@...r.kernel.org, android-mm@...gle.com,
simona@...ll.ch, eddyz87@...il.com, yonghong.song@...ux.dev,
john.fastabend@...il.com, kpsingh@...nel.org, sdf@...ichev.me,
jolsa@...nel.org, mykolal@...com, shuah@...nel.org, song@...nel.org,
"T.J. Mercier" <tjmercier@...gle.com>
Subject: [PATCH bpf-next v7 5/5] 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: T.J. Mercier <tjmercier@...gle.com>
Acked-by: Christian König <christian.koenig@....com>
Acked-by: Song Liu <song@...nel.org>
---
.../testing/selftests/bpf/bpf_experimental.h | 5 ++
.../selftests/bpf/prog_tests/dmabuf_iter.c | 41 ++++++++++++++++
.../testing/selftests/bpf/progs/dmabuf_iter.c | 48 +++++++++++++++++++
3 files changed, 94 insertions(+)
diff --git a/tools/testing/selftests/bpf/bpf_experimental.h b/tools/testing/selftests/bpf/bpf_experimental.h
index 6535c8ae3c46..5e512a1d09d1 100644
--- a/tools/testing/selftests/bpf/bpf_experimental.h
+++ b/tools/testing/selftests/bpf/bpf_experimental.h
@@ -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
diff --git a/tools/testing/selftests/bpf/prog_tests/dmabuf_iter.c b/tools/testing/selftests/bpf/prog_tests/dmabuf_iter.c
index dc740bd0e2bd..6c2b0c3dbcd8 100644
--- a/tools/testing/selftests/bpf/prog_tests/dmabuf_iter.c
+++ b/tools/testing/selftests/bpf/prog_tests/dmabuf_iter.c
@@ -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);
}
diff --git a/tools/testing/selftests/bpf/progs/dmabuf_iter.c b/tools/testing/selftests/bpf/progs/dmabuf_iter.c
index e53d7646d07a..13cdb11fdeb2 100644
--- a/tools/testing/selftests/bpf/progs/dmabuf_iter.c
+++ b/tools/testing/selftests/bpf/progs/dmabuf_iter.c
@@ -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;
+}
--
2.49.0.1151.ga128411c76-goog
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