Re: [PATCH bpf-next v4 4/5] selftests/bpf: Add test for dmabuf_iter

[Song Liu <song@kernel.org>]

On Thu, May 8, 2025 at 11:20 AM T.J. Mercier <tjmercier@google.com> wrote:
[...]
> diff --git a/tools/testing/selftests/bpf/prog_tests/dmabuf_iter.c b/tools/testing/selftests/bpf/prog_tests/dmabuf_iter.c
> new file mode 100644
> index 000000000000..35745f4ce0f8
> --- /dev/null
> +++ b/tools/testing/selftests/bpf/prog_tests/dmabuf_iter.c
> @@ -0,0 +1,224 @@
> +// SPDX-License-Identifier: GPL-2.0
> +/* Copyright (c) 2025 Google */
> +
> +#include <test_progs.h>
> +#include <bpf/libbpf.h>
> +#include <bpf/btf.h>
> +#include "dmabuf_iter.skel.h"
> +
> +#include <fcntl.h>
> +#include <stdbool.h>
> +#include <stdio.h>
> +#include <stdlib.h>
> +#include <string.h>
> +#include <sys/ioctl.h>
> +#include <sys/mman.h>
> +#include <unistd.h>
> +
> +#include <linux/dma-buf.h>
> +#include <linux/dma-heap.h>
> +#include <linux/udmabuf.h>
> +
> +static int memfd, udmabuf;

Global fds are weird. AFAICT, we don't really need them
to be global? If we really need them to be global, please
initialize them to -1, just in case we close(0) by accident.

> +static const char udmabuf_test_buffer_name[DMA_BUF_NAME_LEN] = "udmabuf_test_buffer_for_iter";
> +static size_t udmabuf_test_buffer_size;
> +static int sysheap_dmabuf;
> +static const char sysheap_test_buffer_name[DMA_BUF_NAME_LEN] = "sysheap_test_buffer_for_iter";
> +static size_t sysheap_test_buffer_size;