This test creates a udmabuf and uses a BPF program that prints dmabuf metadata with the new dmabuf_iter to verify it can be found.
Signed-off-by: T.J. Mercier tjmercier@google.com --- tools/testing/selftests/bpf/config | 1 + .../selftests/bpf/prog_tests/dmabuf_iter.c | 116 ++++++++++++++++++ .../testing/selftests/bpf/progs/dmabuf_iter.c | 31 +++++ 3 files changed, 148 insertions(+) create mode 100644 tools/testing/selftests/bpf/prog_tests/dmabuf_iter.c create mode 100644 tools/testing/selftests/bpf/progs/dmabuf_iter.c
diff --git a/tools/testing/selftests/bpf/config b/tools/testing/selftests/bpf/config index c378d5d07e02..a791c60813df 100644 --- a/tools/testing/selftests/bpf/config +++ b/tools/testing/selftests/bpf/config @@ -106,6 +106,7 @@ CONFIG_SECURITY=y CONFIG_SECURITYFS=y CONFIG_SYN_COOKIES=y CONFIG_TEST_BPF=m +CONFIG_UDMABUF=y CONFIG_USERFAULTFD=y CONFIG_VSOCKETS=y CONFIG_VXLAN=y 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..af215a4e0520 --- /dev/null +++ b/tools/testing/selftests/bpf/prog_tests/dmabuf_iter.c @@ -0,0 +1,116 @@ +// 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/udmabuf.h> + + +static void subtest_dmabuf_iter_check_udmabuf(struct dmabuf_iter *skel) +{ + static const char test_buffer_name[] = "udmabuf_test_buffer_for_iter"; + const size_t test_buffer_size = 10 * getpagesize(); + + ASSERT_LE(sizeof(test_buffer_name), DMA_BUF_NAME_LEN, "NAMETOOLONG"); + + int memfd = memfd_create("memfd_test", MFD_ALLOW_SEALING); + ASSERT_OK_FD(memfd, "memfd_create"); + + ASSERT_OK(ftruncate(memfd, test_buffer_size), "ftruncate"); + + ASSERT_OK(fcntl(memfd, F_ADD_SEALS, F_SEAL_SHRINK), "seal"); + + int dev_udmabuf = open("/dev/udmabuf", O_RDONLY); + ASSERT_OK_FD(dev_udmabuf, "open udmabuf"); + + struct udmabuf_create create; + create.memfd = memfd; + create.flags = UDMABUF_FLAGS_CLOEXEC; + create.offset = 0; + create.size = test_buffer_size; + + int udmabuf = ioctl(dev_udmabuf, UDMABUF_CREATE, &create); + close(dev_udmabuf); + ASSERT_OK_FD(udmabuf, "udmabuf_create"); + + ASSERT_OK(ioctl(udmabuf, DMA_BUF_SET_NAME_B, test_buffer_name), "name"); + + int iter_fd = bpf_iter_create(bpf_link__fd(skel->links.dmabuf_collector)); + ASSERT_OK_FD(iter_fd, "iter_create"); + + FILE *iter_file = fdopen(iter_fd, "r"); + ASSERT_OK_PTR(iter_file, "fdopen"); + + char *line = NULL; + size_t linesize = 0; + bool found_test_udmabuf = false; + while (getline(&line, &linesize, iter_file) != -1) { + long inode, size; + char name[DMA_BUF_NAME_LEN], exporter[32]; + + int nelements = sscanf(line, "ino:%ld size:%ld name:%s exp_name:%s", + &inode, &size, name, exporter); + + if (nelements == 4 && size == test_buffer_size && + !strcmp(name, test_buffer_name) && + !strcmp(exporter, "udmabuf")) { + found_test_udmabuf = true; + break; + } + } + + ASSERT_TRUE(found_test_udmabuf, "found_test_buffer"); + + free(line); + fclose(iter_file); + close(iter_fd); + close(udmabuf); + close(memfd); +} + +void test_dmabuf_iter(void) +{ + struct dmabuf_iter *skel = NULL; + char buf[256]; + int iter_fd; + + skel = dmabuf_iter__open_and_load(); + if (!ASSERT_OK_PTR(skel, "dmabuf_iter__open_and_load")) + return; + + if (!ASSERT_OK(dmabuf_iter__attach(skel), "skel_attach")) + goto destroy; + + iter_fd = bpf_iter_create(bpf_link__fd(skel->links.dmabuf_collector)); + if (!ASSERT_GE(iter_fd, 0, "iter_create")) + goto destroy; + + memset(buf, 0, sizeof(buf)); + while (read(iter_fd, buf, sizeof(buf) > 0)) { + /* Read out all contents */ + } + + /* Next reads should return 0 */ + ASSERT_EQ(read(iter_fd, buf, sizeof(buf)), 0, "read"); + + if (test__start_subtest("check_udmabuf")) + subtest_dmabuf_iter_check_udmabuf(skel); + + close(iter_fd); + +destroy: + dmabuf_iter__destroy(skel); +} diff --git a/tools/testing/selftests/bpf/progs/dmabuf_iter.c b/tools/testing/selftests/bpf/progs/dmabuf_iter.c new file mode 100644 index 000000000000..b2af14ceb609 --- /dev/null +++ b/tools/testing/selftests/bpf/progs/dmabuf_iter.c @@ -0,0 +1,31 @@ +// SPDX-License-Identifier: GPL-2.0 +/* Copyright (c) 2025 Google LLC */ +#include <vmlinux.h> +#include <bpf/bpf_core_read.h> +#include <bpf/bpf_helpers.h> + +char _license[] SEC("license") = "GPL"; + +SEC("iter/dmabuf") +int dmabuf_collector(struct bpf_iter__dmabuf *ctx) +{ + struct seq_file *seq = ctx->meta->seq; + const struct dma_buf *dmabuf = ctx->dmabuf; + + if (dmabuf) { + size_t size; + unsigned long inode; + const char *name, *exp_name; + + if (bpf_core_read(&size, sizeof(size), &dmabuf->size) || + BPF_CORE_READ_INTO(&inode, dmabuf, file, f_inode, i_ino) || + bpf_core_read(&name, sizeof(name), &dmabuf->name) || + bpf_core_read(&exp_name, sizeof(exp_name), &dmabuf->exp_name)) + return 1; + + BPF_SEQ_PRINTF(seq, "ino:%lu size:%llu name:%s exp_name:%s\n", + inode, size, name ? name : "", exp_name ? exp_name : ""); + } + + return 0; +}