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git://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git
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7594dcb71f
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@google.com> Acked-by: Christian König <christian.koenig@amd.com> Acked-by: Song Liu <song@kernel.org> Link: https://lore.kernel.org/r/20250522230429.941193-6-tjmercier@google.com Signed-off-by: Alexei Starovoitov <ast@kernel.org>
101 lines
2.3 KiB
C
101 lines
2.3 KiB
C
// SPDX-License-Identifier: GPL-2.0
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/* Copyright (c) 2025 Google LLC */
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#include <vmlinux.h>
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#include <bpf/bpf_core_read.h>
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#include <bpf/bpf_helpers.h>
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/* From uapi/linux/dma-buf.h */
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#define DMA_BUF_NAME_LEN 32
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char _license[] SEC("license") = "GPL";
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struct {
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__uint(type, BPF_MAP_TYPE_HASH);
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__uint(key_size, DMA_BUF_NAME_LEN);
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__type(value, bool);
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__uint(max_entries, 5);
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} testbuf_hash SEC(".maps");
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/*
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* Fields output by this iterator are delimited by newlines. Convert any
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* newlines in user-provided printed strings to spaces.
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*/
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static void sanitize_string(char *src, size_t size)
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{
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for (char *c = src; (size_t)(c - src) < size && *c; ++c)
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if (*c == '\n')
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*c = ' ';
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}
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SEC("iter/dmabuf")
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int dmabuf_collector(struct bpf_iter__dmabuf *ctx)
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{
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const struct dma_buf *dmabuf = ctx->dmabuf;
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struct seq_file *seq = ctx->meta->seq;
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unsigned long inode = 0;
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size_t size;
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const char *pname, *exporter;
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char name[DMA_BUF_NAME_LEN] = {'\0'};
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if (!dmabuf)
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return 0;
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if (BPF_CORE_READ_INTO(&inode, dmabuf, file, f_inode, i_ino) ||
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bpf_core_read(&size, sizeof(size), &dmabuf->size) ||
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bpf_core_read(&pname, sizeof(pname), &dmabuf->name) ||
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bpf_core_read(&exporter, sizeof(exporter), &dmabuf->exp_name))
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return 1;
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/* Buffers are not required to be named */
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if (pname) {
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if (bpf_probe_read_kernel(name, sizeof(name), pname))
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return 1;
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/* Name strings can be provided by userspace */
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sanitize_string(name, sizeof(name));
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}
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BPF_SEQ_PRINTF(seq, "%lu\n%llu\n%s\n%s\n", inode, size, name, exporter);
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return 0;
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}
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SEC("syscall")
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int iter_dmabuf_for_each(const void *ctx)
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{
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struct dma_buf *d;
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bpf_for_each(dmabuf, d) {
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char name[DMA_BUF_NAME_LEN];
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const char *pname;
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bool *found;
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long len;
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int i;
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if (bpf_core_read(&pname, sizeof(pname), &d->name))
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return 1;
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/* Buffers are not required to be named */
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if (!pname)
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continue;
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len = bpf_probe_read_kernel_str(name, sizeof(name), pname);
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if (len < 0)
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return 1;
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/*
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* The entire name buffer is used as a map key.
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* Zeroize any uninitialized trailing bytes after the NUL.
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*/
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bpf_for(i, len, DMA_BUF_NAME_LEN)
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name[i] = 0;
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found = bpf_map_lookup_elem(&testbuf_hash, name);
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if (found) {
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bool t = true;
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bpf_map_update_elem(&testbuf_hash, name, &t, BPF_EXIST);
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}
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}
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return 0;
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}
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