495d2d8133
GCC's -Wall includes -Wsign-compare while clang does not. Since BPF programs are built with clang we need to add this flag explicitly to catch problematic comparisons like: int i = -1; unsigned int j = 1; if (i < j) // this is false. long i = -1; unsigned int j = 1; if (i < j) // this is true. C standard for reference: - If either operand is unsigned long the other shall be converted to unsigned long. - Otherwise, if one operand is a long int and the other unsigned int, then if a long int can represent all the values of an unsigned int, the unsigned int shall be converted to a long int; otherwise both operands shall be converted to unsigned long int. - Otherwise, if either operand is long, the other shall be converted to long. - Otherwise, if either operand is unsigned, the other shall be converted to unsigned. Unfortunately clang's -Wsign-compare is very noisy. It complains about (s32)a == (u32)b which is safe and doen't have surprising behavior. This patch fixes some of the issues. It needs a follow up to fix the rest. Signed-off-by: Alexei Starovoitov <ast@kernel.org> Signed-off-by: Andrii Nakryiko <andrii@kernel.org> Acked-by: Jiri Olsa <jolsa@kernel.org> Acked-by: Kumar Kartikeya Dwivedi <memxor@gmail.com> Link: https://lore.kernel.org/bpf/20231226191148.48536-2-alexei.starovoitov@gmail.com
52 lines
1.1 KiB
C
52 lines
1.1 KiB
C
// SPDX-License-Identifier: GPL-2.0
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/* Copyright (c) 2020 Facebook */
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#include "bpf_iter.h"
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#include <bpf/bpf_helpers.h>
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char _license[] SEC("license") = "GPL";
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__u32 map1_id = 0, map2_id = 0;
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__u32 map1_accessed = 0, map2_accessed = 0;
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__u64 map1_seqnum = 0, map2_seqnum1 = 0, map2_seqnum2 = 0;
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volatile const __u32 print_len;
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volatile const __u32 ret1;
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SEC("iter/bpf_map")
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int dump_bpf_map(struct bpf_iter__bpf_map *ctx)
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{
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struct seq_file *seq = ctx->meta->seq;
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struct bpf_map *map = ctx->map;
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__u64 seq_num;
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int i, ret = 0;
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if (map == (void *)0)
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return 0;
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/* only dump map1_id and map2_id */
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if (map->id != map1_id && map->id != map2_id)
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return 0;
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seq_num = ctx->meta->seq_num;
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if (map->id == map1_id) {
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map1_seqnum = seq_num;
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map1_accessed++;
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}
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if (map->id == map2_id) {
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if (map2_accessed == 0) {
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map2_seqnum1 = seq_num;
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if (ret1)
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ret = 1;
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} else {
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map2_seqnum2 = seq_num;
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}
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map2_accessed++;
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}
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/* fill seq_file buffer */
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for (i = 0; i < (int)print_len; i++)
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bpf_seq_write(seq, &seq_num, sizeof(seq_num));
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return ret;
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}
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