86 lines
2.0 KiB
C
86 lines
2.0 KiB
C
// SPDX-License-Identifier: GPL-2.0
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// Copyright (c) 2020 Wenbo Zhang
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#include <vmlinux.h>
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#include <bpf/bpf_helpers.h>
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#include <bpf/bpf_tracing.h>
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#include <bpf/bpf_core_read.h>
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#include "bitesize.h"
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#include "bits.bpf.h"
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const volatile char targ_comm[TASK_COMM_LEN] = {};
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const volatile bool filter_dev = false;
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const volatile __u32 targ_dev = 0;
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extern __u32 LINUX_KERNEL_VERSION __kconfig;
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struct {
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__uint(type, BPF_MAP_TYPE_HASH);
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__uint(max_entries, 10240);
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__type(key, struct hist_key);
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__type(value, struct hist);
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__uint(map_flags, BPF_F_NO_PREALLOC);
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} hists SEC(".maps");
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static struct hist initial_hist;
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static __always_inline bool comm_allowed(const char *comm)
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{
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int i;
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for (i = 0; targ_comm[i] != '\0' && i < TASK_COMM_LEN; i++) {
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if (comm[i] != targ_comm[i])
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return false;
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}
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return true;
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}
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static int trace_rq_issue(struct request *rq)
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{
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struct hist_key hkey;
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struct hist *histp;
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u64 slot;
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if (filter_dev) {
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struct gendisk *disk = BPF_CORE_READ(rq, rq_disk);
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u32 dev;
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dev = disk ? MKDEV(BPF_CORE_READ(disk, major),
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BPF_CORE_READ(disk, first_minor)) : 0;
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if (targ_dev != dev)
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return 0;
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}
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bpf_get_current_comm(&hkey.comm, sizeof(hkey.comm));
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if (!comm_allowed(hkey.comm))
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return 0;
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histp = bpf_map_lookup_elem(&hists, &hkey);
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if (!histp) {
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bpf_map_update_elem(&hists, &hkey, &initial_hist, 0);
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histp = bpf_map_lookup_elem(&hists, &hkey);
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if (!histp)
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return 0;
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}
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slot = log2l(rq->__data_len / 1024);
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if (slot >= MAX_SLOTS)
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slot = MAX_SLOTS - 1;
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__sync_fetch_and_add(&histp->slots[slot], 1);
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return 0;
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}
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SEC("tp_btf/block_rq_issue")
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int BPF_PROG(block_rq_issue)
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{
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/**
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* commit a54895fa (v5.11-rc1) changed tracepoint argument list
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* from TP_PROTO(struct request_queue *q, struct request *rq)
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* to TP_PROTO(struct request *rq)
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*/
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if (LINUX_KERNEL_VERSION > KERNEL_VERSION(5, 10, 0))
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return trace_rq_issue((void *)ctx[0]);
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else
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return trace_rq_issue((void *)ctx[1]);
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}
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char LICENSE[] SEC("license") = "GPL";
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