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