From 1ca1cc98bf7418c680415bfce05699f67510a7fd Mon Sep 17 00:00:00 2001 From: Daniel Borkmann Date: Tue, 28 Jun 2016 12:18:23 +0200 Subject: bpf: minor cleanups on fd maps and helpers Some minor cleanups: i) Remove the unlikely() from fd array map lookups and let the CPU branch predictor do its job, scenarios where there is not always a map entry are very well valid. ii) Move the attribute type check in the bpf_perf_event_read() helper a bit earlier so it's consistent wrt checks with bpf_perf_event_output() helper as well. iii) remove some comments that are self-documenting in kprobe_prog_is_valid_access() and therefore make it consistent to tp_prog_is_valid_access() as well. Signed-off-by: Daniel Borkmann Acked-by: Alexei Starovoitov Signed-off-by: David S. Miller --- kernel/bpf/core.c | 3 +-- kernel/trace/bpf_trace.c | 18 ++++++------------ 2 files changed, 7 insertions(+), 14 deletions(-) diff --git a/kernel/bpf/core.c b/kernel/bpf/core.c index b94a36550591..d638062f66d6 100644 --- a/kernel/bpf/core.c +++ b/kernel/bpf/core.c @@ -719,14 +719,13 @@ select_insn: if (unlikely(index >= array->map.max_entries)) goto out; - if (unlikely(tail_call_cnt > MAX_TAIL_CALL_CNT)) goto out; tail_call_cnt++; prog = READ_ONCE(array->ptrs[index]); - if (unlikely(!prog)) + if (!prog) goto out; /* ARG1 at this point is guaranteed to point to CTX from diff --git a/kernel/trace/bpf_trace.c b/kernel/trace/bpf_trace.c index 3de25fbed785..4e61f74a5d73 100644 --- a/kernel/trace/bpf_trace.c +++ b/kernel/trace/bpf_trace.c @@ -199,19 +199,19 @@ static u64 bpf_perf_event_read(u64 r1, u64 index, u64 r3, u64 r4, u64 r5) return -E2BIG; ee = READ_ONCE(array->ptrs[index]); - if (unlikely(!ee)) + if (!ee) return -ENOENT; event = ee->event; + if (unlikely(event->attr.type != PERF_TYPE_HARDWARE && + event->attr.type != PERF_TYPE_RAW)) + return -EINVAL; + /* make sure event is local and doesn't have pmu::count */ if (event->oncpu != smp_processor_id() || event->pmu->count) return -EINVAL; - if (unlikely(event->attr.type != PERF_TYPE_HARDWARE && - event->attr.type != PERF_TYPE_RAW)) - return -EINVAL; - /* * we don't know if the function is run successfully by the * return value. It can be judged in other places, such as @@ -251,7 +251,7 @@ static u64 bpf_perf_event_output(u64 r1, u64 r2, u64 flags, u64 r4, u64 size) return -E2BIG; ee = READ_ONCE(array->ptrs[index]); - if (unlikely(!ee)) + if (!ee) return -ENOENT; event = ee->event; @@ -354,18 +354,12 @@ static const struct bpf_func_proto *kprobe_prog_func_proto(enum bpf_func_id func static bool kprobe_prog_is_valid_access(int off, int size, enum bpf_access_type type, enum bpf_reg_type *reg_type) { - /* check bounds */ if (off < 0 || off >= sizeof(struct pt_regs)) return false; - - /* only read is allowed */ if (type != BPF_READ) return false; - - /* disallow misaligned access */ if (off % size != 0) return false; - return true; } -- cgit v1.2.3