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| author | Daniel Borkmann <daniel@iogearbox.net> | 2016-06-28 12:18:23 +0200 |
|---|---|---|
| committer | David S. Miller <davem@davemloft.net> | 2016-06-30 05:54:40 -0400 |
| commit | 1ca1cc98bf7418c680415bfce05699f67510a7fd (patch) | |
| tree | c7f9924f35a3645b99208534b887c84077cfb975 /kernel/trace/bpf_trace.c | |
| parent | ee58b57100ca953da7320c285315a95db2f7053d (diff) | |
| download | lwn-1ca1cc98bf7418c680415bfce05699f67510a7fd.tar.gz lwn-1ca1cc98bf7418c680415bfce05699f67510a7fd.zip | |
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 <daniel@iogearbox.net>
Acked-by: Alexei Starovoitov <ast@kernel.org>
Signed-off-by: David S. Miller <davem@davemloft.net>
Diffstat (limited to 'kernel/trace/bpf_trace.c')
| -rw-r--r-- | kernel/trace/bpf_trace.c | 18 |
1 files changed, 6 insertions, 12 deletions
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; } |