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authorDaniel Borkmann <daniel@iogearbox.net>2016-06-28 12:18:23 +0200
committerDavid S. Miller <davem@davemloft.net>2016-06-30 05:54:40 -0400
commit1ca1cc98bf7418c680415bfce05699f67510a7fd (patch)
treec7f9924f35a3645b99208534b887c84077cfb975 /kernel/trace
parentee58b57100ca953da7320c285315a95db2f7053d (diff)
downloadop-kernel-dev-1ca1cc98bf7418c680415bfce05699f67510a7fd.zip
op-kernel-dev-1ca1cc98bf7418c680415bfce05699f67510a7fd.tar.gz
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')
-rw-r--r--kernel/trace/bpf_trace.c18
1 files changed, 6 insertions, 12 deletions
diff --git a/kernel/trace/bpf_trace.c b/kernel/trace/bpf_trace.c
index 3de25fb..4e61f74 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;
}
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