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authorDaniel Borkmann <daniel@iogearbox.net>2016-06-28 12:18:24 +0200
committerDavid S. Miller <davem@davemloft.net>2016-06-30 05:54:40 -0400
commitd79313303181d357d293453fb8486bdc87bfd2f4 (patch)
tree275cae8d173c2fdec0c95b9a797cb1ddad62f266 /kernel/trace/bpf_trace.c
parent1ca1cc98bf7418c680415bfce05699f67510a7fd (diff)
bpf, trace: fetch current cpu only once
We currently have two invocations, which is unnecessary. Fetch it only once and use the smp_processor_id() variant, so we also get preemption checks along with it when DEBUG_PREEMPT is set. 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.c5
1 files changed, 3 insertions, 2 deletions
diff --git a/kernel/trace/bpf_trace.c b/kernel/trace/bpf_trace.c
index 4e61f74a5d73..505f9e9cdb3b 100644
--- a/kernel/trace/bpf_trace.c
+++ b/kernel/trace/bpf_trace.c
@@ -233,6 +233,7 @@ static u64 bpf_perf_event_output(u64 r1, u64 r2, u64 flags, u64 r4, u64 size)
struct pt_regs *regs = (struct pt_regs *) (long) r1;
struct bpf_map *map = (struct bpf_map *) (long) r2;
struct bpf_array *array = container_of(map, struct bpf_array, map);
+ unsigned int cpu = smp_processor_id();
u64 index = flags & BPF_F_INDEX_MASK;
void *data = (void *) (long) r4;
struct perf_sample_data sample_data;
@@ -246,7 +247,7 @@ static u64 bpf_perf_event_output(u64 r1, u64 r2, u64 flags, u64 r4, u64 size)
if (unlikely(flags & ~(BPF_F_INDEX_MASK)))
return -EINVAL;
if (index == BPF_F_CURRENT_CPU)
- index = raw_smp_processor_id();
+ index = cpu;
if (unlikely(index >= array->map.max_entries))
return -E2BIG;
@@ -259,7 +260,7 @@ static u64 bpf_perf_event_output(u64 r1, u64 r2, u64 flags, u64 r4, u64 size)
event->attr.config != PERF_COUNT_SW_BPF_OUTPUT))
return -EINVAL;
- if (unlikely(event->oncpu != smp_processor_id()))
+ if (unlikely(event->oncpu != cpu))
return -EOPNOTSUPP;
perf_sample_data_init(&sample_data, 0, 0);