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Commit d7931330 authored by Daniel Borkmann's avatar Daniel Borkmann Committed by David S. Miller
Browse files

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: default avatarDaniel Borkmann <daniel@iogearbox.net>
Acked-by: default avatarAlexei Starovoitov <ast@kernel.org>
Signed-off-by: default avatarDavid S. Miller <davem@davemloft.net>
parent 1ca1cc98

kernel/trace/bpf_trace.c

+3 −2
Original line number Diff line number Diff line
@@ -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);