samples/bpf: Remove perf_event_open() declaration

This declaration was made in samples/bpf/libbpf.c for convenience, but
there's already one in tools/perf/perf-sys.h. Reuse that one.

Committer notes:

Testing it:

  $ make -j4 O=../build/v4.9.0-rc8+ samples/bpf/
  make[1]: Entering directory '/home/build/v4.9.0-rc8+'
    CHK     include/config/kernel.release
    GEN     ./Makefile
    CHK     include/generated/uapi/linux/version.h
    Using /home/acme/git/linux as source for kernel
    CHK     include/generated/utsrelease.h
    CHK     include/generated/timeconst.h
    CHK     include/generated/bounds.h
    CHK     include/generated/asm-offsets.h
    CALL    /home/acme/git/linux/scripts/checksyscalls.sh
    HOSTCC  samples/bpf/test_verifier.o
    HOSTCC  samples/bpf/libbpf.o
    HOSTCC  samples/bpf/../../tools/lib/bpf/bpf.o
    HOSTCC  samples/bpf/test_maps.o
    HOSTCC  samples/bpf/sock_example.o
    HOSTCC  samples/bpf/bpf_load.o
<SNIP>
    HOSTLD  samples/bpf/trace_event
    HOSTLD  samples/bpf/sampleip
    HOSTLD  samples/bpf/tc_l2_redirect
  make[1]: Leaving directory '/home/build/v4.9.0-rc8+'
  $

Also tested the offwaketime resulting from the rebuild, seems to work as
before.

Signed-off-by: Joe Stringer <joe@ovn.org>
Tested-by: Arnaldo Carvalho de Melo <acme@redhat.com>
Cc: Alexei Starovoitov <ast@fb.com>
Cc: Daniel Borkmann <daniel@iogearbox.net>
Cc: Wang Nan <wangnan0@huawei.com>
Link: http://lkml.kernel.org/r/20161209024620.31660-7-joe@ovn.org
[ Use -I$(srctree)/tools/lib/ to support out of source code tree builds ]
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>

1 files changed, 2 insertions, 1 deletions

diff --git a/samples/bpf/tracex6_user.c b/samples/bpf/tracex6_user.c
index 179297cb4d35..ca7874ed77f4 100644
--- a/samples/bpf/tracex6_user.c
+++ b/samples/bpf/tracex6_user.c
@@ -10,6 +10,7 @@
 #include <linux/bpf.h>
 #include "libbpf.h"
 #include "bpf_load.h"
+#include "perf-sys.h"
 
 #define SAMPLE_PERIOD  0x7fffffffffffffffULL
 
@@ -30,7 +31,7 @@ static void test_bpf_perf_event(void)
 	};
 
 	for (i = 0; i < nr_cpus; i++) {
-		pmu_fd[i] = perf_event_open(&attr_insn_pmu, -1/*pid*/, i/*cpu*/, -1/*group_fd*/, 0);
+		pmu_fd[i] = sys_perf_event_open(&attr_insn_pmu, -1/*pid*/, i/*cpu*/, -1/*group_fd*/, 0);
 		if (pmu_fd[i] < 0) {
 			printf("event syscall failed\n");
 			goto exit;