samples: bpf: Refactor task_fd_query program with libbpf

This commit refactors the existing kprobe program with libbpf bpf
loader. To attach bpf program, this uses generic bpf_program__attach()
approach rather than using bpf_load's load_bpf_file().

To attach bpf to perf_event, instead of using previous ioctl method,
this commit uses bpf_program__attach_perf_event since it manages the
enable of perf_event and attach of BPF programs to it, which is much
more intuitive way to achieve.

Also, explicit close(fd) has been removed since event will be closed
inside bpf_link__destroy() automatically.

Furthermore, to prevent conflict of same named uprobe events, O_TRUNC
flag has been used to clear 'uprobe_events' interface.

Signed-off-by: Daniel T. Lee <danieltimlee@gmail.com>
Signed-off-by: Andrii Nakryiko <andrii@kernel.org>
Link: https://lore.kernel.org/bpf/20201124090310.24374-4-danieltimlee@gmail.com

1 files changed, 1 insertions, 1 deletions

diff --git a/samples/bpf/Makefile b/samples/bpf/Makefile
index d31e082c369e..3bffd42e1482 100644
--- a/samples/bpf/Makefile
+++ b/samples/bpf/Makefile
@@ -107,7 +107,7 @@ xdp_adjust_tail-objs := xdp_adjust_tail_user.o
 xdpsock-objs := xdpsock_user.o
 xsk_fwd-objs := xsk_fwd.o
 xdp_fwd-objs := xdp_fwd_user.o
-task_fd_query-objs := bpf_load.o task_fd_query_user.o $(TRACE_HELPERS)
+task_fd_query-objs := task_fd_query_user.o $(TRACE_HELPERS)
 xdp_sample_pkts-objs := xdp_sample_pkts_user.o $(TRACE_HELPERS)
 ibumad-objs := bpf_load.o ibumad_user.o $(TRACE_HELPERS)
 hbm-objs := hbm.o $(CGROUP_HELPERS)