samples: bpf: remove bpf_load loader completely

Numerous refactoring that rewrites BPF programs written with bpf_load
to use the libbpf loader was finally completed, resulting in BPF
programs using bpf_load within the kernel being completely no longer
present.

This commit removes bpf_load, an outdated bpf loader that is difficult
to keep up with the latest kernel BPF and causes confusion.

Also, this commit removes the unused trace_helper and bpf_load from
samples/bpf target objects from Makefile.

Signed-off-by: Daniel T. Lee <[email protected]>
Acked-by: Jesper Dangaard Brouer <[email protected]>
Acked-by: Andrii Nakryiko <[email protected]>

Author: DanielTimLee

samples/bpf/Makefile

@@ -73,7 +73,7 @@ tracex5-objs := tracex5_user.o $(TRACE_HELPERS)
 tracex6-objs := tracex6_user.o
 tracex7-objs := tracex7_user.o
 test_probe_write_user-objs := test_probe_write_user_user.o
-trace_output-objs := trace_output_user.o $(TRACE_HELPERS)
+trace_output-objs := trace_output_user.o
 lathist-objs := lathist_user.o
 offwaketime-objs := offwaketime_user.o $(TRACE_HELPERS)
 spintest-objs := spintest_user.o $(TRACE_HELPERS)
@@ -91,8 +91,8 @@ test_current_task_under_cgroup-objs := $(CGROUP_HELPERS) \
 				       test_current_task_under_cgroup_user.o
 trace_event-objs := trace_event_user.o $(TRACE_HELPERS)
 sampleip-objs := sampleip_user.o $(TRACE_HELPERS)
-tc_l2_redirect-objs := bpf_load.o tc_l2_redirect_user.o
-lwt_len_hist-objs := bpf_load.o lwt_len_hist_user.o
+tc_l2_redirect-objs := tc_l2_redirect_user.o
+lwt_len_hist-objs := lwt_len_hist_user.o
 xdp_tx_iptunnel-objs := xdp_tx_iptunnel_user.o
 test_map_in_map-objs := test_map_in_map_user.o
 per_socket_stats_example-objs := cookie_uid_helper_example.o
@@ -108,7 +108,7 @@ xdpsock-objs := xdpsock_user.o
 xsk_fwd-objs := xsk_fwd.o
 xdp_fwd-objs := xdp_fwd_user.o
 task_fd_query-objs := task_fd_query_user.o $(TRACE_HELPERS)
-xdp_sample_pkts-objs := xdp_sample_pkts_user.o $(TRACE_HELPERS)
+xdp_sample_pkts-objs := xdp_sample_pkts_user.o
 ibumad-objs := ibumad_user.o
 hbm-objs := hbm.o $(CGROUP_HELPERS)
 
@@ -197,8 +197,6 @@ TPROGS_CFLAGS += --sysroot=$(SYSROOT)
 TPROGS_LDFLAGS := -L$(SYSROOT)/usr/lib
 endif
 
-TPROGCFLAGS_bpf_load.o += -Wno-unused-variable
-
 TPROGS_LDLIBS			+= $(LIBBPF) -lelf -lz
 TPROGLDLIBS_tracex4		+= -lrt
 TPROGLDLIBS_trace_output	+= -lrt