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This commit removes bpf_load, an outdated bpf loader that is difficult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 <danieltimlee@gmail.com>
Signed-off-by: Andrii Nakryiko <andrii@kernel.org>
Acked-by: Jesper Dangaard Brouer <brouer@redhat.com>
Acked-by: Andrii Nakryiko <andrii@kernel.org>
Link: https://lore.kernel.org/bpf/20201124090310.24374-8-danieltimlee@gmail.com

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

samples/bpf/bpf_load.h

-/* SPDX-License-Identifier: GPL-2.0 */
-#ifndef __BPF_LOAD_H
-#define __BPF_LOAD_H
-
-#include <bpf/bpf.h>
-
-#define MAX_MAPS 32
-#define MAX_PROGS 32
-
-struct bpf_load_map_def {
-	unsigned int type;
-	unsigned int key_size;
-	unsigned int value_size;
-	unsigned int max_entries;
-	unsigned int map_flags;
-	unsigned int inner_map_idx;
-	unsigned int numa_node;
-};
-
-struct bpf_map_data {
-	int fd;
-	char *name;
-	size_t elf_offset;
-	struct bpf_load_map_def def;
-};
-
-typedef void (*fixup_map_cb)(struct bpf_map_data *map, int idx);
-
-extern int prog_fd[MAX_PROGS];
-extern int event_fd[MAX_PROGS];
-extern char bpf_log_buf[BPF_LOG_BUF_SIZE];
-extern int prog_cnt;
-
-/* There is a one-to-one mapping between map_fd[] and map_data[].
- * The map_data[] just contains more rich info on the given map.
- */
-extern int map_fd[MAX_MAPS];
-extern struct bpf_map_data map_data[MAX_MAPS];
-extern int map_data_count;
-
-/* parses elf file compiled by llvm .c->.o
- * . parses 'maps' section and creates maps via BPF syscall
- * . parses 'license' section and passes it to syscall
- * . parses elf relocations for BPF maps and adjusts BPF_LD_IMM64 insns by
- *   storing map_fd into insn->imm and marking such insns as BPF_PSEUDO_MAP_FD
- * . loads eBPF programs via BPF syscall
- *
- * One ELF file can contain multiple BPF programs which will be loaded
- * and their FDs stored stored in prog_fd array
- *
- * returns zero on success
- */
-int load_bpf_file(char *path);
-int load_bpf_file_fixup_map(const char *path, fixup_map_cb fixup_map);
-
-int bpf_set_link_xdp_fd(int ifindex, int fd, __u32 flags);
-#endif

samples/bpf/xdp2skb_meta_kern.c

@@ -6,7 +6,7 @@
  * This uses the XDP data_meta infrastructure, and is a cooperation
  * between two bpf-programs (1) XDP and (2) clsact at TC-ingress hook.
  *
- * Notice: This example does not use the BPF C-loader (bpf_load.c),
+ * Notice: This example does not use the BPF C-loader,
  * but instead rely on the iproute2 TC tool for loading BPF-objects.
  */
 #include <uapi/linux/bpf.h>