Merge branch 'bpf: remove bpf_load loader completely'

"Daniel T. says:

====================

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 patchset refactors remaining bpf programs with libbpf and
completely removes bpf_load, an outdated bpf loader that is difficult
to keep up with the latest kernel BPF and causes confusion.

Changes in v2:
 - drop 'move tracing helpers to trace_helper' patch
 - add link pinning to prevent cleaning up on process exit
 - add static at global variable and remove unused variable
 - change to destroy link even after link__pin()
 - fix return error code on exit
 - merge commit with changing Makefile

Changes in v3:
 - cleanup bpf_link, bpf_object and cgroup fd both on success and error
====================
Signed-off-by: Andrii Nakryiko <andrii@kernel.org>

samples/bpf/.gitignore

@@ -52,3 +52,6 @@ xdp_tx_iptunnel
 xdpsock
 xsk_fwd
 testfile.img
+hbm_out.log
+iperf.*
+*.out

samples/bpf/Makefile

@@ -73,16 +73,16 @@ 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)
 map_perf_test-objs := map_perf_test_user.o
-test_overhead-objs := bpf_load.o test_overhead_user.o
+test_overhead-objs := test_overhead_user.o
 test_cgrp2_array_pin-objs := test_cgrp2_array_pin.o
 test_cgrp2_attach-objs := test_cgrp2_attach.o
 test_cgrp2_sock-objs := test_cgrp2_sock.o
-test_cgrp2_sock2-objs := bpf_load.o test_cgrp2_sock2.o
+test_cgrp2_sock2-objs := test_cgrp2_sock2.o
 xdp1-objs := xdp1_user.o
 # reuse xdp1 source intentionally
 xdp2-objs := xdp1_user.o
@@ -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
@@ -107,10 +107,10 @@ 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)
-xdp_sample_pkts-objs := xdp_sample_pkts_user.o $(TRACE_HELPERS)
-ibumad-objs := bpf_load.o ibumad_user.o $(TRACE_HELPERS)
-hbm-objs := bpf_load.o hbm.o $(CGROUP_HELPERS)
+task_fd_query-objs := task_fd_query_user.o $(TRACE_HELPERS)
+xdp_sample_pkts-objs := xdp_sample_pkts_user.o
+ibumad-objs := ibumad_user.o
+hbm-objs := hbm.o $(CGROUP_HELPERS)
 
 # Tell kbuild to always build the programs
 always-y := $(tprogs-y)
@@ -197,8 +197,6 @@ TPROGS_CFLAGS += --sysroot=$(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/do_hbm_test.sh

@@ -91,6 +91,16 @@ qdisc=""
 flags=""
 do_stats=0
 
+BPFFS=/sys/fs/bpf
+function config_bpffs () {
+	if mount | grep $BPFFS > /dev/null; then
+		echo "bpffs already mounted"
+	else
+		echo "bpffs not mounted. Mounting..."
+		mount -t bpf none $BPFFS
+	fi
+}
+
 function start_hbm () {
   rm -f hbm.out
   echo "./hbm $dir -n $id -r $rate -t $dur $flags $dbg $prog" > hbm.out
@@ -192,6 +202,7 @@ processArgs () {
 }
 
 processArgs
+config_bpffs
 
 if [ $debug_flag -eq 1 ] ; then
   rm -f hbm_out.log
@@ -201,7 +212,7 @@ hbm_pid=$(start_hbm)
 usleep 100000
 
 host=`hostname`
-cg_base_dir=/sys/fs/cgroup
+cg_base_dir=/sys/fs/cgroup/unified
 cg_dir="$cg_base_dir/cgroup-test-work-dir/hbm$id"
 
 echo $$ >> $cg_dir/cgroup.procs
@@ -411,23 +422,8 @@ fi
 
 sleep 1
 
-# Detach any BPF programs that may have lingered
-ttx=`bpftool cgroup tree | grep hbm`
-v=2
-for x in $ttx ; do
-    if [ "${x:0:36}" == "/sys/fs/cgroup/cgroup-test-work-dir/" ] ; then
-	cg=$x ; v=0
-    else
-	if [ $v -eq 0 ] ; then
-	    id=$x ; v=1
-	else
-	    if [ $v -eq 1 ] ; then
-		type=$x ; bpftool cgroup detach $cg $type id $id
-		v=0
-	    fi
-	fi
-    fi
-done
+# Detach any pinned BPF programs that may have lingered
+rm -rf $BPFFS/hbm*
 
 if [ $use_netperf -ne 0 ] ; then
   if [ "$server" == "" ] ; then

samples/bpf/hbm.c

@@ -46,7 +46,6 @@
 #include <bpf/bpf.h>
 #include <getopt.h>
 
-#include "bpf_load.h"
 #include "bpf_rlimit.h"
 #include "cgroup_helpers.h"
 #include "hbm.h"
@@ -70,9 +69,9 @@ static void do_error(char *msg, bool errno_flag);
 
 #define DEBUGFS "/sys/kernel/debug/tracing/"
 
-struct bpf_object *obj;
-int bpfprog_fd;
-int cgroup_storage_fd;
+static struct bpf_program *bpf_prog;
+static struct bpf_object *obj;
+static int queue_stats_fd;
 
 static void read_trace_pipe2(void)
 {
@@ -121,56 +120,50 @@ static void do_error(char *msg, bool errno_flag)
 
 static int prog_load(char *prog)
 {
-	struct bpf_prog_load_attr prog_load_attr = {
-		.prog_type = BPF_PROG_TYPE_CGROUP_SKB,
-		.file = prog,
-		.expected_attach_type = BPF_CGROUP_INET_EGRESS,
-	};
-	int map_fd;
-	struct bpf_map *map;
-
-	int ret = 0;
-
-	if (access(prog, O_RDONLY) < 0) {
-		printf("Error accessing file %s: %s\n", prog, strerror(errno));
+	obj = bpf_object__open_file(prog, NULL);
+	if (libbpf_get_error(obj)) {
+		printf("ERROR: opening BPF object file failed\n");
 		return 1;
 	}
-	if (bpf_prog_load_xattr(&prog_load_attr, &obj, &bpfprog_fd))
-		ret = 1;
-	if (!ret) {
-		map = bpf_object__find_map_by_name(obj, "queue_stats");
-		map_fd = bpf_map__fd(map);
-		if (map_fd < 0) {
-			printf("Map not found: %s\n", strerror(map_fd));
-			ret = 1;
-		}
+
+	/* load BPF program */
+	if (bpf_object__load(obj)) {
+		printf("ERROR: loading BPF object file failed\n");
+		goto err;
 	}
 
-	if (ret) {
-		printf("ERROR: bpf_prog_load_xattr failed for: %s\n", prog);
-		printf("  Output from verifier:\n%s\n------\n", bpf_log_buf);
-		ret = -1;
-	} else {
-		ret = map_fd;
+	bpf_prog = bpf_object__find_program_by_title(obj, "cgroup_skb/egress");
+	if (!bpf_prog) {
+		printf("ERROR: finding a prog in obj file failed\n");
+		goto err;
+	}
+
+	queue_stats_fd = bpf_object__find_map_fd_by_name(obj, "queue_stats");
+	if (queue_stats_fd < 0) {
+		printf("ERROR: finding a map in obj file failed\n");
+		goto err;
 	}
 
-	return ret;
+	return 0;
+
+err:
+	bpf_object__close(obj);
+	return 1;
 }
 
 static int run_bpf_prog(char *prog, int cg_id)
 {
-	int map_fd;
-	int rc = 0;
+	struct hbm_queue_stats qstats = {0};
+	char cg_dir[100], cg_pin_path[100];
+	struct bpf_link *link = NULL;
 	int key = 0;
 	int cg1 = 0;
-	int type = BPF_CGROUP_INET_EGRESS;
-	char cg_dir[100];
-	struct hbm_queue_stats qstats = {0};
+	int rc = 0;
 
 	sprintf(cg_dir, "/hbm%d", cg_id);
-	map_fd = prog_load(prog);
-	if (map_fd  == -1)
-		return 1;
+	rc = prog_load(prog);
+	if (rc != 0)
+		return rc;
 
 	if (setup_cgroup_environment()) {
 		printf("ERROR: setting cgroup environment\n");
@@ -190,16 +183,24 @@ static int run_bpf_prog(char *prog, int cg_id)
 	qstats.stats = stats_flag ? 1 : 0;
 	qstats.loopback = loopback_flag ? 1 : 0;
 	qstats.no_cn = no_cn_flag ? 1 : 0;
-	if (bpf_map_update_elem(map_fd, &key, &qstats, BPF_ANY)) {
+	if (bpf_map_update_elem(queue_stats_fd, &key, &qstats, BPF_ANY)) {
 		printf("ERROR: Could not update map element\n");
 		goto err;
 	}
 
 	if (!outFlag)
-		type = BPF_CGROUP_INET_INGRESS;
-	if (bpf_prog_attach(bpfprog_fd, cg1, type, 0)) {
-		printf("ERROR: bpf_prog_attach fails!\n");
-		log_err("Attaching prog");
+		bpf_program__set_expected_attach_type(bpf_prog, BPF_CGROUP_INET_INGRESS);
+
+	link = bpf_program__attach_cgroup(bpf_prog, cg1);
+	if (libbpf_get_error(link)) {
+		fprintf(stderr, "ERROR: bpf_program__attach_cgroup failed\n");
+		goto err;
+	}
+
+	sprintf(cg_pin_path, "/sys/fs/bpf/hbm%d", cg_id);
+	rc = bpf_link__pin(link, cg_pin_path);
+	if (rc < 0) {
+		printf("ERROR: bpf_link__pin failed: %d\n", rc);
 		goto err;
 	}
 
@@ -213,7 +214,7 @@ static int run_bpf_prog(char *prog, int cg_id)
 #define DELTA_RATE_CHECK 10000		/* in us */
 #define RATE_THRESHOLD 9500000000	/* 9.5 Gbps */
 
-		bpf_map_lookup_elem(map_fd, &key, &qstats);
+		bpf_map_lookup_elem(queue_stats_fd, &key, &qstats);
 		if (gettimeofday(&t0, NULL) < 0)
 			do_error("gettimeofday failed", true);
 		t_last = t0;
@@ -242,7 +243,7 @@ static int run_bpf_prog(char *prog, int cg_id)
 			fclose(fin);
 			printf("  new_eth_tx_bytes:%llu\n",
 			       new_eth_tx_bytes);
-			bpf_map_lookup_elem(map_fd, &key, &qstats);
+			bpf_map_lookup_elem(queue_stats_fd, &key, &qstats);
 			new_cg_tx_bytes = qstats.bytes_total;
 			delta_bytes = new_eth_tx_bytes - last_eth_tx_bytes;
 			last_eth_tx_bytes = new_eth_tx_bytes;
@@ -289,14 +290,14 @@ static int run_bpf_prog(char *prog, int cg_id)
 					rate = minRate;
 				qstats.rate = rate;
 			}
-			if (bpf_map_update_elem(map_fd, &key, &qstats, BPF_ANY))
+			if (bpf_map_update_elem(queue_stats_fd, &key, &qstats, BPF_ANY))
 				do_error("update map element fails", false);
 		}
 	} else {
 		sleep(dur);
 	}
 	// Get stats!
-	if (stats_flag && bpf_map_lookup_elem(map_fd, &key, &qstats)) {
+	if (stats_flag && bpf_map_lookup_elem(queue_stats_fd, &key, &qstats)) {
 		char fname[100];
 		FILE *fout;
 
@@ -394,14 +395,20 @@ static int run_bpf_prog(char *prog, int cg_id)
 
 	if (debugFlag)
 		read_trace_pipe2();
-	return rc;
+	goto cleanup;
+
 err:
 	rc = 1;
 
-	if (cg1)
+cleanup:
+	bpf_link__destroy(link);
+	bpf_object__close(obj);
+
+	if (cg1 != -1)
 		close(cg1);
-	cleanup_cgroup_environment();
 
+	if (rc != 0)
+		cleanup_cgroup_environment();
 	return rc;
 }
 

samples/bpf/hbm_kern.h

@@ -69,7 +69,7 @@ struct {
 	__uint(type, BPF_MAP_TYPE_ARRAY);
 	__uint(max_entries, 1);
 	__type(key, u32);
-	__type(value, struct hvm_queue_stats);
+	__type(value, struct hbm_queue_stats);
 } queue_stats SEC(".maps");
 
 struct hbm_pkt_info {

samples/bpf/ibumad_kern.c

@@ -16,19 +16,19 @@
 #include <bpf/bpf_helpers.h>
 
 
-struct bpf_map_def SEC("maps") read_count = {
-	.type        = BPF_MAP_TYPE_ARRAY,
-	.key_size    = sizeof(u32), /* class; u32 required */
-	.value_size  = sizeof(u64), /* count of mads read */
-	.max_entries = 256, /* Room for all Classes */
-};
-
-struct bpf_map_def SEC("maps") write_count = {
-	.type        = BPF_MAP_TYPE_ARRAY,
-	.key_size    = sizeof(u32), /* class; u32 required */
-	.value_size  = sizeof(u64), /* count of mads written */
-	.max_entries = 256, /* Room for all Classes */
-};
+struct {
+	__uint(type, BPF_MAP_TYPE_ARRAY);
+	__type(key, u32); /* class; u32 required */
+	__type(value, u64); /* count of mads read */
+	__uint(max_entries, 256); /* Room for all Classes */
+} read_count SEC(".maps");
+
+struct {
+	__uint(type, BPF_MAP_TYPE_ARRAY);
+	__type(key, u32); /* class; u32 required */
+	__type(value, u64); /* count of mads written */
+	__uint(max_entries, 256); /* Room for all Classes */
+} write_count SEC(".maps");
 
 #undef DEBUG
 #ifndef DEBUG

samples/bpf/ibumad_user.c

@@ -23,10 +23,15 @@
 #include <getopt.h>
 #include <net/if.h>
 
-#include "bpf_load.h"
+#include <bpf/bpf.h>
 #include "bpf_util.h"
 #include <bpf/libbpf.h>
 
+static struct bpf_link *tp_links[3];
+static struct bpf_object *obj;
+static int map_fd[2];
+static int tp_cnt;
+
 static void dump_counts(int fd)
 {
 	__u32 key;
@@ -53,6 +58,11 @@ static void dump_all_counts(void)
 static void dump_exit(int sig)
 {
 	dump_all_counts();
+	/* Detach tracepoints */
+	while (tp_cnt)
+		bpf_link__destroy(tp_links[--tp_cnt]);
+
+	bpf_object__close(obj);
 	exit(0);
 }
 
@@ -73,19 +83,11 @@ static void usage(char *cmd)
 
 int main(int argc, char **argv)
 {
+	struct bpf_program *prog;
 	unsigned long delay = 5;
+	char filename[256];
 	int longindex = 0;
-	int opt;
-	char bpf_file[256];
-
-	/* Create the eBPF kernel code path name.
-	 * This follows the pattern of all of the other bpf samples
-	 */
-	snprintf(bpf_file, sizeof(bpf_file), "%s_kern.o", argv[0]);
-
-	/* Do one final dump when exiting */
-	signal(SIGINT, dump_exit);
-	signal(SIGTERM, dump_exit);
+	int opt, err = -1;
 
 	while ((opt = getopt_long(argc, argv, "hd:rSw",
 				  long_options, &longindex)) != -1) {
@@ -107,16 +109,51 @@ int main(int argc, char **argv)
 		}
 	}
 
-	if (load_bpf_file(bpf_file)) {
-		fprintf(stderr, "ERROR: failed to load eBPF from file : %s\n",
-			bpf_file);
-		return 1;
+	/* Do one final dump when exiting */
+	signal(SIGINT, dump_exit);
+	signal(SIGTERM, dump_exit);
+
+	snprintf(filename, sizeof(filename), "%s_kern.o", argv[0]);
+	obj = bpf_object__open_file(filename, NULL);
+	if (libbpf_get_error(obj)) {
+		fprintf(stderr, "ERROR: opening BPF object file failed\n");
+		return err;
+	}
+
+	/* load BPF program */
+	if (bpf_object__load(obj)) {
+		fprintf(stderr, "ERROR: loading BPF object file failed\n");
+		goto cleanup;
+	}
+
+	map_fd[0] = bpf_object__find_map_fd_by_name(obj, "read_count");
+	map_fd[1] = bpf_object__find_map_fd_by_name(obj, "write_count");
+	if (map_fd[0] < 0 || map_fd[1] < 0) {
+		fprintf(stderr, "ERROR: finding a map in obj file failed\n");
+		goto cleanup;
+	}
+
+	bpf_object__for_each_program(prog, obj) {
+		tp_links[tp_cnt] = bpf_program__attach(prog);
+		if (libbpf_get_error(tp_links[tp_cnt])) {
+			fprintf(stderr, "ERROR: bpf_program__attach failed\n");
+			tp_links[tp_cnt] = NULL;
+			goto cleanup;
+		}
+		tp_cnt++;
 	}
 
 	while (1) {
 		sleep(delay);
 		dump_all_counts();
 	}
+	err = 0;
+
+cleanup:
+	/* Detach tracepoints */
+	while (tp_cnt)
+		bpf_link__destroy(tp_links[--tp_cnt]);
 
-	return 0;
+	bpf_object__close(obj);
+	return err;
 }

samples/bpf/lwt_len_hist.sh

@@ -8,6 +8,8 @@ VETH1=tst_lwt1b
 TRACE_ROOT=/sys/kernel/debug/tracing
 
 function cleanup {
+	# To reset saved histogram, remove pinned map
+	rm /sys/fs/bpf/tc/globals/lwt_len_hist_map
 	ip route del 192.168.253.2/32 dev $VETH0 2> /dev/null
 	ip link del $VETH0 2> /dev/null
 	ip link del $VETH1 2> /dev/null

samples/bpf/task_fd_query_user.c

@@ -15,12 +15,15 @@
 #include <sys/stat.h>
 #include <linux/perf_event.h>
 
+#include <bpf/bpf.h>
 #include <bpf/libbpf.h>
-#include "bpf_load.h"
 #include "bpf_util.h"
 #include "perf-sys.h"
 #include "trace_helpers.h"
 
+static struct bpf_program *progs[2];
+static struct bpf_link *links[2];
+
 #define CHECK_PERROR_RET(condition) ({			\
 	int __ret = !!(condition);			\
 	if (__ret) {					\
@@ -86,21 +89,22 @@ static int bpf_get_retprobe_bit(const char *event_type)
 	return ret;
 }
 
-static int test_debug_fs_kprobe(int prog_fd_idx, const char *fn_name,
+static int test_debug_fs_kprobe(int link_idx, const char *fn_name,
 				__u32 expected_fd_type)
 {
 	__u64 probe_offset, probe_addr;
 	__u32 len, prog_id, fd_type;
+	int err, event_fd;
 	char buf[256];
-	int err;
 
 	len = sizeof(buf);
-	err = bpf_task_fd_query(getpid(), event_fd[prog_fd_idx], 0, buf, &len,
+	event_fd = bpf_link__fd(links[link_idx]);
+	err = bpf_task_fd_query(getpid(), event_fd, 0, buf, &len,
 				&prog_id, &fd_type, &probe_offset,
 				&probe_addr);
 	if (err < 0) {
 		printf("FAIL: %s, for event_fd idx %d, fn_name %s\n",
-		       __func__, prog_fd_idx, fn_name);
+		       __func__, link_idx, fn_name);
 		perror("    :");
 		return -1;
 	}
@@ -108,7 +112,7 @@ static int test_debug_fs_kprobe(int prog_fd_idx, const char *fn_name,
 	    fd_type != expected_fd_type ||
 	    probe_offset != 0x0 || probe_addr != 0x0) {
 		printf("FAIL: bpf_trace_event_query(event_fd[%d]):\n",
-		       prog_fd_idx);
+		       link_idx);
 		printf("buf: %s, fd_type: %u, probe_offset: 0x%llx,"
 		       " probe_addr: 0x%llx\n",
 		       buf, fd_type, probe_offset, probe_addr);
@@ -125,12 +129,13 @@ static int test_nondebug_fs_kuprobe_common(const char *event_type,
 	int is_return_bit = bpf_get_retprobe_bit(event_type);
 	int type = bpf_find_probe_type(event_type);
 	struct perf_event_attr attr = {};
-	int fd;
+	struct bpf_link *link;
+	int fd, err = -1;
 
 	if (type < 0 || is_return_bit < 0) {
 		printf("FAIL: %s incorrect type (%d) or is_return_bit (%d)\n",
 			__func__, type, is_return_bit);
-		return -1;
+		return err;
 	}
 
 	attr.sample_period = 1;
@@ -149,14 +154,21 @@ static int test_nondebug_fs_kuprobe_common(const char *event_type,
 	attr.type = type;
 
 	fd = sys_perf_event_open(&attr, -1, 0, -1, 0);
-	CHECK_PERROR_RET(fd < 0);
+	link = bpf_program__attach_perf_event(progs[0], fd);
+	if (libbpf_get_error(link)) {
+		printf("ERROR: bpf_program__attach_perf_event failed\n");
+		link = NULL;
+		close(fd);
+		goto cleanup;
+	}
 
-	CHECK_PERROR_RET(ioctl(fd, PERF_EVENT_IOC_ENABLE, 0) < 0);
-	CHECK_PERROR_RET(ioctl(fd, PERF_EVENT_IOC_SET_BPF, prog_fd[0]) < 0);
 	CHECK_PERROR_RET(bpf_task_fd_query(getpid(), fd, 0, buf, buf_len,
 			 prog_id, fd_type, probe_offset, probe_addr) < 0);
+	err = 0;
 
-	return 0;
+cleanup:
+	bpf_link__destroy(link);
+	return err;
 }
 
 static int test_nondebug_fs_probe(const char *event_type, const char *name,
@@ -215,17 +227,18 @@ static int test_nondebug_fs_probe(const char *event_type, const char *name,
 
 static int test_debug_fs_uprobe(char *binary_path, long offset, bool is_return)
 {
+	char buf[256], event_alias[sizeof("test_1234567890")];
 	const char *event_type = "uprobe";
 	struct perf_event_attr attr = {};
-	char buf[256], event_alias[sizeof("test_1234567890")];
 	__u64 probe_offset, probe_addr;
 	__u32 len, prog_id, fd_type;
-	int err, res, kfd, efd;
+	int err = -1, res, kfd, efd;
+	struct bpf_link *link;
 	ssize_t bytes;
 
 	snprintf(buf, sizeof(buf), "/sys/kernel/debug/tracing/%s_events",
 		 event_type);
-	kfd = open(buf, O_WRONLY | O_APPEND, 0);
+	kfd = open(buf, O_WRONLY | O_TRUNC, 0);
 	CHECK_PERROR_RET(kfd < 0);
 
 	res = snprintf(event_alias, sizeof(event_alias), "test_%d", getpid());
@@ -254,10 +267,15 @@ static int test_debug_fs_uprobe(char *binary_path, long offset, bool is_return)
 	attr.type = PERF_TYPE_TRACEPOINT;
 	attr.sample_period = 1;
 	attr.wakeup_events = 1;
+
 	kfd = sys_perf_event_open(&attr, -1, 0, -1, PERF_FLAG_FD_CLOEXEC);
-	CHECK_PERROR_RET(kfd < 0);
-	CHECK_PERROR_RET(ioctl(kfd, PERF_EVENT_IOC_SET_BPF, prog_fd[0]) < 0);
-	CHECK_PERROR_RET(ioctl(kfd, PERF_EVENT_IOC_ENABLE, 0) < 0);
+	link = bpf_program__attach_perf_event(progs[0], kfd);
+	if (libbpf_get_error(link)) {
+		printf("ERROR: bpf_program__attach_perf_event failed\n");
+		link = NULL;
+		close(kfd);
+		goto cleanup;
+	}
 
 	len = sizeof(buf);
 	err = bpf_task_fd_query(getpid(), kfd, 0, buf, &len,
@@ -283,9 +301,11 @@ static int test_debug_fs_uprobe(char *binary_path, long offset, bool is_return)
 		       probe_offset);
 		return -1;
 	}
+	err = 0;
 
-	close(kfd);
-	return 0;
+cleanup:
+	bpf_link__destroy(link);
+	return err;
 }
 
 int main(int argc, char **argv)
@@ -294,21 +314,42 @@ int main(int argc, char **argv)
 	extern char __executable_start;
 	char filename[256], buf[256];
 	__u64 uprobe_file_offset;
+	struct bpf_program *prog;
+	struct bpf_object *obj;
+	int i = 0, err = -1;
 
-	snprintf(filename, sizeof(filename), "%s_kern.o", argv[0]);
 	if (setrlimit(RLIMIT_MEMLOCK, &r)) {
 		perror("setrlimit(RLIMIT_MEMLOCK)");
-		return 1;
+		return err;
 	}
 
 	if (load_kallsyms()) {
 		printf("failed to process /proc/kallsyms\n");
-		return 1;
+		return err;
+	}
+
+	snprintf(filename, sizeof(filename), "%s_kern.o", argv[0]);
+	obj = bpf_object__open_file(filename, NULL);
+	if (libbpf_get_error(obj)) {
+		fprintf(stderr, "ERROR: opening BPF object file failed\n");
+		return err;
 	}
 
-	if (load_bpf_file(filename)) {
-		printf("%s", bpf_log_buf);
-		return 1;
+	/* load BPF program */
+	if (bpf_object__load(obj)) {
+		fprintf(stderr, "ERROR: loading BPF object file failed\n");
+		goto cleanup;
+	}
+
+	bpf_object__for_each_program(prog, obj) {
+		progs[i] = prog;
+		links[i] = bpf_program__attach(progs[i]);
+		if (libbpf_get_error(links[i])) {
+			fprintf(stderr, "ERROR: bpf_program__attach failed\n");
+			links[i] = NULL;
+			goto cleanup;
+		}
+		i++;
 	}
 
 	/* test two functions in the corresponding *_kern.c file */
@@ -378,6 +419,12 @@ int main(int argc, char **argv)
 					   false));
 	CHECK_AND_RET(test_debug_fs_uprobe((char *)argv[0], uprobe_file_offset,
 					   true));
+	err = 0;
 
-	return 0;
+cleanup:
+	for (i--; i >= 0; i--)
+		bpf_link__destroy(links[i]);
+
+	bpf_object__close(obj);
+	return err;
 }

samples/bpf/test_cgrp2_sock2.c

@@ -20,9 +20,9 @@
 #include <net/if.h>
 #include <linux/bpf.h>
 #include <bpf/bpf.h>
+#include <bpf/libbpf.h>
 
 #include "bpf_insn.h"
-#include "bpf_load.h"
 
 static int usage(const char *argv0)
 {
@@ -32,37 +32,64 @@ static int usage(const char *argv0)
 
 int main(int argc, char **argv)
 {
-	int cg_fd, ret, filter_id = 0;
+	int cg_fd, err, ret = EXIT_FAILURE, filter_id = 0, prog_cnt = 0;
+	const char *link_pin_path = "/sys/fs/bpf/test_cgrp2_sock2";
+	struct bpf_link *link = NULL;
+	struct bpf_program *progs[2];
+	struct bpf_program *prog;
+	struct bpf_object *obj;
 
 	if (argc < 3)
 		return usage(argv[0]);
 
+	if (argc > 3)
+		filter_id = atoi(argv[3]);
+
 	cg_fd = open(argv[1], O_DIRECTORY | O_RDONLY);
 	if (cg_fd < 0) {
 		printf("Failed to open cgroup path: '%s'\n", strerror(errno));
-		return EXIT_FAILURE;
+		return ret;
 	}
 
-	if (load_bpf_file(argv[2]))
-		return EXIT_FAILURE;
-
-	printf("Output from kernel verifier:\n%s\n-------\n", bpf_log_buf);
+	obj = bpf_object__open_file(argv[2], NULL);
+	if (libbpf_get_error(obj)) {
+		printf("ERROR: opening BPF object file failed\n");
+		return ret;
+	}
 
-	if (argc > 3)
-		filter_id = atoi(argv[3]);
+	bpf_object__for_each_program(prog, obj) {
+		progs[prog_cnt] = prog;
+		prog_cnt++;
+	}
 
 	if (filter_id >= prog_cnt) {
 		printf("Invalid program id; program not found in file\n");
-		return EXIT_FAILURE;
+		goto cleanup;
+	}
+
+	/* load BPF program */
+	if (bpf_object__load(obj)) {
+		printf("ERROR: loading BPF object file failed\n");
+		goto cleanup;
 	}
 
-	ret = bpf_prog_attach(prog_fd[filter_id], cg_fd,
-			      BPF_CGROUP_INET_SOCK_CREATE, 0);
-	if (ret < 0) {
-		printf("Failed to attach prog to cgroup: '%s'\n",
-		       strerror(errno));
-		return EXIT_FAILURE;
+	link = bpf_program__attach_cgroup(progs[filter_id], cg_fd);
+	if (libbpf_get_error(link)) {
+		printf("ERROR: bpf_program__attach failed\n");
+		link = NULL;
+		goto cleanup;
 	}
 
-	return EXIT_SUCCESS;
+	err = bpf_link__pin(link, link_pin_path);
+	if (err < 0) {
+		printf("ERROR: bpf_link__pin failed: %d\n", err);
+		goto cleanup;
+	}
+
+	ret = EXIT_SUCCESS;
+
+cleanup:
+	bpf_link__destroy(link);
+	bpf_object__close(obj);
+	return ret;
 }

samples/bpf/test_cgrp2_sock2.sh

 #!/bin/bash
 # SPDX-License-Identifier: GPL-2.0
 
+BPFFS=/sys/fs/bpf
+LINK_PIN=$BPFFS/test_cgrp2_sock2
+
 function config_device {
 	ip netns add at_ns0
 	ip link add veth0 type veth peer name veth0b
@@ -21,16 +24,22 @@ function config_cgroup {
 	echo $$ >> /tmp/cgroupv2/foo/cgroup.procs
 }
 
+function config_bpffs {
+	if mount | grep $BPFFS > /dev/null; then
+		echo "bpffs already mounted"
+	else
+		echo "bpffs not mounted. Mounting..."
+		mount -t bpf none $BPFFS
+	fi
+}
 
 function attach_bpf {
-	test_cgrp2_sock2 /tmp/cgroupv2/foo sock_flags_kern.o $1
+	./test_cgrp2_sock2 /tmp/cgroupv2/foo sock_flags_kern.o $1
 	[ $? -ne 0 ] && exit 1
 }
 
 function cleanup {
-	if [ -d /tmp/cgroupv2/foo ]; then
-		test_cgrp2_sock -d /tmp/cgroupv2/foo
-	fi
+	rm -rf $LINK_PIN
 	ip link del veth0b
 	ip netns delete at_ns0
 	umount /tmp/cgroupv2
@@ -42,6 +51,7 @@ cleanup 2>/dev/null
 set -e
 config_device
 config_cgroup
+config_bpffs
 set +e
 
 #
@@ -62,6 +72,9 @@ if [ $? -eq 0 ]; then
 	exit 1
 fi
 
+rm -rf $LINK_PIN
+sleep 1                 # Wait for link detach
+
 #
 # Test 2 - fail ping
 #

samples/bpf/test_overhead_user.c

@@ -18,10 +18,14 @@
 #include <time.h>
 #include <sys/resource.h>
 #include <bpf/bpf.h>
-#include "bpf_load.h"
+#include <bpf/libbpf.h>
 
 #define MAX_CNT 1000000
 
+static struct bpf_link *links[2];
+static struct bpf_object *obj;
+static int cnt;
+
 static __u64 time_get_ns(void)
 {
 	struct timespec ts;
@@ -115,20 +119,54 @@ static void run_perf_test(int tasks, int flags)
 	}
 }
 
+static int load_progs(char *filename)
+{
+	struct bpf_program *prog;
+	int err = 0;
+
+	obj = bpf_object__open_file(filename, NULL);
+	err = libbpf_get_error(obj);
+	if (err < 0) {
+		fprintf(stderr, "ERROR: opening BPF object file failed\n");
+		return err;
+	}
+
+	/* load BPF program */
+	err = bpf_object__load(obj);
+	if (err < 0) {
+		fprintf(stderr, "ERROR: loading BPF object file failed\n");
+		return err;
+	}
+
+	bpf_object__for_each_program(prog, obj) {
+		links[cnt] = bpf_program__attach(prog);
+		err = libbpf_get_error(links[cnt]);
+		if (err < 0) {
+			fprintf(stderr, "ERROR: bpf_program__attach failed\n");
+			links[cnt] = NULL;
+			return err;
+		}
+		cnt++;
+	}
+
+	return err;
+}
+
 static void unload_progs(void)
 {
-	close(prog_fd[0]);
-	close(prog_fd[1]);
-	close(event_fd[0]);
-	close(event_fd[1]);
+	while (cnt)
+		bpf_link__destroy(links[--cnt]);
+
+	bpf_object__close(obj);
 }
 
 int main(int argc, char **argv)
 {
 	struct rlimit r = {RLIM_INFINITY, RLIM_INFINITY};
-	char filename[256];
-	int num_cpu = 8;
+	int num_cpu = sysconf(_SC_NPROCESSORS_ONLN);
 	int test_flags = ~0;
+	char filename[256];
+	int err = 0;
 
 	setrlimit(RLIMIT_MEMLOCK, &r);
 
@@ -145,38 +183,36 @@ int main(int argc, char **argv)
 	if (test_flags & 0xC) {
 		snprintf(filename, sizeof(filename),
 			 "%s_kprobe_kern.o", argv[0]);
-		if (load_bpf_file(filename)) {
-			printf("%s", bpf_log_buf);
-			return 1;
-		}
+
 		printf("w/KPROBE\n");
-		run_perf_test(num_cpu, test_flags >> 2);
+		err = load_progs(filename);
+		if (!err)
+			run_perf_test(num_cpu, test_flags >> 2);
+
 		unload_progs();
 	}
 
 	if (test_flags & 0x30) {
 		snprintf(filename, sizeof(filename),
 			 "%s_tp_kern.o", argv[0]);
-		if (load_bpf_file(filename)) {
-			printf("%s", bpf_log_buf);
-			return 1;
-		}
 		printf("w/TRACEPOINT\n");
-		run_perf_test(num_cpu, test_flags >> 4);
+		err = load_progs(filename);
+		if (!err)
+			run_perf_test(num_cpu, test_flags >> 4);
+
 		unload_progs();
 	}
 
 	if (test_flags & 0xC0) {
 		snprintf(filename, sizeof(filename),
 			 "%s_raw_tp_kern.o", argv[0]);
-		if (load_bpf_file(filename)) {
-			printf("%s", bpf_log_buf);
-			return 1;
-		}
 		printf("w/RAW_TRACEPOINT\n");
-		run_perf_test(num_cpu, test_flags >> 6);
+		err = load_progs(filename);
+		if (!err)
+			run_perf_test(num_cpu, test_flags >> 6);
+
 		unload_progs();
 	}
 
-	return 0;
+	return err;
 }

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>