selftests/bpf: fix lots of silly mistakes pointed out by compiler

Once we enable -Wall for BPF sources, compiler will complain about lots
of unused variables, variables that are set but never read, etc.

Fix all these issues first before enabling -Wall in Makefile.

Signed-off-by: Andrii Nakryiko <andrii@kernel.org>
Link: https://lore.kernel.org/r/20230309054015.4068562-4-andrii@kernel.org
Signed-off-by: Alexei Starovoitov <ast@kernel.org>

tools/testing/selftests/bpf/progs/bpf_iter_ksym.c

@@ -33,7 +33,6 @@ int dump_ksym(struct bpf_iter__ksym *ctx)
 	__u32 seq_num = ctx->meta->seq_num;
 	unsigned long value;
 	char type;
-	int ret;
 
 	if (!iter)
 		return 0;

tools/testing/selftests/bpf/progs/bpf_iter_setsockopt.c

@@ -42,7 +42,6 @@ int change_tcp_cc(struct bpf_iter__tcp *ctx)
 	char cur_cc[TCP_CA_NAME_MAX];
 	struct tcp_sock *tp;
 	struct sock *sk;
-	int ret;
 
 	if (!bpf_tcp_sk(ctx->sk_common))
 		return 0;

tools/testing/selftests/bpf/progs/bpf_loop.c

@@ -138,8 +138,6 @@ static int callback_set_0f(int i, void *ctx)
 SEC("fentry/" SYS_PREFIX "sys_nanosleep")
 int prog_non_constant_callback(void *ctx)
 {
-	struct callback_ctx data = {};
-
 	if (bpf_get_current_pid_tgid() >> 32 != pid)
 		return 0;
 

tools/testing/selftests/bpf/progs/cb_refs.c

@@ -52,7 +52,6 @@ int leak_prog(void *ctx)
 {
 	struct prog_test_ref_kfunc *p;
 	struct map_value *v;
-	unsigned long sl;
 
 	v = bpf_map_lookup_elem(&array_map, &(int){0});
 	if (!v)

tools/testing/selftests/bpf/progs/cgroup_skb_sk_lookup_kern.c

@@ -66,7 +66,6 @@ static inline int is_allowed_peer_cg(struct __sk_buff *skb,
 SEC("cgroup_skb/ingress")
 int ingress_lookup(struct __sk_buff *skb)
 {
-	__u32 serv_port_key = 0;
 	struct ipv6hdr ip6h;
 	struct tcphdr tcph;
 

tools/testing/selftests/bpf/progs/cgrp_kfunc_failure.c

@@ -109,6 +109,7 @@ int BPF_PROG(cgrp_kfunc_acquire_unreleased, struct cgroup *cgrp, const char *pat
 	acquired = bpf_cgroup_acquire(cgrp);
 
 	/* Acquired cgroup is never released. */
+	__sink(acquired);
 
 	return 0;
 }

tools/testing/selftests/bpf/progs/cgrp_ls_attach_cgroup.c

@@ -84,7 +84,6 @@ int BPF_PROG(update_cookie_tracing, struct socket *sock,
 	     struct sockaddr *uaddr, int addr_len, int flags)
 {
 	struct socket_cookie *p;
-	struct tcp_sock *tcp_sk;
 
 	if (uaddr->sa_family != AF_INET6)
 		return 0;

tools/testing/selftests/bpf/progs/cgrp_ls_sleepable.c

@@ -24,7 +24,6 @@ void bpf_rcu_read_unlock(void) __ksym;
 SEC("?iter.s/cgroup")
 int cgroup_iter(struct bpf_iter__cgroup *ctx)
 {
-	struct seq_file *seq = ctx->meta->seq;
 	struct cgroup *cgrp = ctx->cgroup;
 	long *ptr;
 

tools/testing/selftests/bpf/progs/core_kern.c

@@ -77,7 +77,7 @@ int balancer_ingress(struct __sk_buff *ctx)
 	void *data_end = (void *)(long)ctx->data_end;
 	void *data = (void *)(long)ctx->data;
 	void *ptr;
-	int ret = 0, nh_off, i = 0;
+	int nh_off, i = 0;
 
 	nh_off = 14;
 

tools/testing/selftests/bpf/progs/cpumask_failure.c

@@ -23,6 +23,7 @@ int BPF_PROG(test_alloc_no_release, struct task_struct *task, u64 clone_flags)
 	struct bpf_cpumask *cpumask;
 
 	cpumask = create_cpumask();
+	__sink(cpumask);
 
 	/* cpumask is never released. */
 	return 0;
@@ -51,6 +52,7 @@ int BPF_PROG(test_acquire_wrong_cpumask, struct task_struct *task, u64 clone_fla
 
 	/* Can't acquire a non-struct bpf_cpumask. */
 	cpumask = bpf_cpumask_acquire((struct bpf_cpumask *)task->cpus_ptr);
+	__sink(cpumask);
 
 	return 0;
 }
@@ -63,6 +65,7 @@ int BPF_PROG(test_mutate_cpumask, struct task_struct *task, u64 clone_flags)
 
 	/* Can't set the CPU of a non-struct bpf_cpumask. */
 	bpf_cpumask_set_cpu(0, (struct bpf_cpumask *)task->cpus_ptr);
+	__sink(cpumask);
 
 	return 0;
 }

tools/testing/selftests/bpf/progs/cpumask_success.c

@@ -353,7 +353,6 @@ SEC("tp_btf/task_newtask")
 int BPF_PROG(test_insert_leave, struct task_struct *task, u64 clone_flags)
 {
 	struct bpf_cpumask *cpumask;
-	struct __cpumask_map_value *v;
 
 	cpumask = create_cpumask();
 	if (!cpumask)

tools/testing/selftests/bpf/progs/dynptr_fail.c

@@ -271,7 +271,7 @@ SEC("?raw_tp")
 __failure __msg("value is outside of the allowed memory range")
 int data_slice_out_of_bounds_map_value(void *ctx)
 {
-	__u32 key = 0, map_val;
+	__u32 map_val;
 	struct bpf_dynptr ptr;
 	void *data;
 
@@ -388,7 +388,6 @@ int data_slice_missing_null_check2(void *ctx)
 		/* this should fail */
 		*data2 = 3;
 
-done:
 	bpf_ringbuf_discard_dynptr(&ptr, 0);
 	return 0;
 }
@@ -440,6 +439,7 @@ int invalid_write1(void *ctx)
 
 	/* this should fail */
 	data = bpf_dynptr_data(&ptr, 0, 1);
+	__sink(data);
 
 	return 0;
 }
@@ -1374,6 +1374,7 @@ int invalid_slice_rdwr_rdonly(struct __sk_buff *skb)
 	 * changing packet data
 	 */
 	hdr = bpf_dynptr_slice_rdwr(&ptr, 0, buffer, sizeof(buffer));
+	__sink(hdr);
 
 	return 0;
 }

tools/testing/selftests/bpf/progs/dynptr_success.c

@@ -35,7 +35,7 @@ SEC("?tp/syscalls/sys_enter_nanosleep")
 int test_read_write(void *ctx)
 {
 	char write_data[64] = "hello there, world!!";
-	char read_data[64] = {}, buf[64] = {};
+	char read_data[64] = {};
 	struct bpf_dynptr ptr;
 	int i;
 
@@ -170,7 +170,6 @@ int test_skb_readonly(struct __sk_buff *skb)
 {
 	__u8 write_data[2] = {1, 2};
 	struct bpf_dynptr ptr;
-	__u64 *data;
 	int ret;
 
 	if (bpf_dynptr_from_skb(skb, 0, &ptr)) {
@@ -191,10 +190,8 @@ int test_skb_readonly(struct __sk_buff *skb)
 SEC("?cgroup_skb/egress")
 int test_dynptr_skb_data(struct __sk_buff *skb)
 {
-	__u8 write_data[2] = {1, 2};
 	struct bpf_dynptr ptr;
 	__u64 *data;
-	int ret;
 
 	if (bpf_dynptr_from_skb(skb, 0, &ptr)) {
 		err = 1;

tools/testing/selftests/bpf/progs/fexit_bpf2bpf.c

@@ -120,8 +120,6 @@ int new_get_skb_ifindex(int val, struct __sk_buff *skb, int var)
 	void *data = (void *)(long)skb->data;
 	struct ipv6hdr ip6, *ip6p;
 	int ifindex = skb->ifindex;
-	__u32 eth_proto;
-	__u32 nh_off;
 
 	/* check that BPF extension can read packet via direct packet access */
 	if (data + 14 + sizeof(ip6) > data_end)

tools/testing/selftests/bpf/progs/freplace_attach_probe.c

@@ -23,7 +23,7 @@ struct {
 SEC("freplace/handle_kprobe")
 int new_handle_kprobe(struct pt_regs *ctx)
 {
-	struct hmap_elem zero = {}, *val;
+	struct hmap_elem *val;
 	int key = 0;
 
 	val = bpf_map_lookup_elem(&hash_map, &key);

tools/testing/selftests/bpf/progs/iters.c

@@ -45,7 +45,6 @@ __failure __msg("unbounded memory access")
 int iter_err_unsafe_asm_loop(const void *ctx)
 {
 	struct bpf_iter_num it;
-	int *v, i = 0;
 
 	MY_PID_GUARD();
 
@@ -88,7 +87,7 @@ __success
 int iter_while_loop(const void *ctx)
 {
 	struct bpf_iter_num it;
-	int *v, i;
+	int *v;
 
 	MY_PID_GUARD();
 
@@ -106,7 +105,7 @@ __success
 int iter_while_loop_auto_cleanup(const void *ctx)
 {
 	__attribute__((cleanup(bpf_iter_num_destroy))) struct bpf_iter_num it;
-	int *v, i;
+	int *v;
 
 	MY_PID_GUARD();
 
@@ -124,7 +123,7 @@ __success
 int iter_for_loop(const void *ctx)
 {
 	struct bpf_iter_num it;
-	int *v, i;
+	int *v;
 
 	MY_PID_GUARD();
 
@@ -192,7 +191,7 @@ __success
 int iter_manual_unroll_loop(const void *ctx)
 {
 	struct bpf_iter_num it;
-	int *v, i;
+	int *v;
 
 	MY_PID_GUARD();
 
@@ -621,7 +620,7 @@ __success
 int iter_stack_array_loop(const void *ctx)
 {
 	long arr1[16], arr2[16], sum = 0;
-	int *v, i;
+	int i;
 
 	MY_PID_GUARD();
 

tools/testing/selftests/bpf/progs/linked_funcs1.c

@@ -5,6 +5,7 @@
 #include <bpf/bpf_helpers.h>
 #include <bpf/bpf_tracing.h>
 #include <bpf/bpf_core_read.h>
+#include "bpf_misc.h"
 
 /* weak and shared between two files */
 const volatile int my_tid __weak;
@@ -51,6 +52,7 @@ __weak int set_output_weak(int x)
 	 * cause problems for BPF static linker
 	 */
 	whatever = bpf_core_type_size(struct task_struct);
+	__sink(whatever);
 
 	output_weak1 = x;
 	return x;
@@ -71,6 +73,7 @@ int BPF_PROG(handler1, struct pt_regs *regs, long id)
 
 	/* make sure we have CO-RE relocations in main program */
 	whatever = bpf_core_type_size(struct task_struct);
+	__sink(whatever);
 
 	set_output_val2(1000);
 	set_output_ctx2(ctx); /* ctx definition is hidden in BPF_PROG macro */

tools/testing/selftests/bpf/progs/linked_funcs2.c

@@ -5,6 +5,7 @@
 #include <bpf/bpf_helpers.h>
 #include <bpf/bpf_tracing.h>
 #include <bpf/bpf_core_read.h>
+#include "bpf_misc.h"
 
 /* weak and shared between both files */
 const volatile int my_tid __weak;
@@ -51,6 +52,7 @@ __weak int set_output_weak(int x)
 	 * cause problems for BPF static linker
 	 */
 	whatever = 2 * bpf_core_type_size(struct task_struct);
+	__sink(whatever);
 
 	output_weak2 = x;
 	return 2 * x;
@@ -71,6 +73,7 @@ int BPF_PROG(handler2, struct pt_regs *regs, long id)
 
 	/* make sure we have CO-RE relocations in main program */
 	whatever = bpf_core_type_size(struct task_struct);
+	__sink(whatever);
 
 	set_output_val1(2000);
 	set_output_ctx1(ctx); /* ctx definition is hidden in BPF_PROG macro */

tools/testing/selftests/bpf/progs/linked_list.c

@@ -313,7 +313,6 @@ SEC("tc")
 int map_list_push_pop_multiple(void *ctx)
 {
 	struct map_value *v;
-	int ret;
 
 	v = bpf_map_lookup_elem(&array_map, &(int){0});
 	if (!v)
@@ -326,7 +325,6 @@ int inner_map_list_push_pop_multiple(void *ctx)
 {
 	struct map_value *v;
 	void *map;
-	int ret;
 
 	map = bpf_map_lookup_elem(&map_of_maps, &(int){0});
 	if (!map)
@@ -352,7 +350,6 @@ SEC("tc")
 int map_list_in_list(void *ctx)
 {
 	struct map_value *v;
-	int ret;
 
 	v = bpf_map_lookup_elem(&array_map, &(int){0});
 	if (!v)
@@ -365,7 +362,6 @@ int inner_map_list_in_list(void *ctx)
 {
 	struct map_value *v;
 	void *map;
-	int ret;
 
 	map = bpf_map_lookup_elem(&map_of_maps, &(int){0});
 	if (!map)

tools/testing/selftests/bpf/progs/linked_list_fail.c

@@ -557,7 +557,6 @@ SEC("?tc")
 int incorrect_head_off2(void *ctx)
 {
 	struct foo *f;
-	struct bar *b;
 
 	f = bpf_obj_new(typeof(*f));
 	if (!f)