Merge branch 'libbpf: fix several issues reported by static analysers'

Viktor Malik says:

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

Fixing several issues reported by Coverity and Clang Static Analyzer
(scan-build) for libbpf, mostly removing unnecessary symbols and
assignments.

No functional changes should be introduced.
====================

Signed-off-by: Andrii Nakryiko <andrii@kernel.org>

tools/lib/bpf/btf.c

@@ -1000,8 +1000,6 @@ static struct btf *btf_parse_elf(const char *path, struct btf *base_btf,
 		}
 	}
 
-	err = 0;
-
 	if (!btf_data) {
 		pr_warn("failed to find '%s' ELF section in %s\n", BTF_ELF_SEC, path);
 		err = -ENODATA;

tools/lib/bpf/libbpf.c

@@ -798,7 +798,6 @@ bpf_object__add_programs(struct bpf_object *obj, Elf_Data *sec_data,
 	progs = obj->programs;
 	nr_progs = obj->nr_programs;
 	nr_syms = symbols->d_size / sizeof(Elf64_Sym);
-	sec_off = 0;
 
 	for (i = 0; i < nr_syms; i++) {
 		sym = elf_sym_by_idx(obj, i);
@@ -2615,7 +2614,7 @@ static int bpf_object__init_maps(struct bpf_object *obj,
 	strict = !OPTS_GET(opts, relaxed_maps, false);
 	pin_root_path = OPTS_GET(opts, pin_root_path, NULL);
 
-	err = err ?: bpf_object__init_user_btf_maps(obj, strict, pin_root_path);
+	err = bpf_object__init_user_btf_maps(obj, strict, pin_root_path);
 	err = err ?: bpf_object__init_global_data_maps(obj);
 	err = err ?: bpf_object__init_kconfig_map(obj);
 	err = err ?: bpf_object__init_struct_ops_maps(obj);

tools/lib/bpf/linker.c

@@ -1997,7 +1997,6 @@ static int linker_append_elf_sym(struct bpf_linker *linker, struct src_obj *obj,
 static int linker_append_elf_relos(struct bpf_linker *linker, struct src_obj *obj)
 {
 	struct src_sec *src_symtab = &obj->secs[obj->symtab_sec_idx];
-	struct dst_sec *dst_symtab;
 	int i, err;
 
 	for (i = 1; i < obj->sec_cnt; i++) {
@@ -2030,9 +2029,6 @@ static int linker_append_elf_relos(struct bpf_linker *linker, struct src_obj *ob
 			return -1;
 		}
 
-		/* add_dst_sec() above could have invalidated linker->secs */
-		dst_symtab = &linker->secs[linker->symtab_sec_idx];
-
 		/* shdr->sh_link points to SYMTAB */
 		dst_sec->shdr->sh_link = linker->symtab_sec_idx;
 
@@ -2049,16 +2045,13 @@ static int linker_append_elf_relos(struct bpf_linker *linker, struct src_obj *ob
 		dst_rel = dst_sec->raw_data + src_sec->dst_off;
 		n = src_sec->shdr->sh_size / src_sec->shdr->sh_entsize;
 		for (j = 0; j < n; j++, src_rel++, dst_rel++) {
-			size_t src_sym_idx = ELF64_R_SYM(src_rel->r_info);
-			size_t sym_type = ELF64_R_TYPE(src_rel->r_info);
-			Elf64_Sym *src_sym, *dst_sym;
-			size_t dst_sym_idx;
+			size_t src_sym_idx, dst_sym_idx, sym_type;
+			Elf64_Sym *src_sym;
 
 			src_sym_idx = ELF64_R_SYM(src_rel->r_info);
 			src_sym = src_symtab->data->d_buf + sizeof(*src_sym) * src_sym_idx;
 
 			dst_sym_idx = obj->sym_map[src_sym_idx];
-			dst_sym = dst_symtab->raw_data + sizeof(*dst_sym) * dst_sym_idx;
 			dst_rel->r_offset += src_linked_sec->dst_off;
 			sym_type = ELF64_R_TYPE(src_rel->r_info);
 			dst_rel->r_info = ELF64_R_INFO(dst_sym_idx, sym_type);

tools/lib/bpf/relo_core.c

@@ -1551,9 +1551,6 @@ int __bpf_core_types_match(const struct btf *local_btf, __u32 local_id, const st
 	if (level <= 0)
 		return -EINVAL;
 
-	local_t = btf_type_by_id(local_btf, local_id);
-	targ_t = btf_type_by_id(targ_btf, targ_id);
-
 recur:
 	depth--;
 	if (depth < 0)