bpf: Change insn_offset to insn_off in bpf_func_info

The later patch will introduce "struct bpf_line_info" which
has member "line_off" and "file_off" referring back to the
string section in btf.  The line_"off" and file_"off"
are more consistent to the naming convention in btf.h that
means "offset" (e.g. name_off in "struct btf_type").

The to-be-added "struct bpf_line_info" also has another
member, "insn_off" which is the same as the "insn_offset"
in "struct bpf_func_info".  Hence, this patch renames "insn_offset"
to "insn_off" for "struct bpf_func_info".
Signed-off-by: Martin KaFai Lau <kafai@fb.com>
Acked-by: Yonghong Song <yhs@fb.com>
Signed-off-by: Alexei Starovoitov <ast@kernel.org>

include/uapi/linux/bpf.h

@@ -2991,7 +2991,7 @@ struct bpf_flow_keys {
 };
 
 struct bpf_func_info {
-	__u32	insn_offset;
+	__u32	insn_off;
 	__u32	type_id;
 };
 

kernel/bpf/verifier.c

@@ -4707,24 +4707,24 @@ static int check_btf_func(struct bpf_prog *prog, struct bpf_verifier_env *env,
 			goto free_btf;
 		}
 
-		/* check insn_offset */
+		/* check insn_off */
 		if (i == 0) {
-			if (krecord[i].insn_offset) {
+			if (krecord[i].insn_off) {
 				verbose(env,
-					"nonzero insn_offset %u for the first func info record",
-					krecord[i].insn_offset);
+					"nonzero insn_off %u for the first func info record",
+					krecord[i].insn_off);
 				ret = -EINVAL;
 				goto free_btf;
 			}
-		} else if (krecord[i].insn_offset <= prev_offset) {
+		} else if (krecord[i].insn_off <= prev_offset) {
 			verbose(env,
 				"same or smaller insn offset (%u) than previous func info record (%u)",
-				krecord[i].insn_offset, prev_offset);
+				krecord[i].insn_off, prev_offset);
 			ret = -EINVAL;
 			goto free_btf;
 		}
 
-		if (env->subprog_info[i].start != krecord[i].insn_offset) {
+		if (env->subprog_info[i].start != krecord[i].insn_off) {
 			verbose(env, "func_info BTF section doesn't match subprog layout in BPF program\n");
 			ret = -EINVAL;
 			goto free_btf;
@@ -4739,7 +4739,7 @@ static int check_btf_func(struct bpf_prog *prog, struct bpf_verifier_env *env,
 			goto free_btf;
 		}
 
-		prev_offset = krecord[i].insn_offset;
+		prev_offset = krecord[i].insn_off;
 		urecord += urec_size;
 	}
 
@@ -4762,7 +4762,7 @@ static void adjust_btf_func(struct bpf_verifier_env *env)
 		return;
 
 	for (i = 0; i < env->subprog_cnt; i++)
-		env->prog->aux->func_info[i].insn_offset = env->subprog_info[i].start;
+		env->prog->aux->func_info[i].insn_off = env->subprog_info[i].start;
 }
 
 /* check %cur's range satisfies %old's */