bpf: introduce in_sleepable() helper

No code change, but it'll allow to have only one place to change
everything when we add in_sleepable in cur_state.

Signed-off-by: Benjamin Tissoires <bentiss@kernel.org>
Link: https://lore.kernel.org/r/20240221-hid-bpf-sleepable-v3-2-1fb378ca6301@kernel.org
Signed-off-by: Alexei Starovoitov <ast@kernel.org>

Author: Benjamin Tissoires

kernel/bpf/verifier.c

@@ -5255,14 +5255,19 @@ static int map_kptr_match_type(struct bpf_verifier_env *env,
 	return -EINVAL;
 }
 
+static bool in_sleepable(struct bpf_verifier_env *env)
+{
+	return env->prog->aux->sleepable;
+}
+
 /* The non-sleepable programs and sleepable programs with explicit bpf_rcu_read_lock()
  * can dereference RCU protected pointers and result is PTR_TRUSTED.
  */
 static bool in_rcu_cs(struct bpf_verifier_env *env)
 {
 	return env->cur_state->active_rcu_lock ||
 	       env->cur_state->active_lock.ptr ||
-	       !env->prog->aux->sleepable;
+	       !in_sleepable(env);
 }
 
 /* Once GCC supports btf_type_tag the following mechanism will be replaced with tag check */
@@ -10164,7 +10169,7 @@ static int check_helper_call(struct bpf_verifier_env *env, struct bpf_insn *insn
 		return -EINVAL;
 	}
 
-	if (!env->prog->aux->sleepable && fn->might_sleep) {
+	if (!in_sleepable(env) && fn->might_sleep) {
 		verbose(env, "helper call might sleep in a non-sleepable prog\n");
 		return -EINVAL;
 	}
@@ -10194,7 +10199,7 @@ static int check_helper_call(struct bpf_verifier_env *env, struct bpf_insn *insn
 			return -EINVAL;
 		}
 
-		if (env->prog->aux->sleepable && is_storage_get_function(func_id))
+		if (in_sleepable(env) && is_storage_get_function(func_id))
 			env->insn_aux_data[insn_idx].storage_get_func_atomic = true;
 	}
 
@@ -11535,7 +11540,7 @@ static bool check_css_task_iter_allowlist(struct bpf_verifier_env *env)
 			return true;
 		fallthrough;
 	default:
-		return env->prog->aux->sleepable;
+		return in_sleepable(env);
 	}
 }
 
@@ -12056,7 +12061,7 @@ static int check_kfunc_call(struct bpf_verifier_env *env, struct bpf_insn *insn,
 	}
 
 	sleepable = is_kfunc_sleepable(&meta);
-	if (sleepable && !env->prog->aux->sleepable) {
+	if (sleepable && !in_sleepable(env)) {
 		verbose(env, "program must be sleepable to call sleepable kfunc %s\n", func_name);
 		return -EACCES;
 	}
@@ -19669,7 +19674,7 @@ static int do_misc_fixups(struct bpf_verifier_env *env)
 		}
 
 		if (is_storage_get_function(insn->imm)) {
-			if (!env->prog->aux->sleepable ||
+			if (!in_sleepable(env) ||
 			    env->insn_aux_data[i + delta].storage_get_func_atomic)
 				insn_buf[0] = BPF_MOV64_IMM(BPF_REG_5, (__force __s32)GFP_ATOMIC);
 			else