From 21e48a8e1271129cf884b4574aa357cdc140e8d6 Mon Sep 17 00:00:00 2001
From: Alexander Boettcher <alexander.boettcher@genode-labs.com>
Date: Tue, 7 Jul 2020 16:48:04 +0200
Subject: [PATCH] trace: extend for_each_subject_infos return value

Fixes #3811
---
 repos/base/include/trace_session/client.h     | 6 ++++--
 repos/base/include/trace_session/connection.h | 2 +-
 repos/os/src/app/top/main.cc                  | 2 +-
 3 files changed, 6 insertions(+), 4 deletions(-)

diff --git a/repos/base/include/trace_session/client.h b/repos/base/include/trace_session/client.h
index d5df12eba..683d5214e 100644
--- a/repos/base/include/trace_session/client.h
+++ b/repos/base/include/trace_session/client.h
@@ -86,8 +86,10 @@ struct Genode::Trace::Session_client : Genode::Rpc_client<Genode::Trace::Session
 			return num_subjects;
 		}
 
+		struct For_each_subject_info_result { size_t count; size_t limit; };
+
 		template <typename FN>
-		size_t for_each_subject_info(FN const &fn)
+		For_each_subject_info_result for_each_subject_info(FN const &fn)
 		{
 			size_t const num_subjects = call<Rpc_subject_infos>();
 			size_t const max_subjects = _argument_buffer.size / (sizeof(Subject_info) + sizeof(Subject_id));
@@ -99,7 +101,7 @@ struct Genode::Trace::Session_client : Genode::Rpc_client<Genode::Trace::Session
 				fn(ids[i], infos[i]);
 			}
 
-			return num_subjects;
+			return { .count = num_subjects, .limit = max_subjects };
 		}
 
 		Policy_id alloc_policy(size_t size) override {
diff --git a/repos/base/include/trace_session/connection.h b/repos/base/include/trace_session/connection.h
index 6a7c6e753..260d3eff7 100644
--- a/repos/base/include/trace_session/connection.h
+++ b/repos/base/include/trace_session/connection.h
@@ -63,7 +63,7 @@ struct Genode::Trace::Connection : Genode::Connection<Genode::Trace::Session>,
 	}
 
 	template <typename FN>
-	size_t for_each_subject_info(FN const &fn)
+	For_each_subject_info_result for_each_subject_info(FN const &fn)
 	{
 		return _retry([&] () {
 			return Session_client::for_each_subject_info(fn); });
diff --git a/repos/os/src/app/top/main.cc b/repos/os/src/app/top/main.cc
index 0a1282911..c4f63aea0 100644
--- a/repos/os/src/app/top/main.cc
+++ b/repos/os/src/app/top/main.cc
@@ -91,7 +91,7 @@ struct Trace_subject_registry
 
 			do {
 				try {
-					return trace.for_each_subject_info(fn);
+					return trace.for_each_subject_info(fn).count;
 				} catch (Genode::Out_of_ram) {
 					trace.upgrade_ram(4096);
 				}