From 0c8c65299bc6df94413cf6e3d7b48c838f281b01 Mon Sep 17 00:00:00 2001
From: Uwe Seimet <Uwe.Seimet@seimet.de>
Date: Wed, 11 Dec 2024 16:54:50 +0100
Subject: [PATCH] Set next transfer read size based on previous read length

---
 cpp/controllers/abstract_controller.cpp | 5 ++---
 cpp/controllers/abstract_controller.h   | 2 +-
 cpp/controllers/controller.cpp          | 7 ++++---
 cpp/test/abstract_controller_test.cpp   | 6 +++---
 4 files changed, 10 insertions(+), 10 deletions(-)

diff --git a/cpp/controllers/abstract_controller.cpp b/cpp/controllers/abstract_controller.cpp
index 79094217..131860e9 100644
--- a/cpp/controllers/abstract_controller.cpp
+++ b/cpp/controllers/abstract_controller.cpp
@@ -78,13 +78,12 @@ void AbstractController::SetTransferSize(int length, int size)
     chunk_size = length < size ? length : size;
 }
 
-bool AbstractController::UpdateTransferSize()
+void AbstractController::UpdateTransferSize(int length)
 {
-    remaining_length -= chunk_size;
+    remaining_length -= length < chunk_size ? length : chunk_size;
     if (remaining_length < chunk_size) {
         chunk_size = remaining_length;
     }
-    return remaining_length > 0;
 }
 
 void AbstractController::UpdateOffsetAndLength()
diff --git a/cpp/controllers/abstract_controller.h b/cpp/controllers/abstract_controller.h
index 588cac37..20bde4ac 100644
--- a/cpp/controllers/abstract_controller.h
+++ b/cpp/controllers/abstract_controller.h
@@ -131,7 +131,7 @@ class AbstractController : public PhaseHandler
         offset = 0;
     }
 
-    bool UpdateTransferSize();
+    void UpdateTransferSize(int);
     void UpdateOffsetAndLength();
 
     void LogTrace(const string &s) const
diff --git a/cpp/controllers/controller.cpp b/cpp/controllers/controller.cpp
index 29e82feb..431695e8 100644
--- a/cpp/controllers/controller.cpp
+++ b/cpp/controllers/controller.cpp
@@ -355,7 +355,7 @@ void Controller::Send()
         return;
     }
 
-    const bool pending_data = UpdateTransferSize();
+    const bool pending_data = GetRemainingLength();
 
     if (pending_data && IsDataIn() && !TransferToHost()) {
         return;
@@ -427,7 +427,7 @@ void Controller::Receive()
 
     const int current_remaining_length = GetRemainingLength();
     const int current_chunk_size = GetChunkSize();
-    const bool pending_data = UpdateTransferSize();
+    const bool pending_data = current_remaining_length;
 
     // Processing after receiving data
     switch (GetPhase()) {
@@ -474,7 +474,8 @@ bool Controller::TransferToHost()
     assert(!CommandMetaData::Instance().GetCdbMetaData(static_cast<scsi_command>(GetCdb()[0])).has_data_out);
 
     try {
-        SetCurrentLength(GetDeviceForLun(GetEffectiveLun())->ReadData(GetBuffer()));
+        const int length = GetDeviceForLun(GetEffectiveLun())->ReadData(GetBuffer());
+        UpdateTransferSize(length);
     }
     catch (const scsi_exception &e) {
         Error(e.get_sense_key(), e.get_asc());
diff --git a/cpp/test/abstract_controller_test.cpp b/cpp/test/abstract_controller_test.cpp
index d825ad3d..be85eb13 100644
--- a/cpp/test/abstract_controller_test.cpp
+++ b/cpp/test/abstract_controller_test.cpp
@@ -101,15 +101,15 @@ TEST(AbstractControllerTest, TransferSize)
     EXPECT_EQ(3, controller.GetTotalLength());
     EXPECT_EQ(3, controller.GetRemainingLength());
     EXPECT_EQ(1, controller.GetChunkSize());
-    EXPECT_TRUE(controller.UpdateTransferSize());
+    controller.UpdateTransferSize(1);
     EXPECT_EQ(3, controller.GetTotalLength());
     EXPECT_EQ(2, controller.GetRemainingLength());
     EXPECT_EQ(1, controller.GetChunkSize());
-    EXPECT_TRUE(controller.UpdateTransferSize());
+    controller.UpdateTransferSize(1);
     EXPECT_EQ(3, controller.GetTotalLength());
     EXPECT_EQ(1, controller.GetRemainingLength());
     EXPECT_EQ(1, controller.GetChunkSize());
-    EXPECT_FALSE(controller.UpdateTransferSize());
+    controller.UpdateTransferSize(1);
     EXPECT_EQ(3, controller.GetTotalLength());
     EXPECT_EQ(0, controller.GetRemainingLength());
     EXPECT_EQ(0, controller.GetChunkSize());