From 2dc91865a4d96430081fed928009a8f65764a72b Mon Sep 17 00:00:00 2001
From: Idan Horowitz <idan.horowitz@gmail.com>
Date: Thu, 3 Feb 2022 16:25:15 +0200
Subject: [PATCH] Kernel: Stop allocating VirtIO configuration structs on the
 heap

These are trivially-copyable 12-byte structs, so there's no point in
allocating them on the heap.
---
 Kernel/Bus/VirtIO/Device.cpp | 22 +++++++++++-----------
 Kernel/Bus/VirtIO/Device.h   |  2 +-
 2 files changed, 12 insertions(+), 12 deletions(-)

diff --git a/Kernel/Bus/VirtIO/Device.cpp b/Kernel/Bus/VirtIO/Device.cpp
index 885566b5ac..67fbd7a098 100644
--- a/Kernel/Bus/VirtIO/Device.cpp
+++ b/Kernel/Bus/VirtIO/Device.cpp
@@ -97,32 +97,32 @@ UNMAP_AFTER_INIT void Device::initialize()
     for (auto& capability : capabilities) {
         if (capability.id().value() == PCI::Capabilities::ID::VendorSpecific) {
             // We have a virtio_pci_cap
-            auto cfg = make<Configuration>();
+            Configuration config {};
             auto raw_config_type = capability.read8(0x3);
             if (raw_config_type < static_cast<u8>(ConfigurationType::Common) || raw_config_type > static_cast<u8>(ConfigurationType::PCI)) {
                 dbgln("{}: Unknown capability configuration type: {}", m_class_name, raw_config_type);
                 return;
             }
-            cfg->cfg_type = static_cast<ConfigurationType>(raw_config_type);
+            config.cfg_type = static_cast<ConfigurationType>(raw_config_type);
             auto cap_length = capability.read8(0x2);
             if (cap_length < 0x10) {
                 dbgln("{}: Unexpected capability size: {}", m_class_name, cap_length);
                 break;
             }
-            cfg->bar = capability.read8(0x4);
-            if (cfg->bar > 0x5) {
-                dbgln("{}: Unexpected capability bar value: {}", m_class_name, cfg->bar);
+            config.bar = capability.read8(0x4);
+            if (config.bar > 0x5) {
+                dbgln("{}: Unexpected capability bar value: {}", m_class_name, config.bar);
                 break;
             }
-            cfg->offset = capability.read32(0x8);
-            cfg->length = capability.read32(0xc);
-            dbgln_if(VIRTIO_DEBUG, "{}: Found configuration {}, bar: {}, offset: {}, length: {}", m_class_name, (u32)cfg->cfg_type, cfg->bar, cfg->offset, cfg->length);
-            if (cfg->cfg_type == ConfigurationType::Common)
+            config.offset = capability.read32(0x8);
+            config.length = capability.read32(0xc);
+            dbgln_if(VIRTIO_DEBUG, "{}: Found configuration {}, bar: {}, offset: {}, length: {}", m_class_name, (u32)config.cfg_type, config.bar, config.offset, config.length);
+            if (config.cfg_type == ConfigurationType::Common)
                 m_use_mmio = true;
-            else if (cfg->cfg_type == ConfigurationType::Notify)
+            else if (config.cfg_type == ConfigurationType::Notify)
                 m_notify_multiplier = capability.read32(0x10);
 
-            m_configs.append(move(cfg));
+            m_configs.append(config);
         }
     }
 
diff --git a/Kernel/Bus/VirtIO/Device.h b/Kernel/Bus/VirtIO/Device.h
index 993574a1c7..e42be0bb97 100644
--- a/Kernel/Bus/VirtIO/Device.h
+++ b/Kernel/Bus/VirtIO/Device.h
@@ -227,7 +227,7 @@ private:
     virtual bool handle_irq(const RegisterState&) override;
 
     NonnullOwnPtrVector<Queue> m_queues;
-    NonnullOwnPtrVector<Configuration> m_configs;
+    Vector<Configuration> m_configs;
     const Configuration* m_common_cfg { nullptr }; // Cached due to high usage
     const Configuration* m_notify_cfg { nullptr }; // Cached due to high usage
     const Configuration* m_isr_cfg { nullptr };    // Cached due to high usage