Kernel/Net: Introduce a new mechanism to initialize a PCI device

Instead of using a clunky if-statement paradigm, we now have all drivers
being declaring two methods for their adapter class - create and probe.
These methods are linked in each PCINetworkDriverInitializer structure,
in a new s_initializers static list of them.
Then, when we probe for a PCI device, we use each probe method and if
there's a match, then the corresponding create method is called. After
the adapter instance is created, we call the virtual initialize method
on it, because many drivers actually require a sort of post-construction
initialization sequence to ensure the network adapter can properly
function.

As a result of this change, it's much more easy to add more drivers and
the initialization code is more readable and it's easier to understand
when and where things could fail in the whole initialization sequence.

Kernel/Net/Intel/E1000ENetworkAdapter.cpp

@@ -181,12 +181,15 @@ static bool is_valid_device_id(u16 device_id)
     }
 }
 
-UNMAP_AFTER_INIT ErrorOr<LockRefPtr<E1000ENetworkAdapter>> E1000ENetworkAdapter::try_to_initialize(PCI::DeviceIdentifier const& pci_device_identifier)
+UNMAP_AFTER_INIT ErrorOr<bool> E1000ENetworkAdapter::probe(PCI::DeviceIdentifier const& pci_device_identifier)
 {
     if (pci_device_identifier.hardware_id().vendor_id != PCI::VendorID::Intel)
-        return nullptr;
+        return false;
-    if (!is_valid_device_id(pci_device_identifier.hardware_id().device_id))
+    return is_valid_device_id(pci_device_identifier.hardware_id().device_id);
-        return nullptr;
+}
+
+UNMAP_AFTER_INIT ErrorOr<NonnullLockRefPtr<NetworkAdapter>> E1000ENetworkAdapter::create(PCI::DeviceIdentifier const& pci_device_identifier)
+{
     u8 irq = pci_device_identifier.interrupt_line().value();
     auto interface_name = TRY(NetworkingManagement::generate_interface_name_from_pci_address(pci_device_identifier));
     auto registers_io_window = TRY(IOWindow::create_for_pci_device_bar(pci_device_identifier, PCI::HeaderType0BaseRegister::BAR0));
@@ -196,20 +199,16 @@ UNMAP_AFTER_INIT ErrorOr<LockRefPtr<E1000ENetworkAdapter>> E1000ENetworkAdapter:
     auto rx_descriptors_region = TRY(MM.allocate_contiguous_kernel_region(TRY(Memory::page_round_up(sizeof(e1000_rx_desc) * number_of_rx_descriptors)), "E1000 RX Descriptors"sv, Memory::Region::Access::ReadWrite));
     auto tx_descriptors_region = TRY(MM.allocate_contiguous_kernel_region(TRY(Memory::page_round_up(sizeof(e1000_tx_desc) * number_of_tx_descriptors)), "E1000 TX Descriptors"sv, Memory::Region::Access::ReadWrite));
 
-    auto adapter = TRY(adopt_nonnull_lock_ref_or_enomem(new (nothrow) E1000ENetworkAdapter(pci_device_identifier.address(),
+    return TRY(adopt_nonnull_lock_ref_or_enomem(new (nothrow) E1000ENetworkAdapter(pci_device_identifier.address(),
         irq, move(registers_io_window),
         move(rx_buffer_region),
         move(tx_buffer_region),
         move(rx_descriptors_region),
         move(tx_descriptors_region),
         move(interface_name))));
-
-    if (!adapter->initialize())
-        return Error::from_string_literal("E1000ENetworkAdapter: Unable to initialize adapter");
-    return adapter;
 }
 
-UNMAP_AFTER_INIT bool E1000ENetworkAdapter::initialize()
+UNMAP_AFTER_INIT ErrorOr<void> E1000ENetworkAdapter::initialize(Badge<NetworkingManagement>)
 {
     dmesgln("E1000e: Found @ {}", pci_address());
     enable_bus_mastering(pci_address());
@@ -227,7 +226,7 @@ UNMAP_AFTER_INIT bool E1000ENetworkAdapter::initialize()
 
     setup_link();
     setup_interrupts();
-    return true;
+    return {};
 }
 
 UNMAP_AFTER_INIT E1000ENetworkAdapter::E1000ENetworkAdapter(PCI::Address address, u8 irq,

Kernel/Net/Intel/E1000ENetworkAdapter.h

@@ -21,9 +21,9 @@ namespace Kernel {
 class E1000ENetworkAdapter final
     : public E1000NetworkAdapter {
 public:
-    static ErrorOr<LockRefPtr<E1000ENetworkAdapter>> try_to_initialize(PCI::DeviceIdentifier const&);
+    static ErrorOr<bool> probe(PCI::DeviceIdentifier const&);
-
+    static ErrorOr<NonnullLockRefPtr<NetworkAdapter>> create(PCI::DeviceIdentifier const&);
-    virtual bool initialize() override;
+    virtual ErrorOr<void> initialize(Badge<NetworkingManagement>) override;
 
     virtual ~E1000ENetworkAdapter() override;
 

Kernel/Net/Intel/E1000NetworkAdapter.cpp

@@ -159,12 +159,15 @@ UNMAP_AFTER_INIT static bool is_valid_device_id(u16 device_id)
     }
 }
 
-UNMAP_AFTER_INIT ErrorOr<LockRefPtr<E1000NetworkAdapter>> E1000NetworkAdapter::try_to_initialize(PCI::DeviceIdentifier const& pci_device_identifier)
+UNMAP_AFTER_INIT ErrorOr<bool> E1000NetworkAdapter::probe(PCI::DeviceIdentifier const& pci_device_identifier)
 {
     if (pci_device_identifier.hardware_id().vendor_id != PCI::VendorID::Intel)
-        return nullptr;
+        return false;
-    if (!is_valid_device_id(pci_device_identifier.hardware_id().device_id))
+    return is_valid_device_id(pci_device_identifier.hardware_id().device_id);
-        return nullptr;
+}
+
+UNMAP_AFTER_INIT ErrorOr<NonnullLockRefPtr<NetworkAdapter>> E1000NetworkAdapter::create(PCI::DeviceIdentifier const& pci_device_identifier)
+{
     u8 irq = pci_device_identifier.interrupt_line().value();
     auto interface_name = TRY(NetworkingManagement::generate_interface_name_from_pci_address(pci_device_identifier));
     auto registers_io_window = TRY(IOWindow::create_for_pci_device_bar(pci_device_identifier, PCI::HeaderType0BaseRegister::BAR0));
@@ -174,34 +177,16 @@ UNMAP_AFTER_INIT ErrorOr<LockRefPtr<E1000NetworkAdapter>> E1000NetworkAdapter::t
     auto rx_descriptors_region = TRY(MM.allocate_contiguous_kernel_region(TRY(Memory::page_round_up(sizeof(e1000_rx_desc) * number_of_rx_descriptors)), "E1000 RX Descriptors"sv, Memory::Region::Access::ReadWrite));
     auto tx_descriptors_region = TRY(MM.allocate_contiguous_kernel_region(TRY(Memory::page_round_up(sizeof(e1000_tx_desc) * number_of_tx_descriptors)), "E1000 TX Descriptors"sv, Memory::Region::Access::ReadWrite));
 
-    auto adapter = TRY(adopt_nonnull_lock_ref_or_enomem(new (nothrow) E1000NetworkAdapter(pci_device_identifier.address(),
+    return TRY(adopt_nonnull_lock_ref_or_enomem(new (nothrow) E1000NetworkAdapter(pci_device_identifier.address(),
         irq, move(registers_io_window),
         move(rx_buffer_region),
         move(tx_buffer_region),
         move(rx_descriptors_region),
         move(tx_descriptors_region),
         move(interface_name))));
-
-    if (!adapter->initialize())
-        return Error::from_string_literal("E1000NetworkAdapter: Unable to initialize adapter");
-    return adapter;
 }
 
-UNMAP_AFTER_INIT void E1000NetworkAdapter::setup_link()
+UNMAP_AFTER_INIT ErrorOr<void> E1000NetworkAdapter::initialize(Badge<NetworkingManagement>)
-{
-    u32 flags = in32(REG_CTRL);
-    out32(REG_CTRL, flags | ECTRL_SLU);
-}
-
-UNMAP_AFTER_INIT void E1000NetworkAdapter::setup_interrupts()
-{
-    out32(REG_INTERRUPT_RATE, 6000); // Interrupt rate of 1.536 milliseconds
-    out32(REG_INTERRUPT_MASK_SET, INTERRUPT_LSC | INTERRUPT_RXT0 | INTERRUPT_RXO);
-    in32(REG_INTERRUPT_CAUSE_READ);
-    enable_irq();
-}
-
-UNMAP_AFTER_INIT bool E1000NetworkAdapter::initialize()
 {
     dmesgln_pci(*this, "Found @ {}", pci_address());
 
@@ -223,7 +208,21 @@ UNMAP_AFTER_INIT bool E1000NetworkAdapter::initialize()
 
     m_link_up = ((in32(REG_STATUS) & STATUS_LU) != 0);
 
-    return true;
+    return {};
+}
+
+UNMAP_AFTER_INIT void E1000NetworkAdapter::setup_link()
+{
+    u32 flags = in32(REG_CTRL);
+    out32(REG_CTRL, flags | ECTRL_SLU);
+}
+
+UNMAP_AFTER_INIT void E1000NetworkAdapter::setup_interrupts()
+{
+    out32(REG_INTERRUPT_RATE, 6000); // Interrupt rate of 1.536 milliseconds
+    out32(REG_INTERRUPT_MASK_SET, INTERRUPT_LSC | INTERRUPT_RXT0 | INTERRUPT_RXO);
+    in32(REG_INTERRUPT_CAUSE_READ);
+    enable_irq();
 }
 
 UNMAP_AFTER_INIT E1000NetworkAdapter::E1000NetworkAdapter(PCI::Address address, u8 irq,

Kernel/Net/Intel/E1000NetworkAdapter.h

@@ -20,9 +20,9 @@ class E1000NetworkAdapter : public NetworkAdapter
     , public PCI::Device
     , public IRQHandler {
 public:
-    static ErrorOr<LockRefPtr<E1000NetworkAdapter>> try_to_initialize(PCI::DeviceIdentifier const&);
+    static ErrorOr<bool> probe(PCI::DeviceIdentifier const&);
-
+    static ErrorOr<NonnullLockRefPtr<NetworkAdapter>> create(PCI::DeviceIdentifier const&);
-    virtual bool initialize();
+    virtual ErrorOr<void> initialize(Badge<NetworkingManagement>) override;
 
     virtual ~E1000NetworkAdapter() override;
 

Kernel/Net/LoopbackAdapter.h

@@ -18,6 +18,8 @@ public:
     static LockRefPtr<LoopbackAdapter> try_create();
     virtual ~LoopbackAdapter() override;
 
+    virtual ErrorOr<void> initialize(Badge<NetworkingManagement>) override { VERIFY_NOT_REACHED(); }
+
     virtual void send_raw(ReadonlyBytes) override;
     virtual StringView class_name() const override { return "LoopbackAdapter"sv; }
     virtual bool link_up() override { return true; }

Kernel/Net/NE2000/NetworkAdapter.cpp

@@ -138,7 +138,7 @@ struct [[gnu::packed]] received_packet_header {
     u16 length;
 };
 
-UNMAP_AFTER_INIT ErrorOr<LockRefPtr<NE2000NetworkAdapter>> NE2000NetworkAdapter::try_to_initialize(PCI::DeviceIdentifier const& pci_device_identifier)
+UNMAP_AFTER_INIT ErrorOr<bool> NE2000NetworkAdapter::probe(PCI::DeviceIdentifier const& pci_device_identifier)
 {
     constexpr auto ne2k_ids = Array {
         PCI::HardwareID { 0x10EC, 0x8029 }, // RealTek RTL-8029(AS)
@@ -155,19 +155,18 @@ UNMAP_AFTER_INIT ErrorOr<LockRefPtr<NE2000NetworkAdapter>> NE2000NetworkAdapter:
         PCI::HardwareID { 0x12c3, 0x5598 }, // Holtek HT80229
         PCI::HardwareID { 0x8c4a, 0x1980 }, // Winbond W89C940 (misprogrammed)
     };
-    if (!ne2k_ids.span().contains_slow(pci_device_identifier.hardware_id()))
+    return ne2k_ids.span().contains_slow(pci_device_identifier.hardware_id());
-        return nullptr;
+}
+
+UNMAP_AFTER_INIT ErrorOr<NonnullLockRefPtr<NetworkAdapter>> NE2000NetworkAdapter::create(PCI::DeviceIdentifier const& pci_device_identifier)
+{
     u8 irq = pci_device_identifier.interrupt_line().value();
     auto interface_name = TRY(NetworkingManagement::generate_interface_name_from_pci_address(pci_device_identifier));
     auto registers_io_window = TRY(IOWindow::create_for_pci_device_bar(pci_device_identifier, PCI::HeaderType0BaseRegister::BAR0));
     return TRY(adopt_nonnull_lock_ref_or_enomem(new (nothrow) NE2000NetworkAdapter(pci_device_identifier.address(), irq, move(registers_io_window), move(interface_name))));
 }
 
-UNMAP_AFTER_INIT NE2000NetworkAdapter::NE2000NetworkAdapter(PCI::Address address, u8 irq, NonnullOwnPtr<IOWindow> registers_io_window, NonnullOwnPtr<KString> interface_name)
+UNMAP_AFTER_INIT ErrorOr<void> NE2000NetworkAdapter::initialize(Badge<NetworkingManagement>)
-    : NetworkAdapter(move(interface_name))
-    , PCI::Device(address)
-    , IRQHandler(irq)
-    , m_registers_io_window(move(registers_io_window))
 {
     dmesgln_pci(*this, "Found @ {}", pci_address());
 
@@ -181,6 +180,15 @@ UNMAP_AFTER_INIT NE2000NetworkAdapter::NE2000NetworkAdapter(PCI::Address address
     set_mac_address(m_mac_address);
     dmesgln_pci(*this, "MAC address: {}", m_mac_address.to_string());
     enable_irq();
+    return {};
+}
+
+UNMAP_AFTER_INIT NE2000NetworkAdapter::NE2000NetworkAdapter(PCI::Address address, u8 irq, NonnullOwnPtr<IOWindow> registers_io_window, NonnullOwnPtr<KString> interface_name)
+    : NetworkAdapter(move(interface_name))
+    , PCI::Device(address)
+    , IRQHandler(irq)
+    , m_registers_io_window(move(registers_io_window))
+{
 }
 
 UNMAP_AFTER_INIT NE2000NetworkAdapter::~NE2000NetworkAdapter() = default;

Kernel/Net/NE2000/NetworkAdapter.h

@@ -20,7 +20,9 @@ class NE2000NetworkAdapter final : public NetworkAdapter
     , public PCI::Device
     , public IRQHandler {
 public:
-    static ErrorOr<LockRefPtr<NE2000NetworkAdapter>> try_to_initialize(PCI::DeviceIdentifier const&);
+    static ErrorOr<bool> probe(PCI::DeviceIdentifier const&);
+    static ErrorOr<NonnullLockRefPtr<NetworkAdapter>> create(PCI::DeviceIdentifier const&);
+    virtual ErrorOr<void> initialize(Badge<NetworkingManagement>) override;
 
     virtual ~NE2000NetworkAdapter() override;
 

Kernel/Net/NetworkAdapter.h

@@ -42,6 +42,7 @@ struct PacketWithTimestamp final : public AtomicRefCounted<PacketWithTimestamp>
     IntrusiveListNode<PacketWithTimestamp, LockRefPtr<PacketWithTimestamp>> packet_node;
 };
 
+class NetworkingManagement;
 class NetworkAdapter
     : public AtomicRefCounted<NetworkAdapter>
     , public LockWeakable<NetworkAdapter> {
@@ -51,6 +52,7 @@ public:
     virtual ~NetworkAdapter();
 
     virtual StringView class_name() const = 0;
+    virtual ErrorOr<void> initialize(Badge<NetworkingManagement>) = 0;
 
     StringView name() const { return m_name->view(); }
     MACAddress mac_address() { return m_mac_address; }

Kernel/Net/NetworkingManagement.cpp

@@ -93,18 +93,34 @@ ErrorOr<NonnullOwnPtr<KString>> NetworkingManagement::generate_interface_name_fr
     return name;
 }
 
+struct PCINetworkDriverInitializer {
+    ErrorOr<bool> (*probe)(PCI::DeviceIdentifier const&) = nullptr;
+    ErrorOr<NonnullLockRefPtr<NetworkAdapter>> (*create)(PCI::DeviceIdentifier const&) = nullptr;
+};
+
+static constexpr PCINetworkDriverInitializer s_initializers[] = {
+    { RTL8168NetworkAdapter::probe, RTL8168NetworkAdapter::create },
+    { RTL8139NetworkAdapter::probe, RTL8139NetworkAdapter::create },
+    { NE2000NetworkAdapter::probe, NE2000NetworkAdapter::create },
+    { E1000NetworkAdapter::probe, E1000NetworkAdapter::create },
+    { E1000ENetworkAdapter::probe, E1000ENetworkAdapter::create },
+};
+
 UNMAP_AFTER_INIT ErrorOr<NonnullLockRefPtr<NetworkAdapter>> NetworkingManagement::determine_network_device(PCI::DeviceIdentifier const& device_identifier) const
 {
-    if (auto candidate = TRY(E1000NetworkAdapter::try_to_initialize(device_identifier)))
+    for (auto& initializer : s_initializers) {
-        return candidate.release_nonnull();
+        auto initializer_probe_found_driver_match_or_error = initializer.probe(device_identifier);
-    if (auto candidate = TRY(E1000ENetworkAdapter::try_to_initialize(device_identifier)))
+        if (initializer_probe_found_driver_match_or_error.is_error()) {
-        return candidate.release_nonnull();
+            dmesgln("Networking: Failed to probe device {}, due to {}", device_identifier.address(), initializer_probe_found_driver_match_or_error.error());
-    if (auto candidate = TRY(RTL8139NetworkAdapter::try_to_initialize(device_identifier)))
+            continue;
-        return candidate.release_nonnull();
+        }
-    if (auto candidate = TRY(RTL8168NetworkAdapter::try_to_initialize(device_identifier)))
+        auto initializer_probe_found_driver_match = initializer_probe_found_driver_match_or_error.release_value();
-        return candidate.release_nonnull();
+        if (initializer_probe_found_driver_match) {
-    if (auto candidate = TRY(NE2000NetworkAdapter::try_to_initialize(device_identifier)))
+            auto adapter = TRY(initializer.create(device_identifier));
-        return candidate.release_nonnull();
+            TRY(adapter->initialize({}));
+            return adapter;
+        }
+    }
     return Error::from_string_literal("Unsupported network adapter");
 }
 

Kernel/Net/Realtek/RTL8139NetworkAdapter.cpp

@@ -112,11 +112,14 @@ namespace Kernel {
 #define RX_BUFFER_SIZE 32768
 #define TX_BUFFER_SIZE PACKET_SIZE_MAX
 
-UNMAP_AFTER_INIT ErrorOr<LockRefPtr<RTL8139NetworkAdapter>> RTL8139NetworkAdapter::try_to_initialize(PCI::DeviceIdentifier const& pci_device_identifier)
+UNMAP_AFTER_INIT ErrorOr<bool> RTL8139NetworkAdapter::probe(PCI::DeviceIdentifier const& pci_device_identifier)
 {
     constexpr PCI::HardwareID rtl8139_id = { 0x10EC, 0x8139 };
-    if (pci_device_identifier.hardware_id() != rtl8139_id)
+    return pci_device_identifier.hardware_id() == rtl8139_id;
-        return nullptr;
+}
+
+UNMAP_AFTER_INIT ErrorOr<NonnullLockRefPtr<NetworkAdapter>> RTL8139NetworkAdapter::create(PCI::DeviceIdentifier const& pci_device_identifier)
+{
     u8 irq = pci_device_identifier.interrupt_line().value();
     auto rx_buffer = TRY(MM.allocate_contiguous_kernel_region(TRY(Memory::page_round_up(RX_BUFFER_SIZE + PACKET_SIZE_MAX)), "RTL8139 RX"sv, Memory::Region::Access::ReadWrite));
     auto packet_buffer = TRY(MM.allocate_contiguous_kernel_region(TRY(Memory::page_round_up(PACKET_SIZE_MAX)), "RTL8139 Packet buffer"sv, Memory::Region::Access::ReadWrite));
@@ -125,15 +128,9 @@ UNMAP_AFTER_INIT ErrorOr<LockRefPtr<RTL8139NetworkAdapter>> RTL8139NetworkAdapte
     return TRY(adopt_nonnull_lock_ref_or_enomem(new (nothrow) RTL8139NetworkAdapter(pci_device_identifier.address(), irq, move(rx_buffer), move(packet_buffer), move(registers_io_window), move(interface_name))));
 }
 
-UNMAP_AFTER_INIT RTL8139NetworkAdapter::RTL8139NetworkAdapter(PCI::Address address, u8 irq, NonnullOwnPtr<Memory::Region> rx_buffer, NonnullOwnPtr<Memory::Region> packet_buffer, NonnullOwnPtr<IOWindow> registers_io_window, NonnullOwnPtr<KString> interface_name)
+UNMAP_AFTER_INIT ErrorOr<void> RTL8139NetworkAdapter::initialize(Badge<NetworkingManagement>)
-    : NetworkAdapter(move(interface_name))
-    , PCI::Device(address)
-    , IRQHandler(irq)
-    , m_registers_io_window(move(registers_io_window))
-    , m_rx_buffer(move(rx_buffer))
-    , m_packet_buffer(move(packet_buffer))
 {
-    m_tx_buffers.ensure_capacity(RTL8139_TX_BUFFER_COUNT);
+    TRY(m_tx_buffers.try_ensure_capacity(RTL8139_TX_BUFFER_COUNT));
 
     dmesgln_pci(*this, "Found @ {}", pci_address());
 
@@ -148,7 +145,8 @@ UNMAP_AFTER_INIT RTL8139NetworkAdapter::RTL8139NetworkAdapter(PCI::Address addre
     dbgln("RTL8139: RX buffer: {}", m_rx_buffer->physical_page(0)->paddr());
 
     for (int i = 0; i < RTL8139_TX_BUFFER_COUNT; i++) {
-        m_tx_buffers.append(MM.allocate_contiguous_kernel_region(Memory::page_round_up(TX_BUFFER_SIZE).release_value_but_fixme_should_propagate_errors(), "RTL8139 TX"sv, Memory::Region::Access::Write | Memory::Region::Access::Read).release_value());
+        auto buffer = TRY(MM.allocate_contiguous_kernel_region(TRY(Memory::page_round_up(TX_BUFFER_SIZE)), "RTL8139 TX"sv, Memory::Region::Access::Write | Memory::Region::Access::Read));
+        m_tx_buffers.append(move(buffer));
         dbgln("RTL8139: TX buffer {}: {}", i, m_tx_buffers[i]->physical_page(0)->paddr());
     }
 
@@ -159,6 +157,17 @@ UNMAP_AFTER_INIT RTL8139NetworkAdapter::RTL8139NetworkAdapter(PCI::Address addre
     dmesgln_pci(*this, "MAC address: {}", mac.to_string());
 
     enable_irq();
+    return {};
+}
+
+UNMAP_AFTER_INIT RTL8139NetworkAdapter::RTL8139NetworkAdapter(PCI::Address address, u8 irq, NonnullOwnPtr<Memory::Region> rx_buffer, NonnullOwnPtr<Memory::Region> packet_buffer, NonnullOwnPtr<IOWindow> registers_io_window, NonnullOwnPtr<KString> interface_name)
+    : NetworkAdapter(move(interface_name))
+    , PCI::Device(address)
+    , IRQHandler(irq)
+    , m_registers_io_window(move(registers_io_window))
+    , m_rx_buffer(move(rx_buffer))
+    , m_packet_buffer(move(packet_buffer))
+{
 }
 
 UNMAP_AFTER_INIT RTL8139NetworkAdapter::~RTL8139NetworkAdapter() = default;

Kernel/Net/Realtek/RTL8139NetworkAdapter.h

@@ -22,7 +22,9 @@ class RTL8139NetworkAdapter final : public NetworkAdapter
     , public PCI::Device
     , public IRQHandler {
 public:
-    static ErrorOr<LockRefPtr<RTL8139NetworkAdapter>> try_to_initialize(PCI::DeviceIdentifier const&);
+    static ErrorOr<bool> probe(PCI::DeviceIdentifier const&);
+    static ErrorOr<NonnullLockRefPtr<NetworkAdapter>> create(PCI::DeviceIdentifier const&);
+    virtual ErrorOr<void> initialize(Badge<NetworkingManagement>) override;
 
     virtual ~RTL8139NetworkAdapter() override;
 

Kernel/Net/Realtek/RTL8168NetworkAdapter.cpp

@@ -182,12 +182,17 @@ namespace Kernel {
 #define TX_BUFFER_SIZE 0x1FF8
 #define RX_BUFFER_SIZE 0x1FF8 // FIXME: this should be increased (0x3FFF)
 
-UNMAP_AFTER_INIT ErrorOr<LockRefPtr<RTL8168NetworkAdapter>> RTL8168NetworkAdapter::try_to_initialize(PCI::DeviceIdentifier const& pci_device_identifier)
+UNMAP_AFTER_INIT ErrorOr<bool> RTL8168NetworkAdapter::probe(PCI::DeviceIdentifier const& pci_device_identifier)
 {
     if (pci_device_identifier.hardware_id().vendor_id != PCI::VendorID::Realtek)
-        return nullptr;
+        return false;
     if (pci_device_identifier.hardware_id().device_id != 0x8168)
-        return nullptr;
+        return false;
+    return true;
+}
+
+UNMAP_AFTER_INIT ErrorOr<NonnullLockRefPtr<NetworkAdapter>> RTL8168NetworkAdapter::create(PCI::DeviceIdentifier const& pci_device_identifier)
+{
     u8 irq = pci_device_identifier.interrupt_line().value();
     auto interface_name = TRY(NetworkingManagement::generate_interface_name_from_pci_address(pci_device_identifier));
     auto registers_io_window = TRY(IOWindow::create_for_pci_device_bar(pci_device_identifier, PCI::HeaderType0BaseRegister::BAR0));
@@ -249,21 +254,17 @@ UNMAP_AFTER_INIT RTL8168NetworkAdapter::RTL8168NetworkAdapter(PCI::Address addre
 {
     dmesgln_pci(*this, "Found @ {}", pci_address());
     dmesgln_pci(*this, "I/O port base: {}", m_registers_io_window);
+}
 
+UNMAP_AFTER_INIT ErrorOr<void> RTL8168NetworkAdapter::initialize(Badge<NetworkingManagement>)
+{
     identify_chip_version();
     dmesgln_pci(*this, "Version detected - {} ({}{})", possible_device_name(), (u8)m_version, m_version_uncertain ? "?" : "");
 
     if (!determine_supported_version()) {
         dmesgln_pci(*this, "Aborting initialization! Support for your chip version ({}) is not implemented yet, please open a GH issue and include this message.", (u8)m_version);
-        return; // Each ChipVersion requires a specific implementation of configure_phy and hardware_quirks
+        return Error::from_errno(ENODEV); // Each ChipVersion requires a specific implementation of configure_phy and hardware_quirks
     }
-
-    initialize();
-    startup();
-}
-
-void RTL8168NetworkAdapter::initialize()
-{
     // set initial REG_RXCFG
     auto rx_config = RXCFG_MAX_DMA_UNLIMITED;
     if (m_version <= ChipVersion::Version3) {
@@ -344,6 +345,9 @@ void RTL8168NetworkAdapter::initialize()
         //  notify
         TODO();
     }
+
+    startup();
+    return {};
 }
 
 void RTL8168NetworkAdapter::startup()

Kernel/Net/Realtek/RTL8168NetworkAdapter.h

@@ -22,7 +22,9 @@ class RTL8168NetworkAdapter final : public NetworkAdapter
     , public PCI::Device
     , public IRQHandler {
 public:
-    static ErrorOr<LockRefPtr<RTL8168NetworkAdapter>> try_to_initialize(PCI::DeviceIdentifier const&);
+    static ErrorOr<bool> probe(PCI::DeviceIdentifier const&);
+    static ErrorOr<NonnullLockRefPtr<NetworkAdapter>> create(PCI::DeviceIdentifier const&);
+    virtual ErrorOr<void> initialize(Badge<NetworkingManagement>) override;
 
     virtual ~RTL8168NetworkAdapter() override;