Kernel: Split the SysFS core files into smaller components

Author: https://github.com/supercomputer7
Commit: https://github.com/SerenityOS/serenity/commit/f53149d5f6
Pull-request: https://github.com/SerenityOS/serenity/pull/15771
Reviewed-by: https://github.com/ADKaster ✅
Reviewed-by: https://github.com/bgianfo

Kernel/Arch/x86/init.cpp

@@ -30,7 +30,7 @@
 #include <Kernel/Devices/SerialDevice.h>
 #include <Kernel/Devices/ZeroDevice.h>
 #include <Kernel/FileSystem/Ext2FileSystem.h>
-#include <Kernel/FileSystem/SysFS.h>
+#include <Kernel/FileSystem/SysFS/Registry.h>
 #include <Kernel/FileSystem/SysFS/Subsystems/Firmware/Directory.h>
 #include <Kernel/FileSystem/VirtualFileSystem.h>
 #include <Kernel/Firmware/ACPI/Initialize.h>

Kernel/Bus/PCI/Access.h

@@ -7,11 +7,11 @@
 #pragma once
 
 #include <AK/Bitmap.h>
+#include <AK/HashMap.h>
 #include <AK/Try.h>
 #include <AK/Vector.h>
 #include <Kernel/Bus/PCI/Controller/HostController.h>
 #include <Kernel/Bus/PCI/Definitions.h>
-#include <Kernel/FileSystem/SysFS.h>
 #include <Kernel/Locking/Spinlock.h>
 
 namespace Kernel::PCI {
@@ -59,7 +59,7 @@ private:
     mutable RecursiveSpinlock m_access_lock { LockRank::None };
     mutable Spinlock m_scan_lock { LockRank::None };
 
-    HashMap<u32, NonnullOwnPtr<HostController>> m_host_controllers;
+    HashMap<u32, NonnullOwnPtr<PCI::HostController>> m_host_controllers;
     Vector<DeviceIdentifier> m_device_identifiers;
 };
 }

Kernel/Bus/PCI/Controller/MemoryBackedHostBridge.cpp

@@ -7,6 +7,7 @@
 #include <AK/ByteReader.h>
 #include <Kernel/Bus/PCI/Access.h>
 #include <Kernel/Bus/PCI/Controller/MemoryBackedHostBridge.h>
+#include <Kernel/Memory/MemoryManager.h>
 
 namespace Kernel::PCI {
 

Kernel/Bus/PCI/Controller/MemoryBackedHostBridge.h

@@ -10,6 +10,7 @@
 #include <AK/Vector.h>
 #include <Kernel/Bus/PCI/Controller/HostController.h>
 #include <Kernel/Locking/Spinlock.h>
+#include <Kernel/Memory/Region.h>
 
 namespace Kernel::PCI {
 

Kernel/CMakeLists.txt

@@ -125,8 +125,11 @@ set(KERNEL_SOURCES
     FileSystem/OpenFileDescription.cpp
     FileSystem/Plan9FileSystem.cpp
     FileSystem/ProcFS.cpp
-    FileSystem/SysFS.cpp
     FileSystem/SysFS/Component.cpp
+    FileSystem/SysFS/DirectoryInode.cpp
+    FileSystem/SysFS/FileSystem.cpp
+    FileSystem/SysFS/Inode.cpp
+    FileSystem/SysFS/LinkInode.cpp
     FileSystem/SysFS/Registry.cpp
     FileSystem/SysFS/RootDirectory.cpp
     FileSystem/SysFS/Subsystems/Bus/PCI/BusDirectory.cpp

Kernel/Devices/Device.cpp

@@ -8,7 +8,7 @@
 #include <Kernel/Devices/Device.h>
 #include <Kernel/Devices/DeviceManagement.h>
 #include <Kernel/FileSystem/InodeMetadata.h>
-#include <Kernel/FileSystem/SysFS.h>
+#include <Kernel/FileSystem/SysFS/Component.h>
 #include <Kernel/FileSystem/SysFS/Subsystems/DeviceIdentifiers/BlockDevicesDirectory.h>
 #include <Kernel/FileSystem/SysFS/Subsystems/DeviceIdentifiers/CharacterDevicesDirectory.h>
 #include <Kernel/Sections.h>

Kernel/FileSystem/SysFS/Component.cpp

@@ -4,8 +4,10 @@
  * SPDX-License-Identifier: BSD-2-Clause
  */
 
-#include <Kernel/FileSystem/SysFS.h>
 #include <Kernel/FileSystem/SysFS/Component.h>
+#include <Kernel/FileSystem/SysFS/DirectoryInode.h>
+#include <Kernel/FileSystem/SysFS/Inode.h>
+#include <Kernel/FileSystem/SysFS/LinkInode.h>
 #include <Kernel/FileSystem/SysFS/Registry.h>
 #include <Kernel/KLexicalPath.h>
 

Kernel/FileSystem/SysFS/DirectoryInode.cpp

@@ -0,0 +1,54 @@
+/*
+ * Copyright (c) 2021, Liav A. <liavalb@hotmail.co.il>
+ *
+ * SPDX-License-Identifier: BSD-2-Clause
+ */
+
+#include <AK/StringView.h>
+#include <Kernel/FileSystem/SysFS/DirectoryInode.h>
+#include <Kernel/Sections.h>
+#include <Kernel/Time/TimeManagement.h>
+
+namespace Kernel {
+
+ErrorOr<NonnullLockRefPtr<SysFSDirectoryInode>> SysFSDirectoryInode::try_create(SysFS const& sysfs, SysFSComponent const& component)
+{
+    return adopt_nonnull_lock_ref_or_enomem(new (nothrow) SysFSDirectoryInode(sysfs, component));
+}
+
+SysFSDirectoryInode::SysFSDirectoryInode(SysFS const& fs, SysFSComponent const& component)
+    : SysFSInode(fs, component)
+{
+}
+
+SysFSDirectoryInode::~SysFSDirectoryInode() = default;
+
+InodeMetadata SysFSDirectoryInode::metadata() const
+{
+    // NOTE: No locking required as m_associated_component or its component index will never change during our lifetime.
+    InodeMetadata metadata;
+    metadata.inode = { fsid(), m_associated_component->component_index() };
+    metadata.mode = S_IFDIR | S_IRUSR | S_IRGRP | S_IROTH | S_IXOTH;
+    metadata.uid = 0;
+    metadata.gid = 0;
+    metadata.size = 0;
+    metadata.mtime = TimeManagement::boot_time();
+    return metadata;
+}
+
+ErrorOr<void> SysFSDirectoryInode::traverse_as_directory(Function<ErrorOr<void>(FileSystem::DirectoryEntryView const&)> callback) const
+{
+    MutexLocker locker(fs().m_lock);
+    return m_associated_component->traverse_as_directory(fs().fsid(), move(callback));
+}
+
+ErrorOr<NonnullLockRefPtr<Inode>> SysFSDirectoryInode::lookup(StringView name)
+{
+    MutexLocker locker(fs().m_lock);
+    auto component = m_associated_component->lookup(name);
+    if (!component)
+        return ENOENT;
+    return TRY(component->to_inode(fs()));
+}
+
+}

Kernel/FileSystem/SysFS/DirectoryInode.h

@@ -0,0 +1,31 @@
+/*
+ * Copyright (c) 2021, Liav A. <liavalb@hotmail.co.il>
+ *
+ * SPDX-License-Identifier: BSD-2-Clause
+ */
+
+#pragma once
+
+#include <Kernel/FileSystem/SysFS/Inode.h>
+
+namespace Kernel {
+
+class SysFSDirectoryInode : public SysFSInode {
+    friend class SysFS;
+
+public:
+    static ErrorOr<NonnullLockRefPtr<SysFSDirectoryInode>> try_create(SysFS const&, SysFSComponent const&);
+    virtual ~SysFSDirectoryInode() override;
+
+    SysFS& fs() { return static_cast<SysFS&>(Inode::fs()); }
+    SysFS const& fs() const { return static_cast<SysFS const&>(Inode::fs()); }
+
+protected:
+    SysFSDirectoryInode(SysFS const&, SysFSComponent const&);
+    // ^Inode
+    virtual InodeMetadata metadata() const override;
+    virtual ErrorOr<void> traverse_as_directory(Function<ErrorOr<void>(FileSystem::DirectoryEntryView const&)>) const override;
+    virtual ErrorOr<NonnullLockRefPtr<Inode>> lookup(StringView name) override;
+};
+
+}

Kernel/FileSystem/SysFS/FileSystem.cpp

@@ -0,0 +1,33 @@
+/*
+ * Copyright (c) 2021, Liav A. <liavalb@hotmail.co.il>
+ *
+ * SPDX-License-Identifier: BSD-2-Clause
+ */
+
+#include <AK/StringView.h>
+#include <Kernel/FileSystem/SysFS/FileSystem.h>
+#include <Kernel/FileSystem/SysFS/Inode.h>
+#include <Kernel/FileSystem/SysFS/Registry.h>
+
+namespace Kernel {
+
+ErrorOr<NonnullLockRefPtr<FileSystem>> SysFS::try_create()
+{
+    return TRY(adopt_nonnull_lock_ref_or_enomem(new (nothrow) SysFS));
+}
+
+SysFS::SysFS() = default;
+SysFS::~SysFS() = default;
+
+ErrorOr<void> SysFS::initialize()
+{
+    m_root_inode = TRY(SysFSComponentRegistry::the().root_directory().to_inode(*this));
+    return {};
+}
+
+Inode& SysFS::root_inode()
+{
+    return *m_root_inode;
+}
+
+}

Kernel/FileSystem/SysFS/FileSystem.h

@@ -0,0 +1,36 @@
+/*
+ * Copyright (c) 2021, Liav A. <liavalb@hotmail.co.il>
+ *
+ * SPDX-License-Identifier: BSD-2-Clause
+ */
+
+#pragma once
+
+#include <Kernel/FileSystem/FileSystem.h>
+#include <Kernel/FileSystem/Inode.h>
+#include <Kernel/FileSystem/SysFS/Component.h>
+#include <Kernel/Forward.h>
+#include <Kernel/Locking/MutexProtected.h>
+
+namespace Kernel {
+
+class SysFS final : public FileSystem {
+    friend class SysFSInode;
+    friend class SysFSDirectoryInode;
+
+public:
+    virtual ~SysFS() override;
+    static ErrorOr<NonnullLockRefPtr<FileSystem>> try_create();
+
+    virtual ErrorOr<void> initialize() override;
+    virtual StringView class_name() const override { return "SysFS"sv; }
+
+    virtual Inode& root_inode() override;
+
+private:
+    SysFS();
+
+    LockRefPtr<SysFSInode> m_root_inode;
+};
+
+}

Kernel/FileSystem/SysFS/Inode.cpp

@@ -5,32 +5,11 @@
  */
 
 #include <AK/StringView.h>
-#include <Kernel/FileSystem/SysFS.h>
-#include <Kernel/FileSystem/SysFS/Registry.h>
-#include <Kernel/Sections.h>
+#include <Kernel/FileSystem/SysFS/Inode.h>
 #include <Kernel/Time/TimeManagement.h>
 
 namespace Kernel {
 
-ErrorOr<NonnullLockRefPtr<FileSystem>> SysFS::try_create()
-{
-    return TRY(adopt_nonnull_lock_ref_or_enomem(new (nothrow) SysFS));
-}
-
-SysFS::SysFS() = default;
-SysFS::~SysFS() = default;
-
-ErrorOr<void> SysFS::initialize()
-{
-    m_root_inode = TRY(SysFSComponentRegistry::the().root_directory().to_inode(*this));
-    return {};
-}
-
-Inode& SysFS::root_inode()
-{
-    return *m_root_inode;
-}
-
 ErrorOr<NonnullLockRefPtr<SysFSInode>> SysFSInode::try_create(SysFS const& fs, SysFSComponent const& component)
 {
     return adopt_nonnull_lock_ref_or_enomem(new (nothrow) SysFSInode(fs, component));
@@ -131,68 +110,4 @@ ErrorOr<void> SysFSInode::update_timestamps(Optional<time_t>, Optional<time_t>,
     return {};
 }
 
-ErrorOr<NonnullLockRefPtr<SysFSLinkInode>> SysFSLinkInode::try_create(SysFS const& sysfs, SysFSComponent const& component)
-{
-    return adopt_nonnull_lock_ref_or_enomem(new (nothrow) SysFSLinkInode(sysfs, component));
-}
-
-SysFSLinkInode::SysFSLinkInode(SysFS const& fs, SysFSComponent const& component)
-    : SysFSInode(fs, component)
-{
-}
-
-SysFSLinkInode::~SysFSLinkInode() = default;
-
-InodeMetadata SysFSLinkInode::metadata() const
-{
-    // NOTE: No locking required as m_associated_component or its component index will never change during our lifetime.
-    InodeMetadata metadata;
-    metadata.inode = { fsid(), m_associated_component->component_index() };
-    metadata.mode = S_IFLNK | S_IRUSR | S_IRGRP | S_IROTH | S_IXOTH;
-    metadata.uid = 0;
-    metadata.gid = 0;
-    metadata.size = 0;
-    metadata.mtime = TimeManagement::boot_time();
-    return metadata;
-}
-
-ErrorOr<NonnullLockRefPtr<SysFSDirectoryInode>> SysFSDirectoryInode::try_create(SysFS const& sysfs, SysFSComponent const& component)
-{
-    return adopt_nonnull_lock_ref_or_enomem(new (nothrow) SysFSDirectoryInode(sysfs, component));
-}
-
-SysFSDirectoryInode::SysFSDirectoryInode(SysFS const& fs, SysFSComponent const& component)
-    : SysFSInode(fs, component)
-{
-}
-
-SysFSDirectoryInode::~SysFSDirectoryInode() = default;
-
-InodeMetadata SysFSDirectoryInode::metadata() const
-{
-    // NOTE: No locking required as m_associated_component or its component index will never change during our lifetime.
-    InodeMetadata metadata;
-    metadata.inode = { fsid(), m_associated_component->component_index() };
-    metadata.mode = S_IFDIR | S_IRUSR | S_IRGRP | S_IROTH | S_IXOTH;
-    metadata.uid = 0;
-    metadata.gid = 0;
-    metadata.size = 0;
-    metadata.mtime = TimeManagement::boot_time();
-    return metadata;
-}
-ErrorOr<void> SysFSDirectoryInode::traverse_as_directory(Function<ErrorOr<void>(FileSystem::DirectoryEntryView const&)> callback) const
-{
-    MutexLocker locker(fs().m_lock);
-    return m_associated_component->traverse_as_directory(fs().fsid(), move(callback));
-}
-
-ErrorOr<NonnullLockRefPtr<Inode>> SysFSDirectoryInode::lookup(StringView name)
-{
-    MutexLocker locker(fs().m_lock);
-    auto component = m_associated_component->lookup(name);
-    if (!component)
-        return ENOENT;
-    return TRY(component->to_inode(fs()));
-}
-
 }

Kernel/FileSystem/SysFS/Inode.h

@@ -6,32 +6,12 @@
 
 #pragma once
 
-#include <Kernel/FileSystem/FileSystem.h>
 #include <Kernel/FileSystem/Inode.h>
 #include <Kernel/FileSystem/SysFS/Component.h>
-#include <Kernel/Locking/MutexProtected.h>
+#include <Kernel/FileSystem/SysFS/FileSystem.h>
 
 namespace Kernel {
 
-class SysFS final : public FileSystem {
-    friend class SysFSInode;
-    friend class SysFSDirectoryInode;
-
-public:
-    virtual ~SysFS() override;
-    static ErrorOr<NonnullLockRefPtr<FileSystem>> try_create();
-
-    virtual ErrorOr<void> initialize() override;
-    virtual StringView class_name() const override { return "SysFS"sv; }
-
-    virtual Inode& root_inode() override;
-
-private:
-    SysFS();
-
-    LockRefPtr<SysFSInode> m_root_inode;
-};
-
 class SysFSInode : public Inode {
     friend class SysFS;
     friend class SysFSDirectoryInode;
@@ -62,35 +42,4 @@ protected:
     NonnullLockRefPtr<SysFSComponent> m_associated_component;
 };
 
-class SysFSLinkInode : public SysFSInode {
-    friend class SysFS;
-
-public:
-    static ErrorOr<NonnullLockRefPtr<SysFSLinkInode>> try_create(SysFS const&, SysFSComponent const&);
-    virtual ~SysFSLinkInode() override;
-
-protected:
-    SysFSLinkInode(SysFS const&, SysFSComponent const&);
-    // ^Inode
-    virtual InodeMetadata metadata() const override;
-};
-
-class SysFSDirectoryInode : public SysFSInode {
-    friend class SysFS;
-
-public:
-    static ErrorOr<NonnullLockRefPtr<SysFSDirectoryInode>> try_create(SysFS const&, SysFSComponent const&);
-    virtual ~SysFSDirectoryInode() override;
-
-    SysFS& fs() { return static_cast<SysFS&>(Inode::fs()); }
-    SysFS const& fs() const { return static_cast<SysFS const&>(Inode::fs()); }
-
-protected:
-    SysFSDirectoryInode(SysFS const&, SysFSComponent const&);
-    // ^Inode
-    virtual InodeMetadata metadata() const override;
-    virtual ErrorOr<void> traverse_as_directory(Function<ErrorOr<void>(FileSystem::DirectoryEntryView const&)>) const override;
-    virtual ErrorOr<NonnullLockRefPtr<Inode>> lookup(StringView name) override;
-};
-
 }

Kernel/FileSystem/SysFS/LinkInode.cpp

@@ -0,0 +1,37 @@
+/*
+ * Copyright (c) 2021, Liav A. <liavalb@hotmail.co.il>
+ *
+ * SPDX-License-Identifier: BSD-2-Clause
+ */
+
+#include <Kernel/FileSystem/SysFS/LinkInode.h>
+#include <Kernel/Time/TimeManagement.h>
+
+namespace Kernel {
+
+ErrorOr<NonnullLockRefPtr<SysFSLinkInode>> SysFSLinkInode::try_create(SysFS const& sysfs, SysFSComponent const& component)
+{
+    return adopt_nonnull_lock_ref_or_enomem(new (nothrow) SysFSLinkInode(sysfs, component));
+}
+
+SysFSLinkInode::SysFSLinkInode(SysFS const& fs, SysFSComponent const& component)
+    : SysFSInode(fs, component)
+{
+}
+
+SysFSLinkInode::~SysFSLinkInode() = default;
+
+InodeMetadata SysFSLinkInode::metadata() const
+{
+    // NOTE: No locking required as m_associated_component or its component index will never change during our lifetime.
+    InodeMetadata metadata;
+    metadata.inode = { fsid(), m_associated_component->component_index() };
+    metadata.mode = S_IFLNK | S_IRUSR | S_IRGRP | S_IROTH | S_IXOTH;
+    metadata.uid = 0;
+    metadata.gid = 0;
+    metadata.size = 0;
+    metadata.mtime = TimeManagement::boot_time();
+    return metadata;
+}
+
+}

Kernel/FileSystem/SysFS/LinkInode.h

@@ -0,0 +1,26 @@
+/*
+ * Copyright (c) 2021, Liav A. <liavalb@hotmail.co.il>
+ *
+ * SPDX-License-Identifier: BSD-2-Clause
+ */
+
+#pragma once
+
+#include <Kernel/FileSystem/SysFS/Inode.h>
+
+namespace Kernel {
+
+class SysFSLinkInode : public SysFSInode {
+    friend class SysFS;
+
+public:
+    static ErrorOr<NonnullLockRefPtr<SysFSLinkInode>> try_create(SysFS const&, SysFSComponent const&);
+    virtual ~SysFSLinkInode() override;
+
+protected:
+    SysFSLinkInode(SysFS const&, SysFSComponent const&);
+    // ^Inode
+    virtual InodeMetadata metadata() const override;
+};
+
+}

Kernel/FileSystem/SysFS/Subsystems/Firmware/BIOS/Directory.h

@@ -8,7 +8,6 @@
 
 #include <AK/Types.h>
 #include <AK/Vector.h>
-#include <Kernel/FileSystem/SysFS.h>
 #include <Kernel/FileSystem/SysFS/Subsystems/Firmware/Directory.h>
 #include <Kernel/Library/LockRefPtr.h>
 #include <Kernel/PhysicalAddress.h>

Kernel/FileSystem/SysFS/Subsystems/Firmware/Directory.h

@@ -7,7 +7,7 @@
 #pragma once
 
 #include <AK/Types.h>
-#include <Kernel/FileSystem/SysFS.h>
+#include <Kernel/FileSystem/SysFS/Component.h>
 
 namespace Kernel {
 

Kernel/FileSystem/SysFS/Subsystems/Kernel/PowerStateSwitch.h

@@ -9,7 +9,6 @@
 
 #include <AK/Types.h>
 #include <AK/Vector.h>
-#include <Kernel/FileSystem/SysFS.h>
 #include <Kernel/FileSystem/SysFS/Subsystems/Kernel/Directory.h>
 #include <Kernel/KBuffer.h>
 #include <Kernel/Library/LockRefPtr.h>

Kernel/Syscalls/mount.cpp

@@ -11,7 +11,7 @@
 #include <Kernel/FileSystem/ISO9660FileSystem.h>
 #include <Kernel/FileSystem/Plan9FileSystem.h>
 #include <Kernel/FileSystem/ProcFS.h>
-#include <Kernel/FileSystem/SysFS.h>
+#include <Kernel/FileSystem/SysFS/FileSystem.h>
 #include <Kernel/FileSystem/TmpFS.h>
 #include <Kernel/FileSystem/VirtualFileSystem.h>
 #include <Kernel/Process.h>