Kernel: Remove most String usage from storage_name() API

This change is another minor step towards removing `AK::String` from
the Kernel. Instead of dynamically allocating the storage_name we can
instead allocate it via a KString in the factory for each device, and
then push the device name down into the StorageDevice base class.

We don't have a way of doing `AK::String::formatted(..)` with a KString
at the moment, so cleaning that up will be left for a later day.

Kernel/Storage/PATADiskDevice.cpp

@@ -11,19 +11,26 @@
 #include <Kernel/Storage/IDEChannel.h>
 #include <Kernel/Storage/IDEController.h>
 #include <Kernel/Storage/PATADiskDevice.h>
+#include <Kernel/Storage/StorageManagement.h>
 
 namespace Kernel {
 
 UNMAP_AFTER_INIT NonnullRefPtr<PATADiskDevice> PATADiskDevice::create(const IDEController& controller, IDEChannel& channel, DriveType type, InterfaceType interface_type, u16 capabilities, u64 max_addressable_block)
 {
-    auto device_or_error = DeviceManagement::try_create_device<PATADiskDevice>(controller, channel, type, interface_type, capabilities, max_addressable_block);
+    auto minor_device_number = StorageManagement::minor_number();
+
+    // FIXME: We need a way of formatting strings with KString.
+    auto device_name = String::formatted("hd{:c}", 'a' + minor_device_number);
+    auto device_name_kstring = KString::must_create(device_name.view());
+
+    auto device_or_error = DeviceManagement::try_create_device<PATADiskDevice>(controller, channel, type, interface_type, capabilities, max_addressable_block, minor_device_number, move(device_name_kstring));
     // FIXME: Find a way to propagate errors
     VERIFY(!device_or_error.is_error());
     return device_or_error.release_value();
 }
 
-UNMAP_AFTER_INIT PATADiskDevice::PATADiskDevice(const IDEController& controller, IDEChannel& channel, DriveType type, InterfaceType interface_type, u16 capabilities, u64 max_addressable_block)
-    : StorageDevice(controller, 512, max_addressable_block)
+UNMAP_AFTER_INIT PATADiskDevice::PATADiskDevice(const IDEController& controller, IDEChannel& channel, DriveType type, InterfaceType interface_type, u16 capabilities, u64 max_addressable_block, int minor_device_number, NonnullOwnPtr<KString> device_name)
+    : StorageDevice(controller, StorageManagement::major_number(), minor_device_number, 512, max_addressable_block, move(device_name))
     , m_capabilities(capabilities)
     , m_channel(channel)
     , m_drive_type(type)
@@ -45,11 +52,6 @@ void PATADiskDevice::start_request(AsyncBlockDeviceRequest& request)
     m_channel->start_request(request, is_slave(), m_capabilities);
 }
 
-String PATADiskDevice::storage_name() const
-{
-    return String::formatted("hd{:c}", 'a' + minor());
-}
-
 bool PATADiskDevice::is_slave() const
 {
     return m_drive_type == DriveType::Slave;

Kernel/Storage/PATADiskDevice.h

@@ -43,10 +43,9 @@ public:
 
     // ^BlockDevice
     virtual void start_request(AsyncBlockDeviceRequest&) override;
-    virtual String storage_name() const override;
 
 private:
-    PATADiskDevice(const IDEController&, IDEChannel&, DriveType, InterfaceType, u16, u64);
+    PATADiskDevice(const IDEController&, IDEChannel&, DriveType, InterfaceType, u16, u64, int, NonnullOwnPtr<KString>);
 
     // ^DiskDevice
     virtual StringView class_name() const override;

Kernel/Storage/RamdiskDevice.cpp

@@ -15,14 +15,20 @@ namespace Kernel {
 
 NonnullRefPtr<RamdiskDevice> RamdiskDevice::create(const RamdiskController& controller, NonnullOwnPtr<Memory::Region>&& region, int major, int minor)
 {
-    auto device_or_error = DeviceManagement::try_create_device<RamdiskDevice>(controller, move(region), major, minor);
+    // FIXME: Try to not hardcode a maximum of 16 partitions per drive!
+    size_t drive_index = minor / 16;
+    // FIXME: We need a way of formatting strings with KString!
+    auto device_name = String::formatted("ramdisk{}", drive_index);
+    auto device_name_kstring = KString::must_create(device_name.view());
+
+    auto device_or_error = DeviceManagement::try_create_device<RamdiskDevice>(controller, move(region), major, minor, move(device_name_kstring));
     // FIXME: Find a way to propagate errors
     VERIFY(!device_or_error.is_error());
     return device_or_error.release_value();
 }
 
-RamdiskDevice::RamdiskDevice(const RamdiskController& controller, NonnullOwnPtr<Memory::Region>&& region, int major, int minor)
-    : StorageDevice(controller, major, minor, 512, region->size() / 512)
+RamdiskDevice::RamdiskDevice(const RamdiskController& controller, NonnullOwnPtr<Memory::Region>&& region, int major, int minor, NonnullOwnPtr<KString> device_name)
+    : StorageDevice(controller, major, minor, 512, region->size() / 512, move(device_name))
     , m_region(move(region))
 {
     dmesgln("Ramdisk: Device #{} @ {}, Capacity={}", minor, m_region->vaddr(), max_addressable_block() * 512);
@@ -59,11 +65,4 @@ void RamdiskDevice::start_request(AsyncBlockDeviceRequest& request)
     }
 }
 
-String RamdiskDevice::storage_name() const
-{
-    // FIXME: Try to not hardcode a maximum of 16 partitions per drive!
-    size_t drive_index = minor() / 16;
-    return String::formatted("ramdisk{}", drive_index);
-}
-
 }

Kernel/Storage/RamdiskDevice.h

@@ -23,10 +23,9 @@ public:
 
     // ^DiskDevice
     virtual StringView class_name() const override;
-    virtual String storage_name() const override;
 
 private:
-    RamdiskDevice(const RamdiskController&, NonnullOwnPtr<Memory::Region>&&, int major, int minor);
+    RamdiskDevice(const RamdiskController&, NonnullOwnPtr<Memory::Region>&&, int major, int minor, NonnullOwnPtr<KString> device_name);
 
     // ^BlockDevice
     virtual void start_request(AsyncBlockDeviceRequest&) override;

Kernel/Storage/SATADiskDevice.cpp

@@ -10,19 +10,26 @@
 #include <Kernel/Storage/AHCIController.h>
 #include <Kernel/Storage/IDEChannel.h>
 #include <Kernel/Storage/SATADiskDevice.h>
+#include <Kernel/Storage/StorageManagement.h>
 
 namespace Kernel {
 
 NonnullRefPtr<SATADiskDevice> SATADiskDevice::create(const AHCIController& controller, const AHCIPort& port, size_t sector_size, u64 max_addressable_block)
 {
-    auto device_or_error = DeviceManagement::try_create_device<SATADiskDevice>(controller, port, sector_size, max_addressable_block);
+    auto minor_device_number = StorageManagement::minor_number();
+
+    // FIXME: We need a way of formatting strings with KString.
+    auto device_name = String::formatted("hd{:c}", 'a' + minor_device_number);
+    auto device_name_kstring = KString::must_create(device_name.view());
+
+    auto device_or_error = DeviceManagement::try_create_device<SATADiskDevice>(controller, port, sector_size, max_addressable_block, minor_device_number, move(device_name_kstring));
     // FIXME: Find a way to propagate errors
     VERIFY(!device_or_error.is_error());
     return device_or_error.release_value();
 }
 
-SATADiskDevice::SATADiskDevice(const AHCIController& controller, const AHCIPort& port, size_t sector_size, u64 max_addressable_block)
-    : StorageDevice(controller, sector_size, max_addressable_block)
+SATADiskDevice::SATADiskDevice(const AHCIController& controller, const AHCIPort& port, size_t sector_size, u64 max_addressable_block, int minor_number, NonnullOwnPtr<KString> device_name)
+    : StorageDevice(controller, StorageManagement::major_number(), minor_number, sector_size, max_addressable_block, move(device_name))
     , m_port(port)
 {
 }
@@ -41,9 +48,4 @@ void SATADiskDevice::start_request(AsyncBlockDeviceRequest& request)
     m_port.strong_ref()->start_request(request);
 }
 
-String SATADiskDevice::storage_name() const
-{
-    return String::formatted("hd{:c}", 'a' + minor());
-}
-
 }

Kernel/Storage/SATADiskDevice.h

@@ -31,10 +31,9 @@ public:
     // ^StorageDevice
     // ^BlockDevice
     virtual void start_request(AsyncBlockDeviceRequest&) override;
-    virtual String storage_name() const override;
 
 private:
-    SATADiskDevice(const AHCIController&, const AHCIPort&, size_t sector_size, u64 max_addressable_block);
+    SATADiskDevice(const AHCIController&, const AHCIPort&, size_t sector_size, u64 max_addressable_block, int minor_device_number, NonnullOwnPtr<KString> device_name);
 
     // ^DiskDevice
     virtual StringView class_name() const override;

Kernel/Storage/StorageDevice.cpp

@@ -13,16 +13,18 @@
 
 namespace Kernel {
 
-StorageDevice::StorageDevice(const StorageController& controller, size_t sector_size, u64 max_addressable_block)
+StorageDevice::StorageDevice(const StorageController& controller, size_t sector_size, u64 max_addressable_block, NonnullOwnPtr<KString> device_name)
     : BlockDevice(StorageManagement::major_number(), StorageManagement::minor_number(), sector_size)
     , m_storage_controller(controller)
+    , m_device_name(move(device_name))
     , m_max_addressable_block(max_addressable_block)
 {
 }
 
-StorageDevice::StorageDevice(const StorageController& controller, int major, int minor, size_t sector_size, u64 max_addressable_block)
+StorageDevice::StorageDevice(const StorageController& controller, int major, int minor, size_t sector_size, u64 max_addressable_block, NonnullOwnPtr<KString> device_name)
     : BlockDevice(major, minor, sector_size)
     , m_storage_controller(controller)
+    , m_storage_device_name(move(device_name))
     , m_max_addressable_block(max_addressable_block)
 {
 }
@@ -189,6 +191,11 @@ KResultOr<size_t> StorageDevice::write(OpenFileDescription&, u64 offset, const U
     return pos + remaining;
 }
 
+StringView StorageDevice::storage_name() const
+{
+    return m_storage_device_name->view();
+}
+
 bool StorageDevice::can_write(const OpenFileDescription&, size_t offset) const
 {
     return offset < (max_addressable_block() * block_size());

Kernel/Storage/StorageDevice.h

@@ -28,17 +28,14 @@ public:
     virtual bool can_read(const OpenFileDescription&, size_t) const override;
     virtual KResultOr<size_t> write(OpenFileDescription&, u64, const UserOrKernelBuffer&, size_t) override;
     virtual bool can_write(const OpenFileDescription&, size_t) const override;
-
-    // FIXME: This is being used only during early boot, find a better way to find devices...
-    virtual String storage_name() const = 0;
-
     virtual void prepare_for_unplug() { m_partitions.clear(); }
 
+    StringView storage_name() const;
     NonnullRefPtrVector<DiskPartition> partitions() const { return m_partitions; }
 
 protected:
-    StorageDevice(const StorageController&, size_t, u64);
-    StorageDevice(const StorageController&, int, int, size_t, u64);
+    StorageDevice(const StorageController&, size_t, u64, NonnullOwnPtr<KString>);
+    StorageDevice(const StorageController&, int, int, size_t, u64, NonnullOwnPtr<KString>);
     // ^DiskDevice
     virtual StringView class_name() const override;
 
@@ -46,6 +43,7 @@ private:
     mutable IntrusiveListNode<StorageDevice, RefPtr<StorageDevice>> m_list_node;
     NonnullRefPtr<StorageController> m_storage_controller;
     NonnullRefPtrVector<DiskPartition> m_partitions;
+    NonnullOwnPtr<KString> m_storage_device_name;
     u64 m_max_addressable_block;
 };