Kernel: Make device generate their own names

Besides removing the monolithic DevFSDeviceInode::determine_name()
method, being able to determine a device's name inside the /dev
hierarchy outside of DevFS has its uses.

Kernel/Storage/PATADiskDevice.cpp

@@ -65,6 +65,13 @@ void PATADiskDevice::start_request(AsyncBlockDeviceRequest& request)
     m_channel.start_request(request, use_dma, is_slave());
 }
 
+String PATADiskDevice::device_name() const
+{
+    // FIXME: Try to not hardcode a maximum of 16 partitions per drive!
+    size_t drive_index = minor() / 16;
+    return String::formatted("hd{:c}{}", 'a' + drive_index, minor() + 1);
+}
+
 size_t PATADiskDevice::max_addressable_block() const
 {
     return m_cylinders * m_heads * m_sectors_per_track;

Kernel/Storage/PATADiskDevice.h

@@ -61,6 +61,7 @@ public:
 
     // ^BlockDevice
     virtual void start_request(AsyncBlockDeviceRequest&) override;
+    virtual String device_name() const override;
 
 private:
     PATADiskDevice(const IDEController&, IDEChannel&, DriveType, u8, u8, u8, int major, int minor);

Kernel/Storage/Partition/DiskPartition.cpp

@@ -102,6 +102,13 @@ bool DiskPartition::can_write(const FileDescription& fd, size_t offset) const
     return m_device->can_write(fd, offset + adjust);
 }
 
+String DiskPartition::device_name() const
+{
+    // FIXME: Try to not hardcode a maximum of 16 partitions per drive!
+    size_t partition_index = minor() % 16;
+    return String::formatted("{}{}", m_device->device_name(), partition_index + 1);
+}
+
 const char* DiskPartition::class_name() const
 {
     return "DiskPartition";

Kernel/Storage/Partition/DiskPartition.h

@@ -47,6 +47,7 @@ public:
 
     // ^Device
     virtual mode_t required_mode() const override { return 0600; }
+    virtual String device_name() const override;
 
     const DiskPartitionMetadata& metadata() const;
 

Kernel/Storage/RamdiskDevice.cpp

@@ -82,4 +82,11 @@ void RamdiskDevice::start_request(AsyncBlockDeviceRequest& request)
     }
 }
 
+String RamdiskDevice::device_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

@@ -50,6 +50,7 @@ public:
 
     // ^DiskDevice
     virtual const char* class_name() const override;
+    virtual String device_name() const override;
 
     bool is_slave() const;