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Kernel: Introduce the DeviceManagement singleton

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This singleton simplifies many aspects that we struggled with before:
1. There's no need to make derived classes of Device expose the
constructor as public anymore. The singleton is a friend of them, so he
can call the constructor. This solves the issue with try_create_device
helper neatly, hopefully for good.
2. Getting a reference of the NullDevice is now being done from this
singleton, which means that NullDevice no longer needs to use its own
singleton, and we can apply the try_create_device helper on it too :)
3. We can now defer registration completely after the Device constructor
which means the Device constructor is merely assigning the major and
minor numbers of the Device, and the try_create_device helper ensures it
calls the after_inserting method immediately after construction. This
creates a great opportunity to make registration more OOM-safe.
This commit is contained in:
Liav A 2021-09-11 09:19:20 +03:00 • committed by Idan Horowitz
parent 9aa6dd6b78
commit aee4786d8e
43 changed files with 244 additions and 123 deletions
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14
Kernel/Devices/Device.h
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@ -27,14 +27,6 @@
namespace Kernel {
template<typename DeviceType, typename... Args>
inline KResultOr<NonnullRefPtr<DeviceType>> try_create_device(Args&&... args)
{
auto device = TRY(adopt_nonnull_ref_or_enomem(new DeviceType(forward<Args>(args)...)));
device->after_inserting();
return device;
}
class Device : public File {
protected:
enum class State {
@ -57,10 +49,6 @@ public:
virtual bool is_device() const override { return true; }
virtual void before_removing() override;
virtual void after_inserting();
static void for_each(Function<void(Device&)>);
static Device* get_device(unsigned major, unsigned minor);
void process_next_queued_request(Badge<AsyncDeviceRequest>, const AsyncDeviceRequest&);
template<typename AsyncRequestType, typename... Args>
@ -80,8 +68,6 @@ protected:
void set_uid(UserID uid) { m_uid = uid; }
void set_gid(GroupID gid) { m_gid = gid; }
static MutexProtected<HashMap<u32, Device*>>& all_devices();
private:
unsigned m_major { 0 };
unsigned m_minor { 0 };