Kernel: Use RefPtr instead of LockRefPtr for File and subclasses

This was mostly straightforward, as all the storage locations are
guarded by some related mutex.

The use of old-school associated mutexes instead of MutexProtected
is unfortunate, but the process to modernize such code is ongoing.

Kernel/FileSystem/AnonymousFile.h

@@ -13,9 +13,9 @@ namespace Kernel {
 
 class AnonymousFile final : public File {
 public:
-    static ErrorOr<NonnullLockRefPtr<AnonymousFile>> try_create(NonnullLockRefPtr<Memory::AnonymousVMObject> vmobject)
+    static ErrorOr<NonnullRefPtr<AnonymousFile>> try_create(NonnullLockRefPtr<Memory::AnonymousVMObject> vmobject)
     {
-        return adopt_nonnull_lock_ref_or_enomem(new (nothrow) AnonymousFile(move(vmobject)));
+        return adopt_nonnull_ref_or_enomem(new (nothrow) AnonymousFile(move(vmobject)));
     }
 
     virtual ~AnonymousFile() override;

Kernel/FileSystem/FIFO.cpp

@@ -16,10 +16,10 @@ namespace Kernel {
 
 static Atomic<int> s_next_fifo_id = 1;
 
-ErrorOr<NonnullLockRefPtr<FIFO>> FIFO::try_create(UserID uid)
+ErrorOr<NonnullRefPtr<FIFO>> FIFO::try_create(UserID uid)
 {
     auto buffer = TRY(DoubleBuffer::try_create("FIFO: Buffer"sv));
-    return adopt_nonnull_lock_ref_or_enomem(new (nothrow) FIFO(uid, move(buffer)));
+    return adopt_nonnull_ref_or_enomem(new (nothrow) FIFO(uid, move(buffer)));
 }
 
 ErrorOr<NonnullRefPtr<OpenFileDescription>> FIFO::open_direction(FIFO::Direction direction)

Kernel/FileSystem/FIFO.h

@@ -24,7 +24,7 @@ public:
         Writer
     };
 
-    static ErrorOr<NonnullLockRefPtr<FIFO>> try_create(UserID);
+    static ErrorOr<NonnullRefPtr<FIFO>> try_create(UserID);
     virtual ~FIFO() override;
 
     UserID uid() const { return m_uid; }

Kernel/FileSystem/Inode.cpp

@@ -180,7 +180,7 @@ void Inode::unregister_watcher(Badge<InodeWatcher>, InodeWatcher& watcher)
     });
 }
 
-ErrorOr<NonnullLockRefPtr<FIFO>> Inode::fifo()
+ErrorOr<NonnullRefPtr<FIFO>> Inode::fifo()
 {
     MutexLocker locker(m_inode_lock);
     VERIFY(metadata().is_fifo());
@@ -189,7 +189,7 @@ ErrorOr<NonnullLockRefPtr<FIFO>> Inode::fifo()
     if (!m_fifo)
         m_fifo = TRY(FIFO::try_create(metadata().uid));
 
-    return NonnullLockRefPtr { *m_fifo };
+    return NonnullRefPtr { *m_fifo };
 }
 
 void Inode::set_metadata_dirty(bool metadata_dirty)

Kernel/FileSystem/Inode.h

@@ -102,7 +102,7 @@ public:
     ErrorOr<void> register_watcher(Badge<InodeWatcher>, InodeWatcher&);
     void unregister_watcher(Badge<InodeWatcher>, InodeWatcher&);
 
-    ErrorOr<NonnullLockRefPtr<FIFO>> fifo();
+    ErrorOr<NonnullRefPtr<FIFO>> fifo();
 
     bool can_apply_flock(flock const&, Optional<OpenFileDescription const&> = {}) const;
     ErrorOr<void> apply_flock(Process const&, OpenFileDescription const&, Userspace<flock const*>, ShouldBlock);
@@ -134,7 +134,7 @@ private:
     LockWeakPtr<LocalSocket> m_bound_socket;
     SpinlockProtected<HashTable<InodeWatcher*>, LockRank::None> m_watchers {};
     bool m_metadata_dirty { false };
-    LockRefPtr<FIFO> m_fifo;
+    RefPtr<FIFO> m_fifo;
     IntrusiveListNode<Inode> m_inode_list_node;
 
     struct Flock {

Kernel/FileSystem/InodeFile.h

@@ -14,9 +14,9 @@ class Inode;
 
 class InodeFile final : public File {
 public:
-    static ErrorOr<NonnullLockRefPtr<InodeFile>> create(NonnullRefPtr<Inode> inode)
+    static ErrorOr<NonnullRefPtr<InodeFile>> create(NonnullRefPtr<Inode> inode)
     {
-        auto file = adopt_lock_ref_if_nonnull(new (nothrow) InodeFile(move(inode)));
+        auto file = adopt_ref_if_nonnull(new (nothrow) InodeFile(move(inode)));
         if (!file)
             return ENOMEM;
         return file.release_nonnull();

Kernel/FileSystem/InodeWatcher.cpp

@@ -11,9 +11,9 @@
 
 namespace Kernel {
 
-ErrorOr<NonnullLockRefPtr<InodeWatcher>> InodeWatcher::try_create()
+ErrorOr<NonnullRefPtr<InodeWatcher>> InodeWatcher::try_create()
 {
-    return adopt_nonnull_lock_ref_or_enomem(new (nothrow) InodeWatcher);
+    return adopt_nonnull_ref_or_enomem(new (nothrow) InodeWatcher);
 }
 
 InodeWatcher::~InodeWatcher()

Kernel/FileSystem/InodeWatcher.h

@@ -40,7 +40,7 @@ private:
 
 class InodeWatcher final : public File {
 public:
-    static ErrorOr<NonnullLockRefPtr<InodeWatcher>> try_create();
+    static ErrorOr<NonnullRefPtr<InodeWatcher>> try_create();
     virtual ~InodeWatcher() override;
 
     virtual bool can_read(OpenFileDescription const&, u64) const override;

Kernel/FileSystem/OpenFileDescription.h

@@ -141,7 +141,7 @@ private:
     }
 
     RefPtr<Inode> m_inode;
-    NonnullLockRefPtr<File> m_file;
+    NonnullRefPtr<File> m_file;
 
     struct State {
         OwnPtr<OpenFileDescriptionData> data;