Kernel: Use RefPtr instead of LockRefPtr for Custody

By protecting all the RefPtr<Custody> objects that may be accessed from
multiple threads at the same time (with spinlocks), we remove the need
for using LockRefPtr<Custody> (which is basically a RefPtr with a
built-in spinlock.)

1 files changed, 19 insertions, 13 deletions

diff --git a/Kernel/FileSystem/Mount.cpp b/Kernel/FileSystem/Mount.cpp
index e934d2eb71..733147d746 100644
--- a/Kernel/FileSystem/Mount.cpp
+++ b/Kernel/FileSystem/Mount.cpp
@@ -14,7 +14,7 @@ namespace Kernel {
 Mount::Mount(FileSystem& guest_fs, Custody* host_custody, int flags)
     : m_guest(guest_fs.root_inode())
     , m_guest_fs(guest_fs)
-    , m_host_custody(host_custody)
+    , m_host_custody(LockRank::None, host_custody)
     , m_flags(flags)
 {
 }
@@ -22,30 +22,36 @@ Mount::Mount(FileSystem& guest_fs, Custody* host_custody, int flags)
 Mount::Mount(Inode& source, Custody& host_custody, int flags)
     : m_guest(source)
     , m_guest_fs(source.fs())
-    , m_host_custody(host_custody)
+    , m_host_custody(LockRank::None, host_custody)
     , m_flags(flags)
 {
 }
 
 ErrorOr<NonnullOwnPtr<KString>> Mount::absolute_path() const
 {
-    if (!m_host_custody)
-        return KString::try_create("/"sv);
-    return m_host_custody->try_serialize_absolute_path();
+    return m_host_custody.with([&](auto& host_custody) -> ErrorOr<NonnullOwnPtr<KString>> {
+        if (!host_custody)
+            return KString::try_create("/"sv);
+        return host_custody->try_serialize_absolute_path();
+    });
 }
 
-Inode* Mount::host()
+LockRefPtr<Inode> Mount::host()
 {
-    if (!m_host_custody)
-        return nullptr;
-    return &m_host_custody->inode();
+    return m_host_custody.with([](auto& host_custody) -> LockRefPtr<Inode> {
+        if (!host_custody)
+            return nullptr;
+        return &host_custody->inode();
+    });
 }
 
-Inode const* Mount::host() const
+LockRefPtr<Inode const> Mount::host() const
 {
-    if (!m_host_custody)
-        return nullptr;
-    return &m_host_custody->inode();
+    return m_host_custody.with([](auto& host_custody) -> LockRefPtr<Inode const> {
+        if (!host_custody)
+            return nullptr;
+        return &host_custody->inode();
+    });
 }
 
 }