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Kernel: Support Mutex Protected lists in ListedRefCounted

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This will allow us to support Mutex Protected lists like the custodies
list as well.
This commit is contained in:
Idan Horowitz 2021-12-29 00:22:14 +02:00 • committed by Andreas Kling
parent 7204b292c5
commit be91b4fe3e
4 changed files with 19 additions and 8 deletions
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21
Kernel/Library/ListedRefCounted.h
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@ -11,21 +11,32 @@
namespace Kernel {
// ListedRefCounted<T> is a slot-in replacement for RefCounted<T> to use in classes
// that add themselves to a SpinlockProtected<IntrusiveList> when constructed.
// The custom unref() implementation here ensures that the the list is locked during
// that add themselves to a {Spinlock, Mutex}Protected<IntrusiveList> when constructed.
// The custom unref() implementation here ensures that the list is locked during
// unref(), and that the T is removed from the list before ~T() is invoked.
template<typename T>
enum class LockType {
Spinlock,
Mutex,
};
template<typename T, LockType Lock>
class ListedRefCounted : public RefCountedBase {
public:
bool unref() const
{
auto new_ref_count = T::all_instances().with([&](auto& list) {
auto callback = [&](auto& list) {
auto new_ref_count = deref_base();
if (new_ref_count == 0)
list.remove(const_cast<T&>(static_cast<T const&>(*this)));
return new_ref_count;
});
};
RefCountType new_ref_count;
if constexpr (Lock == LockType::Spinlock)
new_ref_count = T::all_instances().with(callback);
else if constexpr (Lock == LockType::Mutex)
new_ref_count = T::all_instances().with_exclusive(callback);
if (new_ref_count == 0) {
call_will_be_destroyed_if_present(static_cast<const T*>(this));
delete const_cast<T*>(static_cast<T const*>(this));