From da7ea2556e2dc2b027609feec35204b12693afd4 Mon Sep 17 00:00:00 2001
From: Andreas Kling <kling@serenityos.org>
Date: Tue, 5 Apr 2022 11:57:53 +0200
Subject: [PATCH] Kernel: Add RegionTree::remove(Region&)

This allows clients to remove a region from the tree without reaching
into the RegionTree internals.
---
 Kernel/Memory/AddressSpace.cpp  | 4 +---
 Kernel/Memory/MemoryManager.cpp | 4 +---
 Kernel/Memory/RegionTree.cpp    | 6 ++++++
 Kernel/Memory/RegionTree.h      | 2 ++
 4 files changed, 10 insertions(+), 6 deletions(-)

diff --git a/Kernel/Memory/AddressSpace.cpp b/Kernel/Memory/AddressSpace.cpp
index d4cd3bafad..5e84decbdd 100644
--- a/Kernel/Memory/AddressSpace.cpp
+++ b/Kernel/Memory/AddressSpace.cpp
@@ -229,9 +229,7 @@ void AddressSpace::deallocate_region(Region& region)
 
 NonnullOwnPtr<Region> AddressSpace::take_region(Region& region)
 {
-    SpinlockLocker lock(m_lock);
-    SpinlockLocker tree_locker(m_region_tree.get_lock());
-    auto did_remove = m_region_tree.regions().remove(region.vaddr().get());
+    auto did_remove = m_region_tree.remove(region);
     VERIFY(did_remove);
     return NonnullOwnPtr { NonnullOwnPtr<Region>::Adopt, region };
 }
diff --git a/Kernel/Memory/MemoryManager.cpp b/Kernel/Memory/MemoryManager.cpp
index 7bce3b3504..9384fa6a98 100644
--- a/Kernel/Memory/MemoryManager.cpp
+++ b/Kernel/Memory/MemoryManager.cpp
@@ -1168,9 +1168,7 @@ bool MemoryManager::validate_user_stack(AddressSpace& space, VirtualAddress vadd
 void MemoryManager::unregister_kernel_region(Region& region)
 {
     VERIFY(region.is_kernel());
-    SpinlockLocker lock(s_mm_lock);
-    SpinlockLocker tree_locker(m_region_tree.get_lock());
-    m_region_tree.regions().remove(region.vaddr().get());
+    m_region_tree.remove(region);
 }
 
 void MemoryManager::dump_kernel_regions()
diff --git a/Kernel/Memory/RegionTree.cpp b/Kernel/Memory/RegionTree.cpp
index ecbac58d2f..ed0baa952c 100644
--- a/Kernel/Memory/RegionTree.cpp
+++ b/Kernel/Memory/RegionTree.cpp
@@ -164,4 +164,10 @@ ErrorOr<NonnullOwnPtr<Memory::Region>> RegionTree::create_identity_mapped_region
     return region;
 }
 
+bool RegionTree::remove(Region& region)
+{
+    SpinlockLocker locker(m_lock);
+    return m_regions.remove(region.range().base().get());
+}
+
 }
diff --git a/Kernel/Memory/RegionTree.h b/Kernel/Memory/RegionTree.h
index f94892d583..d55b52affb 100644
--- a/Kernel/Memory/RegionTree.h
+++ b/Kernel/Memory/RegionTree.h
@@ -52,6 +52,8 @@ public:
     // FIXME: Access the region tree through a SpinlockProtected or similar.
     RecursiveSpinlock& get_lock() const { return m_lock; }
 
+    bool remove(Region&);
+
 private:
     ErrorOr<VirtualRange> allocate_range_anywhere(size_t size, size_t alignment = PAGE_SIZE);
     ErrorOr<VirtualRange> allocate_range_specific(VirtualAddress base, size_t size);