Kernel: Move region map/unmap operations into the Region class

The more Region can take care of itself, the better.

Kernel/Process.cpp

@@ -122,7 +122,7 @@ Region* Process::allocate_region(VirtualAddress vaddr, size_t size, const String
     if (!range.is_valid())
         return nullptr;
     m_regions.append(Region::create_user_accessible(range, name, prot_to_region_access_flags(prot)));
-    MM.map_region(*this, m_regions.last());
+    m_regions.last().map(*this);
     if (commit)
         m_regions.last().commit();
     return &m_regions.last();
@@ -134,7 +134,7 @@ Region* Process::allocate_file_backed_region(VirtualAddress vaddr, size_t size,
     if (!range.is_valid())
         return nullptr;
     m_regions.append(Region::create_user_accessible(range, inode, name, prot_to_region_access_flags(prot)));
-    MM.map_region(*this, m_regions.last());
+    m_regions.last().map(*this);
     return &m_regions.last();
 }
 
@@ -145,7 +145,7 @@ Region* Process::allocate_region_with_vmo(VirtualAddress vaddr, size_t size, Non
         return nullptr;
     offset_in_vmo &= PAGE_MASK;
     m_regions.append(Region::create_user_accessible(range, move(vmo), offset_in_vmo, name, prot_to_region_access_flags(prot)));
-    MM.map_region(*this, m_regions.last());
+    m_regions.last().map(*this);
     return &m_regions.last();
 }
 
@@ -259,7 +259,7 @@ int Process::sys$munmap(void* addr, size_t size)
         }
 
         // We manually unmap the old region here, specifying that we *don't* want the VM deallocated.
-        MM.unmap_region(*old_region, false);
+        old_region->unmap(Region::ShouldDeallocateVirtualMemoryRange::No);
         deallocate_region(*old_region);
 
         // Instead we give back the unwanted VM manually.
@@ -267,7 +267,7 @@ int Process::sys$munmap(void* addr, size_t size)
 
         // And finally we map the new region(s).
         for (auto* new_region : new_regions) {
-            MM.map_region(*this, *new_region);
+            new_region->map(*this);
         }
         return 0;
     }
@@ -313,7 +313,7 @@ Process* Process::fork(RegisterDump& regs)
         dbg() << "fork: cloning Region{" << &region << "} '" << region.name() << "' @ " << region.vaddr();
 #endif
         child->m_regions.append(region.clone());
-        MM.map_region(*child, child->m_regions.last());
+        child->m_regions.last().map(*child);
 
         if (&region == m_master_tls_region)
             child->m_master_tls_region = &child->m_regions.last();

Kernel/VM/MemoryManager.cpp

@@ -713,35 +713,6 @@ void MemoryManager::map_region_at_address(PageDirectory& page_directory, Region&
     }
 }
 
-bool MemoryManager::unmap_region(Region& region, bool deallocate_range)
-{
-    ASSERT(region.page_directory());
-    InterruptDisabler disabler;
-    for (size_t i = 0; i < region.page_count(); ++i) {
-        auto vaddr = region.vaddr().offset(i * PAGE_SIZE);
-        auto& pte = ensure_pte(*region.page_directory(), vaddr);
-        pte.set_physical_page_base(0);
-        pte.set_present(false);
-        pte.set_writable(false);
-        pte.set_user_allowed(false);
-        region.page_directory()->flush(vaddr);
-#ifdef MM_DEBUG
-        auto& physical_page = region.vmobject().physical_pages()[region.first_page_index() + i];
-        dbgprintf("MM: >> Unmapped V%p => P%p <<\n", vaddr, physical_page ? physical_page->paddr().get() : 0);
-#endif
-    }
-    if (deallocate_range)
-        region.page_directory()->range_allocator().deallocate(region.range());
-    region.release_page_directory();
-    return true;
-}
-
-bool MemoryManager::map_region(Process& process, Region& region)
-{
-    map_region_at_address(process.page_directory(), region, region.vaddr());
-    return true;
-}
-
 bool MemoryManager::validate_user_read(const Process& process, VirtualAddress vaddr) const
 {
     auto* region = region_from_vaddr(process, vaddr);

Kernel/VM/MemoryManager.h

@@ -47,9 +47,6 @@ public:
 
     PageFaultResponse handle_page_fault(const PageFault&);
 
-    bool map_region(Process&, Region&);
-    bool unmap_region(Region&, bool deallocate_range = true);
-
     void populate_page_directory(PageDirectory&);
 
     void enter_process_paging_scope(Process&);

Kernel/VM/Region.cpp

@@ -41,7 +41,7 @@ Region::~Region()
     // find the address<->region mappings in an invalid state there.
     InterruptDisabler disabler;
     if (m_page_directory) {
-        MM.unmap_region(*this);
+        unmap(ShouldDeallocateVirtualMemoryRange::Yes);
         ASSERT(!m_page_directory);
     }
     MM.unregister_region(*this);
@@ -192,3 +192,31 @@ void Region::remap_page(size_t index)
 #endif
 
 }
+
+
+void Region::unmap(ShouldDeallocateVirtualMemoryRange deallocate_range)
+{
+    InterruptDisabler disabler;
+    ASSERT(page_directory());
+    for (size_t i = 0; i < page_count(); ++i) {
+        auto vaddr = this->vaddr().offset(i * PAGE_SIZE);
+        auto& pte = MM.ensure_pte(*page_directory(), vaddr);
+        pte.set_physical_page_base(0);
+        pte.set_present(false);
+        pte.set_writable(false);
+        pte.set_user_allowed(false);
+        page_directory()->flush(vaddr);
+#ifdef MM_DEBUG
+        auto& physical_page = region.vmobject().physical_pages()[region.first_page_index() + i];
+        dbgprintf("MM: >> Unmapped V%p => P%p <<\n", vaddr, physical_page ? physical_page->paddr().get() : 0);
+#endif
+    }
+    if (deallocate_range == ShouldDeallocateVirtualMemoryRange::Yes)
+        page_directory()->range_allocator().deallocate(range());
+    release_page_directory();
+}
+
+void Region::map(Process& process)
+{
+    MM.map_region_at_address(process.page_directory(), *this, vaddr());
+}

Kernel/VM/Region.h

@@ -114,6 +114,13 @@ public:
             m_access &= ~Access::Write;
     }
 
+    void map(Process&);
+    enum class ShouldDeallocateVirtualMemoryRange {
+        No,
+        Yes,
+    };
+    void unmap(ShouldDeallocateVirtualMemoryRange = ShouldDeallocateVirtualMemoryRange::Yes);
+
     void remap_page(size_t index);
 
     // For InlineLinkedListNode