Kernel: Let Region keep a Range internally.

Kernel/Process.cpp

@@ -79,7 +79,7 @@ Region* Process::allocate_region(LinearAddress laddr, size_t size, String&& name
     else
         range = m_range_allocator.allocate_specific(laddr, size);
 
-    m_regions.append(adopt(*new Region(range.base(), range.size(), move(name), is_readable, is_writable)));
+    m_regions.append(adopt(*new Region(range, move(name), is_readable, is_writable)));
     MM.map_region(*this, *m_regions.last());
     if (commit)
         m_regions.last()->commit();
@@ -97,7 +97,7 @@ Region* Process::allocate_file_backed_region(LinearAddress laddr, size_t size, R
     else
         range = m_range_allocator.allocate_specific(laddr, size);
 
-    m_regions.append(adopt(*new Region(range.base(), range.size(), move(inode), move(name), is_readable, is_writable)));
+    m_regions.append(adopt(*new Region(range, move(inode), move(name), is_readable, is_writable)));
     MM.map_region(*this, *m_regions.last());
     return m_regions.last().ptr();
 }
@@ -115,7 +115,7 @@ Region* Process::allocate_region_with_vmo(LinearAddress laddr, size_t size, Reta
 
     offset_in_vmo &= PAGE_MASK;
     size = ceil_div(size, PAGE_SIZE) * PAGE_SIZE;
-    m_regions.append(adopt(*new Region(range.base(), range.size(), move(vmo), offset_in_vmo, move(name), is_readable, is_writable)));
+    m_regions.append(adopt(*new Region(range, move(vmo), offset_in_vmo, move(name), is_readable, is_writable)));
     MM.map_region(*this, *m_regions.last());
     return m_regions.last().ptr();
 }

Kernel/VM/MemoryManager.cpp

@@ -404,7 +404,7 @@ RetainPtr<Region> MemoryManager::allocate_kernel_region(size_t size, String&& na
     ASSERT(!(size % PAGE_SIZE));
     auto range = m_range_allocator.allocate_anywhere(size);
     ASSERT(range.is_valid());
-    auto region = adopt(*new Region(range.base(), range.size(), move(name), true, true, false));
+    auto region = adopt(*new Region(range, move(name), true, true, false));
     MM.map_region_at_address(*m_kernel_page_directory, *region, range.base(), false);
     // FIXME: It would be cool if these could zero-fill on demand instead.
     region->commit();

Kernel/VM/RangeAllocator.h

@@ -17,6 +17,8 @@ public:
     size_t size() const { return m_size; }
     bool is_valid() const { return !m_base.is_null(); }
 
+    bool contains(LinearAddress laddr) const { return laddr >= base() && laddr < end(); }
+
     LinearAddress end() const { return m_base.offset(m_size); }
 
     bool operator==(const Range& other) const

Kernel/VM/Region.cpp

@@ -4,10 +4,9 @@
 #include <Kernel/Process.h>
 #include <Kernel/Thread.h>
 
-Region::Region(LinearAddress a, size_t s, String&& n, bool r, bool w, bool cow)
-    : m_laddr(a)
-    , m_size(s)
-    , m_vmo(VMObject::create_anonymous(s))
+Region::Region(const Range& range, String&& n, bool r, bool w, bool cow)
+    : m_range(range)
+    , m_vmo(VMObject::create_anonymous(size()))
     , m_name(move(n))
     , m_readable(r)
     , m_writable(w)
@@ -17,9 +16,8 @@ Region::Region(LinearAddress a, size_t s, String&& n, bool r, bool w, bool cow)
     MM.register_region(*this);
 }
 
-Region::Region(LinearAddress a, size_t s, RetainPtr<Inode>&& inode, String&& n, bool r, bool w)
-    : m_laddr(a)
-    , m_size(s)
+Region::Region(const Range& range, RetainPtr<Inode>&& inode, String&& n, bool r, bool w)
+    : m_range(range)
     , m_vmo(VMObject::create_file_backed(move(inode)))
     , m_name(move(n))
     , m_readable(r)
@@ -29,9 +27,8 @@ Region::Region(LinearAddress a, size_t s, RetainPtr<Inode>&& inode, String&& n,
     MM.register_region(*this);
 }
 
-Region::Region(LinearAddress a, size_t s, Retained<VMObject>&& vmo, size_t offset_in_vmo, String&& n, bool r, bool w, bool cow)
-    : m_laddr(a)
-    , m_size(s)
+Region::Region(const Range& range, Retained<VMObject>&& vmo, size_t offset_in_vmo, String&& n, bool r, bool w, bool cow)
+    : m_range(range)
     , m_offset_in_vmo(offset_in_vmo)
     , m_vmo(move(vmo))
     , m_name(move(n))
@@ -83,7 +80,7 @@ Retained<Region> Region::clone()
                   laddr().get());
 #endif
         // Create a new region backed by the same VMObject.
-        return adopt(*new Region(laddr(), size(), m_vmo.copy_ref(), m_offset_in_vmo, String(m_name), m_readable, m_writable));
+        return adopt(*new Region(m_range, m_vmo.copy_ref(), m_offset_in_vmo, String(m_name), m_readable, m_writable));
     }
 
 #ifdef MM_DEBUG
@@ -96,7 +93,7 @@ Retained<Region> Region::clone()
     // Set up a COW region. The parent (this) region becomes COW as well!
     m_cow_map.fill(true);
     MM.remap_region(current->process().page_directory(), *this);
-    return adopt(*new Region(laddr(), size(), m_vmo->clone(), m_offset_in_vmo, String(m_name), m_readable, m_writable, true));
+    return adopt(*new Region(m_range, m_vmo->clone(), m_offset_in_vmo, String(m_name), m_readable, m_writable, true));
 }
 
 int Region::commit()

Kernel/VM/Region.h

@@ -3,6 +3,7 @@
 #include <AK/AKString.h>
 #include <AK/Bitmap.h>
 #include <Kernel/VM/PageDirectory.h>
+#include <Kernel/VM/RangeAllocator.h>
 
 class Inode;
 class VMObject;
@@ -10,13 +11,13 @@ class VMObject;
 class Region : public Retainable<Region> {
     friend class MemoryManager;
 public:
-    Region(LinearAddress, size_t, String&&, bool r, bool w, bool cow = false);
-    Region(LinearAddress, size_t, Retained<VMObject>&&, size_t offset_in_vmo, String&&, bool r, bool w, bool cow = false);
-    Region(LinearAddress, size_t, RetainPtr<Inode>&&, String&&, bool r, bool w);
+    Region(const Range&, String&&, bool r, bool w, bool cow = false);
+    Region(const Range&, Retained<VMObject>&&, size_t offset_in_vmo, String&&, bool r, bool w, bool cow = false);
+    Region(const Range&, RetainPtr<Inode>&&, String&&, bool r, bool w);
     ~Region();
 
-    LinearAddress laddr() const { return m_laddr; }
-    size_t size() const { return m_size; }
+    LinearAddress laddr() const { return m_range.base(); }
+    size_t size() const { return m_range.size(); }
     bool is_readable() const { return m_readable; }
     bool is_writable() const { return m_writable; }
     String name() const { return m_name; }
@@ -30,14 +31,15 @@ public:
     void set_shared(bool shared) { m_shared = shared; }
 
     Retained<Region> clone();
+
     bool contains(LinearAddress laddr) const
     {
-        return laddr >= m_laddr && laddr < m_laddr.offset(size());
+        return m_range.contains(laddr);
     }
 
     unsigned page_index_from_address(LinearAddress laddr) const
     {
-        return (laddr - m_laddr).get() / PAGE_SIZE;
+        return (laddr - m_range.base()).get() / PAGE_SIZE;
     }
 
     size_t first_page_index() const
@@ -52,7 +54,7 @@ public:
 
     size_t page_count() const
     {
-        return m_size / PAGE_SIZE;
+        return size() / PAGE_SIZE;
     }
 
     bool page_in();
@@ -82,8 +84,7 @@ public:
 
 private:
     RetainPtr<PageDirectory> m_page_directory;
-    LinearAddress m_laddr;
-    size_t m_size { 0 };
+    Range m_range;
     size_t m_offset_in_vmo { 0 };
     Retained<VMObject> m_vmo;
     String m_name;