Kernel: Implement helper to find multiple Regions in a Range

Kernel/VM/Space.cpp

@@ -1,5 +1,6 @@
 /*
  * Copyright (c) 2021, Andreas Kling <[email protected]>
+ * Copyright (c) 2021, Leon Albrecht <[email protected]>
  * All rights reserved.
  *
  * Redistribution and use in source and binary forms, with or without
@@ -158,6 +159,27 @@ Region* Space::find_region_containing(const Range& range)
  return nullptr;
 }
 
+Vector<Region*> Space::find_regions_intersecting(const Range& range)
+{
+ Vector<Region*> regions = {};
+ size_t total_size_collected = 0;
+
+ ScopedSpinLock lock(m_lock);
+
+ // FIXME: Maybe take the cache from the single lookup?
+ for (auto& region : m_regions) {
+ if (region.range().base() < range.end() && region.range().end() > range.base()) {
+ regions.append(&region);
+
+ total_size_collected += region.size() - region.range().intersect(range).size();
+ if (total_size_collected == range.size())
+ break;
+ }
+ }
+
+ return regions;
+}
+
 Region& Space::add_region(NonnullOwnPtr<Region> region)
 {
  auto* ptr = region.ptr();

Kernel/VM/Space.h

@@ -1,5 +1,6 @@
 /*
  * Copyright (c) 2018-2021, Andreas Kling <[email protected]>
+ * Copyright (c) 2021, Leon Albrecht <[email protected]>
  * All rights reserved.
  *
  * Redistribution and use in source and binary forms, with or without
@@ -27,6 +28,7 @@
 #pragma once
 
 #include <AK/NonnullOwnPtrVector.h>
+#include <AK/Vector.h>
 #include <AK/WeakPtr.h>
 #include <Kernel/UnixTypes.h>
 #include <Kernel/VM/AllocationStrategy.h>
@@ -63,6 +65,8 @@ class Space {
  Region* find_region_from_range(const Range&);
  Region* find_region_containing(const Range&);
 
+ Vector<Region*> find_regions_intersecting(const Range&);
+
  bool enforces_syscall_regions() const { return m_enforces_syscall_regions; }
  void set_enforces_syscall_regions(bool b) { m_enforces_syscall_regions = b; }