From 944d32de36d1116a3cdebd1fe9e68ca234ad918c Mon Sep 17 00:00:00 2001
From: apio <blobs.trading@gmail.com>
Date: Sat, 21 Jan 2023 23:16:50 +0100
Subject: [PATCH] Bitmap: Introduce new malloc-aware initialization functions

Lets us call resize(new_size) instead of initialize(realloc(location, new_size), new_size)
---
 kernel/src/memory/UserVM.cpp | 13 +++++--------
 luna/include/luna/Bitmap.h   |  6 ++++++
 luna/src/Bitmap.cpp          | 19 +++++++++++++++++++
 3 files changed, 30 insertions(+), 8 deletions(-)

diff --git a/kernel/src/memory/UserVM.cpp b/kernel/src/memory/UserVM.cpp
index c6f39f55..5fb02bfb 100644
--- a/kernel/src/memory/UserVM.cpp
+++ b/kernel/src/memory/UserVM.cpp
@@ -33,18 +33,15 @@ Result<bool> UserVM::try_expand(usize size)
 {
     if (m_bitmap.size_in_bytes() == MAX_VM_SIZE) { return false; }
 
-    usize new_size = m_bitmap.size_in_bytes() + size;
+    const usize old_size = m_bitmap.size_in_bytes();
+    usize new_size = old_size + size;
 
     if (new_size > MAX_VM_SIZE) new_size = MAX_VM_SIZE;
 
-    usize old_size = m_bitmap.size_in_bytes();
-
-    void* const base = TRY(krealloc(m_bitmap.location(), new_size));
-
-    m_bitmap.initialize(base, new_size);
+    m_bitmap.resize(new_size);
     m_bitmap.clear_region(old_size * 8, (new_size - old_size) * 8, false);
 
-    kdbgln("user vm expanded to base=%p, size=%zu", base, new_size);
+    kdbgln("user vm expanded to base=%p, size=%zu", m_bitmap.location(), new_size);
 
     return true;
 }
@@ -110,5 +107,5 @@ Result<void> UserVM::free_several_pages(u64 address, usize count)
 UserVM::~UserVM()
 {
     kdbgln("user vm destroyed: base=%p, size=%zu", m_bitmap.location(), m_bitmap.size_in_bytes());
-    kfree(m_bitmap.location());
+    m_bitmap.deallocate();
 }
diff --git a/luna/include/luna/Bitmap.h b/luna/include/luna/Bitmap.h
index 1e35d655..6c628927 100644
--- a/luna/include/luna/Bitmap.h
+++ b/luna/include/luna/Bitmap.h
@@ -8,9 +8,15 @@ class Bitmap
     Bitmap();
     Bitmap(void* location, usize size_in_bytes);
 
+    // Naive initialization functions.
     void initialize(void* location, usize size_in_bytes);
     void* move(void* new_location, usize new_location_size_in_bytes);
 
+    // Dynamic memory initialization functions.
+    Result<void> allocate(usize size_in_bytes);
+    Result<void*> resize(usize new_size_in_bytes);
+    Result<void> deallocate();
+
     void set(usize index, bool value);
     bool get(usize index) const;
 
diff --git a/luna/src/Bitmap.cpp b/luna/src/Bitmap.cpp
index 5326c891..989e3f26 100644
--- a/luna/src/Bitmap.cpp
+++ b/luna/src/Bitmap.cpp
@@ -1,6 +1,7 @@
 #include <luna/Bitmap.h>
 #include <luna/CString.h>
 #include <luna/Check.h>
+#include <luna/Heap.h>
 
 Bitmap::Bitmap()
 {
@@ -16,6 +17,24 @@ void Bitmap::initialize(void* location, usize size_in_bytes)
     m_size_in_bytes = size_in_bytes;
 }
 
+Result<void> Bitmap::allocate(usize size_in_bytes)
+{
+    initialize(TRY(malloc_impl(size_in_bytes)), size_in_bytes);
+    return {};
+}
+
+Result<void*> Bitmap::resize(usize new_size_in_bytes)
+{
+    m_location = (u8*)TRY(realloc_impl(m_location, new_size_in_bytes));
+    m_size_in_bytes = new_size_in_bytes;
+    return (void*)m_location;
+}
+
+Result<void> Bitmap::deallocate()
+{
+    return free_impl(m_location);
+}
+
 void* Bitmap::move(void* new_location, usize new_location_size_in_bytes)
 {
     expect(initialized(), "Bitmap was never initialized");