implement clear_memory_block_header

1 files changed, 15 insertions, 7 deletions

diff --git a/arch/x86_64/src/memory/heap/linked_list_allocator.cpp b/arch/x86_64/src/memory/heap/linked_list_allocator.cpp
index 63a762e..07d7e5e 100644
--- a/arch/x86_64/src/memory/heap/linked_list_allocator.cpp
+++ b/arch/x86_64/src/memory/heap/linked_list_allocator.cpp
@@ -3,6 +3,8 @@
 #include "arch/exception_handling/assert.hpp"
 #include "arch/exception_handling/panic.hpp"
 
+#include <string.h>
+
 #include <algorithm>
 
 namespace teachos::arch::memory::heap
@@ -14,7 +16,7 @@ namespace teachos::arch::memory::heap
   {
     auto const heap_size = heap_end - heap_start;
     exception_handling::assert(
-        heap_size < min_allocatable_size(),
+        heap_size > min_allocatable_size(),
         "[Linked List Allocator] Total heap size can not be smaller than minimum of 16 bytes to hold "
         "atleast one memory hole entry");
     first = new (reinterpret_cast<void *>(heap_start)) memory_block(heap_size, nullptr);
@@ -22,7 +24,7 @@ namespace teachos::arch::memory::heap
 
   auto linked_list_allocator::allocate(std::size_t size) -> void *
   {
-    exception_handling::assert(size < min_allocatable_size(),
+    exception_handling::assert(size > min_allocatable_size(),
                                "[Linked List Allocator] Allocated memory cannot be smaller than 16 bytes");
 
     auto & previous = first;
@@ -34,7 +36,8 @@ namespace teachos::arch::memory::heap
       {
         return split_free_memory_block(current, size);
       }
-      else if (current->size >= size)
+
+      if (current->size >= size)
       {
         if (previous != current)
         {
@@ -42,10 +45,10 @@ namespace teachos::arch::memory::heap
         }
         else
         {
-          current = current->next;
+          first = current->next;
         }
 
-        delete current;
+        clear_memory_block_header(current);
         return static_cast<void *>(current);
       }
 
@@ -57,7 +60,7 @@ namespace teachos::arch::memory::heap
 
   auto linked_list_allocator::deallocate(void * pointer, std::size_t size) -> void
   {
-    exception_handling::assert(size < min_allocatable_size(),
+    exception_handling::assert(size > min_allocatable_size(),
                                "[Linked List Allocator] Allocated memory cannot be smaller than 16 bytes");
 
     auto const start_address = reinterpret_cast<std::size_t>(pointer);
@@ -118,7 +121,7 @@ namespace teachos::arch::memory::heap
       block_size += current_block->size;
       next_block = current_block->next;
 
-      delete current_block;
+      clear_memory_block_header(current_block);
     }
 
     // If the block we want to deallocate is behind another free block and we can therefore combine both into one.
@@ -137,4 +140,9 @@ namespace teachos::arch::memory::heap
     previous_block->next = new_block;
   }
 
+  auto linked_list_allocator::clear_memory_block_header(void * pointer) -> void
+  {
+    memset(pointer, 0, min_allocatable_size());
+  }
+
 }  // namespace teachos::arch::memory::heap