From 25250590d0aebfa8d5861ce7cad7aeaf3478ecf0 Mon Sep 17 00:00:00 2001
From: Andreas Kling <kling@serenityos.org>
Date: Tue, 26 Oct 2021 09:03:41 +0200
Subject: [PATCH] Kernel: Take VMObject lock once in
 Region::remap_vmobject_page()

We were taking and releasing the lock repeatedly instead of holding it
across the entire remap operation.
---
 Kernel/Memory/Region.cpp | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/Kernel/Memory/Region.cpp b/Kernel/Memory/Region.cpp
index 8a5e04c87c..534909c035 100644
--- a/Kernel/Memory/Region.cpp
+++ b/Kernel/Memory/Region.cpp
@@ -204,7 +204,6 @@ bool Region::map_individual_page_impl(size_t page_index)
 
 bool Region::do_remap_vmobject_page(size_t page_index, bool with_flush)
 {
-    SpinlockLocker lock(vmobject().m_lock);
     if (!m_page_directory)
         return true; // not an error, region may have not yet mapped it
     if (!translate_vmobject_page(page_index))
@@ -221,6 +220,7 @@ bool Region::remap_vmobject_page(size_t page_index, bool with_flush)
 {
     auto& vmobject = this->vmobject();
     bool success = true;
+    SpinlockLocker lock(vmobject.m_lock);
     vmobject.for_each_region([&](auto& region) {
         if (!region.do_remap_vmobject_page(page_index, with_flush))
             success = false;