From 3f89a1b1314a080b5f3a3c9555b22a81efc80513 Mon Sep 17 00:00:00 2001
From: Idan Horowitz <idan.horowitz@gmail.com>
Date: Tue, 4 Apr 2023 14:16:24 +0300
Subject: [PATCH] Kernel: Mark sys$msync as not needing the big lock

All accesses to shared mutable data are already serialized behind the
process address space spinlock.
---
 Kernel/API/Syscall.h     | 2 +-
 Kernel/Syscalls/mmap.cpp | 1 +
 2 files changed, 2 insertions(+), 1 deletion(-)

diff --git a/Kernel/API/Syscall.h b/Kernel/API/Syscall.h
index ccbaf63212..1ab7d2d41c 100644
--- a/Kernel/API/Syscall.h
+++ b/Kernel/API/Syscall.h
@@ -129,7 +129,7 @@ enum class NeedsBigProcessLock {
     S(mount, NeedsBigProcessLock::Yes)                     \
     S(mprotect, NeedsBigProcessLock::No)                   \
     S(mremap, NeedsBigProcessLock::No)                     \
-    S(msync, NeedsBigProcessLock::Yes)                     \
+    S(msync, NeedsBigProcessLock::No)                      \
     S(munmap, NeedsBigProcessLock::No)                     \
     S(open, NeedsBigProcessLock::No)                       \
     S(perf_event, NeedsBigProcessLock::Yes)                \
diff --git a/Kernel/Syscalls/mmap.cpp b/Kernel/Syscalls/mmap.cpp
index b38521176a..16cba676ee 100644
--- a/Kernel/Syscalls/mmap.cpp
+++ b/Kernel/Syscalls/mmap.cpp
@@ -606,6 +606,7 @@ ErrorOr<FlatPtr> Process::sys$annotate_mapping(Userspace<void*> address, int fla
 
 ErrorOr<FlatPtr> Process::sys$msync(Userspace<void*> address, size_t size, int flags)
 {
+    VERIFY_NO_PROCESS_BIG_LOCK(this);
     if ((flags & (MS_SYNC | MS_ASYNC | MS_INVALIDATE)) != flags)
         return EINVAL;