From a02c945ef22c84a0b833cf2f9a93111e5467d48a Mon Sep 17 00:00:00 2001
From: Andreas Kling <awesomekling@gmail.com>
Date: Wed, 20 Mar 2019 02:12:03 +0100
Subject: [PATCH] Kernel: DoubleBuffer can return early if read/write is called
 with !size.

---
 Kernel/DoubleBuffer.cpp | 4 ++++
 1 file changed, 4 insertions(+)

diff --git a/Kernel/DoubleBuffer.cpp b/Kernel/DoubleBuffer.cpp
index 60b11f05d3..3aed54aef7 100644
--- a/Kernel/DoubleBuffer.cpp
+++ b/Kernel/DoubleBuffer.cpp
@@ -19,6 +19,8 @@ void DoubleBuffer::flip()
 
 ssize_t DoubleBuffer::write(const byte* data, ssize_t size)
 {
+    if (!size)
+        return 0;
     LOCKER(m_lock);
     m_write_buffer->append(data, size);
     compute_emptiness();
@@ -27,6 +29,8 @@ ssize_t DoubleBuffer::write(const byte* data, ssize_t size)
 
 ssize_t DoubleBuffer::read(byte* data, ssize_t size)
 {
+    if (!size)
+        return 0;
     LOCKER(m_lock);
     if (m_read_buffer_index >= m_read_buffer->size() && !m_write_buffer->is_empty())
         flip();